Cannot get the value

Hello, I am new to this platform. What I am trying to do is that when I click on the login button, it will check username and password input areas if they are empty or not. If they are empty a popup will appear, if not screen will navigate to next page. But when I try neither of them happens. Here is my code;

HTML;

<div ng-app="" ng-controller="PopupCtrl" class="list">
                <label class="item item-input">
                    <span class="input-label">Kullanıcı Adı</span>
                    <input ng-model="username" type="text">
                </label>
                <label class="item item-input">
                    <span class="input-label">Şifre</span>
                    <input ng-model="password" type="password">
                </label>
            </div>
            <center>
               <a ng-app="" ng-controller="PopupCtrl" class="button size icon-right ion-log-in headerColor title headerTitle" 
                  ng-click="ChechIsEmpty()">GİRİŞ</a>
            </center>

JS;

app.controller('PopupCtrl',function($scope, $ionicPopup, $timeout) {
    $scope.ChechIsEmpty = function () {

        if ($scope.username == "" || $scope.password == ""){
            var alertPopup = $ionicPopup.alert({
                 title: 'Yetersiz Bilgi!',
                 template: 'Kullanıcı adı veya şifrenizi kontrol ediniz.'})
        }
        else
            $state.go('#/templates/second');
    }
});

What am I doing wrong?

I have the same problem… I don’t know what i’m doing wrong