title: getApplication() and spanning Activities within a given Applications
body: <p>I've spent a while reading up on this and have yet to find an answer.</p>
  
  <p>I have a few activities all within one app. I'd like to share some data between them that is not suitable for intents or serialized data files. I know I can use the overall Application for this purpose, but I'm not fully understanding how it works.</p>
  
  <p>We'll call my overall application class "MyApplication" and the main activity "MyActivity". I would expect that once the app begins from a cold start, it first instantiates and initializes MyApplication (calling onCreate()) and then goes on to instantiate and start my activity (MyActivity) (which was marked with the intent android.intent.action.MAIN). The logs seem to bear this out.</p>
  
  <p>But... if I try to set the following Activity-wide variable, it gets set to null:
    private final MyApplication THISAPP = (MyApplication)getApplication();</p>
  
  <p>This is peculiar because the application definitely exists at this point. (Also, I can't delay setting a final variable til MyActivity.onCreate() gets called - that's disallowed ("The final field...cannot be assigned")).</p>
  
  <p>Note that this works if I don't call THISAPP "final" and I assign it in onCreate(). That of course defeats the purpose of protecting a variable with "final" though, and it seems like it should be possible to do.</p>
  
  <p><strong>So, why isn't getApplication() producing a non-null value before onCreate()? Or is this some strange matter of context?</strong> (I've found a vague reference to context not being valid til after onCreate() is done, but would that apply to the parent Application's context as seen from a child Activity? I'd expect the parent to already have that set at that point.)</p>
  
  <p>Edit: to emphasize, I can get this to work if I don't try to use final and if I remember to put the "." before the application name in the manifest (a mistake I made and corrected well-before this I wrote this question). It just isn't clear why getApplication() (or getApplicationContext() for that matter) aren't usable before onCreate() in a child Activity... unless "that's just how it is".</p>