ResideLayout.java 文件源码

private static boolean viewIsOpaque(View v) {
    if (ViewCompat.isOpaque(v)) return true;

    // View#isOpaque didn't take all valid opaque scrollbar modes into account
    // before API 18 (JB-MR2). On newer devices rely solely on isOpaque above and return false
    // here. On older devices, check the view's background drawable directly as a fallback.
    if (Build.VERSION.SDK_INT >= 18) return false;

    final Drawable bg = v.getBackground();
    if (bg != null) {
        return bg.getOpacity() == PixelFormat.OPAQUE;
    }
    return false;
}