Android: How to store list of values in SharedPreferences

In almost all our applications we are required to store application related user preferences or settings like favorites, language settings etc. Android provides a lot of options for storing data but the preference related settings can be easily stored and maintained using SharedPreferences class.

In this Android example, we will see how to store multiple or list of values in SharedPreferences under same key and retrieve values from it. To explain this concept, we display a list of items with favorites icon. When the list item is long pressed, the item is added to the favorites. When we say the item is added to the favorites, we actually store the list of items in shared preferences mapped to a key.

Android SharedPreferences class does not provide a way to store a List or ArrayList or any collection. In order to store a list (even array, set or any collection) under a key, we convert the list (or collection) to JSON format using Gson and store it as string . While retrieving we convert the JSON string back to list and return it.

In this Android SharedPreferences tutorial we will be doing the following,

Create a separate SharedPreference utility class with methods to save, add, remove and get favorites from SharedPreferences.
Display list of products in ListView in list fragment. When a list item is long pressed, it is added to favorites list stored in SharedPreferences.
Add an Action bar favorite menu item icon to display all the stored favorite items in a ListView. FavoriteListFragment is used to display this ListView. When an item is long pressed in this ListView it is removed from favorites i.e.) removed from SharedPreferences.

Android Project

Create a new Android project and name it as SharedPreferencesFavorites .

Download “Android SharedPreferences Storing Favorites” SharedPreferenceDemo.zip – Downloaded 9907 times – 2 MB

Resources

colors.xml

Create a new file res/values/colors.xml and copy paste the following content.

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="transparent">#00000000</color>
    <color name="product_list_item_bg">#ffffff</color>
    <color name="view_divider_color">#BABABA</color>
</resources>

<? xml version = "1.0" encoding = "utf-8" ?>

< resources >

< color name = "transparent" > #00000000</color>

< color name = "product_list_item_bg" > #ffffff</color>

< color name = "view_divider_color" > #BABABA</color>

< / resources >

strings.xml

Open res/values/strings.xml and edit to have the content as shown below.

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string name="app_name">SharedPreferencesFavorites</string>
    <string name="action_settings">Settings</string>
    <string name="hello_world">Hello world!</string>
    <string name="favorites">Favorites</string>
</resources>

<? xml version = "1.0" encoding = "utf-8" ?>

< resources >

< string name = "app_name" > SharedPreferencesFavorites < / string >

< string name = "action_settings" > Settings < / string >

< string name = "hello_world" > Hello world ! < / string >

< string name = "favorites" > Favorites < / string >

< / resources >

strings_fav_msg.xml

Create a new file res/values/strings_fav_msg.xml and copy paste the following content. This file defines string messages related to favourites.

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string name="add_favr">Added to Favorites</string>
    <string name="remove_favr">Removed from Favorites</string>
    <string name="no_favorites_items">No Favorites</string>
    <string name="no_favorites_msg">Long press on item to add to favorites.</string>
    <string name="favorites_remove_msg">Long press on item to remove from favorites.</string>
</resources>

<? xml version = "1.0" encoding = "utf-8" ?>

< resources >

< string name = "add_favr" > Added to Favorites < / string >

< string name = "remove_favr" > Removed from Favorites < / string >

< string name = "no_favorites_items" > No Favorites < / string >

< string name = "no_favorites_msg" > Long press on item to add to favorites . < / string >

< string name = "favorites_remove_msg" > Long press on item to remove from favorites . < / string >

< / resources >

Action Bar Menu Item (main.xml)

Open res/menu/main.xml and edit to have the content as shown below. When this menu item is clicked, it displays FavoriteListFragment.

<menu xmlns:android="http://schemas.android.com/apk/res/android" >
     <item
        android:id="@+id/menu_favorites"
        android:icon="@drawable/heart_red"
        android:orderInCategory="200"
        android:showAsAction="ifRoom|withText"
        android:title="@string/favorites"/>
</menu>

< menu xmlns : android = "http://schemas.android.com/apk/res/android" >

< item

android : id = "@+id/menu_favorites"

android : icon = "@drawable/heart_red"

android : orderInCategory = "200"

android : showAsAction = "ifRoom|withText"

android : title = "@string/favorites" / >

< / menu >

Layout Files

activity_main.xml

This layout file defines Framelayout which holds all fragments. Open res/layout/activity_main.xml and edit to have the content as shown below.

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >
     
        <FrameLayout
        android:id="@+id/content_frame"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</RelativeLayout>

< RelativeLayout xmlns : android = "http://schemas.android.com/apk/res/android"

xmlns : tools = "http://schemas.android.com/tools"

android : layout_width = "match_parent"

android : layout_height = "match_parent"

tools : context = ".MainActivity" >

< FrameLayout

android : id = "@+id/content_frame"

android : layout_width = "match_parent"

android : layout_height = "match_parent" / >

< / RelativeLayout >

fragment_product_list.xml

This layout file defines a ListView which is used by ProductListFragment to display list of products.

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#EDEDED" >

    <ListView
        android:id="@+id/list_product"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:divider="@color/transparent"
        android:dividerHeight="10dp"
        android:drawSelectorOnTop="true"
        android:footerDividersEnabled="false"
        android:padding="10dp"
        android:scrollbarStyle="outsideOverlay" >
    </ListView>

</RelativeLayout>

< RelativeLayout xmlns : android = "http://schemas.android.com/apk/res/android"

xmlns : tools = "http://schemas.android.com/tools"

android : layout_width = "match_parent"

android : layout_height = "match_parent"

android : background = "#EDEDED" >

< ListView

android : id = "@+id/list_product"

android : layout_width = "fill_parent"

android : layout_height = "wrap_content"

android : divider = "@color/transparent"

android : dividerHeight = "10dp"

android : drawSelectorOnTop = "true"

android : footerDividersEnabled = "false"

android : padding = "10dp"

android : scrollbarStyle = "outsideOverlay" >

< / ListView >

< / RelativeLayout >

product_list_item.xml

This file defines custom layout for ListView item which is used by ProductListAdapter .

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:background="@color/product_list_item_bg"
    android:descendantFocusability="blocksDescendants" >

    <RelativeLayout
        android:id="@+id/pdt_layout_item"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" >

        <TextView
            android:id="@+id/txt_pdt_name"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:padding="6dp" />

        <TextView
            android:id="@+id/txt_pdt_price"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@+id/txt_pdt_name"
            android:padding="6dp" />

        <TextView
            android:id="@+id/txt_pdt_desc"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@+id/txt_pdt_price"
            android:padding="6dp" />

        <ImageView
            android:id="@+id/imgbtn_favorite"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignBottom="@+id/txt_pdt_desc"
            android:layout_alignParentRight="true"
            android:layout_marginRight="3dp"
            android:background="@null"
            android:contentDescription="@string/favorites" />
    </RelativeLayout>

    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:layout_below="@+id/pdt_layout_item"
        android:background="@color/view_divider_color" />

</RelativeLayout>

<? xml version = "1.0" encoding = "utf-8" ?>

< RelativeLayout xmlns : android = "http://schemas.android.com/apk/res/android"

android : layout_width = "fill_parent"

android : layout_height = "wrap_content"

android : background = "@color/product_list_item_bg"

android : descendantFocusability = "blocksDescendants" >

< RelativeLayout

android : id = "@+id/pdt_layout_item"

android : layout_width = "fill_parent"

android : layout_height = "wrap_content" >

< TextView

android : id = "@+id/txt_pdt_name"

android : layout_width = "wrap_content"

android : layout_height = "wrap_content"

android : padding = "6dp" / >

< TextView

android : id = "@+id/txt_pdt_price"

android : layout_width = "wrap_content"

android : layout_height = "wrap_content"

android : layout_below = "@+id/txt_pdt_name"

android : padding = "6dp" / >

< TextView

android : id = "@+id/txt_pdt_desc"

android : layout_width = "wrap_content"

android : layout_height = "wrap_content"

android : layout_below = "@+id/txt_pdt_price"

android : padding = "6dp" / >

< ImageView

android : id = "@+id/imgbtn_favorite"

android : layout_width = "wrap_content"

android : layout_height = "wrap_content"

android : layout_alignBottom = "@+id/txt_pdt_desc"

android : layout_alignParentRight = "true"

android : layout_marginRight = "3dp"

android : background = "@null"

android : contentDescription = "@string/favorites" / >

< / RelativeLayout >

< View

android : layout_width = "match_parent"

android : layout_height = "1dp"

android : layout_below = "@+id/pdt_layout_item"

android : background = "@color/view_divider_color" / >

< / RelativeLayout >

Source files

Product

In src folder, create a new class Product in the package com.androidopentutorials.spfavorites.beans . This class represents a Product displayed in the ListView.

package com.androidopentutorials.spfavorites.beans;

public class Product {

	private int id;
	private String name;
	private String description;
	private double price;

	public Product() {
		super();
	}

	public Product(int id, String name, String description, double price) {
		super();
		this.id = id;
		this.name = name;
		this.description = description;
		this.price = price;
	}
	public int getId() {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public String getDescription() {
		return description;
	}

	public void setDescription(String description) {
		this.description = description;
	}

	public double getPrice() {
		return price;
	}

	public void setPrice(double price) {
		this.price = price;
	}

	@Override
	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result + id;
		return result;
	}

	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		Product other = (Product) obj;
		if (id != other.id)
			return false;
		return true;
	}

	@Override
	public String toString() {
		return "Product [id=" + id + ", name=" + name + ", description="
				+ description + ", price=" + price + "]";
	}	
}

package com . androidopentutorials . spfavorites . beans ;

public class Product {

private int id ;

private String name ;

private String description ;

private double price ;

public Product ( ) {

super ( ) ;

}

public Product ( int id , String name , String description , double price ) {

super ( ) ;

this . id = id ;

this . name = name ;

this . description = description ;

this . price = price ;

}

public int getId ( ) {

return id ;

}

public void setId ( int id ) {

this . id = id ;

}

public String getName ( ) {

return name ;

}

public void setName ( String name ) {

this . name = name ;

}

public String getDescription ( ) {

return description ;

}

public void setDescription ( String description ) {

this . description = description ;

}

public double getPrice ( ) {

return price ;

}

public void setPrice ( double price ) {

this . price = price ;

}

@ Override

public int hashCode ( ) {

final int prime = 31 ;

int result = 1 ;

result = prime * result + id ;

return result ;

}

@ Override

public boolean equals ( Object obj ) {

if ( this == obj )

return true ;

if ( obj == null )

return false ;

if ( getClass ( ) != obj . getClass ( ) )

return false ;

Product other = ( Product ) obj ;

if ( id != other . id )

return false ;

return true ;

}

@ Override

public String toString ( ) {

return "Product [id=" + id + ", name=" + name + ", description="

+ description + ", price=" + price + "]" ;

}

SharedPreference class

Create a new class SharedPreference in the package com.androidopentutorials.spfavorites.utils . This class defines methods to save, add, remove and get favorites from SharedPreferences.

Here we use Gson to convert List to JSON string in saveFavorites method and back again to List in getFavorites method.

package com.androidopentutorials.spfavorites.utils;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

import android.content.Context;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import com.androidopentutorials.spfavorites.beans.Product;
import com.google.gson.Gson;

public class SharedPreference {

	public static final String PREFS_NAME = "PRODUCT_APP";
	public static final String FAVORITES = "Product_Favorite";
	
	public SharedPreference() {
		super();
	}

	// This four methods are used for maintaining favorites.
	public void saveFavorites(Context context, List<Product> favorites) {
		SharedPreferences settings;
		Editor editor;

		settings = context.getSharedPreferences(PREFS_NAME,
				Context.MODE_PRIVATE);
		editor = settings.edit();

		Gson gson = new Gson();
		String jsonFavorites = gson.toJson(favorites);

		editor.putString(FAVORITES, jsonFavorites);

		editor.commit();
	}

	public void addFavorite(Context context, Product product) {
		List<Product> favorites = getFavorites(context);
		if (favorites == null)
			favorites = new ArrayList<Product>();
		favorites.add(product);
		saveFavorites(context, favorites);
	}

	public void removeFavorite(Context context, Product product) {
		ArrayList<Product> favorites = getFavorites(context);
		if (favorites != null) {
			favorites.remove(product);
			saveFavorites(context, favorites);
		}
	}

	public ArrayList<Product> getFavorites(Context context) {
		SharedPreferences settings;
		List<Product> favorites;

		settings = context.getSharedPreferences(PREFS_NAME,
				Context.MODE_PRIVATE);

		if (settings.contains(FAVORITES)) {
			String jsonFavorites = settings.getString(FAVORITES, null);
			Gson gson = new Gson();
			Product[] favoriteItems = gson.fromJson(jsonFavorites,
					Product[].class);

			favorites = Arrays.asList(favoriteItems);
			favorites = new ArrayList<Product>(favorites);
		} else
			return null;

		return (ArrayList<Product>) favorites;
	}
}

package com . androidopentutorials . spfavorites . utils ;

import java . util . ArrayList ;

import java . util . Arrays ;

import java . util . List ;

import android . content . Context ;

import android . content . SharedPreferences ;

import android . content . SharedPreferences . Editor ;

import com . androidopentutorials . spfavorites . beans . Product ;

import com . google . gson . Gson ;

public class SharedPreference {

public static final String PREFS_NAME = "PRODUCT_APP" ;

public static final String FAVORITES = "Product_Favorite" ;

public SharedPreference ( ) {

super ( ) ;

}

// This four methods are used for maintaining favorites.

public void saveFavorites ( Context context , List < Product > favorites ) {

SharedPreferences settings ;

Editor editor ;

settings = context . getSharedPreferences ( PREFS_NAME ,

Context . MODE_PRIVATE ) ;

editor = settings . edit ( ) ;

Gson gson = new Gson ( ) ;

String jsonFavorites = gson . toJson ( favorites ) ;

editor . putString ( FAVORITES , jsonFavorites ) ;

editor . commit ( ) ;

}

public void addFavorite ( Context context , Product product ) {

List < Product > favorites = getFavorites ( context ) ;

if ( favorites == null )

favorites = new ArrayList < Product > ( ) ;

favorites . add ( product ) ;

saveFavorites ( context , favorites ) ;

}

public void removeFavorite ( Context context , Product product ) {

ArrayList < Product > favorites = getFavorites ( context ) ;

if ( favorites != null ) {

favorites . remove ( product ) ;

saveFavorites ( context , favorites ) ;

}

public ArrayList < Product > getFavorites ( Context context ) {

SharedPreferences settings ;

List < Product > favorites ;

settings = context . getSharedPreferences ( PREFS_NAME ,

Context . MODE_PRIVATE ) ;

if ( settings . contains ( FAVORITES ) ) {

String jsonFavorites = settings . getString ( FAVORITES , null ) ;

Gson gson = new Gson ( ) ;

Product [ ] favoriteItems = gson . fromJson ( jsonFavorites ,

Product [ ] . class ) ;

favorites = Arrays . asList ( favoriteItems ) ;

favorites = new ArrayList < Product > ( favorites ) ;

} else

return null ;

return ( ArrayList < Product > ) favorites ;

}

ProductListAdapter

In src folder, create a new class ProductListAdapter in the package com.androidopentutorials.spfavorites.adapter . This is the custom list adapter class which displays product name, description, price and favorite icon.

package com.androidopentutorials.spfavorites.adapter;

import java.util.List;

import android.app.Activity;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;

import com.androidopentutorials.spfavorites.R;
import com.androidopentutorials.spfavorites.beans.Product;
import com.androidopentutorials.spfavorites.utils.SharedPreference;

public class ProductListAdapter extends ArrayAdapter<Product> {

	private Context context;
	List<Product> products;
	SharedPreference sharedPreference;

	public ProductListAdapter(Context context, List<Product> products) {
		super(context, R.layout.product_list_item, products);
		this.context = context;
		this.products = products;
		sharedPreference = new SharedPreference();
	}

	private class ViewHolder {
		TextView productNameTxt;
		TextView productDescTxt;
		TextView productPriceTxt;
		ImageView favoriteImg;
	}

	@Override
	public int getCount() {
		return products.size();
	}

	@Override
	public Product getItem(int position) {
		return products.get(position);
	}

	@Override
	public long getItemId(int position) {
		return 0;
	}

	@Override
	public View getView(int position, View convertView, ViewGroup parent) {
		ViewHolder holder = null;
		if (convertView == null) {
			LayoutInflater inflater = (LayoutInflater) context
					.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
			convertView = inflater.inflate(R.layout.product_list_item, null);
			holder = new ViewHolder();
			holder.productNameTxt = (TextView) convertView
					.findViewById(R.id.txt_pdt_name);
			holder.productDescTxt = (TextView) convertView
					.findViewById(R.id.txt_pdt_desc);
			holder.productPriceTxt = (TextView) convertView
					.findViewById(R.id.txt_pdt_price);
			holder.favoriteImg = (ImageView) convertView
					.findViewById(R.id.imgbtn_favorite);
			
			convertView.setTag(holder);
		} else {
			holder = (ViewHolder) convertView.getTag();
		}
		Product product = (Product) getItem(position);
		holder.productNameTxt.setText(product.getName());
		holder.productDescTxt.setText(product.getDescription());
		holder.productPriceTxt.setText(product.getPrice() + "");
		
		/*If a product exists in shared preferences then set heart_red drawable
		 * and set a tag*/
		if (checkFavoriteItem(product)) {
			holder.favoriteImg.setImageResource(R.drawable.heart_red);
			holder.favoriteImg.setTag("red");
		} else {
			holder.favoriteImg.setImageResource(R.drawable.heart_grey);
			holder.favoriteImg.setTag("grey");
		}
		
		return convertView;
	}
	
	/*Checks whether a particular product exists in SharedPreferences*/
	public boolean checkFavoriteItem(Product checkProduct) {
		boolean check = false;
		List<Product> favorites = sharedPreference.getFavorites(context);
		if (favorites != null) {
			for (Product product : favorites) {
				if (product.equals(checkProduct)) {
					check = true;
					break;
				}
			}
		}
		return check;
	}

	@Override
	public void add(Product product) {
		super.add(product);
		products.add(product);
		notifyDataSetChanged();
	}

	@Override
	public void remove(Product product) {
		super.remove(product);
		products.remove(product);
		notifyDataSetChanged();
	}	
}

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

package com . androidopentutorials . spfavorites . adapter ;

import java . util . List ;

import android . app . Activity ;

import android . content . Context ;

import android . view . LayoutInflater ;

import android . view . View ;

import android . view . ViewGroup ;

import android . widget . ArrayAdapter ;

import android . widget . ImageView ;

import android . widget . TextView ;

import com . androidopentutorials . spfavorites . R ;

import com . androidopentutorials . spfavorites . beans . Product ;

import com . androidopentutorials . spfavorites . utils . SharedPreference ;

public class ProductListAdapter extends ArrayAdapter < Product > {

private Context context ;

List < Product > products ;

SharedPreference sharedPreference ;

public ProductListAdapter ( Context context , List < Product > products ) {

super ( context , R . layout . product_list_item , products ) ;

this . context = context ;

this . products = products ;

sharedPreference = new SharedPreference ( ) ;

}

private class ViewHolder {

TextView productNameTxt ;

TextView productDescTxt ;

TextView productPriceTxt ;

ImageView favoriteImg ;

}

@ Override

public int getCount ( ) {

return products . size ( ) ;

}

@ Override

public Product getItem ( int position ) {

return products . get ( position ) ;

}

@ Override

public long getItemId ( int position ) {

return 0 ;

}

@ Override

public View getView ( int position , View convertView , ViewGroup parent ) {

ViewHolder holder = null ;

if ( convertView == null ) {

LayoutInflater inflater = ( LayoutInflater ) context

. getSystemService ( Activity . LAYOUT_INFLATER_SERVICE ) ;

convertView = inflater . inflate ( R . layout . product_list_item , null ) ;

holder = new ViewHolder ( ) ;

holder . productNameTxt = ( TextView ) convertView

. findViewById ( R . id . txt_pdt_name ) ;

holder . productDescTxt = ( TextView ) convertView

. findViewById ( R . id . txt_pdt_desc ) ;

holder . productPriceTxt = ( TextView ) convertView

. findViewById ( R . id . txt_pdt_price ) ;

holder . favoriteImg = ( ImageView ) convertView

. findViewById ( R . id . imgbtn_favorite ) ;

convertView . setTag ( holder ) ;

} else {

holder = ( ViewHolder ) convertView . getTag ( ) ;

}

Product product = ( Product ) getItem ( position ) ;

holder . productNameTxt . setText ( product . getName ( ) ) ;

holder . productDescTxt . setText ( product . getDescription ( ) ) ;

holder . productPriceTxt . setText ( product . getPrice ( ) + "" ) ;

/*If a product exists in shared preferences then set heart_red drawable

* and set a tag*/

if ( checkFavoriteItem ( product ) ) {

holder . favoriteImg . setImageResource ( R . drawable . heart_red ) ;

holder . favoriteImg . setTag ( "red" ) ;

} else {

holder . favoriteImg . setImageResource ( R . drawable . heart_grey ) ;

holder . favoriteImg . setTag ( "grey" ) ;

}

return convertView ;

}

/*Checks whether a particular product exists in SharedPreferences*/

public boolean checkFavoriteItem ( Product checkProduct ) {

boolean check = false ;

List < Product > favorites = sharedPreference . getFavorites ( context ) ;

if ( favorites != null ) {

for ( Product product : favorites ) {

if ( product . equals ( checkProduct ) ) {

check = true ;

break ;

}

return check ;

}

@ Override

public void add ( Product product ) {

super . add ( product ) ;

products . add ( product ) ;

notifyDataSetChanged ( ) ;

}

@ Override

public void remove ( Product product ) {

super . remove ( product ) ;

products . remove ( product ) ;

notifyDataSetChanged ( ) ;

}

ProductListFragment

In src folder, create a new class ProductListFragment in the package com.androidopentutorials.spfavorites.fragment .

This class displays list of products.
On item long click it adds that product in favorites by saving it in SharedPreferences. If the same item is long clicked again it is removed from favorites.

package com.androidopentutorials.spfavorites.fragment;

import java.util.ArrayList;
import java.util.List;

import android.app.Activity;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.AdapterView.OnItemLongClickListener;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.Toast;

import com.androidopentutorials.spfavorites.R;
import com.androidopentutorials.spfavorites.adapter.ProductListAdapter;
import com.androidopentutorials.spfavorites.beans.Product;
import com.androidopentutorials.spfavorites.utils.SharedPreference;

public class ProductListFragment extends Fragment implements
		OnItemClickListener, OnItemLongClickListener {

	public static final String ARG_ITEM_ID = "product_list";

	Activity activity;
	ListView productListView;
	List<Product> products;
	ProductListAdapter productListAdapter;

	SharedPreference sharedPreference;

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		activity = getActivity();
		sharedPreference = new SharedPreference();
	}

	@Override
	public View onCreateView(LayoutInflater inflater, ViewGroup container,
			Bundle savedInstanceState) {
		View view = inflater.inflate(R.layout.fragment_product_list, container,
				false);
		findViewsById(view);

		setProducts();

		productListAdapter = new ProductListAdapter(activity, products);
		productListView.setAdapter(productListAdapter);
		productListView.setOnItemClickListener(this);
		productListView.setOnItemLongClickListener(this);
		return view;
	}

	private void setProducts() {

		Product product1 = new Product(1, "Dell XPS", "Dell XPS Laptop", 60000);
		Product product2 = new Product(2, "HP Pavilion G6-2014TX",
				"HP Pavilion G6-2014TX Laptop", 50000);
		Product product3 = new Product(3, "ProBook HP 4540",
				"ProBook HP 4540 Laptop", 45000);
		Product product4 = new Product(4, "HP Envy 4-1025TX",
				"HP Envy 4-1025TX Laptop", 46000);
		Product product5 = new Product(5, "Dell Inspiron",
				"Dell Inspiron Laptop", 48000);
		Product product6 = new Product(6, "Dell Vostro", "Dell Vostro Laptop",
				50000);
		Product product7 = new Product(7, "IdeaPad Z Series",
				"Lenovo IdeaPad Z Series Laptop", 40000);
		Product product8 = new Product(8, "ThinkPad X Series",
				"Lenovo ThinkPad X Series Laptop", 38000);
		Product product9 = new Product(9, "VAIO S Series",
				"Sony VAIO S Series Laptop", 39000);
		Product product10 = new Product(10, "Series 5",
				"Samsung Series 5 Laptop", 50000);

		products = new ArrayList<Product>();
		products.add(product1);
		products.add(product2);
		products.add(product3);
		products.add(product4);
		products.add(product5);
		products.add(product6);
		products.add(product7);
		products.add(product8);
		products.add(product9);
		products.add(product10);
	}

	private void findViewsById(View view) {
		productListView = (ListView) view.findViewById(R.id.list_product);
	}

	@Override
	public void onItemClick(AdapterView<?> parent, View view, int position,
			long id) {
		Product product = (Product) parent.getItemAtPosition(position);
		Toast.makeText(activity, product.toString(), Toast.LENGTH_LONG).show();
	}

	@Override
	public boolean onItemLongClick(AdapterView<?> arg0, View view,
			int position, long arg3) {
		ImageView button = (ImageView) view.findViewById(R.id.imgbtn_favorite);

		String tag = button.getTag().toString();
		if (tag.equalsIgnoreCase("grey")) {
			sharedPreference.addFavorite(activity, products.get(position));
			Toast.makeText(activity,
					activity.getResources().getString(R.string.add_favr),
					Toast.LENGTH_SHORT).show();

			button.setTag("red");
			button.setImageResource(R.drawable.heart_red);
		} else {
			sharedPreference.removeFavorite(activity, products.get(position));
			button.setTag("grey");
			button.setImageResource(R.drawable.heart_grey);
			Toast.makeText(activity,
					activity.getResources().getString(R.string.remove_favr),
					Toast.LENGTH_SHORT).show();
		}

		return true;
	}
	
	@Override
	public void onResume() {
		getActivity().setTitle(R.string.app_name);
		getActivity().getActionBar().setTitle(R.string.app_name);
		super.onResume();
	}
}

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

package com . androidopentutorials . spfavorites . fragment ;

import java . util . ArrayList ;

import java . util . List ;

import android . app . Activity ;

import android . os . Bundle ;

import android . support . v4 . app . Fragment ;

import android . view . LayoutInflater ;

import android . view . View ;

import android . view . ViewGroup ;

import android . widget . AdapterView ;

import android . widget . AdapterView . OnItemClickListener ;

import android . widget . AdapterView . OnItemLongClickListener ;

import android . widget . ImageView ;

import android . widget . ListView ;

import android . widget . Toast ;

import com . androidopentutorials . spfavorites . R ;

import com . androidopentutorials . spfavorites . adapter . ProductListAdapter ;

import com . androidopentutorials . spfavorites . beans . Product ;

import com . androidopentutorials . spfavorites . utils . SharedPreference ;

public class ProductListFragment extends Fragment implements

OnItemClickListener , OnItemLongClickListener {

public static final String ARG_ITEM_ID = "product_list" ;

Activity activity ;

ListView productListView ;

List < Product > products ;

ProductListAdapter productListAdapter ;

SharedPreference sharedPreference ;

@ Override

public void onCreate ( Bundle savedInstanceState ) {

super . onCreate ( savedInstanceState ) ;

activity = getActivity ( ) ;

sharedPreference = new SharedPreference ( ) ;

}

@ Override

public View onCreateView ( LayoutInflater inflater , ViewGroup container ,

Bundle savedInstanceState ) {

View view = inflater . inflate ( R . layout . fragment_product_list , container ,

false ) ;

findViewsById ( view ) ;

setProducts ( ) ;

productListAdapter = new ProductListAdapter ( activity , products ) ;

productListView . setAdapter ( productListAdapter ) ;

productListView . setOnItemClickListener ( this ) ;

productListView . setOnItemLongClickListener ( this ) ;

return view ;

}

private void setProducts ( ) {

Product product1 = new Product ( 1 , "Dell XPS" , "Dell XPS Laptop" , 60000 ) ;

Product product2 = new Product ( 2 , "HP Pavilion G6-2014TX" ,

"HP Pavilion G6-2014TX Laptop" , 50000 ) ;

Product product3 = new Product ( 3 , "ProBook HP 4540" ,

"ProBook HP 4540 Laptop" , 45000 ) ;

Product product4 = new Product ( 4 , "HP Envy 4-1025TX" ,

"HP Envy 4-1025TX Laptop" , 46000 ) ;

Product product5 = new Product ( 5 , "Dell Inspiron" ,

"Dell Inspiron Laptop" , 48000 ) ;

Product product6 = new Product ( 6 , "Dell Vostro" , "Dell Vostro Laptop" ,

50000 ) ;

Product product7 = new Product ( 7 , "IdeaPad Z Series" ,

"Lenovo IdeaPad Z Series Laptop" , 40000 ) ;

Product product8 = new Product ( 8 , "ThinkPad X Series" ,

"Lenovo ThinkPad X Series Laptop" , 38000 ) ;

Product product9 = new Product ( 9 , "VAIO S Series" ,

"Sony VAIO S Series Laptop" , 39000 ) ;

Product product10 = new Product ( 10 , "Series 5" ,

"Samsung Series 5 Laptop" , 50000 ) ;

products = new ArrayList < Product > ( ) ;

products . add ( product1 ) ;

products . add ( product2 ) ;

products . add ( product3 ) ;

products . add ( product4 ) ;

products . add ( product5 ) ;

products . add ( product6 ) ;

products . add ( product7 ) ;

products . add ( product8 ) ;

products . add ( product9 ) ;

products . add ( product10 ) ;

}

private void findViewsById ( View view ) {

productListView = ( ListView ) view . findViewById ( R . id . list_product ) ;

}

@ Override

public void onItemClick ( AdapterView <? > parent , View view , int position ,

long id ) {

Product product = ( Product ) parent . getItemAtPosition ( position ) ;

Toast . makeText ( activity , product . toString ( ) , Toast . LENGTH_LONG ) . show ( ) ;

}

@ Override

public boolean onItemLongClick ( AdapterView <? > arg0 , View view ,

int position , long arg3 ) {

ImageView button = ( ImageView ) view . findViewById ( R . id . imgbtn_favorite ) ;

String tag = button . getTag ( ) . toString ( ) ;

if ( tag . equalsIgnoreCase ( "grey" ) ) {

sharedPreference . addFavorite ( activity , products . get ( position ) ) ;

Toast . makeText ( activity ,

activity . getResources ( ) . getString ( R . string . add_favr ) ,

Toast . LENGTH_SHORT ) . show ( ) ;

button . setTag ( "red" ) ;

button . setImageResource ( R . drawable . heart_red ) ;

} else {

sharedPreference . removeFavorite ( activity , products . get ( position ) ) ;

button . setTag ( "grey" ) ;

button . setImageResource ( R . drawable . heart_grey ) ;

Toast . makeText ( activity ,

activity . getResources ( ) . getString ( R . string . remove_favr ) ,

Toast . LENGTH_SHORT ) . show ( ) ;

}

return true ;

}

@ Override

public void onResume ( ) {

getActivity ( ) . setTitle ( R . string . app_name ) ;

getActivity ( ) . getActionBar ( ) . setTitle ( R . string . app_name ) ;

super . onResume ( ) ;

}

FavoriteListFragment

In src folder, create a new class FavoriteListFragment in the package com.androidopentutorials.spfavorites.fragment .

This fragment displays all the stored favorite items in a ListView. When an item is long pressed in this ListView it is removed from favorites i.e.) removed from SharedPreferences.
This fragment is displayed when favorite icon in Action bar is clicked.

package com.androidopentutorials.spfavorites.fragment;

import java.util.List;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.AdapterView.OnItemLongClickListener;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.Toast;

import com.androidopentutorials.spfavorites.R;
import com.androidopentutorials.spfavorites.adapter.ProductListAdapter;
import com.androidopentutorials.spfavorites.beans.Product;
import com.androidopentutorials.spfavorites.utils.SharedPreference;

public class FavoriteListFragment extends Fragment {

	public static final String ARG_ITEM_ID = "favorite_list";

	ListView favoriteList;
	SharedPreference sharedPreference;
	List<Product> favorites;

	Activity activity;
	ProductListAdapter productListAdapter;

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		activity = getActivity();
	}

	@Override
	public View onCreateView(LayoutInflater inflater, ViewGroup container,
			Bundle savedInstanceState) {
		View view = inflater.inflate(R.layout.fragment_product_list, container,
				false);
		// Get favorite items from SharedPreferences.
		sharedPreference = new SharedPreference();
		favorites = sharedPreference.getFavorites(activity);

		if (favorites == null) {
			showAlert(getResources().getString(R.string.no_favorites_items),
					getResources().getString(R.string.no_favorites_msg));
		} else {

			if (favorites.size() == 0) {
				showAlert(
						getResources().getString(R.string.no_favorites_items),
						getResources().getString(R.string.no_favorites_msg));
			}

			favoriteList = (ListView) view.findViewById(R.id.list_product);
			if (favorites != null) {
				productListAdapter = new ProductListAdapter(activity, favorites);
				favoriteList.setAdapter(productListAdapter);

				favoriteList.setOnItemClickListener(new OnItemClickListener() {

					public void onItemClick(AdapterView<?> parent, View arg1,
							int position, long arg3) {

					}
				});

				favoriteList
						.setOnItemLongClickListener(new OnItemLongClickListener() {

							@Override
							public boolean onItemLongClick(
									AdapterView<?> parent, View view,
									int position, long id) {

								ImageView button = (ImageView) view
										.findViewById(R.id.imgbtn_favorite);

								String tag = button.getTag().toString();
								if (tag.equalsIgnoreCase("grey")) {
									sharedPreference.addFavorite(activity,
											favorites.get(position));
									Toast.makeText(
											activity,
											activity.getResources().getString(
													R.string.add_favr),
											Toast.LENGTH_SHORT).show();

									button.setTag("red");
									button.setImageResource(R.drawable.heart_red);
								} else {
									sharedPreference.removeFavorite(activity,
											favorites.get(position));
									button.setTag("grey");
									button.setImageResource(R.drawable.heart_grey);
									productListAdapter.remove(favorites
											.get(position));
									Toast.makeText(
											activity,
											activity.getResources().getString(
													R.string.remove_favr),
											Toast.LENGTH_SHORT).show();
								}
								return true;
							}
						});
			}
		}
		return view;
	}

	public void showAlert(String title, String message) {
		if (activity != null && !activity.isFinishing()) {
			AlertDialog alertDialog = new AlertDialog.Builder(activity)
					.create();
			alertDialog.setTitle(title);
			alertDialog.setMessage(message);
			alertDialog.setCancelable(false);

			// setting OK Button
			alertDialog.setButton(AlertDialog.BUTTON_POSITIVE, "OK",
					new DialogInterface.OnClickListener() {

						public void onClick(DialogInterface dialog, int which) {
							dialog.dismiss();
							// activity.finish();
							getFragmentManager().popBackStackImmediate();
						}
					});
			alertDialog.show();
		}
	}
	
	@Override
	public void onResume() {
		getActivity().setTitle(R.string.favorites);
		getActivity().getActionBar().setTitle(R.string.favorites);
		super.onResume();
	}
}

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

package com . androidopentutorials . spfavorites . fragment ;

import java . util . List ;

import android . app . Activity ;

import android . app . AlertDialog ;

import android . content . DialogInterface ;

import android . os . Bundle ;

import android . support . v4 . app . Fragment ;

import android . view . LayoutInflater ;

import android . view . View ;

import android . view . ViewGroup ;

import android . widget . AdapterView ;

import android . widget . AdapterView . OnItemClickListener ;

import android . widget . AdapterView . OnItemLongClickListener ;

import android . widget . ImageView ;

import android . widget . ListView ;

import android . widget . Toast ;

import com . androidopentutorials . spfavorites . R ;

import com . androidopentutorials . spfavorites . adapter . ProductListAdapter ;

import com . androidopentutorials . spfavorites . beans . Product ;

import com . androidopentutorials . spfavorites . utils . SharedPreference ;

public class FavoriteListFragment extends Fragment {

public static final String ARG_ITEM_ID = "favorite_list" ;

ListView favoriteList ;

SharedPreference sharedPreference ;

List < Product > favorites ;

Activity activity ;

ProductListAdapter productListAdapter ;

@ Override

public void onCreate ( Bundle savedInstanceState ) {

super . onCreate ( savedInstanceState ) ;

activity = getActivity ( ) ;

}

@ Override

public View onCreateView ( LayoutInflater inflater , ViewGroup container ,

Bundle savedInstanceState ) {

View view = inflater . inflate ( R . layout . fragment_product_list , container ,

false ) ;

// Get favorite items from SharedPreferences.

sharedPreference = new SharedPreference ( ) ;

favorites = sharedPreference . getFavorites ( activity ) ;

if ( favorites == null ) {

showAlert ( getResources ( ) . getString ( R . string . no_favorites_items ) ,

getResources ( ) . getString ( R . string . no_favorites_msg ) ) ;

} else {

if ( favorites . size ( ) == 0 ) {

showAlert (

getResources ( ) . getString ( R . string . no_favorites_items ) ,

getResources ( ) . getString ( R . string . no_favorites_msg ) ) ;

}

favoriteList = ( ListView ) view . findViewById ( R . id . list_product ) ;

if ( favorites != null ) {

productListAdapter = new ProductListAdapter ( activity , favorites ) ;

favoriteList . setAdapter ( productListAdapter ) ;

favoriteList . setOnItemClickListener ( new OnItemClickListener ( ) {

public void onItemClick ( AdapterView <? > parent , View arg1 ,

int position , long arg3 ) {

}

} ) ;

favoriteList

. setOnItemLongClickListener ( new OnItemLongClickListener ( ) {

@ Override

public boolean onItemLongClick (

AdapterView <? > parent , View view ,

int position , long id ) {

ImageView button = ( ImageView ) view

. findViewById ( R . id . imgbtn_favorite ) ;

String tag = button . getTag ( ) . toString ( ) ;

if ( tag . equalsIgnoreCase ( "grey" ) ) {

sharedPreference . addFavorite ( activity ,

favorites . get ( position ) ) ;

Toast . makeText (

activity ,

activity . getResources ( ) . getString (

R . string . add_favr ) ,

Toast . LENGTH_SHORT ) . show ( ) ;

button . setTag ( "red" ) ;

button . setImageResource ( R . drawable . heart_red ) ;

} else {

sharedPreference . removeFavorite ( activity ,

favorites . get ( position ) ) ;

button . setTag ( "grey" ) ;

button . setImageResource ( R . drawable . heart_grey ) ;

productListAdapter . remove ( favorites

. get ( position ) ) ;

Toast . makeText (

activity ,

activity . getResources ( ) . getString (

R . string . remove_favr ) ,

Toast . LENGTH_SHORT ) . show ( ) ;

}

return true ;

}

} ) ;

}

return view ;

}

public void showAlert ( String title , String message ) {

if ( activity != null && ! activity . isFinishing ( ) ) {

AlertDialog alertDialog = new AlertDialog . Builder ( activity )

. create ( ) ;

alertDialog . setTitle ( title ) ;

alertDialog . setMessage ( message ) ;

alertDialog . setCancelable ( false ) ;

// setting OK Button

alertDialog . setButton ( AlertDialog . BUTTON_POSITIVE , "OK" ,

new DialogInterface . OnClickListener ( ) {

public void onClick ( DialogInterface dialog , int which ) {

dialog . dismiss ( ) ;

// activity.finish();

getFragmentManager ( ) . popBackStackImmediate ( ) ;

}

} ) ;

alertDialog . show ( ) ;

}

@ Override

public void onResume ( ) {

getActivity ( ) . setTitle ( R . string . favorites ) ;

getActivity ( ) . getActionBar ( ) . setTitle ( R . string . favorites ) ;

super . onResume ( ) ;

}

MainActivity

This is the main activity class.

When the app starts, it begins a new FragmentTransaction and starts ProductListFragment.
When an Action bar icon is clicked, it starts FavoriteListFragment.
Proper back navigation of fragments on back key pressed is handled by overriding onBackPressed()
It also handles fragment orientation changes and retains the state of the fragment by overriding onSaveInstanceState()

package com.androidopentutorials.spfavorites;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.view.Menu;
import android.view.MenuItem;

import com.androidopentutorials.spfavorites.fragment.FavoriteListFragment;
import com.androidopentutorials.spfavorites.fragment.ProductListFragment;

public class MainActivity extends FragmentActivity {

	private Fragment contentFragment;
	ProductListFragment pdtListFragment;
	FavoriteListFragment  favListFragment;
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		
		FragmentManager fragmentManager = getSupportFragmentManager();
		
		/*
		 * This is called when orientation is changed.
		 */
		if (savedInstanceState != null) {
			if (savedInstanceState.containsKey("content")) {
				String content = savedInstanceState.getString("content");
				if (content.equals(FavoriteListFragment.ARG_ITEM_ID)) {
					if (fragmentManager.findFragmentByTag(FavoriteListFragment.ARG_ITEM_ID) != null) {
						setFragmentTitle(R.string.favorites);
						contentFragment = fragmentManager
								.findFragmentByTag(FavoriteListFragment.ARG_ITEM_ID);
					}
				}
			}
			if (fragmentManager.findFragmentByTag(ProductListFragment.ARG_ITEM_ID) != null) {
				pdtListFragment = (ProductListFragment) fragmentManager
						.findFragmentByTag(ProductListFragment.ARG_ITEM_ID);
				contentFragment = pdtListFragment;
			}
		} else {
			pdtListFragment = new ProductListFragment();
			setFragmentTitle(R.string.app_name);
			switchContent(pdtListFragment, ProductListFragment.ARG_ITEM_ID);
		}
	}

	@Override
	protected void onSaveInstanceState(Bundle outState) {
		if (contentFragment instanceof FavoriteListFragment) {
			outState.putString("content", FavoriteListFragment.ARG_ITEM_ID);
		} else {
			outState.putString("content", ProductListFragment.ARG_ITEM_ID);
		}
		super.onSaveInstanceState(outState);
	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		getMenuInflater().inflate(R.menu.main, menu);
		return true;
	}

	@Override
	public boolean onOptionsItemSelected(MenuItem item) {
		switch (item.getItemId()) {
		case R.id.menu_favorites:
			setFragmentTitle(R.string.favorites);
			favListFragment = new FavoriteListFragment();
			switchContent(favListFragment, FavoriteListFragment.ARG_ITEM_ID);

			return true;
		}
		return super.onOptionsItemSelected(item);
	}
	
	public void switchContent(Fragment fragment, String tag) {
		FragmentManager fragmentManager = getSupportFragmentManager();
		while (fragmentManager.popBackStackImmediate());

		if (fragment != null) {
			FragmentTransaction transaction = fragmentManager
					.beginTransaction();
			transaction.replace(R.id.content_frame, fragment, tag);
			//Only FavoriteListFragment is added to the back stack.
			if (!(fragment instanceof ProductListFragment)) {
				transaction.addToBackStack(tag);
			}
			transaction.commit();
			contentFragment = fragment;
		}
	}

	protected void setFragmentTitle(int resourseId) {
		setTitle(resourseId);
		getActionBar().setTitle(resourseId);

	}
	
	/*
	 * We call super.onBackPressed(); when the stack entry count is > 0. if it
	 * is instanceof ProductListFragment or if the stack entry count is == 0, then
	 * we finish the activity.
	 * In other words, from ProductListFragment on back press it quits the app.
	 */
	@Override
	public void onBackPressed() {
		FragmentManager fm = getSupportFragmentManager();
		if (fm.getBackStackEntryCount() > 0) {
			super.onBackPressed();
		} else if (contentFragment instanceof ProductListFragment
				|| fm.getBackStackEntryCount() == 0) {
			finish();
		}
	}
}

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

package com . androidopentutorials . spfavorites ;

import android . os . Bundle ;

import android . support . v4 . app . Fragment ;

import android . support . v4 . app . FragmentActivity ;

import android . support . v4 . app . FragmentManager ;

import android . support . v4 . app . FragmentTransaction ;

import android . view . Menu ;

import android . view . MenuItem ;

import com . androidopentutorials . spfavorites . fragment . FavoriteListFragment ;

import com . androidopentutorials . spfavorites . fragment . ProductListFragment ;

public class MainActivity extends FragmentActivity {

private Fragment contentFragment ;

ProductListFragment pdtListFragment ;

FavoriteListFragment favListFragment ;

@ Override

protected void onCreate ( Bundle savedInstanceState ) {

super . onCreate ( savedInstanceState ) ;

setContentView ( R . layout . activity_main ) ;

FragmentManager fragmentManager = getSupportFragmentManager ( ) ;

* This is called when orientation is changed.

if ( savedInstanceState != null ) {

if ( savedInstanceState . containsKey ( "content" ) ) {

String content = savedInstanceState . getString ( "content" ) ;

if ( content . equals ( FavoriteListFragment . ARG_ITEM_ID ) ) {

if ( fragmentManager . findFragmentByTag ( FavoriteListFragment . ARG_ITEM_ID ) != null ) {

setFragmentTitle ( R . string . favorites ) ;

contentFragment = fragmentManager

. findFragmentByTag ( FavoriteListFragment . ARG_ITEM_ID ) ;

}

if ( fragmentManager . findFragmentByTag ( ProductListFragment . ARG_ITEM_ID ) != null ) {

pdtListFragment = ( ProductListFragment ) fragmentManager

. findFragmentByTag ( ProductListFragment . ARG_ITEM_ID ) ;

contentFragment = pdtListFragment ;

}

} else {

pdtListFragment = new ProductListFragment ( ) ;

setFragmentTitle ( R . string . app_name ) ;

switchContent ( pdtListFragment , ProductListFragment . ARG_ITEM_ID ) ;

}

@ Override

protected void onSaveInstanceState ( Bundle outState ) {

if ( contentFragment instanceof FavoriteListFragment ) {

outState . putString ( "content" , FavoriteListFragment . ARG_ITEM_ID ) ;

} else {

outState . putString ( "content" , ProductListFragment . ARG_ITEM_ID ) ;

}

super . onSaveInstanceState ( outState ) ;

}

@ Override

public boolean onCreateOptionsMenu ( Menu menu ) {

getMenuInflater ( ) . inflate ( R . menu . main , menu ) ;

return true ;

}

@ Override

public boolean onOptionsItemSelected ( MenuItem item ) {

switch ( item . getItemId ( ) ) {

case R . id . menu_favorites :

setFragmentTitle ( R . string . favorites ) ;

favListFragment = new FavoriteListFragment ( ) ;

switchContent ( favListFragment , FavoriteListFragment . ARG_ITEM_ID ) ;

return true ;

}

return super . onOptionsItemSelected ( item ) ;

}

public void switchContent ( Fragment fragment , String tag ) {

FragmentManager fragmentManager = getSupportFragmentManager ( ) ;

while ( fragmentManager . popBackStackImmediate ( ) ) ;

if ( fragment != null ) {

FragmentTransaction transaction = fragmentManager

. beginTransaction ( ) ;

transaction . replace ( R . id . content_frame , fragment , tag ) ;

//Only FavoriteListFragment is added to the back stack.

if ( ! ( fragment instanceof ProductListFragment ) ) {

transaction . addToBackStack ( tag ) ;

}

transaction . commit ( ) ;

contentFragment = fragment ;

}

protected void setFragmentTitle ( int resourseId ) {

setTitle ( resourseId ) ;

getActionBar ( ) . setTitle ( resourseId ) ;

}

* We call super.onBackPressed(); when the stack entry count is > 0. if it

* is instanceof ProductListFragment or if the stack entry count is == 0, then

* we finish the activity.

* In other words, from ProductListFragment on back press it quits the app.

@ Override

public void onBackPressed ( ) {

FragmentManager fm = getSupportFragmentManager ( ) ;

if ( fm . getBackStackEntryCount ( ) > 0 ) {

super . onBackPressed ( ) ;

} else if ( contentFragment instanceof ProductListFragment

|| fm . getBackStackEntryCount ( ) == 0 ) {

finish ( ) ;

}

Output

ProductListFragment screen

FavoriteListFragment screen

About The Author

nithya

Shruti Goyal

Hi.. this method being very useful to me… but it is causing exception when i try to add a item to favorite second time, it gives me below mentioned error :-

java.lang.IllegalArgumentException

at com.google.gson.internal.$Gson$Preconditions.checkArgument($Gson$Preconditions.java:42)

this execption occurs at “String jsonFavorites = gson.toJson(favorites);”

Please tell me what i am doing worng, and what is the other approach i have to follow not to get this error.
- zohain
  
  I do not know about the Gson.
  why you convert to Gson. is without this saving is not possible?
Sadat Mohammad Akash

Hi I have some problem in MainActivity. There is a function switchContent which takes fragment as parameter. But there is a line where ProductListFragment which is another class is being sent…?
Mayank Langalia

HEy Friends I have some problm, when i scroll down icon change. what should i do ?
Om Balakumar

hi guys, I have used this code for my project, I have a viewpager inside tabs of fragments, in first fragment,Insert of list i have used gridview and add images and favorite icon too. All works perfectly,But For example i like to add first image as favorite and i am longclick it and the image added in Favorites. Okay. Now i am going to favorites page the favorited image is present. When i again come back all images favorite icon becomes red. Can anyone help me guys..
- Mohamed Abdiqadir Osman
  
  can you share the code please am having trouble adding the viewpager with tab
Dušan Dimitrijević

I know that this tutorial has written long before, but i’m having a problem with making this to work. I’m trying to do this with recyclerview and the problem i’m experiencing is that when i add to favorite some item and scroll down and come back up, recycler deselect favorite and looses that state. It is also happens when i exit from app and come back and nothing is store in sharedPreference because when i go to the activity where should i see favorites i’m always getting alert dialog that there are no favorites yet.
- Priyanka Patel
  
  Hii… Dusan please tell me how did you solved this problem?
m33ts4k0z

Thanks for this. As of 30 April 2016, this still works great but needs some slight adaptations. First, in the MainActivity class, its better to extend to AppCompatActivity instead of FragmentActivity. Then the getActionBar() call should be changed to getSupportActionBar() if you add the toolbar programmatically. I use a theme based toolbar so using this method to change the title won’t work. setTitle() will suffice if we want to set the title of the current fragmented activity on the toolbar.
- Chuy David Garza Dovalina
  
  Hello sir, i have a problem with that too, it doesn’t show me the bar with the button, can you give a screenshot of that pls!!!! thanks P.S: sorry for my bad english
FaisalHyder

Hi there nice one, but how to make it work with recycler view, items are getting added in favourite shared preferences but not getting deleted from it and lot of duplicate items plus list removes selected heart on app restart from all selected items of main recycler list while they are still present in favorite shared preference..
any one done it using RecylerView?
- FaisalHyder
  
  I have solved it
  - khanZee
    
    hi . can u please tell how did u solve this issue? even i am gettin duplicate items and slected heart is resetting on back press. any help is really appreciated thanks!
    - FaisalHyder
      
      I can tell you the approach, it is simple, i click on recycler view’s item i.e imagebutton, i am handling clicks of both main activity and favourite activity separately from them, when i click on imagebutton it takes main string field puts it in array and saves the arrayList in sharedpreferences, on fetching back i am taking that list and searching RLV’s items in that List inside recycler adapter to put star on selected items, then from clicking on that imagebutton i once again search the list item from sharedpreferences if it exists , i remove it and update list…. i will put its git code tomorrow, in sha Allah, you can check it from there
      - khanZee
        
        thank you so much bhai! the info is appreciated.. please do upload it on git.. counting on you.. jazak allah
      - FaisalHyder
        
        I have added it, github.com/mfaisalhyder no problem, you can improve code a lot, i deliberately have uploaded older version, where there is bug in recycler adapter that it removes element from Mainactivity as well try to fix it else i will upload fixed version #learn
      - engrkamal1
        
        Hello, can you share the fixed version please
      - FaisalHyder
        
        Hi kamal, fix is not that difficult, it is easy. All you have to do is check the remove favorite code and update it to SP instead of actual list
Maham Khan

Found error in this line
getActionBar().setTitle(resourseId);
setFragmentTitle(R.string.app_name);
- David Pilco
  
  me too .. u got the answer?
  - Maham Khan
    
    Thankyou it is working now
  - saad
    
    I’ve changed getActionBar() to getSupportActionBar() in MainActivity but in ProductListFragment it show NPE… Why?
vinod

your tutorial is very well. mam, how to implement add to cart using mysql in recyclerview and cardview in android
Mohamed Abdiqadir Osman

great tutorial but can you tell me how to add that a viewpager with tablayout
Hillarie Kip

Hello…i want help as how can you open activities from the favorite list you created
- Jordan Adcock
  
  Looks like we will never get a response on this, it’s a great set up but the only thing I’ve figured out for opening a new activity from both the favorites and product list is to do the following.. Not sure if I’m on to something but I just tested it and it works but doesn’t work at the same time.
  So under the private void set products where all the products are listed, onItemClick is shown…Copy this and paste it inside @Override
  public void onItemClick(AdapterView parent, View view, int position,
  long id) {
  Intent intent = new Intent(getActivity(), Main2Activity.class);
  intent.putExtra(“Cheese”,productListView.getItemAtPosition(position).toString());
  startActivity(intent);
  Create a new blank activity…
  Toolbar toolbarcookingguide;
  TextView textviewinstructions;
  ImageView imageviewtemp;
  
  @Override
  protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main2);
  
  toolbarcookingguide = (Toolbar) findViewById(R.id.toolbart);
  textviewinstructions = (TextView) findViewById(R.id.textviewinstructions);
  imageviewtemp = (ImageView) findViewById(R.id.imageviewtemp);
  
  Bundle bundle = getIntent().getExtras();
  if (bundle != null) {
  toolbarcookingguide.setTitle(bundle.getString(“Cheese”));
  ///////For every item set this//////////////////////
  {
  if (toolbarcookingguide.getTitle().toString().equalsIgnoreCase(“product1″)) {
  textviewinstructions.setText(R.string.happy);
  
  ////////1////////
  }
  if (toolbarcookingguide.getTitle().toString().equalsIgnoreCase(“product2″)) {
  textviewinstructions.setText(R.string.bull);
  
  ////////1////////
  
  Thisi is what it should look like, but after equalsIgnoreCase doesn’t work because the way this person set this up, they set the string within the fragment and I’m not sure how to call the title (item name) of each.. When I do this in a regular or custom listview and set the string inside a string folder, each one does it’s own action. SO if I had
  
  product1
  product2
  
  product 1 and product 2 would open a textview (xml activity_main2 has a textview template) and list the items that are inside the strings happy and bull. So for example is product 1 was clicked product1 would display the textview of happy string.
  
  So in this I’m not sure how to call the title of each product becasue they are all laid out in a fragment, and the only thing that is happening is the product id name description price etc shows up on the toolbar, but shows as Product[id=1,name=DellXPS etc……
  How do I set a get extra intent so that each product lists it’s own description……….
  
  THKKKKKKKKKKKKKKKKKKKKKS
Jordan Adcock

I’ve tried solving how to set an id or something to each one of the products so once the user clicks on Dell in both favorites and product list they go to a Dell activity that lists all Dell products… This is great for learning how to implement a favorites but I want to be able to let the user once the item is in their favorites folder be able to click on the item in their favorites and open an activity that belongs to that item.. So let say I’ve favorited Dell, HP, and IdeaPad, and later in the week I went to my favorites list and clicked on Dell or HP or IdeaPad, i’d like to be able to open different activities with each product..

Thanks to anyone that knows what I mean and perhaps has the source code
Jordan Adcock

Figured out how to set listeners and getsame resources from main list to favorites list YAYYYYYYYYYYY took me a frigging week to figure it out.. LOVE HOW NO ONE REPLIED STILL
- Girl Candy (Girlcandy)
  
  can you please share the code
Love Songs

where is SherlockActivity class? You did not provide and result in errors
Girl Candy (Girlcandy)

if the activity was closed, does the favorites you have selected will be saved or not?
- Jordan Adcock
  
  Hi Girl Candy, when I get home on Monday I will provide the code for you. Yes it saves even once the application is closed completely. You basically have tp set up a separate fragment for the favourites. I will explain more when I’m home. Take care.
  - Andile Simelane
    
    HI can you help I want to save user favourite on mysql database so that the favourite show up even if you logged in using another device
yilber esteban flor orozco

I can not make it work in Android Studio!!!
can you help me, with the code?
Aditya Narayan

I want to add different images in each column of list view ..can u tell me how to do that ,rest everything is same as your prog
Geethanjali Kondisetti

Please share the source code
Kalpesh

How can i get source code for this example ?
Satria Junanda

Thanks bro
Akash

Maifest file upload please….
kuldeep

Nice post .
But if i clik on list of item then it open in new activity . Then what i do for it .. onitemcliklistner .pls tell
Theerapong Piluk

How to store Recyclerview of values in SharedPreferences

July 2020
M	T	W	T	F	S	S
« Mar
		1	2	3	4	5
6	7	8	9	10	11	12
13	14	15	16	17	18	19
20	21	22	23	24	25	26
27	28	29	30	31

Android Project

Resources

colors.xml

strings.xml

strings_fav_msg.xml

Action Bar Menu Item (main.xml)

Layout Files

activity_main.xml

fragment_product_list.xml

product_list_item.xml

Source files

Product

SharedPreference class

ProductListAdapter

ProductListFragment

FavoriteListFragment

MainActivity

Output

ProductListFragment screen

FavoriteListFragment screen

About The Author

nithya

Related Posts