Ionic2 App Exit Event

 Import {Component, viewchild} from ' @angular/core ';
 Import {Platform, Toastcontroller, Nav, Ionicapp} from ' Ionic-angular ';
 Import {StatusBar, splashscreen} from ' ionic-native '; Import {tabspage} from '.

 /pages/tabs/tabs ';
   @Component ({templateurl: ' app.html '}) Export class MyApp {rootpage = tabspage;  Backbuttonpressed:boolean = false;

   Used to determine whether the return key triggers a @ViewChild (' Mynav ') Nav:nav; Constructor (public Ionicapp:ionicapp, public platform:platform, public Toastctrl:toastcontroller) {Platform.ready
       (). Then (() = {Statusbar.styledefault ();
       Splashscreen.hide ();
   This.registerbackbuttonaction ();//Register Return key event}); } registerbackbuttonaction () {this.platform.registerBackButtonAction () = {//If you want to click the Back button to hide toast or loadin G or overlay Add the following//This.ionicapp._toastportal.getactive () | | This.ionicapp._loadingportal.getactive () | | This.ionicapp._overlayportal.getactive () Let activeportal = This.ionicapp._modalportaL.getactive ();
         if (activeportal) {Activeportal.dismiss (). catch (() = {});
         Activeportal.ondiddismiss (() = {});
       Return
       } Let Activevc = This.nav.getActive ();
       let tabs = ActiveVC.instance.tabs;
       Let Activenav = tabs.getselected (); Return Activenav.cangoback ()?
   Activenav.pop (): This.showexit ()}, 1); }//Double exit cue box Showexit () {if (this.backbuttonpressed) {//When the trigger flag is true, that is, 2 seconds to double-click the Back button to exit the app This.platform.exi
     TAPP ();
       } else {this.toastCtrl.create ({message: ' Press again to exit the app ', duration:2000, Position: ' Top '
       }). present ();
       This.backbuttonpressed = true; SetTimeout (() = This.backbuttonpressed = False, 2000);//2 seconds without a second click Back to mark the trigger flag as false}