How to improve Flex performance for invisible views

Question

We have a medium size Flex 3.6 application that contains around 20 different page views (managed via a single lazy ViewStack) each having multiple components. Most use custom renderers.

All model data is loaded at startup and changes to model instances are communicated via binding and/or collection change events.

Once the user has viewed each page at least once, all page views are instantiated and happily listen to update events.

Which in effect means that each time a model instance changes, all interested views receive that event and compute derived data or trigger item-renderers.

I have tested and confirmed this behaviour in a proof-of-concept application. Even when setting a list to being invisible, it still listens to collection change events and invalidates any renderer affected.

What would you do?

Answer 1

Having a singleton for your views is not a recommended way of doing things because it keeps everything in memory, which can be massive. You should destroy all views appropriately after their use. You should be more vigilant around memory management overall on your system. Also, you should "deactivate" parts of your system that aren't currently in use.

I would recommend that you remove anything from the view that isn't currently needed unless it's appropriate to "preload" them for certain uses. You should also look at the profiler (if you have it) to see what is using the most memory and try to fix the code that's using too much of it.