Workaround for Android issue 9656

gistfile1.java

public class MyLibrary {
  public static final String XMLNS = "http://mylib.com/schema"
}

// in widget class
public class MyWidget {

  public MyWidget(Context context, AttributeSet attrs) {
    // don't use obtainStyledAttributes, but getAttributeResourceValue:
    int myAttr = attrs.getAttributeResourceValue(MyLibrary.XMLNS, "myAttr", -1);
  }

}

// in XML:
<LinearLayout xmlns:mylib="http://mylib.com/schema">

  <com.mylib.MyWidget mylib:myAttr="1" />

</LinearLayout>

Works fine. Thanks a lot!