Exit application from android hardware back button in phonegap

Is there a way to show a confirmation popup when you press the hardware back button in android devices to exit the phonegap/ionic application? In the current status,my app keep going to the previous state upon clicking the back button.Is there a way to exit the app when you press the back button no matter where you are on,in the application?

I found this piece of code but it did not seem to work

 $ionicPlatform.registerBackButtonAction(function () {

                                             var confirmPopup = $ionicPopup.confirm({
                                                                                    title: 'Sign Out Confirm',
                                                                                    template: 'Are you sure you want to Logout?'
                                                                                    });
                                             confirmPopup.then(function(res) {
                                                               if(res) {
                                                               $rootScope.rootScopeUserTransactionPassword = null;
                                                               $state.go('app.playlists');
                                                               } else {
                                                               console.log('You are not sure');
                                                               }
                                                               });


                                             }, 100);

Thanks in advance!!

It is pretty simple dude. Just try this:

document.addEventListener('backbutton', function(event){
  event.preventDefault(); // EDIT
  navigator.app.exitApp(); // exit the app
});

I hope it helps you.