Android歌词秀设计思路（4）通用的音乐播放服务(下)(2)

                 * MusicFocusable appropriately to relay the message. 
                 */
                @Override
                public void onAudioFocusChange(int focusChange) { 
                    if (mFocusable == null) return; 
                    switch (focusChange) { 
                        case AudioManager.AUDIOFOCUS_GAIN: 
                            mAudioFocus = Focused; 
                            mFocusable.onGainedAudioFocus(); 
                            break; 
                        case AudioManager.AUDIOFOCUS_LOSS: 
                        case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT: 
                             mAudioFocus = NoFocusNoDuck; 
                            mFocusable.onLostAudioFocus(); 
                            break; 
                        case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK: 
                             mAudioFocus = NoFocusCanDuck; 
                            mFocusable.onLostAudioFocus();