Stop the mobile ActionBar from transitioning

I was creating a mobile AIR app and the app was to have an ActionBar at the top and depending on the view that was about to get pushed I didn’t want the ActionBar to have a transition effect. Sounds like a simple request, nope, no can do…

So after a bit of digging into the various classes ( mainly the ViewTransitionBase ) I came across what needed to be changed 🙂 but its a mx_internal so use the following fix with caution.

All of the various effects check the actionBarTransitionMode while they create the effects.  Its just that the actionBarTransitionMode is always set to ACTION_BAR_MODE_FADE_AND_SLIDE and never changes from that value. What’s more the actionBarTransitionMode is a mx_internal  variable so you can’t just call it yourself when creating a new effect.

So here is the fix.

  1. Extend whatever effect you wish to use. e.g. SlideViewTransition
  2. add the following lines to your extended class import import mx.core.mx_internal; and use namespace mx_internal;
  3. Either inside your constructor set the value (if you don’t wish to change it at runtime) or create a setter to modify the value actionBarTransitionMode
Possible values are (these can be found in the ViewTransitionBase class),

ACTION_BAR_MODE_FADE:String = “fade”;

ACTION_BAR_MODE_FADE_AND_SLIDE:String = “fadeAndSlide”;

ACTION_BAR_MODE_NONE:String = “none”;

In my case I set it to ACTION_BAR_MODE_NONE as I didn’t wish to have any transition on the ActionBar.

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iOS – Mobile dev, make sure you flush when you’re done.

Developing for Apple’s devices can throw up a few little quirks that don’t happen when using Android devices.

This one happens if you are using shared objects to store information between sessions.
Basically, you should always call the flush mechanism whether you are adding more data to the shared object or if you are deleting something from the shared object.

What you find is if you have a shared object ‘shared’ with a value shared.data.firstValue = “something”, then you delete that value using

delete shared.data.firstValue;

if you try to access the value firstValue you will get null.
This is exactly what I’d expect.

Then lets say you exit the app and you either kill the app from running in the background or iOS stops it. Then the next time you load the app and access the shared object shared.data.firstValue you will get back “something” and not null.

You must flush the shared object for it to be stored locally, otherwise when the app is killed, the local storage will not have been updated.

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IconItemRenderer and LabelItemRenderer, separator lines hardcoded!

Working on a mobile project I needed to create a renderer for a list, so I choose to look at the IconItemRenderer which extends the LabelItemRenderer. These have been optimised for mobile use so it seemed a reasonable place to start. On the whole they seem like good classes to use, but if you’ve ever worked with the Datagrid/DataGridBase in the past you will probably know about the white square which comes about from the hardcoded #FFFFFF values inside the DataGridBase!

Well the IconItemRenderer and LabelItemRenderer have a similar issue. So lets just say you create a list and you wish to skin the list exactly how you like or use it in a tile layout or something other than vertical then you will find some lines above and below your renderers which look out of place. You can’t get rid of them no matter what property styles you set.

The fix is pretty straight forward but why does there have to be some hardcoded values in something that is meant to be very versatile?

So inside the LabelItemRenderer around lines 881 you will see the following. It uses these values to draw separators whether you like it or not.

// separators are a highlight on the top and shadow on the bottom
topSeparatorColor = 0xFFFFFF;
topSeparatorAlpha = .3;
bottomSeparatorColor = 0x000000;
bottomSeparatorAlpha = .3;

So the quickest way of dealing with this is to override the drawBackground function in your own class which is created in LabelItemRenderer. This doesn’t get called from IconItemRenderer so you can quite simple copy the entire function and just remove the separator chunk and do not call super from your function which overrides the drawBackground.

Better still would be to change the hard coded values to styles from a CSS file.

var topSeparatorColor : uint = getStyle( 'topSeparatorColor' );
var topSeparatorAlpha : Number = getStyle( 'topSeparatorAlpha' );
topSeparatorAlpha = isNaN( topSeparatorAlpha ) ? 1 : topSeparatorAlpha;

If you’re setting a Number just remember to check for NaN’s in case you haven’t set a style, uints default to 0 anyway.

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