iOS14画中画功能实现

1.开启后台模式

image.png

2.导入框架#import <AVKit/AVKit.h> 创建AVPictureInPictureController
注：如果是使用系统播放器AVPlayerViewController，设置allowsPictureInPicturePlayback = YES即可

//1.判断是否支持画中画功能
if ([AVPictureInPictureController isPictureInPictureSupported]) {
    //2.开启权限
    @try {
        NSError *error = nil;
        [[AVAudioSession sharedInstance] setCategory:AVAudioSessionOrientationBack error:&error];
        [[AVAudioSession sharedInstance] setActive:YES error:&error];
    } @catch (NSException *exception) {
        NSLog(@"AVAudioSession发生错误");
    }
    self.pipVC = [[AVPictureInPictureController alloc] initWithPlayerLayer:self.player];
    self.pipVC.delegate = self;
}

3.开启或关闭画中画

if (self.pipVC.isPictureInPictureActive) {
    [self.pipVC stopPictureInPicture];
} else {
    [self.pipVC startPictureInPicture];
}

4.代理 AVPictureInPictureControllerDelegate

// 即将开启画中画
- (void)pictureInPictureControllerWillStartPictureInPicture:(AVPictureInPictureController *)pictureInPictureController;
// 已经开启画中画
- (void)pictureInPictureControllerDidStartPictureInPicture:(AVPictureInPictureController *)pictureInPictureController;
// 开启画中画失败
- (void)pictureInPictureController:(AVPictureInPictureController *)pictureInPictureController failedToStartPictureInPictureWithError:(NSError *)error;
// 即将关闭画中画
- (void)pictureInPictureControllerWillStopPictureInPicture:(AVPictureInPictureController *)pictureInPictureController;
// 已经关闭画中画
- (void)pictureInPictureControllerDidStopPictureInPicture:(AVPictureInPictureController *)pictureInPictureController;
// 关闭画中画且恢复播放界面
- (void)pictureInPictureController:(AVPictureInPictureController *)pictureInPictureController restoreUserInterfaceForPictureInPictureStopWithCompletionHandler:(void (^)(BOOL restored))completionHandler;

值得注意的是，关闭画中画会执行
pictureInPictureController:restoreUserInterfaceForPictureInPictureStopWithCompletionHandler: 这个代理方法，用来恢复播放界面的

全局画中画注意点

1. 通过一个全局变量持有画中画控制器，可以在pictureInPictureControllerWillStartPictureInPicture持有，pictureInPictureControllerDidStopPictureInPicture释放；
2. 有可能不是点画中画按钮，而是从其它途径来打开当前画中画控制器，可以在viewWillAppear 进行判断并关闭；
3. 已有画中画的情况下开启新的画中画，需要等完全关闭完再开启新的，防止有未知的错误出现，因为关闭画中画是有过程的；
4. 如果创建AVPictureInPictureController并同时开启画中画功能，有可能会失效，出现这种情况延迟开启画中画功能即可。