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Reading OData contexts in onInit of controller

I've tried to prepare data from an OData source to show it in a bar graph in my fiori app. For this, I setup the OData model in the manifest.json. A test with a list, simply using
items="{path : 'modelname>/dataset'}
works fine and shows the content.
To prepare data for a diagram (VizFrame), I used the onInit() function in the controller of the view (mvc:XMLView). The data preparation is similar to the one discussed in question.
At first I obtain the ODataModel:
var oODataModel = this.getOwnerComponent().getModel("modelname");
Next I do the binding:
var oBindings = oODataModel.bindList("/dataset");
Unfortunately, the oBindings().getContexts() array is always empty, and also oBindings.getLength() is zero. As a consequence, the VizFrame shows only "No Data".
May it be that the data model is not fully loaded during the onInit() function, or do I misunderstand the way to access data?
Thanks in advance
Update
I temporary solved the problem by using the automatically created bind from the view displaying the data as list. I grep the "dataReceived" event from the binding getView().byId("myList").getBindings("items") and do my calculation there. The model for the diagram (since it is used in a different view) is created in the Component.js, and registered in the Core sap.ui.getCore().setModel("graphModel").
I think this solution is dirty, because the graph data depends on the list data from a different view, which causes problems, e.g. when you use a growing list (because the data in the binding gets updated and a different range is selected from the odata model).
Any suggestions, how I can get the odata model entries without depending on a different list?

The following image outlines the lifecycle of your UI5 application.
Important are the steps which are highlighted with a red circle. Basically, in your onInit you don't have full access to your model via this.getView().getModel().
That's probably why you tried using this.getOwnerComponent().getModel(). This gives you access to the model, but it's not bound to the view yet so you don't get any contexts.
Similarly metadataLoaded() returns a Promise that is fullfilled a little too early: Right after the metadata has been loaded, which might be before any view binding has been done.
What I usually do is
use onBeforeRendering
This is the lifecycle hook that gets called right after onInit. The view and its models exist, but they are not yet shown to the user. Good possibility to do stuff with your model.
use onRouteMatched
This is not really a lifecycle hook but an event handler which can be bound to the router object of your app. Since you define the event handler in your onInit it will be called later (but not too late) and you can then do your desired stuff. This obviously works only if you've set up routing.

You'll have to wait until the models metadata has been loaded. Try this:
onInit: function() {
var oBindings;
var oODataModel = this.getComponent().getModel("modelname");
oODataModel.metadataLoaded().then(function() {
oBindings = oODataModel.bindList("/dataset");
}.bind(this));
},

May it be that the data model is not fully loaded during the onInit()
function, or do I misunderstand the way to access data?
You could test if your model is fully loaded by console log it before you do the list binding
console.log(oODataModel);
var oBindings = oODataModel.bindList("/dataset");
If your model contains no data, then that's the problem.

My basic misunderstanding was to force the use of the bindings. This seems to work only with UI elements, which organize the data handling. I switched to
oODataModel.read("/dataset", {success: function(oEvent) {
// do all my calculations on the oEvent.results array
// write result into graphModel
}
});
This whole calculation is in a function attached to the requestSent event of the graphModel, which is set as model for the VizFrame in the onBeforeRendering part of the view/controller.

Ionic and Angularjs - Update/Refresh View from Controller

The usual start to these, I am new to both Ionic and Angularjs. I am developing an Ionic app which at it's heart is very simple. We show a list of classes(sessions), the person clicks on an icon to book the class then the icon changes to allow them to cancel the class. We also update the card to show the number of places remaining in each session on the day.
I have the code working to add and remove a person to and from a class but I am not sure how to update the template view from within the controller.
The controller code is pretty simple
// Check Person in to session.
$scope.addCheckIn = function(schedule){
var promise = sessionDataService.checkinSession(schedule.sessionID);
promise.then(function(data){
// Update (refresh) Schedule Details
// NOT SURE WHAT TO PUT HERE??
});
};
I have tried a number of different approaches including
Refreshing the $state and calling doRefresh and even calling the original controller methods to populate the cards again but the view won't update unless I physically click between states on the screen
//$state.go('app.schedules', {}, {reload: true});
//$scope.doRefresh();
//getScheduleData(formatDate(selectedDate), formatDate(selectedDate), 'true');
I have also looked at $scope.apply and $scope.timeout but I am not sure if this is taking me further from the real solution
What is the correct way to update the view after an update? Should it be after the promise.then in the controller or should I call a service and update everything.
Any tips on what is the best way to do this and a point in the right would be really appreciated.
Thanks everyone.

In your promise, you should add the data to the scope.
$scope.scheduledetails = data;
Then in your template, you will be able to access the object scheduledetails from the controller with AngularJS brackets to bind the data to the HTML.
<h1>{{scheduledetails.title}}</h1>
<p>Details : {{scheduledetails.details}}</p>
AngularJS should take care of refreshing what is needed without having to call any method or anything.
Full example
Controller
$scope.addCheckIn = function(schedule){
var promise = sessionDataService.checkinSession(schedule.sessionID);
promise.then(function(data){
$scope.scheduledetails = data;
});
};
Template
<h1>{{scheduledetails.title}}</h1>
<p>Details : {{scheduledetails.details}}</p>

RiotJS - How to pass events between subtags using Observable pattern?

Im not really sure if Im understanding correctly the way observables work and how to get references from mounted tags. I have a component. Within this component we have a component and a component. The purpose is to avoid coupling between components. Because of that, I would like that my search component triggers an event when a search is done(a button is clicked). This event should be caught by the component which will filter the collection data based on the search.
The index.html file load the tag by using:
index.html
riot.mount(".content", "page", null);
The page is defined as follow:
page.js
<page>
<!-- Search tag controls -->
<search id="searchTag"></search>
<!-- Collection data to display -->
<collection id="collectionTag"></collection>
</page>
The component script is briefly defined like:
search.js
var self = this;
riot.observable(self);
<!-- This function is called when the user click on the button. -->
self.filtering = function()
{
<!-- We get data from inputs -->
var info = Getting data from inputs;
<!-- Trigger the event hoping that someone will observe it -->
self.trigger("filterEvent", info);
}
How can I make the component observe for that event?
To me it seems that I should be able to get references from search tag and collection tag in the page.js. By doing so I could connect the events like follow:
searchComponent = riot.mount('search');
collectionComponent = riot.mount('collection');
searchComponent.on('filterEvent', function()
{
<!-- Trigger function to filter collection data -->
collectionComponent.trigger('filterData');
});
Right now I cannot make it work like that.
At the point of execution, searchComponent and collectionComponent are not defined.
I tried also getting references of these component by using this.searchTag and this.collectionTag instead of mounting them but at the time the code is executed, the components have not been mounted and so I dont get a reference to them.
Any ideas to make it work?

Inspired by the answer given by #gius, this is now my preferred method for sending events in RiotJS from one tag to another.. and it is great to work with!
The difference from #gius approach being that, if you use a lot of nested tags, passing a shared Observable to each tag falls short, because you would need to pass it again and again to each child tag (or call up from the child tags with messy this.parent calls).
Defining a simple Mixin, like this (below), that simply defines an Observable, means that you can now share that in any tag you want.
var SharedMixin = {
observable: riot.observable()
};
Add this line to your tags..
this.mixin(SharedMixin);
And now, any tag that contains the above line can fire events like..
this.observable.trigger('event_of_mine');
..or receive events like this..
this.observable.on('event_of_mine',doSomeStuff());
See my working jsfiddle here http://jsfiddle.net/3b32yqb1/5/ .

Try to pass a shared observable to both tags.
var sharedObservable = riot.observable();
riot.mount('search', {observable: sharedObservable}); // the second argument will be used as opts
riot.mount('collection', {observable: sharedObservable});
And then in the tags, just use it:
this.opts.observable.trigger('myEvent');
this.opts.observable.on('myEvent', function() { ... });
EDIT:
Or even better, since your search and collection tags are child tags of another riot tag (page) (and thus you also don't need to mount them manually), you can use the parent as the shared observable. So just trigger or handle events in your child tags like this:
this.parent.trigger('myEvent');
this.parent.on('myEvent', function() { ... });

Firstly I do not understand your file structure !
In your place I would change filenames :
page.js --> page.tag
search.js --> search.tag
And i dont see your search tag in search.js code.
So I dont see your Collection tag file ...
Are you sure that this one use this code ?
riot.observable({self|this});
Because it's him who will receive an Event.
For me when I use Riot.js(2.2.2) in my browser, if I use
searchComponent = riot.mount('search');
searchComponent will be undefined
But with this code you can save your monted tag reference :
var searchComponent ={};
riot.compile(function() {
searchComponent = riot.mount('search')[0];
});

Another option is to use global observables, which is probably not always best practice. We use Riot's built in conditionals to mount tags when certain conditions are met rather than directly mounting them via JS. This means tags are independent of each other.
For example, a single observable could be used to manage all communication. This isn't a useful example on its own, it's just to demonstrate a technique.
For example, in a plain JS file such as main.js:
var myApp = riot.observable();
One tag file may trigger an update.
var self = this;
message = self.message;
myApp.trigger('NewMessage', message);
Any number of other tag files can listen for an update:
myApp.on('NewMessage', function(message) {
// Do something with the new message "message"
console.log('Message received: ' + message);
});

Maybe overkill but simple. let riot self observable
riot.observable(riot);
So you can use
riot.on('someEvent', () => {
// doing something
});
in a tag, and
riot.trigger('someEvent');
in another.
It's not good to use global variable, but use an already exists one maybe acceptable.

Circular dependencies in JavaScript OOP

// Main class
function App() {
this.task = new Task(this); // pass the instance of this class to Task so
// it has access to doSomething
}
App.prototype.doSomething = function () {
alert("I do something that Task() needs to be able to do!");
};
function Task(app) {
// This class needs access to App()'s doSomething method
this.appInstance = app;
this.appInstance.doSomething(); // Great, now Task can call the method
}
var app = new App();
The aim of the code above is to give Task access to one of App's methods called doSomething. The code is the current way I'd go about it and I'm posting this to see if it's the best way...
To give Task access I simply pass the whole instance of App, is this efficient or is there a better way to go about it? Is the code above general practice in going about doing something like this?

Yes, what you have is fine. It is a circular dependency, however because of JavaScript's dynamic nature there aren't really any issues.
Another way you could reference App from Task would be a Singleton pattern or something similar, but that would probably be harder to test.

jsFiddle Demo
Generally bind would be used in this scenario assuming that the Task "class" didn't also setup other facilities which were not shown here.
Bind allows for the context to be provided for a function. This could be done in app's constructor. At which point only a function task would be required to call "someMethod".
function task(){
return this["someMethod"]();
}
function App(){
task.bind(this)();
}
App.prototype.someMethod = function(){
alert("Task needed access to this");
};
var a = new App();
However, if task must be a "class", and have other responsibilities then the prototype function could be shared.
function Task(){}
function App(){}
App.prototype.someMethod = Task.prototype.someMethod = function(){
alert("Task needed access to this");
};
var a = new App();
a.task();//->"Task needed access to this"
var t = new Task();
t.someMethod();//->"Task needed access to this"

Your app instances and task instances are tightly bound. App instances have tasks and this can be fine.
A design of loosely coupled objects is more flexible and easier to extend but more complicated to initially create. One such pattern is using a mediator/publish subscriber and have app raise an event/publish message any other object function can listen to this and take action on the event.
For example: your app creates an Ajax instance and when that instance is done it raises some event (fetchedData for example). A listener could be DomDependent.updateView function but later you may want to add/remove/change the order of tasks to do after data is fetched. This can all be configured in a app.init function or per procedure in a controller that kicks of certain procedures (like log in, search, ...).
Instead of creating a whole bunch of specific functions in Ajax (fetchUserPrefs, login, search, ...) you can create one general function and have the controller add listeners or pass the next event when fetchData is complete to run the correct next function.
Here is some pseudo code:
var app = {
init:function(){
mediator.add("updateLogin",domDependent.updateView);
mediator.add("updateLogin",app.loadUserPrefs);
mediator.add("failLogin",domDependent.updateView);
},
login: function(){
mediator.trigger("loadingSometing",{type:"login"});
ajax.fetch({
onComplete:"updateLogin",//what listens to updateLogin you decided in init
onFail:"failLogin",
loginDetails:domDependent.getLogin(),
url:settings.loginUrl,
type:"post"
});
}
}
var ajax = {
fetch:function(data){
data = data || {};
//simple check for onComplete, it's mandatory
var complete = data.onComplete || app.raiseError("ajax.fetch needs onComplete");
//other code to validate data and making ajax request
onSuccess:function(resp){
//mutate data object as the mediator will pass it to
// whatever other function is called next
// you don't hard code domDependent.updateView and
// app.loadUserPrefs because fetch can be used generally and
// success may have to do completely different things after its done
// and you want to define procedures in init, not all over your code
data.response=resp;
//trigger event to do whatever needs to be done next
mediator.trigger(complete,data);
}
}
}
As you can see it gets complicated and maybe doesn't look like code you're used to but it's highly configurable.
I may have misunderstood the advantages of the mediator pattern to loose couple and if so please comment. I use it to:
Make methods more general instead of copying a lot of logic only
because what to do after it's done is different. In fetch the ajax
object just fetches, this would be the same for login or getting
user preferences, the only thing different is what function to call
next/on error when it's done.
A procedure like login involves multiple functions in multiple
objects if this function chain hard code what to do next once a
particular function is done your procedure of login is defined all
over your code. When defining it in init/config you can easily change the
order or add/remove functions in the chain.

In Backbone, how do I have an after_render() on all views?

I am maintaining a javascript application and I would like there to be a jquery function invoked on pretty much every view. It would go something like this:
SomeView = Backbone.Marionette.ItemView.extend
initialize: ->
#on( 'render', #after_render )
after_render: ->
this.$el.fadeOut().fadeIn()
Clearly there is a better way to do this than have an after_render() in each view? What is the better way to do it? If you can give an answer that includes jasmine tests, I'll <3 you ;)

The event you are looking for is onDomRefresh. See here for the documentation:
https://github.com/marionettejs/backbone.marionette/blob/master/docs/marionette.view.md#view-domrefresh--ondomrefresh-event

Create your own base view class and put your afterRender code in it. When you create a view, inherit from this class.
var MyApp.ItemView = Backbone.Marionette.ItemView.extend({
afterRender: function() {
// This will be called after rendering every inheriting view.
}
});
var SpecificItemView = MyApp.ItemView.extend({
// this view will automatically inherit the afterRender code.
});
In general, it seems to be considered good practice to define your own base views for all 3 view types. It will enable you to easily add global functionality later.

There is a common pattern used across all Backbone frameworks, normally they have a render method which in turn calls beforeRender, renderTemplate and afterRender methods.
render:function(){
this.beforeRender();
this.renderTemplate();// method names are just indicative
this.afterRender();
return this;
}
In your Base view you can have these methods to be empty functions, and implement them wherever you want it. Not sure this answer applies to Marionette

Combining thibaut's and Robert Levy's answer, the correct solution would be:
var baseView = Backbone.Marionette.ItemView.extend({
onDomRefresh: function() {
// This will be triggered after the view has been rendered, has been shown in the DOM via a Marionette.Region, and has been re-rendered
// if you want to manipulate the dom element of the view, access it via this.$el or this.$('#some-child-selector')
}
});
var SpecificItemView = baseView.extend({
// this view will automatically inherit the onDomRefresh code.
});