iOS录屏框架ReplayKit的应用总结

ReplayKit是iOS自带的一个屏幕录制的框架，其支持应用程序对当前应用内页面进行录屏，并将最终的视频保存到系统相册中。ReplayKit在iOS 9之后引入，其接口简介，可以非常方便的为应用添加录屏功能。需要注意，在某些iOS 12系统上，开启录屏可能会失败(通常需要重启设备解决)。

  在ReplayKit框架中，有两个非常重要的类，分别是RPScreenRecorder类与RPPreviewViewController类。RPScreenRecorder是录屏核心功能类，RPPreviewViewController是录屏结束后的预览控制器类。

  下面，列举了一个简单的录屏示例代码：

@interface ViewController () <RPScreenRecorderDelegate, RPPreviewViewControllerDelegate>

@end

@implementation ViewController

• (void)viewDidLoad {
  self.view.backgroundColor = [UIColor whiteColor];
  [super viewDidLoad];
  // 获取录屏功能是否可用
  NSLog(@"%d", [RPScreenRecorder sharedRecorder].available);
  // 设置录屏代理
  [RPScreenRecorder sharedRecorder].delegate = self;

  UIButton *btn = [UIButton buttonWithType:UIButtonTypeSystem];
  [btn setTitle:@"Start" forState:UIControlStateNormal];
  [btn addTarget:self action:@selector(start) forControlEvents:UIControlEventTouchUpInside];
  btn.frame = CGRectMake(100, 100, 100, 30);
  [self.view addSubview:btn];

  UIButton *btn2 = [UIButton buttonWithType:UIButtonTypeSystem];
  [btn2 setTitle:@"End" forState:UIControlStateNormal];
  [btn2 addTarget:self action:@selector(stop) forControlEvents:UIControlEventTouchUpInside];
  btn2.frame = CGRectMake(100, 150, 100, 30);
  [self.view addSubview:btn2];

}

• (void)stop {
  // 结束录屏
  [[RPScreenRecorder sharedRecorder] stopRecordingWithHandler:^(RPPreviewViewController _Nullable previewViewController, NSError _Nullable error) {

  NSLog(@"stopRecordingWithHandler");
  if (!error) {
      previewViewController.previewControllerDelegate = self;
      // 到视频预览控制器
      [self presentViewController:previewViewController animated:YES completion:nil];
  }

  }];

}

// 开始录屏

• (void)start {
  [[RPScreenRecorder sharedRecorder] startRecordingWithHandler:^(NSError * _Nullable error) {

  NSLog(@"startRecordingWithHandlerError:%@", error);

  }];

}

• (void)touchesBegan:(NSSet)touches withEvent:(UIEvent )event {
  self.view.backgroundColor = [UIColor colorWithRed:arc4random()%255/255.0 green:arc4random()%255/255.0 blue:arc4random()%255/255.0 alpha:1];

}

// 录屏结束的回调

• (void)screenRecorder:(RPScreenRecorder )screenRecorder didStopRecordingWithPreviewViewController:(nullable RPPreviewViewController )previewViewController error:(nullable NSError *)error {
  NSLog(@"didStopRecordingWithPreviewViewControllerError:%@", error);

}

// 录屏可用性改变的回调

• (void)screenRecorderDidChangeAvailability:(RPScreenRecorder *)screenRecorder {
  NSLog(@"screenRecorderDidChangeAvailability:%d", screenRecorder.available);

}

// 录屏预览控制器的代理回调

• (void)previewControllerDidFinish:(RPPreviewViewController *)previewController {
  [previewController dismissViewControllerAnimated:YES completion:nil];

}

• (void)previewController:(RPPreviewViewController )previewController didFinishWithActivityTypes:(NSSet )activityTypes {
  NSLog(@"didFinishWithActivityTypes %@", activityTypes);

}

@end
其中，RPScreenRecorder类中提供了丰富的接口可以使用，列举如下：

@interface RPScreenRecorder : NSObject
// 获取单例

• (RPScreenRecorder *)sharedRecorder;

// iOS 10 之前使用，可以通知是否开启麦克风

• (void)startRecordingWithMicrophoneEnabled:(BOOL)microphoneEnabled handler:(nullable void(^)(NSError * _Nullable error))handler;

// iOS 10 之后使用 开启录屏

• (void)startRecordingWithHandler:(nullable void(^)(NSError * _Nullable error))handler;

// 结束录屏

• (void)stopRecordingWithHandler:(nullable void(^)(RPPreviewViewController _Nullable previewViewController, NSError _Nullable error))handler;

// 放弃录屏

• (void)discardRecordingWithHandler:(void(^)(void))handler;

// 开启录屏，可以获取到视频流数据 iOS 11后可用

• (void)startCaptureWithHandler:(nullable void(^)(CMSampleBufferRef sampleBuffer, RPSampleBufferType bufferType, NSError _Nullable error))captureHandler completionHandler:(nullable void(^)(NSError _Nullable error))completionHandler;

// 结束视频流捕获

• (void)stopCaptureWithHandler:(nullable void(^)(NSError * _Nullable error))handler;

// 设置代理对象
@property (nonatomic, weak, nullable) id delegate;
// 录屏功能是否可用
@property (nonatomic, readonly, getter=isAvailable) BOOL available;
// 是否正在录制中
@property (nonatomic, readonly, getter=isRecording) BOOL recording;
// 是否使用麦克风
@property (nonatomic, getter=isMicrophoneEnabled) BOOL microphoneEnabled;
// 是否可以使用相机
@property (nonatomic, getter=isCameraEnabled) BOOL cameraEnabled;
// 设置摄像头模式 前置/后置
@property (nonatomic) RPCameraPosition cameraPosition;
// 相机预览视图
@property (nonatomic, readonly, nullable) UIView *cameraPreviewView;
@end
在录屏的时候，也支持调用系统的麦克风和摄像头共同完成录制。RPScreenRecorderDelegate协议中定义了一些回调方法，如下：

// 停止录屏后的回调 iOS 10 之前使用

• (void)screenRecorder:(RPScreenRecorder )screenRecorder didStopRecordingWithError:(NSError )error previewViewController:(nullable RPPreviewViewController *)previewViewController;

// 停止录屏后的回调 iOS 10 之后使用

• (void)screenRecorder:(RPScreenRecorder )screenRecorder didStopRecordingWithPreviewViewController:(nullable RPPreviewViewController )previewViewController error:(nullable NSError *)error;

// 录屏权限更改的回调

• (void)screenRecorderDidChangeAvailability:(RPScreenRecorder *)screenRecorder;

RPPreviewViewController类是视频预览控制器类，这个控制器没有暴露太多的属性给开发者使用，其中预览模式可以选择分享模式或编辑模式，除此之外，其中还提供了一个代理协议给开发者进行使用，用来对用户的操作进行处理，如下：

@protocol RPPreviewViewControllerDelegate
@optional
// 预览结束

• (void)previewControllerDidFinish:(RPPreviewViewController *)previewController;

// 用户行为回调

• (void)previewController:(RPPreviewViewController )previewController didFinishWithActivityTypes:(NSSet )activityTypes;

@end