How to override drawables defined in an Android Library Project?

Question

I have two Android applications with a similar functionality but different drawables and layouts.

I'd like to put all the code and resources in a library project and override some of the drawables and layouts in the two applications that would reference that library.

I created an application that references the library. I copied all the resources from the library to the application and changed some of the drawables. I also changed some of the string resources. When I view one of the changed layouts in the layout editor in Eclipse, I see the correct overridden images.

When I launch the application I see that the string resources I changed in the application are displayed correctly (the library strings are overridden by the resources of the application), but the drawables of my ImageViews are all taken from the resources of the library.

I also made changes in some of the layout resources (moved and resized some images). When I launch an activity that uses the changed layout (an activity whose source code is in the library), I see the new (application) layout with the old (library) drawables.

I tried defining the drawables of the ImageViews in two ways :

1. in the layout xml : android:src="@drawable/image_id"

2. in the code of the activity :

   ImageView view = (ImageView)findViewById(R.id.viewId);
   view.setImageResource(R.drawable.image_id);
   

In both cases the image I see is taken from the resources of the library project and not the application.

If I don't manage to solve this problem, I'll have to duplicate all the code in both applications, which would be a shame.

Am I doing something wrong?

Answer 1

Based on my experience, you can replace the drawable resource in the library module by using style and refs.xml.

First you need to declare the drawable resource in a style, like

<style name="drawable_base_style">
    <item name="android:src">@drawable/base</item>
</style>

then in the app (module or project, depending on your IDE), redefine a style

<style name="drawable_base_style_app">
    <item name="android:src">@drawable/app</item>
</style>

and use refs.xml to point the new style.

<item name="drawable_base_style" type="style">@style/drawable_base_style_app</item>

then the last step : cross your fingers.