android.media.AudioManager#FLAG_SHOW_UI源码实例Demo

void setAudioStatus(boolean mute, int volume) {
    if (!isTvDeviceEnabled() || !tv().isSystemAudioActivated()) {
        return;
    }
    AudioManager audioManager = getAudioManager();
    boolean muted = audioManager.isStreamMute(AudioManager.STREAM_MUSIC);
    if (mute) {
        if (!muted) {
            audioManager.setStreamMute(AudioManager.STREAM_MUSIC, true);
        }
    } else {
        if (muted) {
            audioManager.setStreamMute(AudioManager.STREAM_MUSIC, false);
        }
        // FLAG_HDMI_SYSTEM_AUDIO_VOLUME prevents audio manager from announcing
        // volume change notification back to hdmi control service.
        int flag = AudioManager.FLAG_HDMI_SYSTEM_AUDIO_VOLUME;
        if (0 <= volume && volume <= 100) {
            Slog.i(TAG, "volume: " + volume);
            flag |= AudioManager.FLAG_SHOW_UI;
            audioManager.setStreamVolume(AudioManager.STREAM_MUSIC, volume, flag);
        }
    }
}
 

private void dispatchVolumeKeyEventLocked(String packageName, int pid, int uid,
        boolean asSystemService, KeyEvent keyEvent, int stream, boolean musicOnly) {
    boolean down = keyEvent.getAction() == KeyEvent.ACTION_DOWN;
    boolean up = keyEvent.getAction() == KeyEvent.ACTION_UP;
    int direction = 0;
    boolean isMute = false;
    switch (keyEvent.getKeyCode()) {
        case KeyEvent.KEYCODE_VOLUME_UP:
            direction = AudioManager.ADJUST_RAISE;
            break;
        case KeyEvent.KEYCODE_VOLUME_DOWN:
            direction = AudioManager.ADJUST_LOWER;
            break;
        case KeyEvent.KEYCODE_VOLUME_MUTE:
            isMute = true;
            break;
    }
    if (down || up) {
        int flags = AudioManager.FLAG_FROM_KEY;
        if (musicOnly) {
            // This flag is used when the screen is off to only affect active media.
            flags |= AudioManager.FLAG_ACTIVE_MEDIA_ONLY;
        } else {
            // These flags are consistent with the home screen
            if (up) {
                flags |= AudioManager.FLAG_PLAY_SOUND | AudioManager.FLAG_VIBRATE;
            } else {
                flags |= AudioManager.FLAG_SHOW_UI | AudioManager.FLAG_VIBRATE;
            }
        }
        if (direction != 0) {
            // If this is action up we want to send a beep for non-music events
            if (up) {
                direction = 0;
            }
            dispatchAdjustVolumeLocked(packageName, pid, uid, asSystemService, stream,
                    direction, flags);
        } else if (isMute) {
            if (down && keyEvent.getRepeatCount() == 0) {
                dispatchAdjustVolumeLocked(packageName, pid, uid, asSystemService, stream,
                        AudioManager.ADJUST_TOGGLE_MUTE, flags);
            }
        }
    }
}