ionic 双击退出

$ionicPlatform.registerBackButtonAction(function (e) {//双击退出  //判断处于哪个页面时双击退出  if ($location.path() == '/homepage' || $location.path() == '/login') {    if ($rootScope.backButtonPressedOnceToExit) {      ionic.Platform.exitApp();    } else {      $rootScope.backButtonPressedOnceToExit = true;      $cordovaToast.showShortBottom('再按一次退出系统');      setTimeout(function () {        $rootScope.backButtonPressedOnceToExit = false;      }, 2000);    }  }  else if ($ionicHistory.backView()) {    $ionicHistory.goBack();  } else {    $rootScope.backButtonPressedOnceToExit = true;    $cordovaToast.showShortBottom('再按一次退出系统');    setTimeout(function () {      $rootScope.backButtonPressedOnceToExit = false;    }, 2000);  }  e.preventDefault();  return false;}, 101);