控件如何实现 阴影 + 按压切换背景图

Question

现需要做一个按钮，使其具有按压时可以切换背景图片，同时该按钮又具有阴影效果。才疏学浅，试了大半天觉得这两个效果会相互冲突，只能择其一。还请各位前辈支支招，以下为部分代码。
<View
            android:layout_width="50dp"
            android:layout_height="50dp"
            android:layout_alignParentBottom="true"
            android:layout_alignParentRight="true"
            android:layout_marginRight="16dp"
            android:layout_marginBottom="16dp"
            android:elevation="15dp"
            android:background="@drawable/btn_float_round_add"
    >
    </View><?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:drawable="@drawable/ic_add_btn_normal">
        <item>
            <shape android:shape="oval" >
                <corners android:radius="360dp" />
            </shape>
        </item>
    </item>
    <item android:drawable="@drawable/ic_add_btn_pressed" android:state_pressed="true">
        <item>
            <shape android:shape="oval" >
                <corners android:radius="360dp" />
            </shape>
        </item>
    </item>
    <item android:drawable="@drawable/ic_add_btn_pressed" android:state_focused="true">
        <item>
            <shape android:shape="oval" >
                <corners android:radius="360dp" />
            </shape>
        </item>
    </item>
</selector>

Answer 1

你说的阴影应该是图片上的一层遮罩吧，可以用layer-list实现
selector代码<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_pressed="true">
        <layer-list>
            <item android:drawable="按压时背景图"/>
            <item android:drawable="按压时阴影"/>
        </layer-list>
    </item>
    <item android:drawable="普通状态时背景图"/>
</selector>

Answer 2

http://angrytools.com/android/button/
分享一个button maker  希望对你有帮助