How can I access bitmaps created in another activity?

Question

I am currently loading my game bitmaps when the user presses 'start' in my animated splash screen activity (the first / launch activity) and the app progresses from my this activity to the main game activity,

This is causing choppy animation in the splashscreen while it loads/creates the bitmaps for the new activity.

I've been told that I should load all my bitmaps in one go at the very beginning.

However, I can't work out how to do this - could anyone please point me in the right direction?

I have 2 activities, a splash screen and the main game. Each consist of a class that extends activity and a class that extends SurfaceView (with an inner class for the rendering / logic updating).

So, for example at the moment I am creating my bitmaps in the constructor of my SurfaceView class like so:

public class OptionsScreen extends SurfaceView implements
  SurfaceHolder.Callback {

      //Create variables here

 public OptionsScreen(Context context) {


Create bitmaps here
}

public void intialise(){                         //This method is called from onCreate() of corresponding application context

// Create scaled bitmaps here (from bitmaps previously created)

}

Answer 1

Never do massive loading of resources all at once on the GUI thread - that's a certain approach to getting choppiness.

Making sure that your app can access your bitmaps from any activity is not difficult; simply set up a Singleton class that handles your bitmaps. You can use the Application class as Jay suggests, but personally I'd build an own singleton class for such activities as I don't feel that the Application class is the right place for such data.

I have open-sourced my own implementation of an ImageHandler for Android bitmaps in https://github.com/micabyte/android_game

See com.micabyte.android.graphics.ImageHandler

I've not implemented background loading in the ImageHandler (never needed it for the small bitmaps that I load via the ImageHandler, but you can check the SurfaceView implementation also in that project for how I handle loading a very large bitmap of 4096x4096 for game maps).

Answer 2

As RobCurr has mentioned, it's probably best to only load the necessary resources during the splash screen. Then load the absolute critical when you go to run the game. There are a couple different approaches to persisting your graphical resources across different activities. Basically your problem is "How to maintain global variables/state across different activities?"

Based on how you described your App, I think your best bet is to extend the Application class and load all the initial resources there. The Application class can then be accessed "globally" sorta of speak from any Activity. The Application class maintains it's existence during the life of your App. Note, if it's possible to load your resources statically, then creating static references is a better alternative to extending the Application class.

Some helpful links:
Extending Application Class
StackOverFlow post on Extending Application Class
Loading, Processing, Caching, Managing, Displaying Bitmaps Efficiently
Interesting group discussion about different options to maintaing global state