I'm pretty new to Angular and I'm using firebase as my backend. I was hoping someone could debug this issue. When I first go to my page www.mywebsite.com/#defaultHash the data doesn't load into the DOM, it does after visiting another hash link and coming back though.
My controller is like this:
/* initialize data */
var fb = new Firebase('https://asdf.firebaseio.com/');
/* set data to automatically update on change */
fb.on('value', function(snapshot) {
var data = snapshot.val();
$scope.propertyConfiguration = data.products;
console.log($scope.propertyConfiguration);
console.log("Data retrieved");
});
/* save data on button submit */
$scope.saveConfigs = function(){
var setFBref = new Firebase('https://asdf.firebaseio.com/products');
setFBref.update($scope.propertyConfiguration);
console.log("configurations saved!");
};
I have 3 hash routes say "Shared", "Registration", and "Home" with otherwise.redirectTo set to "Shared".(They all use this controller) Here's the error that occurs: (all "links" are href="#hashWhereever")
1) Go to website.com/#Shared or just refresh. Console logs $scope.propertyConfiguration and "Data Retrieved". DOM shows nothing.
2) Click to website.com/#Registration, console logs $scope data properly, DOM is loaded correctly.
3) Click back to website.com/#Shared, console logs $scope data properly yet this time DOM loads correctly.
4) Refresh currently correctly loaded website.com/#Shared. DOM elements disappear.
Since $scope.data is correct in all the cases here, shouldn't Angular make sure the DOM reflects the model properly? Why is it that the DOM loads correctly only when I am clicking to the page from another link.
I can "fix" it by adding window.location.hash = "Shared" but it throws a huge amount of errors in the console.
FIXED:(sorta)
The function $scope.$apply() forces the view to sync with the model. I'd answer this question myself and close it but I'm still wondering why the view doesn't load correctly when I correctly assign a value to $scope. If Angular's "dirty checking" checks whenever there is a possibility the model has changed, doesn't assigning a value to $scope overqualify?
Angular has no way to know you've assigned a value to $scope.variable. There's no magic here. When you run a directive (ng-click/ng-submit) or Angular internal functions, they all call $apply() and trigger a digest (a check of the dirty flags and update routine).
A possibly safer approach than $apply would be to use $timeout. Currently, if you call a write op in Firebase, it could synchronously trigger an event listener (child_added, child_changed, value, etc). This could cause you to call $apply while still within a $apply scope. If you do this, an Error is thrown. $timeout bypasses this.
See this SO Question for a bit more on the topic of digest and $timeout.
This doc in the Angular Developer Guide covers how compile works; very great background read for any serious Angular dev.
Also, you can save yourself a good deal of energy by using the official Firebase bindings for Angular, which already take all of these implementation details into account.
Vaguely Related Note: In the not-too-distant future, Angular will be able to take advantage of Object.observe magic to handle these updates.
Related
While transitioning an existing angular site, I encountered an annoying problem. The initial symptom was that a certain controller was not running it's initialize function immediately following the login. I logged and I tracked, and eventually I realized it was a design flaw of the page. Essentially, index.html contains a <header>, <ng-view>, and <footer>. There are a couple of ng-if attributes that live in the header that I want to evaluate after the login, but since the view is the only thing that is reloaded, it was not reinitializing the header controller, and thus not updating the ng-if values.
Then I was reminded of ngInclude, which seems like the perfect solution, until I got it hooked up and realize that doesn't work either. It loads the template the first time, and doesn't reinitialize when the view changes. So then I got the bright idea of passing the HeaderController to another controller or service, and controlling this one stubborn boolean value through a proxy of sorts. That also didn't work. Then I tried putting a function and a boolean into another service, and mirroring that property in the header controller, but thus far I have not gotten this working.
I have done plenty of research about multiple views in the index, and so far I hear a lot about this ui-router, but I'm still not convinced that is the way I want to go. It does not seem to be a simple solution. I have not tried putting the ng-include into the templates yet either, because then I feel like that is going back in time to when we had to update 100 pages every time we changed the menu.
I lost a whole day to this. If anyone could tell me how to trigger the evaluation of this one property in my header controller which I would like to live outside the other templates, please let me know!
Ok so you need to know in your HeaderController when the view has reloaded. There's a number of ways of doing this but the easier and maybe the more correct in this particular case is with an event.
So when you are refreshing the view you just do this, let's say you need the new value of ob1 and ob2 variables.
// ViewController
$rootScope.$emit('viewRefresh', {ob1: 'newvalue1', ob2: 'newvalue2'});
And in your HeaderController you need to listen for that event, and set on your $scope the new values for those attrs (if you're not using controller as syntax).
// HeaderController
$rootScope.$on('viewRefresh', function onRefresh(event, data) {
$scope.ob1 = data.ob1;
$scope.ob2 = data.ob2;
})
Another Solution
Sharing a Promise through a Service (using $q)
function HeaderService($q) {
var defer = $q.defer();
return {
getPromise: function() {return defer.promise},
notify: function(data) {defer.notify(data)}
}
}
function HeaderController(HeaderService) {
var vm = this;
HeaderService.getPromise().then(function(data) {
vm.ob1 = data.ob1;
vm.ob2 = data.ob2;
})
}
function ViewController(HeaderService) {
var data = {ob1: 'newvalue1', ob2: 'newvalue2'};
HeaderService.notify(data)
}
I have created a sidemenu based app, in that after login I am displaying a number of tasks. If I click on the task it will redirect to the task details page, in that page I can update the tasks.
So after updating a task I need to go back to the previous task list page. I am using $ionicHistory.goBack(); to go back.
My problem is after come back, I need to refresh the task list i.e. updated task should not be there in the task list. How can I refresh/reload the task list?
If you bind your task to a tasks array, which will be used in the task list page, it should be automatically updated.
But the question is about not displaying, newly added tasks (still my previous suggestion should work) if not, performance reasons ionic views are cached, So when you come back to the previous view it doesn't go through the normal loading cycle. But you 2 options
1 - disable the caching by using <ion-view cache-view="false" view-title="My Title!"> in your ion-view, but this is not a very elegant solution. read more
2 - use ionRefresher (my preferred). read more here
https://github.com/angular-ui/ui-router/issues/582
according to #hpawe01 "If you are using the current ionicframework (ionic: v1.0.0-beta.14, angularjs: v1.3.6, angular-ui-router: v0.2.13), the problem with the not-reloading-controller could be caused by the new caching-system of ionic:
Note that because we are caching these views, we aren’t destroying scopes. Instead, scopes are being disconnected from the watch cycle. Because scopes are not being destroyed and recreated,controllers are not loading again on a subsequent viewing.
There are several ways to disable caching. To disable it only for a single state, just add cache: false to the state definition.
This fixed the problem for me (after hours of reading, trying, frustration).
For all others not using ionicframework and still facing this problem: good luck!"
Hope this helps.
You can also listen to ionic events such as $ionicView.enter on $scope and trigger the code that refreshes the list if you haven't bound your list as #sameera207 suggested.
EG:
// List.controller.js
angular.module('app')
.controller('ListController', ['$scope', function($scope) {
// See http://ionicframework.com/docs/api/directive/ionView/ for full events list
$scope.$on('$ionicView.enter', function() {
_someCodeThatFetchesTasks()
.then(function(tasks) {
$scope.tasks = tasks;
});
});
});
Bear in mind that it's not the most proper way (if proper at all) and if you do this you certainly have a design flaw. Instead you should share the same data array via a factory or a service for example.
For your task you can also use ion-nav-view.
It is well documented. And if you are using now Ionic 2 beta you can use some of the view lifecyle hooks like onPageWillLeave() or onPageWillEnter(). I just faced the same problem and defined a refresh() function, but the user had to click on a button to actually update the view. But then I found:
https://webcake.co/page-lifecycle-hooks-in-ionic-2/
You just have to import the Page and NavController module and also define it in the constructor. The you can use for example onPageWillEnter(), which will always invoke when you go again to a view:
onPageWillEnter() {
// Do whatever you want here the following code is just to show you an example. I needed it to refresh the sqlite database
this.storage.query("SELECT * FROM archivedInserates").then((data) = > {
this.archivedInserates =[];
if (data.res.rows.length > 0) {
for (var i = 0; i < data.res.rows.length; i++) {
this.archivedInserates.push({userName:data.res.rows.item(i).userName, email:
data.res.rows.item(i).email});
}
}
},(error) =>{
console.log("ERROR -> " + JSON.stringify(error.err));
});
}
With ionic beta 8 the lifecylcle events changed their names. Check out the official ionic blog for the full list of the lifecycle events.
if you are building data driven app then make sure use $ionicConfigProvider.views.maxCache(0);in your app.config so that each review can refresh for more details read this http://ionicframework.com/docs/api/provider/$ionicConfigProvider/
Background:
I am building my offline application which uses AngularJS for UI and PocuhDB for locally storing the data retrieved from the server.
Issue:
The data retrieved from PouchDB is not getting rendered in the UI.
Controller:
$scope.retrieveView = function (sys, code, majorVer, minorVer) {
var promise;
promise = dataService.getDataFromLocalDb().then(
function(dataFromPouchDb){
$scope.data = dataFromPouchDb.data;
});
return promise;
}
And then in the UI code I have the following :
<h1> {{data}}</h1>
I have debugged the code and everything seem to work fine. But the data is not getting displayed in the UI.
If I hard code a value to the data field then its getting rendered in the UI
$scope.data ="TEST";
This question is kind a old but I just came around it.
Issue is that Angularjs is based on so called digest cycles. When your model or view is changed digest cycle is triggered, watch for changes and update model or view respectively. It is so called two way data binding.
This digest cycle is not triggered periodically on some time base but on events instead. Those events are angular directives like ng-click, ajax calls $http or some other angular events like $timeout. You can find more information about digest here.
In general you should use those things when working with angular application to avoid such situations. In some cases its not possible however like in your case when getting data from DB. Digest cycle is not triggered and your view is not updated by angular.
Workaround for this is manually trigger $digest cycle. Way you have described:
if(!$scope.$$phase) {
$scope.$digest();
}
is working but considered as angular anti-patern and is discouraged by angular team, you should use:
$timeout();
instead. For more information see this answer.
I would maybe consider adding $timeout() call to hook for insert, update, delete hooks or events. Maybe pouchDB sync could be helpfull there.
The code you show seemed correct, maybe you can use console.log() to track the progress of the data. I think the problem might not in this layer. Maybe in the area where you wrapped getDataFromLocalDb(), track and find if the data have transfer to here, or where it disappeared.
The code started to work when i added the following :
if(!$scope.$$phase) {
$scope.$digest();
}
But i have no idea what magic does this code do.
It would be a great help if some some could advice.
The complete code that works now is :
$scope.retrieveView = function (sys, code, majorVer, minorVer) {
var promise;
promise = dataService.getDataFromLocalDb().then(
function(dataFromPouchDb){
$scope.data = dataFromPouchDb.data;
if(!$scope.$$phase) {
$scope.$digest();
}
});
return promise;
}
I'm using the ocModal directive + service (https://github.com/ocombe/ocModal). When someone wants to delete a record they click the delete button which pops up, via ocModal, a modal to confirm.
oc-modal-close ng-click="deleteNote(id)"
So far so good. Within the controller deleteNote runs. Console.log shows the argument is the id I passed. I call an API to delete the note from my database and on a success call a function to delete the note from the Angular variable $scope.notes.
$scope.removeNote = function(id){
console.log(id);
console.log($scope.notes);
delete $scope.notes[id];
console.log($scope.notes);
};
The id is correct and the $scope.notes after the delete command shows it was correctly deleted. Yet, there is no corresponding update on my front-end. Following advise I've seen on Stackover I used apply() which led to a 'digest cycle already in progress' error. I then tried to use $timeout but while that got rid of the digest cycle error, it didn't solve the problem of the bind.
Is it relevant that the $scope.notes is used by a ng-repeat that then uses a directive? I've experimented a bit and don't think so, but just in case wanted to mention it.
Where are you calling $scope.removeNote from? Is it from your main controller or in the modal's controller? maybe a directive?
It feels like it is hitting the wrong scope. You can try to move notes to $scope.model.notes and see if it helps, as it will ensure the correct scope is referenced, but it's hard to say unless you try and provide a fiddle with the issue occurring.
I've created this simple fiddle trying to mimic an API call with $timeout and it works -> http://jsfiddle.net/7eqsc/1/
angular.module('myApp',[])
.controller('myCtrl',function($scope,$timeout){
$scope.notes={
a:'AngularJS',
b:'Rocks'
}
$scope.addRandom=function(){
$scope.notes[parseInt(Math.random()*10000).toString(36)]='New Item';
}
$scope.removeNote=function(id){
//emulate API call
$timeout(function(){
delete $scope.notes[id];
},2000);
}
});
In general, I recommend placing things under an object, such as ".model.yourArray", it ensures references are kept correctly and will save you a lot of trouble.
I've been following this tutorial http://draptik.github.io/blog/2013/07/28/restful-crud-with-angularjs/. I implemented a Grails backend with it instead of the Java one in the tutorial.
I've got the data coming back and forth, with one issue. If I create/update/delete a user, I don't see the changes reflected on my user list when I am redirected back. I have to refresh the page to see the updates.
Looking at the network traffic for an edit, it looks like it does a PUT and fires off the GET before the PUT is complete. Assuming this is because $resource returns a promise so things can be done asynchronously. So how do I handle this so that when $location redirects me, my list is up to date?
I'm guessing the options are to wait for the PUT to complete before redirecting/querying for the list, or to somehow manually manage the $scope.users to match the request?
Or maybe this tutorial is just a bad example? Maybe there is a better way to do it (still using $resource)?
Note: I've seen Restangular out there, and I've seen $http with success callbacks, but I would like to understand the situation above.
One way to overcome this issue would be to not redirect to the list page, till you get a callback, and then do a redirect. You can show some busy indicator till that time. The resource call looks like this.
resource.update(config,data,function() { //gets called on success},
function(error) { //gets called on failure});
In real life scenario waiting for the response of update makes sense as you want to handle the error and success scenarios on the same page.
I don't see your code anywhere so i'm just assuming (based on what you wrote and your current problem)
You are probably doing a full (or partial) get each time you changed a user and (re)binding the result to your scope. Doing this in the callback of the resource should actually start the digest cycle angular does to update modified objects. If you had been doing the fetching outside $resource - for example with custom/jquery ajax you would need to execute $scope.$apply()
What i really don't understand you would need to wait for the callback. You already know you added/modified a user. Instead of 'detaching' that user from your scope, modify it, post it to your rest server, then wait for callback, and reinserting it into the scope - why not modify it directly in the list/array you put on your scope?
var users = Users.get(function () {
$scope.users = users.record; // bind the resulting records to the scope
});
$scope.updateUser = function (user) {
resource.update(...); //pseudo
};
Then in your html, you will keep a reference to the currentUser and the div-list will update automaticly.
<div ng-repeat="user in users" ng-click="currentUser=user">{{user.Name}}</div>
<input ng-model="currentUser.Name">
<button ng-click="updateUser(currentUser);">Update</button>
If you don't want to see the update in the list while you type, but only once your callback fires or when you hit the button, would would instead use another ng-model for your input like this:
<input ng-model="tempUser.Name">
And you would then copy the value other in either the updateUser method or in the resource callback like this:
$scope.updateUser = function (user) {
user.Name = $scope.tempUser.Name; // should update automaticly
resource.update(...) // pseudo
}
Hope it helped!