ImageButton在Android中使用Transitions

我正在尝试创建一个具有自定义选择器的透明(无按钮背景) ImageButton.我让选择器对着按钮工作,但我现在希望选择器drawables相互交叉淡入淡出.
我看到了可以用 XML表示的TransitionDrawable对象.有没有办法将它连接到我的选择器？

下面是在屏幕左下角的屏幕上创建图像按钮的XML布局代码.它目前从一个图像到另一个图像突然忽略了转换XMl.

SELEctor_button.xml

<?xml version="1.0" encoding="utf-8"?>
<SELEctor xmlns:android="http://scheR_569_11845@as.android.com/apk/res/android">
    <item android:state_pressed="true" android:drawable="@drawable/transition_normal_to_pressed" /> <!-- pressed -->
    <item android:state_focused="true" android:drawable="@drawable/transition_pressed_to_normal" /> <!-- focused -->
    <item android:drawable="@drawable/menu_normal" /> <!-- default -->
</SELEctor>

transition_normal_to_pressed.xml

<?xml version="1.0" encoding="utf-8"?>
<transition xmlns:android="http://scheR_569_11845@as.android.com/apk/res/android">
    <item android:drawable="@drawable/menu_pressed" />
    <item android:drawable="@drawable/menu_normal" />
</transition>

activity.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://scheR_569_11845@as.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <ImageButton
        android:id="@+id/btnMenu"
        android:BACkground="@android:color/transparent"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/SELEctor_button"
        android:layout_alignParentLeft="true"
        android:layout_alignParentBottom="true" />
</RelativeLayout>

ImageButton button = (ImageButton) findViewById(R.id.button);
TransitionDrawable drawable = (TransitionDrawablE) button.getDrawable();
drawable.startTransition(500);