RippleCompat.java 文件源码

@TargetApi(Build.VERSION_CODES.LOLLIPOP)
@Override
public Drawable initBackgroundDrawable(View view, Drawable mBackgroundColorDrawable) {
    RippleDrawable mBackgroundRippleDrawable = new RippleDrawable(
            ColorStateList.valueOf(Color.TRANSPARENT),
            null,
            new ShapeDrawable(new RectShape())
    );

    view.setBackground(new LayerDrawable(new Drawable[] {
            mBackgroundColorDrawable,
            mBackgroundRippleDrawable
    }));

    return mBackgroundRippleDrawable;
}