Data binding will not be able to detect assignments to "topLevelApplication"

Question

I am migrating an application from Flex 3 to Flex 4. In some cases there are popup windows of which the width and height is bound to the application width and height.

width="{Application.application.width - 24}" 
height="{Application.application.height - 32}"

Application.application is deprecated in 4.0. so I have replaced this with

width="{FlexGlobals.topLevelApplication.width - 24}" 
height="{FlexGlobals.topLevelApplication.height - 32}"

Now the compiler gives the warning that data bindings cannot be detected for topLevelApplication.

Data binding will not be able to detect assignments to "topLevelApplication"

My question is: Is there another (bindable) property somewhere that I can use to get the same functionality as before?

Answer 1

Just create a variable of type object and make it bindable :

[Bindable]
private var application:Object = FlexGlobals.topLevelApplication;

And then use the variable.

height="{application.height}"

Answer 2

If you use {this.screen.height} your warnings should go away.

Tim

Answer 3

This should work with a cast:

height="{(FlexGlobals.topLevelApplication as Application).height - 32}"

The reason why it isn't working with your current code is because FlexGlobals.topLevelApplication is typed as an Object.

Answer 4

I was stuck for half an hour and found out that Bindable only works with a capital 'B', I did it and it solved my problem.

So, instead of bindable just write Bindable as the referred class is bindable.Bindable.

Answer 5

i was struggling with a similar warning, but instead of an object problem (wich is solved with the [Bindable] prefix) i was using a VBox. I needed to change the source of an image depending on how many childs my vbox has. So the solution to this is only using "this" lol. here's an example:

<mx:Image width="24" height="24" source="{this.vbBox1.getChildren().length>1 ?    'assets/icons/forwardDisable.png':'assets/icons/forward.png'}"/>

If you dont use "this" the IDE will show you a warning similar to the one that you have with the object. I hope it helps others!

Best Regards