Prevent restart when the screen orientation has changed, by android:configChanges

Refer to the last exercise "Activity will be re-started when screen orientation changed"; if you don't want the activity re-start when the screen orientation has changed, you can set android:configChanges in AndroidManifest.xml, and handle the event manually by overriding the callback method onConfigurationChanged().



Please notce that it's not reommended by Google- Note: Using this attribute should be avoided and used only as a last-resort. Please read Handling Runtime Changes for more information about how to properly handle a restart due to a configuration change.

override onConfigurationChanged()

package com.exercise.AndroidOrientation;

import android.app.Activity;
import android.content.pm.ActivityInfo;
import android.content.res.Configuration;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class AndroidOrientationActivity extends Activity {
 
 String msg = "Default without changed";
 
   /** Called when the activity is first created. */
   @Override
   public void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.main);
      
       Button buttonSetPortrait = (Button)findViewById(R.id.setPortrait);
       Button buttonSetLandscape = (Button)findViewById(R.id.setLandscape);
       Button buttonSetUnspecified = (Button)findViewById(R.id.setUnspecified);
       Button buttonShowMsg = (Button)findViewById(R.id.showMsg);
      
       buttonSetPortrait.setOnClickListener(new Button.OnClickListener(){

   @Override
   public void onClick(View arg0) {
    // TODO Auto-generated method stub
    setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
   }});
      
       buttonSetLandscape.setOnClickListener(new Button.OnClickListener(){

   @Override
   public void onClick(View arg0) {
    // TODO Auto-generated method stub
    setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
   }});
      
       buttonSetUnspecified.setOnClickListener(new Button.OnClickListener(){

   @Override
   public void onClick(View arg0) {
    // TODO Auto-generated method stub
    setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_UNSPECIFIED);
   }});
      
       buttonShowMsg.setOnClickListener(new Button.OnClickListener(){

   @Override
   public void onClick(View arg0) {
    // TODO Auto-generated method stub
    Toast.makeText(AndroidOrientationActivity.this,
            "msg:\n" + msg,
            Toast.LENGTH_LONG).show();
   }});
      
       Toast.makeText(AndroidOrientationActivity.this,
         "onCreate\n" + msg,
         Toast.LENGTH_LONG).show();
      
       msg = "Changed!";
   }

 @Override
 public void onConfigurationChanged(Configuration newConfig) {
  // TODO Auto-generated method stub
  super.onConfigurationChanged(newConfig);
  Toast.makeText(AndroidOrientationActivity.this,
         "onConfigurationChanged\n" + msg,
         Toast.LENGTH_LONG).show();
 }
}

set android:configChanges in AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="com.exercise.AndroidOrientation"
     android:versionCode="1"
     android:versionName="1.0">
   <uses-sdk android:minSdkVersion="4" />

   <application android:icon="@drawable/icon" android:label="@string/app_name">
       <activity android:name=".AndroidOrientationActivity"
                 android:label="@string/app_name"
                 android:configChanges="orientation">
           <intent-filter>
               <action android:name="android.intent.action.MAIN" />
               <category android:name="android.intent.category.LAUNCHER" />
           </intent-filter>
       </activity>

   </application>
</manifest>