https://blog.csdn.net/u011277821/article/details/52495354
/** * Show a toast containing the current volume. * * @see #adjustStreamVolume(int, int, int) * @see #adjustVolume(int, int) * @see #setStreamVolume(int, int, int) * @see #setRingerMode(int) */ public static final int FLAG_SHOW_UI = 1 << 0;