[Android] How to exchange an image in a layer-list by a bitmap?

Question

Here is my Bitmap

Bitmap bitmap = BitmapFactory.decodeStream((InputStream) new URL(url).getContent());
//Need some code to access "dynamicItem" and exchange it with my Bitmap

And here is my layer list (nothing spectacular). I want to exchange the dynamicItem with my Bitmap.

<?xml version="1.0" encoding="utf-8"?>
    <layer-list
      xmlns:android="http://schemas.android.com/apk/res/android"&gt;
      <item
        android:id="@+id/dynamicItem"
        android:drawable="@drawable/defaultItem" />
      <item>
        <bitmap

          android:src="@drawable/some_stuff_on_top"
          android:gravity="top|left" />
      </item>
    </layer-list>