Question

I have a Container view that I am using as my main wrapper view, in which other views are swapped in and out.

In Ember 0.9.8 this worked fine. However, now in Ember 1.0pre I get an error when I try to swap in a view that I had previously swapped out.

Here’s my basic code:

App.globalView = Ember.ContainerView.create({
  screenOne: App.screenOne.create(),
  screenTwo: App.screenTwo.create()
});

App.globalView.set('currentView', App.globalView.get('screenOne')); // <-- good
App.globalView.set('currentView', App.globalView.get('screenTwo')); // <-- good
App.globalView.set('currentView', App.globalView.get('screenOne')); // <-- BAD

I now get the error

Error: assertion failed: calling set on destroyed object
   ...from
   Ember.ContainerView.Ember.View.extend.initializeViews
    set(view, '_parentView', parentView);

I have an example of this at http://jsfiddle.net/SamFent/WmfTX/. In the jsFiddle, I don’t see the error but the previous view just fails to load.

Does anyone know what’s going on?

Answer 1

Ember.ContainerView now destroys the view when it is unset, so it cannot be used as you want. Here is a fork of your fiddle that does what you want: http://jsfiddle.net/WmfTX/1/

If you really need to avoid tearing down and recreating views, render both views and use the isVisible property to toggle visibility instead.