View is not refreshed after $scope is updated in Firebase promise - angularjs

Question

I am using Ionic Framework and Firebase is my BaaS.
Controller:
.controller('ProfileCtrl', function($scope, AuthService, DatabaseService) {
console.info('** ProfileCtrl **');
var user = firebase.auth().currentUser;
$scope.public = {};
DatabaseService.getUserPublicInfo(user.uid)
.then(function(infoSnap) {
infoSnap.forEach(function(item) {
$scope.public[item.key] = item.val();
});
});
})
Service:
.service('DatabaseService', function($q) {
this.getUserPublicInfo = function(uid) {
return firebase.database().ref('/users/'+uid+'/public/').once('value');
}
}
In my HTML view I have the following:
<div><h3>{{public.firstname}} {{public.lastname}}</h3></div>
No error and when debugging, $scope.public.firstname as the correct value in it but nothing is displayed.
I have a button in my HTML view ; when I click on it, it changes page but just before page switches, I see the firstname appearing. When I go back to my view, the firstname is well displayed.
I tried to wrap getUserPublicInfo in $scope.$apply() in my controller but I get the "$digest already in progress" error...
Please, help, it's driving me crazy !
Thanks in advance

Answer 1

To resove, "$digest already in progress" error... put $scope .$appy inside timeout service.
DatabaseService.getUserPublicInfo(user.uid)
.then(function(infoSnap) {
infoSnap.forEach(function(item) {
$scope.public[item.key] = item.val();
$timeout(function(){
$scope.$apply()
},1)
});
});
Edit 1: Try this to avoid using $scope.$apply(). I haven't tested it. But it should work.
DatabaseService.getUserPublicInfo(user.uid)
.then(function(infoSnap) {
$scope.updatePublic(infoSnap)
});
});
$scope.updatePublic = function (infoSnap) {
infoSnap.forEach(function(item) {
$scope.public[item.key] = item.val();
})
}

Answer 2

I used $q to create a promise. By doing the initial Firebase promise is resolved within the Angular scope:
this.getUserPublicInfo = function(uid) {
console.info('getUserPublicInfo - get user public information for uid: '+uid);
var deferred = $q.defer();
firebase.database().ref('/users/'+uid+'/public/').once('value')
.then(function(snap) {
deferred.resolve(snap);
})
.catch(function(error) {
deferred.reject(error);
});
return deferred.promise;
}