How do I programmatically "restart" an Android app?

I have slightly modified Ilya_Gazman answer to use new APIs (IntentCompat is deprecated starting API 26). Runtime.getRuntime().exit(0) seems to be better than System.exit(0).

 public static void triggerRebirth(Context context) {
    PackageManager packageManager = context.getPackageManager();
    Intent intent = packageManager.getLaunchIntentForPackage(context.getPackageName());
    ComponentName componentName = intent.getComponent();
    Intent mainIntent = Intent.makeRestartActivityTask(componentName);
    context.startActivity(mainIntent);
    Runtime.getRuntime().exit(0);
}

I've found that this works on API 29 and later - for the purpose of killing and restarting the app as if the user had launched it when it wasn't running.

public void restartApplication(final @NonNull Activity activity) {
   // Systems at 29/Q and later don't allow relaunch, but System.exit(0) on
   // all supported systems will relaunch ... but by killing the process, then
   // restarting the process with the back stack intact. We must make sure that
   // the launch activity is the only thing in the back stack before exiting.
   final PackageManager pm = activity.getPackageManager();
   final Intent intent = pm.getLaunchIntentForPackage(activity.getPackageName());
   activity.finishAffinity(); // Finishes all activities.
   activity.startActivity(intent);    // Start the launch activity
   System.exit(0);    // System finishes and automatically relaunches us.
}

That was done when the launcher activity in the app has this:

<intent-filter>
    <action android:name="android.intent.action.VIEW"/>
    <action android:name="android.intent.action.MAIN" />
    <category android:name="android.intent.category.LAUNCHER" />
</intent-filter>

I've seen comments claiming that a category of DEFAULT is needed, but I haven't found that to be the case. I have confirmed that the Application object in my app is re-created, so I believe that the process really has been killed and restarted.

The only purpose for which I use this is to restart the app after the user has enabled or disabled crash reporting for Firebase Crashlytics. According to their docs, the app has to be restarted (process killed and re-created) for that change to take effect.

Still Working Now

 public void resetApplication() {
    Intent resetApplicationIntent = context.getPackageManager().getLaunchIntentForPackage(context.getPackageName());
    if (resetApplicationIntent != null) {
        resetApplicationIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
    }
    context.startActivity(resetApplicationIntent);
    ((Activity) context).overridePendingTransition(R.anim.fade_in, R.anim.fade_out);
}

My best way to restart application is to use finishAffinity();
Since, finishAffinity(); can be used on JELLY BEAN versions only, so we can use ActivityCompat.finishAffinity(YourCurrentActivity.this); for lower versions.

Then use Intent to launch first activity, so the code will look like this:

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
    finishAffinity();
    Intent intent = new Intent(getApplicationContext(), YourFirstActivity.class);
    startActivity(intent);
} else {
    ActivityCompat.finishAffinity(YourCurrentActivity.this);
    Intent intent = new Intent(getApplicationContext(), YourFirstActivity.class);
    startActivity(intent);
}

Hope it helps.

Kotlin version of this answer:

val intent = Intent(this, YourActivity::class.java)
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK)
startActivity(intent)
Runtime.getRuntime().exit(0)

fun triggerRestart(context: Activity) {
    val intent = Intent(context, MainActivity::class.java)
    intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
    context.startActivity(intent)
    if (context is Activity) {
        (context as Activity).finish()
    }
    Runtime.getRuntime().exit(0)
}

I got this way.

Intent i = getBaseContext().getPackageManager().getLaunchIntentForPackage( 
 getBaseContext().getPackageName() );
 i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
 startActivity(i);
 finish();

try this:

Intent intent = getPackageManager().getLaunchIntentForPackage(getPackageName());
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);

With the Process Phoenix library. The Activity you want to relaunch is named "A".

Java flavor

// Java
public void restart(){
    ProcessPhoenix.triggerRebirth(context);
}

Kotlin flavor

// kotlin
fun restart() {
    ProcessPhoenix.triggerRebirth(context)
}

Apply delay restart

startDelay Startup delay (in milliseconds)

 public static void reStartApp(Context context, long startDelay) {
    //Obtain the startup Intent of the application with the package name of the application
    Intent intent = context.getPackageManager().getLaunchIntentForPackage(context.getPackageName());
    PendingIntent restartIntent = PendingIntent.getActivity(context.getApplicationContext(), -1, intent, PendingIntent.FLAG_CANCEL_CURRENT);

    AlarmManager mgr = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
    if (mgr != null) {
        mgr.set(AlarmManager.RTC, System.currentTimeMillis() + startDelay, restartIntent);
    }
}

val i = baseContext.packageManager.getLaunchIntentForPackage(baseContext.packageName)
i!!.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP)
startActivity(i)
finish()

Mikepenz's Alternative Answer needed some changes in my case. https://stackoverflow.com/a/22345538/12021422 Major Credits to Mikepenz's Answer which I could modify.

Here is the Plug and Play static function that worked for me.

Just pass the Context of Application and this function will handle the restart.

    public static void doRestart(Context c) {
        try {
            // check if the context is given
            if (c != null) {
                // fetch the package manager so we can get the default launch activity
                // (you can replace this intent with any other activity if you want
                PackageManager pm = c.getPackageManager();
                // check if we got the PackageManager
                if (pm != null) {
                    // create the intent with the default start activity for your application
                    Intent mStartActivity = pm.getLaunchIntentForPackage(c.getPackageName());
                    if (mStartActivity != null) {
                        mStartActivity.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                        
                        c.getApplicationContext().startActivity(mStartActivity);
                        // kill the application
                        System.exit(0);
                    }
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
            Log.e("restart", "Could not Restart");
        }
    }

in MainActivity call restartActivity Method:

public static void restartActivity(Activity mActivity) {
    Intent mIntent = mActivity.getIntent();
    mActivity.finish();
    mActivity.startActivity(mIntent);
}

hey bro if you want to restart your app with the click of a button so write this code and remember to change reset with the name of your button and if you will run this in the snippet it will not work because I have chosen javascript and it is java language

reset.setOnClickListener(new View.OnClickListener() {
                        @Override
                        public void onClick(View v) {
                            finish();

                            startActivity(getIntent());
                        }
                    });

You can restart your current activity like this:

Fragment :

activity?.recreate()

Activity :

recreate()