iOS开发--QQ音乐练习,后台播放和锁屏界面

一.设置后台播放

首先允许程序后台播放

代码实现

 1 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
 2     
 3     // 设置后台播放的代码,步骤
 4     // 1.获取音频的会话
 5     AVAudioSession *session = [AVAudioSession sharedInstance];
 6     // 2.设置后台播放类型
 7     [session setCategory:AVAudioSessionCategoryPlayback error:nil];
 8     // 3.激活会话
 9     [session setActive:YES error:nil];
10     
11     return YES;
12 }

二.锁屏界面

适当的时机调用这个方法

#pragma mark - 设置锁屏界面的信息
- (void)setupLockScreenInfo
{
    // 1.获取当前正在播放的歌曲
    ChaosMusic *playingMusic = [ChaosMusicTool playingMusic];
    // 2.获取锁屏界面中心
    MPNowPlayingInfoCenter *playingCenter = [MPNowPlayingInfoCenter defaultCenter];
    // 3.设置展示的信息
    NSMutableDictionary *playingInfo = [NSMutableDictionary dictionary];
    
    playingInfo[MPMediaItemPropertyAlbumTitle] = playingMusic.name;
    playingInfo[MPMediaItemPropertyArtist] = playingMusic.singer;
    MPMediaItemArtwork *artwork = [[MPMediaItemArtwork alloc] initWithImage:[UIImage imageNamed:playingMusic.icon]];
    playingInfo[MPMediaItemPropertyArtwork] = artwork;
    playingInfo[MPMediaItemPropertyArtist] = @(self.player.currentTime);
    
    playingCenter.nowPlayingInfo = playingInfo;
    // 4.让应用程序可以接受远程事件
    [[UIApplication sharedApplication] beginReceivingRemoteControlEvents];
}

实现了锁屏界面,没有实现监听远程事件的话,锁屏界面的下一首之类的按钮没有反应.实现下面的方法

 1 // 监听远程事件
 2 - (void)remoteControlReceivedWithEvent:(UIEvent *)event
 3 {
 4     switch (event.subtype) {
 5         case UIEventSubtypeRemoteControlPlay:
 6         case UIEventSubtypeRemoteControlPause:
 7             [self startOrPause:nil];
 8             break;
 9             
10         case UIEventSubtypeRemoteControlNextTrack:
11             [self nextMusic:nil];
12             break;
13             
14         case UIEventSubtypeRemoteControlPreviousTrack:
15             [self previousMusic:nil];
16             break;
17             
18         default:
19             break;
20     }
21 }