On logout clear Activity history stack preventing back button from opening logged-in-only Activities

Question

All activities in my application require a user to be logged-in to view  Users can log out from almost any activity  This is a requirement of the application  At any point if the user logs-out  I want to send the user to the Login Activity  At this point I want this activity to be at the bottom of the history stack so that pressing the  back  button returns the user to Android s home screen   I ve seen this question asked a few different places  all answered with similar answers  that I outline here   but I want to pose it here to collect feedback   I ve tried opening the Login activity by setting its Intent flags to FLAG ACTIVITY CLEAR TOP which seems to do as is outlined in the documentation  but does not achieve my goal of placing the Login activity at the bottom of the history stack  and preventing the user from navigating back to previously-seen logged-in activities  I also tried using android launchMode  singleTop  for the Login activity in the manifest  but this does not accomplish my goal either  and seems to have no effect anyway    I believe I need to either clear the history stack  or finish all previously- opened activities   One option is to have each activity s onCreate check logged-in status  and finish   if not logged-in  I do not like this option  as the back button will still be available for use  navigating back as activities close themselves   The next option is to maintain a LinkedList of references to all open activities that is statically accessible from everywhere  perhaps using weak references   On logout I will access this list and iterate over all previously-opened activities  invoking finish   on each one  I ll probably begin implementing this method soon   I d rather use some Intent flag trickery to accomplish this  however  I d be beyond happy to find that I can fulfill my application s requirements without having to use either of the two methods that I ve outlined above   Is there a way to accomplish this by using Intent or manifest settings  or is my second option  maintaining a LinkedList of opened activities the best option  Or is there another option that I m completely overlooking

User · Answer

If you are using API 11 or higher you can try this: FLAG_ACTIVITY_CLEAR_TASK--it seems to be addressing exactly the issue you're having. Obviously the pre-API 11 crowd would have to use some combination of having all activities check an extra, as @doreamon suggests, or some other trickery.

(Also note: to use this you have to pass in FLAG_ACTIVITY_NEW_TASK)

Intent intent = new Intent(this, LoginActivity.class);
intent.putExtra("finish", true); // if you are checking for this in your other Activities
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | 
                Intent.FLAG_ACTIVITY_CLEAR_TASK |
                Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
finish();

User · Answer

Accepted solution is not correct  it has problems as using a broadcast receiver is not a good idea for this problem  If your activity has already called onDestroy   method  you will not get receiver  Best solution is having a boolean value on your shared preferences  and checking it in your activty s onCreate   method  If it should not be called when user is not logged in  then finish activity  Here is sample code for that  So simple and works for every condition   protected void onResume       super onResume      if  isAuthRequired          checkAuthStatus           private void checkAuthStatus         check your shared pref value for login in this method   if  checkIfSharedPrefLoginValueIsTrue          finish           boolean isAuthRequired       return true

User · Answer

I d suggest a different approach to this question  Maybe it s not the most efficient one  but I think it s the easiest to apply and requires very little code  Writing the next code in your first activity  log in activity  in my case  won t let the user go back to previously launched activities after logging out    Override public void onBackPressed            disable going back to the MainActivity     moveTaskToBack true       I m assuming that LoginActivity is finished just after the user logs in  so that he can t go back to it later by pressing the back button  Instead  the user must press a log out button inside the app in order to log out properly  What this log out button would implement is a simple intent as follows   Intent intent   new Intent this  LoginActivity class   startActivity intent   finish      All suggestions are welcome

User · Answer

The selected answer is clever and tricky  Here s how I did it   LoginActivity is the root activity of the task  set android noHistory  true  to it in Manifest xml  Say you want to logout from SettingsActivity  you can do it as below       Intent i   new Intent SettingsActivity this  LoginActivity class       i addFlags IntentCompat FLAG ACTIVITY CLEAR TASK               Intent FLAG ACTIVITY NEW TASK       startActivity i

User · Answer

Start you activity with StartActivityForResult and while you logout set your result and according to you result finish your activity   intent setFlags Intent FLAG ACTIVITY SINGLE TOP   startActivityForResult intent  BACK SCREEN     Override protected void onActivityResult int requestCode  int resultCode  Intent data        switch  requestCode        case BACK SCREEN          if  resultCode    REFRESH                setResult REFRESH               finish                      break         Override public boolean onKeyDown int keyCode  KeyEvent event        if  keyCode    KeyEvent KEYCODE BACK            AlertDialog Builder builder   new AlertDialog Builder this           AlertDialog alertDialog   builder create             alertDialog                  setTitle  String  getResources   getText R string home            alertDialog setMessage  String  getResources   getText                  R string gotoHome            alertDialog setButton DialogInterface BUTTON POSITIVE   Yes                   new DialogInterface OnClickListener                         public void onClick DialogInterface dialog                              int whichButton                             setResult REFRESH                           finish                                                        alertDialog setButton DialogInterface BUTTON NEGATIVE   No                   new DialogInterface OnClickListener                         public void onClick DialogInterface dialog                              int whichButton                                                      alertDialog show            return true        else         return super onKeyDown keyCode  event

User · Answer

Lots of answers  May be this one will also help-  Intent intent   new Intent activity  SignInActivity class                   addFlags Intent FLAG ACTIVITY CLEAR TASK                   addFlags Intent FLAG ACTIVITY NEW TASK   this startActivity intent   this finish      Kotlin version-  Intent this  SignInActivity  class java  apply       addFlags Intent FLAG ACTIVITY CLEAR TASK      addFlags Intent FLAG ACTIVITY NEW TASK    also   startActivity it    finish

User · Answer

Use this it should be helpful to you  Slightly modified xbakesx answer   Intent intent   new Intent this  LoginActivity class   if Build VERSION SDK INT  gt   11        intent setFlags Intent FLAG ACTIVITY NEW TASK   Intent FLAG ACTIVITY CLEAR TOP   Intent FLAG ACTIVITY CLEAR TASK     else       intent setFlags Intent FLAG ACTIVITY NEW TASK   Intent FLAG ACTIVITY CLEAR TOP     startActivity intent

User · Answer

It is possible by managing a flag in SharedPreferences or in Application Activity   On starting of app  on Splash Screen  set the flag   false  On Logout Click event just set the flag true and in OnResume   of every activity  check if flag is true then call finish     It works like a charm

User · Answer

Here is the solution I came up with in my app   In my LoginActivity  after successfully processing a login  I start the next one differently depending on the API level   Intent i   new Intent this  MainActivity class   if  Build VERSION SDK INT  gt   Build VERSION CODES HONEYCOMB        startActivity i       finish      else       startActivityForResult i  REQUEST LOGIN GINGERBREAD       Then in my LoginActivity s onActivityForResult method   if  Build VERSION SDK INT  lt  Build VERSION CODES HONEYCOMB  amp  amp          requestCode    REQUEST LOGIN GINGERBREAD  amp  amp          resultCode    Activity RESULT CANCELED        moveTaskToBack true       Finally  after processing a logout in any other Activity   Intent i   new Intent this  LoginActivity class   i setFlags Intent FLAG ACTIVITY CLEAR TOP   Intent FLAG ACTIVITY NEW TASK   Intent FLAG ACTIVITY CLEAR TASK   startActivity i     When on Gingerbread  makes it so if I press the back button from MainActivity  the LoginActivity is immediately hidden   On Honeycomb and later  I just finish the LoginActivity after processing a login and it is properly recreated after processing a logout

User · Answer

I can suggest you another approach IMHO more robust  Basically you need to broadcast a logout message to all your Activities needing to stay under a logged-in status  So you can use the sendBroadcast and install a BroadcastReceiver in all your Actvities  Something like this       on your logout method     Intent broadcastIntent   new Intent    broadcastIntent setAction  com package ACTION LOGOUT    sendBroadcast broadcastIntent     The receiver  secured Activity    protected void onCreate Bundle savedInstanceState        super onCreate savedInstanceState          snip         IntentFilter intentFilter   new IntentFilter        intentFilter addAction  com package ACTION LOGOUT        registerReceiver new BroadcastReceiver              Override         public void onReceive Context context  Intent intent                Log d  onReceive   Logout in progress                  At this point you should start the login activity and finish this one             finish                     intentFilter            snip

User · Answer

This worked for me           After logout redirect user to Loing Activity     Intent i   new Intent  context  MainActivity class          Closing all the Activities     i addFlags Intent FLAG ACTIVITY CLEAR TOP       i addFlags Intent FLAG ACTIVITY CLEAR TASK           Add new Flag to start new Activity     i setFlags Intent FLAG ACTIVITY NEW TASK           Staring Login Activity      context startActivity i

User · Answer

Sometime finish   not working  I have solved that issue with   finishAffinity

User · Answer

UPDATE  the super finishAffinity   method will help to reduce the code but achieve the same  It will finish the current activity as well as all activities in the stack  use getActivity   finishAffinity   if you are in a fragment      finishAffinity     startActivity new Intent mActivity  LoginActivity class      ORIGINAL ANSWER  Assume that LoginActivity --  HomeActivity --      --  SettingsActivity call signOut      void signOut         Intent intent   new Intent this  HomeActivity class       intent putExtra  finish   true       intent setFlags Intent FLAG ACTIVITY CLEAR TOP      To clean up all activities     startActivity intent       finish        HomeActivity     Override protected void onCreate Bundle savedInstanceState        super onCreate savedInstanceState       boolean finish   getIntent   getBooleanExtra  finish   false       if  finish            startActivity new Intent mContext  LoginActivity class            finish            return            initializeView        This works for me  hope that it is helpful for you too

User · Answer

I spent a few hours on this too     and agree that FLAG ACTIVITY CLEAR TOP sounds like what you d want  clear the entire stack  except for the activity being launched  so the Back button exits the application  Yet as Mike Repass mentioned  FLAG ACTIVITY CLEAR TOP only works when the activity you re launching is already in the stack  when the activity s not there  the flag doesn t do anything    What to do  Put the activity being launching in the stack with FLAG ACTIVITY NEW TASK  which makes that activity the start of a new task on the history stack  Then add the FLAG ACTIVITY CLEAR TOP flag    Now  when FLAG ACTIVITY CLEAR TOP goes to find the new activity in the stack  it ll be there and be pulled up before everything else is cleared   Here s my logout function  the View parameter is the button to which the function s attached   public void onLogoutClick final View view        Intent i   new Intent this  Splash class       i setFlags Intent FLAG ACTIVITY NEW TASK   Intent FLAG ACTIVITY CLEAR TASK       startActivity i       finish

User · Answer

The solution  doreamon provided works fine for all the cases except one   If After login  Killing Login screen user navigated direct to a middle screen  e g  In a flow of A- B- C  navigate like   Login -  B -  C -  Press shortcut to home  Using FLAG ACTIVITY CLEAR TOP clears only C activity  As the Home A  is not on stack history  Pressing Back on A screen will lead us back to B    To tackle this problem  We can keep an activity stack Arraylist  and when home is pressed  we have to kill all the activities in this stack

User · Answer

One option is to have each activity s onCreate check logged-in status  and finish   if not logged-in  I do not like this option  as the back button will still be available for use  navigating back as activities close themselves    What you want to do is call logout   and finish   on your onStop   or onPause   methods  This will force Android to call onCreate   when the activity is brought back on since it won t have it in its activity s stack any longer  Then do as you say  in onCreate   check logged in status and forward to login screen if not logged in   Another thing you could do is check logged in status in onResume    and if not logged in  finish   and launch login activity

User · Answer

It seems a rite of passage that a new Android programmer spends a day researching this issue and reading all of these StackOverflow threads  I am now newly initiated and I leave here trace of my humble experience to help a future pilgrim   First  there is no obvious or immediate way to do this per my research  as of September 2012   You d think you could simple startActivity new Intent this  LoginActivity class   CLEAR STACK  but no   You CAN do startActivity new Intent this  LoginActivity class   with FLAG ACTIVITY CLEAR TOP - and this will cause the framework to search down the stack  find your earlier original instance of LoginActivity  recreate it and clear the rest of the  upwards  stack  And since Login is presumably at the bottom of the stack  you now have an empty stack and the Back button just exits the application   BUT - this only works if you previously left that original instance of LoginActivity alive at the base of your stack  If  like many programmers  you chose to finish   that LoginActivity once the user has successfully logged in  then it s no longer on the base of the stack and the FLAG ACTIVITY CLEAR TOP semantics do not apply     you end up creating a new LoginActivity on top of the existing stack  Which is almost certainly NOT what you want  weird behavior where the user can  back  their way out of login into a previous screen    So if you have previously finish   d the LoginActivity  you need to pursue some mechanism for clearing your stack and then starting a new LoginActivity  It seems like the answer by  doreamon in this thread is the best solution  at least to my humble eye    https   stackoverflow com a 9580057 614880  I strongly suspect that the tricky implications of whether you leave LoginActivity alive are causing a lot of this confusion   Good Luck

User · Answer

on click of Logout you may call this  private void GoToPreviousActivity         setResult REQUEST CODE LOGOUT       this finish        onActivityResult   of previous Activity call this above code again until you finished the all activities

[android] On logout, clear Activity history stack, preventing "back" button from opening logged-in-only Activities

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