Apache – synchronous and asynchronous call in flex

Flex doesn't work in a synchronous fashion, as it is a single thread application and so needs your code to hand execution back to the "core" in order to handle user input etc.

The way to do it is to make your dialogue's behaviour asynchronous:

function onApplicationUnload():void
{
    showDialog(resultMethod);
}

function resultMethod(result:Boolean):void
{
    ExternalInterface.call("javaScriptCallback", [result]);
}

There's is absolutely no support for that. The event loop runs between frames and as long as you block the execution with your (infinite) loop, your myMethodListener function will not be called. Anyway, this would be a terrible idea since the absence of threading in the Flash Player will cause your UI to freeze while you wait for your service to return. You should just drop that idea.