可以通过setBackgroundResource（）使背景覆盖上面的视图吗？

Question

我有这个XML

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="45dp"
    android:layout_height="32dp"
    android:id="@+id/switch_bg"
    android:padding="0dp"
    android:background= "@drawable/switch_bg_off" >

        <RelativeLayout
            android:id="@+id/switch_handle"
            android:layout_width="40dp"
            android:layout_height="40dp"
            android:layout_alignParentLeft="true"
            android:layout_centerVertical="true"
            android:background="@drawable/switch_handle"
            android:padding="0dp" >

            <ImageView
                android:id="@+id/switch_v"
                android:layout_width="15dp"
                android:layout_height="15dp"
                android:layout_centerInParent="true"
                android:src="@drawable/switch_v" />
        </RelativeLayout>

</RelativeLayout>

我在用户点击

上调用此方法

然后隐藏背景上方的所有视图。

private void bgTransition(SwitchModes mode) {

    AlphaAnimation alpha = new AlphaAnimation(1, (float) 0.5);
    alpha.setDuration(ALPHA_DURATION);
    mSwitchBg.startAnimation(alpha);

    switch (mode) {
    case CHECKED: {
        // mBgTransition.reverseTransition(BG_TRANSITION_TIME);
        mSwitchBg.setBackgroundResource(R.drawable.switch_bg_off);
        break;
    }
    case UNCHECKED: {
        // mBgTransition.startTransition(BG_TRANSITION_TIME);
        mSwitchBg.setBackgroundResource(R.drawable.switch_bg_on);
        break;
    }
    }

    alpha = new AlphaAnimation((float) 0.5, 1);
    alpha.setDuration(ALPHA_DURATION);
    mSwitchBg.startAnimation(alpha);
}

如何解决这个问题？