How to quit android application programmatically

Create a ExitActivity and declare it in manifest. And call ExitActivity.exit(context) for exiting app.

public class ExitActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        finish();
    }

    public static void exit(Context context) {
        Intent intent = new Intent(context, ExitActivity.class);
        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
        context.startActivity(intent);
    }

}

I think that application should be kill in some case. For example, there is an app can be used only after login. The login activity has two buttons, 'login' and 'cancel'. When you click 'cancel' button, it definitely means 'Terminate the app'. Nobody wants the app alive in the background. So I agree that some cases need to shut down the app.

First of all, this approach requires min Api 16.

I will divide this solution to 3 parts to solve this problem more widely.

1. If you want to quit application in an Activity use this code snippet:

if(Build.VERSION.SDK_INT>=16 && Build.VERSION.SDK_INT<21){
    finishAffinity();
} else if(Build.VERSION.SDK_INT>=21){
    finishAndRemoveTask();
}

2. If you want to quit the application in a non Activity class which has access to Activity then use this code snippet:

if(Build.VERSION.SDK_INT>=16 && Build.VERSION.SDK_INT<21){
    getActivity().finishAffinity();
} else if(Build.VERSION.SDK_INT>=21){
    getActivity().finishAndRemoveTask();
}

3. If you want to quit the application in a non Activity class and cannot access to Activity such as Service I recommend you to use BroadcastReceiver. You can add this approach to all of your Activities in your project.

Create LocalBroadcastManager and BroadcastReceiver instance variables. You can replace getPackageName()+".closeapp" if you want to.

LocalBroadcastManager mLocalBroadcastManager;
BroadcastReceiver mBroadcastReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        if(intent.getAction().equals(getPackageName()+".closeapp")){
            if(Build.VERSION.SDK_INT>=16 && Build.VERSION.SDK_INT<21){
                finishAffinity();
            } else if(Build.VERSION.SDK_INT>=21){
                finishAndRemoveTask();
            }
        }
    }
};

Add these to onCreate() method of Activity.

mLocalBroadcastManager = LocalBroadcastManager.getInstance(this);
IntentFilter mIntentFilter = new IntentFilter();
mIntentFilter.addAction(getPackageName()+".closeapp");
mLocalBroadcastManager.registerReceiver(mBroadcastReceiver, mIntentFilter);

Also, don't forget to call unregister receiver at onDestroy() method of Activity

mLocalBroadcastManager.unregisterReceiver(mBroadcastReceiver);

For quit application, you must send broadcast using LocalBroadcastManager which I use in my PlayService class which extends Service.

LocalBroadcastManager localBroadcastManager = LocalBroadcastManager.getInstance(PlayService.this);
localBroadcastManager.sendBroadcast(new Intent(getPackageName() + ".closeapp"));

Easy and simple way to quit from the application

Intent homeIntent = new Intent(Intent.ACTION_MAIN);
homeIntent.addCategory(Intent.CATEGORY_HOME);
homeIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(homeIntent);

Similar to @MobileMateo, but in Kotlin

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
    this.finishAffinity()
} else{
    this.finish()
    System.exit(0)
}

We want code that is robust and simple. This solution works on old devices and newer devices.

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
        getActivity().finishAffinity();
    } else{
        getActivity().finish();
        System.exit( 0 );
    }

Friends just add this function to exit your application programmatically #java

public void onBackPressed() 
{

    finishAffinity();
    System.exit(0);
}

If you want to close your app:

For API >= 21, use:

finishAndRemoveTask();

For API < 21 use:

finishAffinity();

If you're using Kotlin, the proper way to exit the app and alternative to System.exit() is a built-in method

exitProcess(0)

See the documentation.

Number 0 as a parameter means the exit is intended and no error occurred.

To exit you application you can use the following:

getActivity().finish();
Process.killProcess(Process.myPid());
System.exit(1);

Also to stop the services too call the following method:

private void stopServices() {        
    final ActivityManager activityManager = SystemServices.getActivityManager(context);
    final List<ActivityManager.RunningServiceInfo> runningServices = activityManager.getRunningServices(Integer.MAX_VALUE);
    final int pid = Process.myPid();
    for (ActivityManager.RunningServiceInfo serviceInfo : runningServices) {
        if (serviceInfo.pid == pid && !SenderService.class.getName().equals(serviceInfo.service.getClassName())) {
            try {
                final Intent intent = new Intent();
                intent.setComponent(serviceInfo.service);
                context.stopService(intent);
            } catch (SecurityException e) { 
                 // handle exception
            }
        }
    }
}

Just to add one to the list of brutal methods of terminating an App:

Process.sendSignal(Process.myPid(), Process.SIGNAL_KILL);

@Sivi 's answer closes the app. But on return, if you have some child activities, another unfinished activity might be opened. I added noHistory:true to my activities so the app on return starts from MainActivity.

<activity 
      android:name=".MainActivity"
      android:noHistory="true">
</activity>