Clicking the back button twice to exit an activity

Question

I ve noticed this pattern in a lot of Android apps and games recently  when clicking the back button to  exit  the application  a Toast comes up with a message similar to  Please click BACK again to exit    I was wondering  as I m seeing it more and more often  is that a built-in feature that you can somehow access in an activity  I ve looked at the source code of many classes but I can t seem to find anything about that   Of course  I can think about a few ways to achieve the same functionality quite easily  the easiest is probably to keep a boolean in the activity that indicates whether the user already clicked once     but I was wondering if there s something already here   EDIT  As  LAS VEGAS mentioned  I didn t really mean  exit  in the traditional meaning   i e  terminated  I meant  going back to whatever was open before the application start activity was launched   if that makes sense

User · Answer

Just thought I would share how I did it in the end, I just added in my activity:

private boolean doubleBackToExitPressedOnce = false;

@Override
protected void onResume() {
    super.onResume();
    // .... other stuff in my onResume ....
    this.doubleBackToExitPressedOnce = false;
}

@Override
public void onBackPressed() {
    if (doubleBackToExitPressedOnce) {
        super.onBackPressed();
        return;
    }
    this.doubleBackToExitPressedOnce = true;
    Toast.makeText(this, R.string.exit_press_back_twice_message, Toast.LENGTH_SHORT).show();
}

And it just works exactly as I want. Including the reset of the state whenever the activity is resumed.

User · Answer

After having had to implement the same things many times  decided its about time someone built a simple to use library  And that is DoubleBackPress Android library  The README explains all the APIs provided along with Examples  like ToastDisplay   Exit Activity   but a short rundown of the steps here     To get going  start by adding the dependency to your application    dependencies       implementation  com github kaushikthedeveloper double-back-press 0 0 1         Next  create a DoubleBackPress object in your Activity which provides the required behaviour   DoubleBackPress doubleBackPress   new DoubleBackPress    doubleBackPress setDoublePressDuration 3000                msec   Then create a Toast that needs to be shown upon the First Back Press  Here  you can create your own Toast  or go with Standard Toast provided in the library  Doing so here by the later option   FirstBackPressAction firstBackPressAction   new ToastDisplay   standard this   doubleBackPress setFirstBackPressAction firstBackPressAction        set the action   Now  define what should happen when your Second Back Press happens  Here  we are closing the Activity   DoubleBackPressAction doubleBackPressAction   new DoubleBackPressAction          Override     public void actionCall             finish            System exit 0              Finally  override your back press behaviour with the DoubleBackPress behaviour    Override public void onBackPressed         doubleBackPress onBackPressed        Example GIF of similar behavioural requirements

User · Answer

Process Flow Diagram    Java Code   private long lastPressedTime  private static final int PERIOD   2000    Override public boolean onKeyDown int keyCode  KeyEvent event        if  event getKeyCode      KeyEvent KEYCODE BACK            switch  event getAction              case KeyEvent ACTION DOWN              if  event getDownTime   - lastPressedTime  lt  PERIOD                    finish                  else                   Toast makeText getApplicationContext     Press again to exit                            Toast LENGTH SHORT  show                    lastPressedTime   event getEventTime                              return true                      return false

User · Answer

I know this is a very old question  but this is the easiest way to do what you want    Override public void onBackPressed          k    initialise k when you first start your activity     if k  1           do whatever you want to do on first click for example        Toast makeText this   Press back one more time to exit   Toast LENGTH LONG  show        else          do whatever you want to do on the click after the first for example        finish              I know this isn t the best method  but it works fine

User · Answer

In Kotlin on the back press to exit app you can use   Define a global variable   private var doubleBackToExitPressedOnce   false   Override onBackPressed   override fun onBackPressed             if  doubleBackToExitPressedOnce                super onBackPressed               return                    doubleBackToExitPressedOnce   true         Toast makeText this   Please click BACK again to exit   Toast LENGTH LONG  show            Handler   postDelayed               doubleBackToExitPressedOnce   false             2000

User · Answer

Here  I have generalized write the code for N tap counts  The code is similarly written for the Enable Developer option in android device phone  Even you can use this to enable features while developer testing the app    private Handler tapHandler   private Runnable tapRunnable   private int mTapCount   0   private int milSecDealy   2000   onCreate         tapHandler   new Handler Looper getMainLooper           Call askToExit   on backpress or logout option   private void askToExit        if  mTapCount  gt   2        releaseTapValues                     Exit   TRUE                         mTapCount       validateTapCount               Check with null to avoid create multiple instances of the runnable      private void validateTapCount        if  tapRunnable    null        tapRunnable   new Runnable           Override      public void run           releaseTapValues                       Exit   FALSE                                  tapHandler postDelayed tapRunnable  milSecDealy               private void releaseTapValues           Relase the value        if  tapHandler    null        tapHandler removeCallbacks tapRunnable       tapRunnable   null     release the object        mTapCount   0     release the value                  Override   protected void onDestroy        super onDestroy       releaseTapValues

User · Answer

I think this what you need  I mean when we want to show this toast  when there is only one activity in the stack and user pressing back from this last activity of the stack   var exitOpened false    Declare it globaly   and in onBackPressed method change it like   override fun onBackPressed             if  isTaskRoot  amp  amp   exitOpened                        exitOpened true             toast  Please press back again to exit               return                   super onBackPressed           Here  isTaskRoot will return true if the current activity is the root activity first activity  of the stack and false if it is not   You can check the official documentation here

User · Answer

In this situation  Snackbar is the better option then Toast to display the quit action  Here is the method with snackbar that works    Override         public void onBackPressed                 if  doubleBackToExitPressedOnce                    super onBackPressed                    return                            this doubleBackToExitPressedOnce   true              Snackbar make this getWindow   getDecorView   findViewById android R id content    Please click BACK again to exit   Snackbar LENGTH SHORT  show                 new Handler   postDelayed new Runnable                       Override                 public void run                         doubleBackToExitPressedOnce false                                   2000

User · Answer

Declare a global Toast variable for MainActivity Class  example  Toast exitToast  Initialize it in onCreate view method  example   exitToast   Toast makeText getApplicationContext     Press back again to  exit   Toast LENGTH SHORT   Finally create a onBackPressedMethod as Follows    Override public void onBackPressed          if  exitToast getView   isShown              exitToast cancel            finish          else           exitToast show               This works correctly  i have tested  and I think this is much simpler

User · Answer

It s not a built in functionality  I think it is not even the recommended behavior  Android apps are not meant to exit   Why dont Android applications provide an  quot Exit quot  option

User · Answer

you can even make it more simple  and without using a hander  only do this      Long firstClick   1L  Long secondClick   0L    Override public void onBackPressed     secondClick   System currentTimeMillis        if   secondClick - firstClick    1000  lt  2              super onBackPressed          else             firstClick   System currentTimeMillis              Toast makeText MainActivity this   click BACK again to exit   Toast LENGTH SHORT  show

User · Answer

This also helps when you have previous stack activity stored in stack    I have modified Sudheesh s answer   boolean doubleBackToExitPressedOnce   false    Override public void onBackPressed         if  doubleBackToExitPressedOnce              super onBackPressed       Intent intent   new Intent Intent ACTION MAIN                       intent addCategory Intent CATEGORY HOME                       intent setFlags Intent FLAG ACTIVITY CLEAR TOP       Change Here                        startActivity intent                       finish                        System exit 0           return             this doubleBackToExitPressedOnce   true      Toast makeText this   Please click BACK again to exit   Toast LENGTH SHORT  show         new Handler   postDelayed new Runnable               Override         public void run                 doubleBackToExitPressedOnce false                                          2000

User · Answer

Here is the full working code  And also don t forget to remove the callbacks so that it don t cause a memory leak in the app       private boolean backPressedOnce   false  private Handler statusUpdateHandler  private Runnable statusUpdateRunnable   public void onBackPressed             if  backPressedOnce                finish                       backPressedOnce   true          final Toast toast   Toast makeText this   Press again to exit   Toast LENGTH SHORT           toast show             statusUpdateRunnable   new Runnable                  Override             public void run                     backPressedOnce   false                  toast cancel       Removes the toast after the exit                                    statusUpdateHandler postDelayed statusUpdateRunnable  2000       Override protected void onDestroy         super onDestroy        if  statusUpdateHandler    null            statusUpdateHandler removeCallbacks statusUpdateRunnable

User · Answer

This is the same of the accepted and most voted response but this snipped used Snackbar instead of Toast   boolean doubleBackToExitPressedOnce   false        Override     public void onBackPressed             if  doubleBackToExitPressedOnce                super onBackPressed                return                     this doubleBackToExitPressedOnce   true          Snackbar make content   Please click BACK again to exit   Snackbar LENGTH SHORT                   setAction  Action   null  show              new Handler   postDelayed new Runnable                   Override             public void run                     doubleBackToExitPressedOnce false                           2000

User · Answer

The Accepted answer is Best one but if you are using Android Design Support Library then you can use SnackBar for Better Views       boolean doubleBackToExitPressedOnce   false        Override     public void onBackPressed             if  doubleBackToExitPressedOnce                super onBackPressed                return                     this doubleBackToExitPressedOnce   true           Snackbar make findViewById R id photo album parent view    Please click BACK again to exit   Snackbar LENGTH SHORT  show             new Handler   postDelayed new Runnable                   Override             public void run                     doubleBackToExitPressedOnce false                           2000

User · Answer

It is not a good idea to use a Runnable when exit the application  I recently figure out a much simpler way to record and compare the period between two BACK button clicks  Sample code as following   private static long back pressed time  private static long PERIOD   2000    Override public void onBackPressed             if  back pressed time   PERIOD  gt  System currentTimeMillis    super onBackPressed            else Toast makeText getBaseContext     Press once again to exit    Toast LENGTH SHORT  show            back pressed time   System currentTimeMillis        This will do the trick  to exit the application  by a double BACK button clicks within a certain delay period which is 2000 millisecond in sample

User · Answer

In Java Activity    boolean doubleBackToExitPressedOnce   false    Override public void onBackPressed         if  doubleBackToExitPressedOnce            super onBackPressed            return             this doubleBackToExitPressedOnce   true      Toast makeText this   Please click BACK again to exit   Toast LENGTH SHORT  show         new Handler   postDelayed new Runnable               Override         public void run                 doubleBackToExitPressedOnce false                                          2000           In Kotlin Activity    private var doubleBackToExitPressedOnce   false override fun onBackPressed             if  doubleBackToExitPressedOnce                super onBackPressed               return                    this doubleBackToExitPressedOnce   true         Toast makeText this   Please click BACK again to exit   Toast LENGTH SHORT  show            Handler   postDelayed Runnable   doubleBackToExitPressedOnce   false    2000          I Think this handler helps to reset the variable after 2 second

User · Answer

Here is a way to do it using RxJava   override fun onCreate            backPresses timeInterval TimeUnit MILLISECONDS  Schedulers io                 skip 1    Skip initial event  delay will be 0               onMain                subscribe                   if  it time    lt  7000  super onBackPressed     7000 is the duration of a Toast with length LENGTH LONG                addTo compositeDisposable       backPresses throttleFirst 7000  TimeUnit MILLISECONDS  Schedulers io                 subscribe   Toast makeText this   Press back again to exit    LENGTH LONG  show                  addTo compositeDisposable     override fun onBackPressed     backPresses onNext Unit

User · Answer

There is very simplest way among all these answers   Simply write following code inside onBackPressed   method   long back pressed    Override public void onBackPressed         if  back pressed   1000  gt  System currentTimeMillis             super onBackPressed              else          Toast makeText getBaseContext                     Press once again to exit    Toast LENGTH SHORT                   show              back pressed   System currentTimeMillis        You need to define back pressed object as long in activity

User · Answer

boolean doubleBackToExitPressedOnce   false    Override public void onBackPressed         if  doubleBackToExitPressedOnce            super onBackPressed            return             this doubleBackToExitPressedOnce   true       Snackbar make findViewById R id photo album parent view    Please click BACK again to exit   Snackbar LENGTH SHORT  show         new Handler   postDelayed new Runnable               Override         public void run                 doubleBackToExitPressedOnce false                   2000

User · Answer

A slightly better method than Zefnus I think  Call System currentTimeMillis   just one time and omit return     long previousTime    Override public void onBackPressed         if  2000   previousTime  gt   previousTime   System currentTimeMillis                     super onBackPressed          else           Toast makeText getBaseContext     Tap back button in order to exit   Toast LENGTH SHORT  show

User · Answer

I use this  import android app Activity  import android support annotation StringRes  import android widget Toast   public class ExitApp        private static long lastClickTime       public static void now Activity ctx   StringRes int message            now ctx  ctx getString message   2500              public static void now Activity ctx   StringRes int message  long time            now ctx  ctx getString message   time              public static void now Activity ctx  String message  long time            if  ctx    null  amp  amp   message isEmpty    amp  amp  time    0                if  lastClickTime   time  gt  System currentTimeMillis                      ctx finish                  else                   Toast makeText ctx  message  Toast LENGTH SHORT  show                    lastClickTime   System currentTimeMillis                                       use to in event onBackPressed   Override public void onBackPressed        ExitApp now this  Press again for close        or ExitApp now this R string double back pressed   for change seconds need for close  specified miliseconds  ExitApp now this R string double back pressed 5000

User · Answer

For this purpose I have implemented the following function   private long onRecentBackPressedTime   Override public void onBackPressed         if  System currentTimeMillis   - onRecentBackPressedTime  gt  2000           onRecentBackPressedTime   System currentTimeMillis           Toast makeText this   Please press BACK again to exit   Toast LENGTH SHORT  show           return            super onBackPressed

User · Answer

Recently  I needed to implement this back button feature in an app of mine  The answers on the original question were useful  but I had to take two more points into consideration    At some points in time  the back button is disabled The main activity is using fragments in combination with a back stack   Based on the answers and comments  I created the following code   private static final long BACK PRESS DELAY   1000   private boolean mBackPressCancelled   false  private long mBackPressTimestamp  private Toast mBackPressToast    Override public void onBackPressed            Do nothing if the back button is disabled      if   mBackPressCancelled               Pop fragment if the back stack is not empty          if  getSupportFragmentManager   getBackStackEntryCount    gt  0                super onBackPressed              else               if  mBackPressToast    null                    mBackPressToast cancel                               long currentTimestamp   System currentTimeMillis                 if  currentTimestamp  lt  mBackPressTimestamp   BACK PRESS DELAY                    super onBackPressed                  else                   mBackPressTimestamp   currentTimestamp                   mBackPressToast   Toast makeText this  getString R string warning exit   Toast LENGTH SHORT                   mBackPressToast show                                      The code above assumes that the support library is used  If you use fragments but not the support library  you want to replace getSupportFragmentManager   by getFragmentManager     Remove the first if  if the back button is never cancelled  Remove the second if  if you don t use fragments or a fragment back stack  Also  it is important to be aware that the method onBackPressed is supported since Android 2 0  Check this page for an elaborate description  To make the back press feature work on older versions as well  add the following method to your activity    Override public boolean onKeyDown int keyCode  KeyEvent event         if  android os Build VERSION SDK INT  lt  android os Build VERSION CODES ECLAIR              amp  amp  keyCode    KeyEvent KEYCODE BACK              amp  amp  event getRepeatCount      0               Take care of calling this method on earlier versions of            the platform where it doesn t exist          onBackPressed               return super onKeyDown keyCode  event

User · Answer

I would normally add a comment  but my reputation doesn t allow this  So here s my two cents   In Kotlin you can use coroutines to delay the setting to false   private var doubleBackPressed   false private var toast   Toast    null  override fun onCreate savedInstanceState  Bundle         toast   Toast maketext this   Press back again to exit   Toast LENGTH SHORT     override fun onBackPressed         if  doubleBackPressed            toast  cancel           super onBackPressed           return           this doubleBackPressed   true     toast  show       GlobalScope launch           delay 2000          doubleBackPressed   false           You will have to import   import kotlinx coroutines launch import kotlinx coroutines delay import kotlinx coroutines GlobalScope

User · Answer

For the activity whose is having Navigation Drawer  Use the following code for OnBackPressed    boolean doubleBackToExitPressedOnce   false    Override     public void onBackPressed             DrawerLayout drawer    DrawerLayout  findViewById R id drawer layout           if  drawer isDrawerOpen GravityCompat START                 drawer closeDrawer GravityCompat START             else               if  doubleBackToExitPressedOnce                    if  getFragmentManager   getBackStackEntryCount     0                        finishAffinity                        System exit 0                     else                       getFragmentManager   popBackStackImmediate                                      return                             if  getFragmentManager   getBackStackEntryCount     0                    this doubleBackToExitPressedOnce   true                  Toast makeText this   Please click BACK again to exit   Toast LENGTH SHORT  show                     new Handler   postDelayed new Runnable                           Override                     public void run                             doubleBackToExitPressedOnce   false                                           2000                 else                   getFragmentManager   popBackStackImmediate

User · Answer

Best Solution with Toast     In Java   private Toast exitToast    Override public void onBackPressed         if  exitToast    null    exitToast getView      null    exitToast getView   getWindowToken      null            exitToast   Toast makeText this   Press again to exit   Toast LENGTH LONG           exitToast show          else           exitToast cancel            super onBackPressed                 In Kotlin   private var exitToast  Toast    null  override fun onBackPressed         if  exitToast    null    exitToast   view    null    exitToast   view windowToken    null            exitToast   Toast makeText this   Press again to exit   Toast LENGTH LONG          exitToast   show         else           exitToast   cancel           super onBackPressed

User · Answer

Zefnus s answer using System currentTimeMillis   is the best one   1   The way I did it is not better than that  but still posting it to add to the above ideas   If the toast is not visible when the back button is pressed  the toast is displayed  whereas  if it is visible  back has already been pressed once within the last Toast LENGTH SHORT time   then it exits   exitToast   Toast makeText this   Press again to exit   Toast LENGTH SHORT        Override public void onBackPressed        if  exitToast getView   getWindowToken      null    if toast is currently not visible       exitToast show       then show toast saying  press againt to exit     else                                                if toast is visible then       finish                                           or super onBackPressed          exitToast cancel

User · Answer

Override public void onBackPressed        Log d  CDA    onBackPressed Called       Intent intent   new Intent       intent setAction Intent ACTION MAIN      intent addCategory Intent CATEGORY HOME       startActivity intent

User · Answer

private static final int TIME DELAY   2000      private static long back pressed       Override     protected void onCreate Bundle savedInstanceState            super onCreate savedInstanceState           setContentView R layout activity main              Override     public void onBackPressed             if  back pressed   TIME DELAY  gt  System currentTimeMillis                  super onBackPressed              else               Toast makeText getBaseContext     Press once again to exit                        Toast LENGTH SHORT  show                      back pressed   System currentTimeMillis

User · Answer

You may use a snackbar instead of a toast  so you can rely on their visibility to decide whether to close the app or not  Take this example  Snackbar mSnackbar    Override protected void onCreate Bundle savedInstanceState        super onCreate savedInstanceState       setContentView R layout activity main        final LinearLayout layout   findViewById R id layout main       mSnackbar   Snackbar make layout  R string press back again  Snackbar LENGTH SHORT       Override public void onBackPressed         if  mSnackbar isShown              super onBackPressed          else           mSnackbar show

User · Answer

public void onBackPressed         if  doubleBackToExitPressedOnce            super onBackPressed            return             this doubleBackToExitPressedOnce   true      Toast makeText this   Please click BACK again to exit   Toast LENGTH SHORT  show         new Handler   postDelayed new Runnable               Override         public void run                 doubleBackToExitPressedOnce false                   2000     Declare Variableprivate boolean doubleBackToExitPressedOnce   false      Paste this in your Main Activity and this will solve your issue

User · Answer

The unique thing about this solution is the behaviour  in that a non double tap will show the toast and a successful double tap will show no toast while closing the app  The only disadvantage being the the showing of the toast will have a 650 millisecond delay  I believe this is the best solution with the best behaviour as logic dictates that it would be impossible to have this behaviour without such a delay    App Closing Vars private var doubleBackPressedInterval  Long   650 private var doubleTap   false private var pressCount   0 private var timeLimit  Long   0  override fun onBackPressed         pressCount       if pressCount    1            timeLimit   System currentTimeMillis     doubleBackPressedInterval         if  doubleTap                showExitInstructions                       if pressCount    2            if timeLimit  gt  System currentTimeMillis                  doubleTap   true             super onBackPressed                     else               showExitInstructions                     pressCount   1         timeLimit   System currentTimeMillis     doubleBackPressedInterval          private fun showExitInstructions         Handler   postDelayed           if  doubleTap                Toast makeText this   Try Agian   Toast LENGTH SHORT  show                    doubleBackPressedInterval

User · Answer

When HomeActivity contain navigation drawer and double backPressed   funtion to exit app   Don t forget to initilize global variable     boolean doubleBackToExitPressedOnce   false   new handler after 2 sec set doubleBackPressedOnce variable to false    Override public void onBackPressed         DrawerLayout drawer   findViewById R id drawer layout       if  drawer isDrawerOpen GravityCompat END             drawer closeDrawer GravityCompat END         else           if  doubleBackToExitPressedOnce                super onBackPressed                moveTaskToBack true               return            else               this doubleBackToExitPressedOnce   true              Toast makeText this   Please click BACK again to exit   Toast LENGTH SHORT  show                new Handler   postDelayed new Runnable                      Override                 public void run                         doubleBackToExitPressedOnce   false                                   2000

User · Answer

Back when Button pressed 2 times       public void click View view       if  isBackActivated            this finish              if   isBackActivated            isBackActivated   true          Toast makeText getApplicationContext     Again   Toast LENGTH SHORT  show            Handler handler   new Handler            handler postDelayed new Runnable                  Override             public void run                     isBackActivated   false      setting isBackActivated after 2 second                          2000

User · Answer

Here is another way    using the CountDownTimer method  private boolean exit   false   Override public void onBackPressed             if  exit                finish              else               Toast makeText this   Press back again to exit                       Toast LENGTH SHORT  show                exit   true              new CountDownTimer 3000 1000                      Override                 public void onTick long l                                         Override                 public void onFinish                         exit   false                                  start

User · Answer

Based upon the correct answer and suggestions in comments  I have created a demo which works absolutely fine and removes the handler callbacks after being used   MainActivity java  package com mehuljoisar d pressbacktwicetoexit   import android os Bundle  import android os Handler  import android app Activity  import android widget Toast   public class MainActivity extends Activity        private static final long delay   2000L      private boolean mRecentlyBackPressed   false      private Handler mExitHandler   new Handler        private Runnable mExitRunnable   new Runnable               Override         public void run                 mRecentlyBackPressed false                            Override     protected void onCreate Bundle savedInstanceState            super onCreate savedInstanceState           setContentView R layout activity main               Override     public void onBackPressed                You may also add condition if  doubleBackToExitPressedOnce    fragmentManager getBackStackEntryCount      0     in case of Fragment-based add         if  mRecentlyBackPressed                mExitHandler removeCallbacks mExitRunnable               mExitHandler   null              super onBackPressed                      else                       mRecentlyBackPressed   true              Toast makeText this   press again to exit   Toast LENGTH SHORT  show                mExitHandler postDelayed mExitRunnable  delay                        I hope it will be helpful

User · Answer

In  java  private Boolean exit   false    if  exit    onBackPressed             Override public void onBackPressed         if  exit            finish       finish activity       else           Toast makeText this   Press Back again to Exit                    Toast LENGTH SHORT  show            exit   true          new Handler   postDelayed new Runnable                  Override             public void run                     exit   false                           3   1000                In kotlin   private var exit   false   if  exit            onBackPressed                   override fun onBackPressed               if  exit                  finish      finish activity             else              Toast makeText this   Press Back again to Exit                        Toast LENGTH SHORT  show               exit   true             Handler   postDelayed   exit   false    3   1000

User · Answer

Here s my take on this     int oddeven   0   long backBtnPressed1   long backBtnPressed2    Override  public void onBackPressed          oddeven         if oddeven 2  0            backBtnPressed2   System currentTimeMillis             if backBtnPressed2-backBtnPressed1 lt 2000                super onBackPressed                return                         else if oddeven 2  1              backBtnPressed1   System currentTimeMillis                    Insert toast back button here

User · Answer

Some Improvements in Sudheesh B Nair s answer  i have noticed it will wait for handler even while pressing back twice immediately  so cancel handler as shown below  I have cancled toast also to prevent it to display after app exit    boolean doubleBackToExitPressedOnce   false          Handler myHandler          Runnable myRunnable          Toast myToast        Override         public void onBackPressed                 if  doubleBackToExitPressedOnce                    myHandler removeCallbacks myRunnable                   myToast cancel                    super onBackPressed                    return                             this doubleBackToExitPressedOnce   true              myToast   Toast makeText this   Please click BACK again to exit   Toast LENGTH SHORT               myToast show                 myHandler   new Handler                 myRunnable   new Runnable                       Override                 public void run                         doubleBackToExitPressedOnce   false                                               myHandler postDelayed myRunnable  2000

User · Answer

In my case  I ve depend on Snackbar isShown   for better UX   private Snackbar exitSnackBar    Override public void onBackPressed         if  isNavDrawerOpen              closeNavDrawer          else if  getSupportFragmentManager   getBackStackEntryCount      0            if  exitSnackBar    null  amp  amp  exitSnackBar isShown                  super onBackPressed              else               exitSnackBar   Snackbar make                      binding getRoot                        R string navigation exit                      2000                            exitSnackBar show                    else           super onBackPressed

User · Answer

private static final int TIME INTERVAL   2000  private long mBackPressed       Override         public void onBackPressed                  if  mBackPressed   TIME INTERVAL  gt  System currentTimeMillis                      super onBackPressed                    Intent intent   new Intent FirstpageActivity this                          HomepageActivity class                   startActivity intent                   finish                     return                else                    Toast makeText getBaseContext                             Tap back button twice  to go Home    Toast LENGTH SHORT                           show                     mBackPressed   System currentTimeMillis

User · Answer

I ve tried to create a utils class for this  so any activity or fragment can implement this to be simpler    The code was written with Kotlin  amp  has Java-interop as well   I m using coroutine to delay and reset the flag variable  But you can modify it to your needs   Additional files  SafeToast kt  lateinit var toast  Toast  fun Context safeToast msg  String  length  Int   Toast LENGTH LONG  action   Context  - gt  Toast   default        toast   SafeToast makeText this safeToast  msg  length  apply              do anything new here         action this safeToast          show            fun Context toastSpammable msg  String        cancel       safeToast msg  Toast LENGTH SHORT     fun Fragment toastSpammable msg  String        cancel       requireContext   safeToast msg  Toast LENGTH SHORT     private val default   Context  - gt  Toast     it - gt  SafeToast makeText it      Toast LENGTH LONG     private fun cancel         if    toast isInitialized  toast cancel       ActivityUtils kt   file JvmMultifileClass  file JvmName  ActivityUtils   package your company com  import android app Activity import your company com R import kotlinx coroutines GlobalScope import kotlinx coroutines delay import kotlinx coroutines launch   private var backButtonPressedTwice   false  fun Activity onBackPressedTwiceFinish         onBackPressedTwiceFinish getString R string msg back pressed to exit   2000     fun Activity onBackPressedTwiceFinish  StringRes message  Int  time  Long        onBackPressedTwiceFinish getString message   time     fun Activity onBackPressedTwiceFinish message  String  time  Long        if  backButtonPressedTwice            onBackPressed         else           backButtonPressedTwice   true         toastSpammable message          GlobalScope launch               delay time              backButtonPressedTwice   false                     Usage in Kotlin     ActivityA kt override fun onBackPressed         onBackPressedTwiceFinish       Usage in Java   Override  public void onBackPressed         ActivityUtils onBackPressedTwiceFinish       This code was inspired by  webserveis here

User · Answer

Sudheesh B Nair s has a nice  and accepted  answer on the question  which i think should have a better alternative such as   What s wrong with measuring time passed and checking if TIME INTERVAL miliseconds  say 2000  passed since the last back press  The following sample code uses System currentTimeMillis    to store the time onBackPressed   is called   private static final int TIME INTERVAL   2000       milliseconds  desired time passed between two back presses  private long mBackPressed    Override public void onBackPressed         if  mBackPressed   TIME INTERVAL  gt  System currentTimeMillis                    super onBackPressed             return            else   Toast makeText getBaseContext     Tap back button in order to exit   Toast LENGTH SHORT  show           mBackPressed   System currentTimeMillis          Back on accepted answer critique  Using a flag to indicate if it was pressed in last TIME INTERVAL  say 2000  milliseconds and set - reset is via Handler s postDelayed   method was the first thing to come in my mind  But the postDelayed   action should be cancelled when activity is closing  removing the Runnable   In order to remove the Runnable  it must not be declared anonymous  and be declared as member along with the Handler aswell  Then removeCallbacks   method of Handler can be called appropriately   The following sample is the demonstration   private boolean doubleBackToExitPressedOnce  private Handler mHandler   new Handler     private final Runnable mRunnable   new Runnable          Override     public void run             doubleBackToExitPressedOnce   false                                    Override  protected void onDestroy           super onDestroy         if  mHandler    null    mHandler removeCallbacks mRunnable         Override public void onBackPressed         if  doubleBackToExitPressedOnce            super onBackPressed            return             this doubleBackToExitPressedOnce   true      Toast makeText this   Please click BACK again to exit   Toast LENGTH SHORT  show         mHandler postDelayed mRunnable  2000         Thanks to  NSouth for contributing  In order to prevent toast message appearing even after the application is closed  Toast can be declared as a member - say mExitToast - and can be cancelled via mExitToast cancel    just before super onBackPressed    call

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You can also use the visibility of a Toast  so you don t need that Handler postDelayed ultra solution   Toast doubleBackButtonToast    Override protected void onCreate Bundle savedInstanceState        super onCreate savedInstanceState       setContentView R layout activity main        doubleBackButtonToast   Toast makeText this   Double tap back to exit    Toast LENGTH SHORT       Override public void onBackPressed         if  doubleBackButtonToast getView   isShown              super onBackPressed               doubleBackButtonToast show

[java] Clicking the back button twice to exit an activity

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