I have one main activity "Dashboard" with a action bar containing home screen icon and exit button , i go to activity A -activity B -activity C from dashboard screen . Now on C, i click on action bar dashboard icon which bring to me on Dashboard screen .
Now i go to activity E -activity G-activity H from dashboard screen . From H i press exit button , it come to C screen . When  again click on exit i go through me out of application.
Why there is need to press 2 times exit button for exit application .
On Home Screen Icon :-
    public void onClickHome(View view){
    final Intent intent = new Intent(getBaseContext(), Dashboard.class);
    intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);    
    intent.setFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);   
    getBaseContext().startActivity(intent);     
    //goDashboard();
                           }
ON exit button :-
    AlertDialog.Builder alert = new AlertDialog.Builder(this);      
    alert.setTitle(getString(R.string.logoutDialogTitle));
    alert.setMessage(getString(R.string.logoutDialogMessage));
    final OnlineBookApp app = (OnlineBookApp) getApplicationContext();
    alert.setPositiveButton(getString(R.string.logoutDialogCancel), new
              DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int whichButton) {      
                               }
                          });
    alert.setNegativeButton(getString(R.string.logoutDialogOk),
            new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int whichButton) {  
            //finish();
            //stopService(new Intent(getBaseContext(), DatabaseSyncService.class));
                      //                
                  //    moveTaskToBack(true);
                 ////  stopService(new Intent(getBaseContext(),
                        DatabaseSyncService.class));
                    //  System.runFinalizersOnExit(true);
                    //  android.os.Process.killProcess(android.os.Process.myPid());
                      //moveTaskToBack(true);
                  //    finish();
                       //   app.SetIsExit(true);
    Intent intent = new Intent(getApplicationContext(), Dashboard.class);
            intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
            intent.setFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);
            intent.putExtra("EXIT", true);
            startActivity(intent);
                            }
                                         });
    alert.setNeutralButton(getString(R.string.logoutDialogLogout), new
              DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int whichButton) {      
            //finish();
            //stopService(new Intent(getBaseContext(),
                                DatabaseSyncService.class));
            //finish();
            //app.SetIsExit(true);
            //stopService(new Intent(getBaseContext(),
                                  DatabaseSyncService.class));
            app.logout();
            Intent intent = new Intent(getApplicationContext(),
                               Dashboard.class);
            intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP); 
            intent.setFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);
            intent.putExtra("EXIT", true);
            startActivity(intent);
                              }
                               });
                    alert.show();