How to obtain AssetManager without reference to Context?

Question

I have a class that needs to obtain a reference to it's application's AssetManager. This class does not extend any sort of android UI class, so it doesn't have a getContext() method, or anything similar. Is there some sort of static Context.getCurrentApplicationContext() type of method?

To clarify: my class is intended to be used like a library, for other applications. It has no associated AndroidManifest.xml or control over the context which is calling it.

score 27 · Accepted Answer · answered Dec 10 '10 at 15:25

27

Create a subclass of Application, for instance public class App extends Application {
Set the android:name attribute of your <application> tag in the AndroidManifest.xml to point to your new class, e.g. android:name=".App"
In the onCreate() method of your app instance, save your context (e.g. this) to a static field named app and create a static method that returns this field, e.g. getApp():

This is how it should look:

public class App extends Application{

    private static Context mContext;

    @Override
    public void onCreate() {
        super.onCreate();
        mContext = this;
    }

    public static Context getContext(){
        return mContext;
    }
}

Now you can use: App.getContext() whenever you want to get a context, and then getAssetManager() (or App.getContext().getAssetManager()).

answered Dec 10 '10 at 15:25

Cristian

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To clarify, my class is intended to be used like a library, for other applications. It has no associated AndroidManifest.xml. – ab11 Dec 10 '10 at 17:42
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In that case, create the asset manager in the application and pass it to the library (through a method or constructor). – Cristian Dec 10 '10 at 18:33
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Seeing as how I intend for the library to be used by other developers in their applications, I was hoping there would be an alternative to requiring them to manually set the asset manager. – ab11 Dec 10 '10 at 19:14

score 7 · Answer 2 · edited Jan 16 '13 at 23:32

7

I am not sure of the best answer to the OP question. However, I do know that you have to be very careful when using a static context as suggested in Android developer resources:

In the onCreate() method of your app instance, save your context (e.g. this) to a static field named app and create a static method that returns this field, e.g. getApp():

Using static contexts can leak to leaked memory issues, especially if the static context is used for references to views.

edited Jan 16 '13 at 23:32

ib.

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answered Dec 26 '10 at 22:50

gymshoe

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This concern is moot for the app instance itself, which is what is being stored in mContext, in Cristian's answer. The app instance has the same lifetime as your app; there is nothing to "leak". **The concern does become important if access to UI is needed**; in that case an `Activity` would be passed in as context, and it is important to have the activity make another call to "unregister" itself, in onPause and onDestroy. See http://stackoverflow.com/a/13994622/199364 for such a technique, when Activity context is needed. `static WeakReference mContext` might also be helpful. – ToolmakerSteve Oct 08 '15 at 02:41

How to obtain AssetManager without reference to Context?

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