R – Flex app loading slow without progress bar

I'm about to close down for the day, so this is off the cuff without any research - sorry.

I think what you need to do is set your SWFLoader's tabEnabled property to false and set its tabChildren property to true.

I'm not sure if this is the right one, did I do something wrong in the end, but after a lot of struggle, I've found this one to be stable solution:

private function onAddedToStage(event:Event):void { 
    if (stage.autoOrients) {
        stage.removeEventListener(StageOrientationEvent.ORIENTATION_CHANGING, orientationChanging);
        stage.addEventListener(StageOrientationEvent.ORIENTATION_CHANGING, orientationChanging, false, 100, true);
    }
}      

private function orientationChanging(event:StageOrientationEvent):void {
    event.stopImmediatePropagation();
    if (event.afterOrientation == StageOrientation.DEFAULT || event.afterOrientation == StageOrientation.UPSIDE_DOWN) {
        event.preventDefault(); 
    }   
}  

First thing to note is that addedToStage fires few times (2-3) in mobile application. I don't know why, there's no addChild in my code, obviously. Maybe the AIR runtime does something else. So, to avoid adding unnecessary amount of handlers, the common technique is to remove handler first - it won't do anything, if such handler is not yet registered, but if there is, it will remove it, which will maintain the handler count on 1.

Second thing is the priority of the event - it won't work on 0, it has to be set on something big, to launch before stuff in AIR runtime.

Last thing - event.stopImmediatePropagation() - now, that we're the first to handle the event, we cant prevent this event to be sent further up in this particular scenario.

This together makes the orientation preventing working perfectly - for me the landscape and the reversed landscape (rotated_left, rotated_right) were working and transitioning, while portrait modes did not affect the view at all.

Now, there's danger here - you might want to remove the listener upon leaving the view (on transition animation end, view deactivate or something), because stopImmediatePropagation will prevent the event to be handled in other parts of your application.

I hope Adobe (or Apache now, actually) will take a closer look at this problem and trace my solution.

EDIT

There remaisn a last issue with this solution, which is if application starts while device is in DEFAULT or UPSIDE_DOWN orientation, in this case application will be in portrait mode.

To fix this, a solution is to change Aspect Ratio within addedToStage handler:

   if(Stage.supportsOrientationChange) {
         stage.setAspectRatio(StageAspectRatio.LANDSCAPE);
    }