var myPopup = $ionicPopup.show({
template: '<input type="password" ng-model="data.wifi">',
title: 'Enter Wi-Fi Password',
subTitle: 'Please use normal things',
scope: $scope,
buttons: [
  { text: 'Cancel' },
  {
    text: '<b>Save</b>',
    type: 'button-positive',
    onTap: function(e) {
      if (!$scope.data.wifi) {
        //don't allow the user to close unless he enters wifi password
        e.preventDefault();
      } else {
        return $scope.data.wifi;
      }
    }
  }
]
});

myPopup.close();