Android - How To Override the Back button so it doesn t Finish my Activity

Question

I currently have an Activity that when it gets displayed a Notification will also get displayed in the Notification bar   This is so that when the User presses home and the Activity gets pushed to the background they can get back to the Activity via the Notification   The problem arises when a User presses the back button  my Activity gets destroyed but the Notification remains as I want the user to be able to press back but still be able to get to the Activity via the Notification  But when a USER tries this I get Null Pointers as its trying to start a new activity rather than bringing back the old one   So essentially I want the Back button to act the exact same as the Home button and here is how I have tried so far              Override         public boolean onKeyDown int keyCode  KeyEvent event                 if  Integer parseInt android os Build VERSION SDK   lt  5                      amp  amp  keyCode    KeyEvent KEYCODE BACK                      amp  amp  event getRepeatCount      0                    Log d  CDA    onKeyDown Called                    onBackPressed                               return super onKeyDown keyCode  event                      public void onBackPressed                 Log d  CDA    onBackPressed Called                Intent setIntent   new Intent Intent ACTION MAIN               setIntent addCategory Intent CATEGORY HOME               setIntent setFlags Intent FLAG ACTIVITY NEW TASK               startActivity setIntent                 return                   However the above code still seems to allow my Activity to be destroyed  How can I stop my Activity from being destroyed when the back button is pressed

User · Answer

In Kotlin   val callback   requireActivity   onBackPressedDispatcher addCallback this           Handle the back button event     For more information you can check this   There is also specific question about overriding back button in Kotlin

User · Answer

Override public void onBackPressed        Put your code here       I had to go back to the dashboard  Hence    Override public void onBackPressed         Intent intent   new Intent this Dashboard class       startActivity intent     Just write this above or below the onCreate Method within the class

User · Answer

just do this  Override public void onBackPressed         super onBackPressed

User · Answer

Remove your key listener or return true when you have KEY BACK   You just need the following to catch the back key  Make sure not to call super in onBackPressed      Also  if you plan on having a service run in the background  make sure to look at startForeground   and make sure to have an ongoing notification or else Android will kill your service if it needs to free memory    Override public void onBackPressed        Log d  CDA    onBackPressed Called       Intent setIntent   new Intent Intent ACTION MAIN      setIntent addCategory Intent CATEGORY HOME      setIntent setFlags Intent FLAG ACTIVITY NEW TASK      startActivity setIntent

User · Answer

I think what you want is not to override the back button  that just doesn t seem like a good idea - Android OS defines that behavior  why change it    but to use the Activity Lifecycle and persist your settings data in the onSaveInstanceState Bundle  event    Override onSaveInstanceState Bundle frozenState        frozenState putSerializable  object key           someSerializableClassYouWantToPersist          etc  until you have everything important stored in the bundle     Then you use onCreate Bundle  to get everything out of that persisted bundle and recreate your state    Override onCreate Bundle savedInstanceState        if savedInstanceState  null     It could be null if starting the app          mCustomObject   savedInstanceState getSerializable  object key                 etc  until you have reloaded everything you stored     Consider the above psuedo-code to point you in the right direction  Reading up on the Activity Lifecycle should help you determine the best way to accomplish what you re looking for

User · Answer

Looks like im very late but for those of you who need to switch to new screen and clear back button stack here is a very simple solution  startActivity new Intent this your-new-screen class    finishAffinity     The finishAffinity    method clears back button stack

User · Answer

simply do this     Override public void onBackPressed           super onBackPressed        commenting out the   super onBackPressed    will do the trick

User · Answer

Just in case you want to handle the behaviour of the back button  at the bottom of the phone  and the home button  the one to the left of the action bar   this custom activity I m using in my project may help you   import android os Bundle  import android support v7 app ActionBar  import android support v7 app AppCompatActivity  import android view MenuItem          Activity where the home action bar button behaves like back by default     public class BackActivity extends AppCompatActivity         Override     protected void onCreate Bundle savedInstanceState            super onCreate savedInstanceState           setupHomeButton               private void setupHomeButton             final ActionBar actionBar   getSupportActionBar            if  actionBar    null                actionBar setDisplayHomeAsUpEnabled true               actionBar setHomeButtonEnabled true                         Override     public boolean onOptionsItemSelected MenuItem item            switch  item getItemId                  case android R id home                  onMenuHomePressed                    return true                    return super onOptionsItemSelected item              protected void onMenuHomePressed             onBackPressed              Example of use in your activity   public class SomeActivity extends BackActivity                      Override     public void onBackPressed                    Example of logic         if   yourConditionToOverride                        do your logic               else               super onBackPressed

User · Answer

It was easier to implement it only with one line of code    Override public void onBackPressed        moveTaskToBack true

User · Answer

Try this    Override public void onBackPressed         finish

[android] Android - How To Override the "Back" button so it doesn't Finish() my Activity?

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