How can I reference a drawable class in Android XML

Question

I've created a class that extends drawable that I'd like to reference inside a resource xml. I happen to need it in a selector, like so:

<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_window_focused="false" android:state_pressed="false" 
android:drawable="com.sample.android.contacts.TopBarCollapsed"
/>
<item android:state_window_focused="true" android:state_pressed="true" android:drawable="@drawable/top_switcher_collapsed_selected" />
<item android:state_focused="true" android:drawable="@drawable/top_switcher_collapsed_focused" />

com.sample.android.contacts.TopBarCollapsed is the class that extends drawable.

Answer 1

I believe this was answered well here: https://stackoverflow.com/a/11024035/2662474

Unfortunately it is not possible to use custom drawables in XML files due to potential security issues. See here for a Google Groups thread about this very topic with a response from Romain Guy, one of the Android developers.

You can still use them in your Java code though.

In that link Roman writes:

Custom drawables are not allowed from XML, mostly for security reasons. XML drawables can be loaded as resources by other processes (including Launcher or the system process) and it would be a terrible idea to run random 3rd party code in these processes.

Security is essential, but certainly it would be nice if there was a clean way to have more consistency and control as a developer.