android - Exit App on Back Button Press not working -

i application quit if user presses @ activity. following code activity.

public class mainactivity extends fragmentactivity implements denkolistfragment.listselectlistener {      private slidingmenu menu;      @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_main);          displayview(0);          menu = new slidingmenu(this);         menu.settouchmodeabove(slidingmenu.touchmode_fullscreen);         menu.setshadowwidthres(r.dimen.shadow_width);         menu.setshadowdrawable(r.drawable.shadow);         menu.setbehindoffsetres(r.dimen.slidingmenu_offset);         menu.setfadedegree(0.35f);         menu.attachtoactivity(this, slidingmenu.sliding_content);         menu.setmenu(r.layout.menu_frame);          menu.setselected(true);          getsupportfragmentmanager()                 .begintransaction()                 .replace(r.id.menu_frame, new denkolistfragment())                 .commit();     }      private void displayview(int position) {          fragment fragment = null;         switch (position) {             case 0:                 fragment = new mainviewfragment();                 break;             case 1:                 fragment = new stationviewfragment();                 break;             case 2:                 fragment = new mapviewfragment();                 break;              default:                 break;         }          if (fragment != null) {             fragmentmanager fragmentmanager = getsupportfragmentmanager();             fragmentmanager.begintransaction()                     .replace(r.id.content_frame, fragment).commit();         } else {          }     }      @override     public void select(int index) {         displayview(index);         menu.showcontent();     }      @override     public void onbackpressed() {         if (menu.ismenushowing()) {             menu.showcontent();         } else {             new alertdialog.builder(this).seticon(android.r.drawable.ic_dialog_alert).settitle("exit")                     .setmessage("are sure want exit?")                     .setpositivebutton("yes", new dialoginterface.onclicklistener() {                         @override                         public void onclick(dialoginterface dialog, int which) {                             finish();                             system.exit(0);                         }                     }).setnegativebutton("no", null).show();         }     }  } 

it takes app 2 presses (and 2 confirmations) exit. explains behaviour , there way resolve this?

remove below snippet onbackpress() method. handle slidemenu only.

if (menu.ismenushowing()) {      menu.showcontent(); } 

code slidingfragmentactivity call onbackpress:

@override public boolean onkeyup(int keycode, keyevent event) {     boolean b = mhelper.onkeyup(keycode, event);     if (b) return b;     return super.onkeyup(keycode, event); }  

mhelper.onkeyup(keycode, event) call method of slidingactivityhelper:

public boolean onkeyup(int keycode, keyevent event) {     if (keycode == keyevent.keycode_back && mslidingmenu.ismenushowing()) {         showcontent();   //close slidingmenu , show content view.         return true;     }     return false; }