Passing data in Android using sharedPreferences

For sharing simple data types between Activities or services we can make use or sharedPreferences , in android.

SharedPreferences or preferences are useful for simple dataTypes, where they are stored as Key/Values pairs in a xml file.

The below example will have two simple activities. One for input and the other for output display. We will shared data between the two activities using sharedPreferences.


NOTE: Used android 2.3.3 SDK


Project structure :

1. AndroidManifest.xml

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<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android"     package="com.example.app"     android:versionCode="1"     android:versionName="1.0" >     <uses-sdk android:minSdkVersion="10" />     <application         android:icon="@drawable/ic_launcher"         android:label="@string/app_name" >         <activity             android:name=".MainActivity"             android:label="@string/app_name" >             <intent-filter>                 <action android:name="android.intent.action.MAIN" />                 <category android:name="android.intent.category.LAUNCHER" />             </intent-filter>         </activity>         <activity android:name=".OutputActivity"             android:label="Output screen"/>     </application> </manifest>

The manifest file has only two activities. One for taking user input and another for displaying the output.

2. main.xml (main layout)

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<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"     android:layout_width="fill_parent"     android:layout_height="fill_parent"     android:orientation="vertical" >     <TextView         android:layout_width="fill_parent"         android:layout_height="wrap_content"         android:text="Enter the values" />     <EditText         android:id="@+id/valueOne"         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:ems="10" >         <requestFocus />     </EditText>     <EditText         android:id="@+id/valueTwo"         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:ems="10" />     <EditText         android:id="@+id/valueThree"         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:ems="10" />     <EditText         android:id="@+id/valueFour"         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:ems="10" />     <Button         android:id="@+id/buttonID"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:text="@string/submit" /> </LinearLayout>

The main.xml layout has four input fields and a submit button. Each field will be stored using sharedPreferences and then later used in the OutputActivity.

3. output.xml (layout)

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<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"     android:layout_width="match_parent"     android:layout_height="match_parent"     android:orientation="vertical" >     <TextView         android:id="@+id/textView1"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:text="Output Private"         android:textAppearance="?android:attr/textAppearanceMedium" />     <TextView         android:id="@+id/privateTxt"         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:textAppearance="?android:attr/textAppearanceMedium" />     <TextView         android:id="@+id/textView2"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:text="Output world read"         android:textAppearance="?android:attr/textAppearanceMedium" />     <TextView         android:id="@+id/readTxt"         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:textAppearance="?android:attr/textAppearanceMedium" />     <TextView         android:id="@+id/textView3"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:text="Output world write"         android:textAppearance="?android:attr/textAppearanceMedium" />     <TextView         android:id="@+id/writeTxt"         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:textAppearance="?android:attr/textAppearanceMedium" />     <TextView         android:id="@+id/textView4"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:text="Output world read/write"         android:textAppearance="?android:attr/textAppearanceMedium" />     <TextView         android:id="@+id/readWriteTxt"         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:textAppearance="?android:attr/textAppearanceMedium" /> </LinearLayout>

The output.xml layout has four textView fields. These four fields will display the four values shared by MainActivity using sharedPreferences.

4. MainActivity.java

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package com.example.app; import android.app.Activity; import android.content.Context; import android.content.Intent; import android.content.SharedPreferences; import android.content.SharedPreferences.Editor; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.EditText; /** * *  Activity class which demos the use of sharedPreferences for sharing data among different Activities * * @author Akshat * */ public class MainActivity extends Activity { public static final String PREFS_PRIVATE = "PREFS_PRIVATE"; public static final String PREFS_WORLD_READ = "PREFS_WORLD_READABLE"; public static final String PREFS_WORLD_WRITE = "PREFS_WORLD_WRITABLE"; public static final String PREFS_WORLD_READ_WRITE = "PREFS_WORLD_READABLE_WRITABLE"; public static final String KEY_PRIVATE = "KEY_PRIVATE"; public static final String KEY_WORLD_READ = "KEY_WORLD_READ"; public static final String KEY_WORLD_WRITE = "KEY_WORLD_WRITE"; public static final String KEY_WORLD_READ_WRITE = "KEY_WORLD_READ_WRITE"; private SharedPreferences prefsPrivate; private SharedPreferences prefsWorldRead; private SharedPreferences prefsWorldWrite; private SharedPreferences prefsWorldReadWrite;     /** Called when the activity is first created. */     @Override     public void onCreate(Bundle savedInstanceState)     {         super.onCreate(savedInstanceState);                 //Set the view for this activity to main.xml         setContentView(R.layout.main);                 //Get hold of the submit button         Button button = (Button) findViewById(R.id.buttonID);               //Listener added to the submit button         button.setOnClickListener(new Button.OnClickListener(){ @Override public void onClick(final View v) { //Get the input values EditText valueOneTxt = (EditText) findViewById(R.id.valueOne); EditText valueTwoTxt = (EditText) findViewById(R.id.valueTwo); EditText valueThreeTxt = (EditText) findViewById(R.id.valueThree); EditText valueFourTxt = (EditText) findViewById(R.id.valueFour); // Create shared sharedPreferences // We created four different sharedPreferences with different modes prefsPrivate = getSharedPreferences(MainActivity.PREFS_PRIVATE, Context.MODE_PRIVATE); prefsWorldRead = getSharedPreferences(MainActivity.PREFS_WORLD_READ, Context.MODE_WORLD_READABLE); prefsWorldWrite = getSharedPreferences(MainActivity.PREFS_WORLD_WRITE, Context.MODE_WORLD_WRITEABLE); prefsWorldReadWrite = getSharedPreferences(MainActivity.PREFS_WORLD_READ_WRITE, Context.MODE_WORLD_READABLE+Context.MODE_WORLD_WRITEABLE); // To add values to the sharedPreferences, we get editors from the sharedPreferences Editor privateEdit = prefsPrivate.edit(); Editor worldReadEdit = prefsWorldRead.edit(); Editor worldWriteEdit = prefsWorldWrite.edit(); Editor worldReadWriteEdit = prefsWorldReadWrite.edit(); // With the Editor you can set String, boolean, float, int, and long types as key/value pairs // We save the four input values into the four different sharedPreferences privateEdit.putString(MainActivity.KEY_PRIVATE, valueOneTxt.getText().toString()); worldReadEdit.putString(MainActivity.KEY_WORLD_READ, valueTwoTxt.getText().toString()); worldWriteEdit.putString(MainActivity.KEY_WORLD_WRITE, valueThreeTxt.getText().toString()); worldReadWriteEdit.putString(MainActivity.KEY_WORLD_READ_WRITE, valueFourTxt.getText().toString()); //Commit the sharedPreferences into a file privateEdit.commit(); worldReadEdit.commit(); worldWriteEdit.commit(); worldReadWriteEdit.commit(); //Start another activity by passing an explicit intent Intent intent = new Intent(MainActivity.this, OutputActivity.class); startActivity(intent); }                 });           } }

5. OutputActivity.java

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package com.example.app; import android.app.Activity; import android.content.Context; import android.content.SharedPreferences; import android.os.Bundle; import android.widget.TextView; public class OutputActivity extends Activity { private SharedPreferences prefsPrivate; private SharedPreferences prefsWorldRead; private SharedPreferences prefsWorldWrite; private SharedPreferences prefsWorldReadWrite; @Override protected void onCreate(Bundle savedInstanceState)  { super.onCreate(savedInstanceState); //Set the view for this activity to output.xml setContentView(R.layout.output); // Get hold of sharedPreferences prefsPrivate = getSharedPreferences(MainActivity.PREFS_PRIVATE, Context.MODE_PRIVATE); prefsWorldRead = getSharedPreferences(MainActivity.PREFS_WORLD_READ, Context.MODE_WORLD_READABLE); prefsWorldWrite = getSharedPreferences(MainActivity.PREFS_WORLD_WRITE, Context.MODE_WORLD_WRITEABLE); prefsWorldReadWrite = getSharedPreferences(MainActivity.PREFS_WORLD_READ_WRITE, Context.MODE_WORLD_READABLE+Context.MODE_WORLD_WRITEABLE); //Get hold of output textview - to display values TextView privateTxt = (TextView) findViewById(R.id.privateTxt); TextView readTxt = (TextView) findViewById(R.id.readTxt); TextView writeTxt = (TextView) findViewById(R.id.writeTxt); TextView readWriteTxt = (TextView) findViewById(R.id.readWriteTxt); // Set values form sharedPreferences to the textViews privateTxt.setText(prefsPrivate.getString(MainActivity.KEY_PRIVATE, "NA")); readTxt.setText(prefsWorldRead.getString(MainActivity.KEY_WORLD_READ, "NA")); writeTxt.setText(prefsWorldWrite.getString(MainActivity.KEY_WORLD_WRITE, "NA")); readWriteTxt.setText(prefsWorldReadWrite.getString(MainActivity.KEY_WORLD_READ_WRITE, "NA")); } }

When the app is run, sharedPreferences xml files are created under /data/data/PACKAGE_NAME/

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Screenshots:

MainActivity

OutputActivity