SwitchButton.java 文件源码

private static Bitmap getBitmapFromDrawable(Drawable drawable) {
    if (drawable == null) {
        return null;
    }

    if (drawable instanceof DrawableContainer) {
        return getBitmapFromDrawable(drawable.getCurrent());
    } else if (drawable instanceof BitmapDrawable) {
        return ((BitmapDrawable) drawable).getBitmap();
    } else {
        return null;
    }
}