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微信現(xiàn)在這么普及，功能也做的越來越強大，不知大家對于微信朋友圈發(fā)視頻截取的功能或者蘋果拍視頻對視頻編輯的功能有沒有了解（作者這里也猜測，微信的這個功能也是仿蘋果的）。感覺這個功能確實很方便實用，近來作者也在研究音視頻功能，所以就實現(xiàn)了一下這個功能。

功能其實看著挺簡單，實現(xiàn)過程也踩了不少坑。一方面記錄一下；另一方面也算是對實現(xiàn)過程的再一次梳理，這樣大家看代碼也會比較明白。

效果

我們先看看我實現(xiàn)的效果

實現(xiàn)

實現(xiàn)過程分析

整個功能可以分為三部分：

• 視頻播放

這部分我們單獨封裝一個視頻播放器即可

• 下邊的滑動視圖

這部分實現(xiàn)過程比較復(fù)雜，一共分成了4部分?；疑谏w、左右把手滑塊、滑塊中間上下兩條線、圖片管理視圖

控制器視圖邏輯組裝和功能實現(xiàn)

• 視頻播放器的封裝

這里使用AVPlayer、playerLayer、AVPlayerItem這三個類實現(xiàn)了視頻播放功能；由于整個事件都是基于KVO監(jiān)聽的，所以增加了Block代碼提供了對外監(jiān)聽使用。

#import "FOFMoviePlayer.h"
@interface FOFMoviePlayer()
{
  AVPlayerLooper *_playerLooper;
  AVPlayerItem *_playItem;
  BOOL _loop;
}
@property(nonatomic,strong)NSURL *url;
@property(nonatomic,strong)AVPlayer *player;
@property(nonatomic,strong)AVPlayerLayer *playerLayer;
@property(nonatomic,strong)AVPlayerItem *playItem;
@property (nonatomic,assign) CMTime duration;
@end
@implementation FOFMoviePlayer
-(instancetype)initWithFrame:(CGRect)frame url:(NSURL *)url superLayer:(CALayer *)superLayer{
  self = [super init];
  if (self) {
    [self initplayers:superLayer];
    _playerLayer.frame = frame;
    self.url = url;
  }
  return self;
}
-(instancetype)initWithFrame:(CGRect)frame url:(NSURL *)url superLayer:(CALayer *)superLayer loop:(BOOL)loop{
  self = [self initWithFrame:frame url:url superLayer:superLayer];
  if (self) {
    _loop = loop;
  }
  return self;
}
- (void)initplayers:(CALayer *)superLayer{
  self.player = [[AVPlayer alloc] init];
  self.playerLayer = [AVPlayerLayer playerLayerWithPlayer:self.player];
  self.playerLayer.videoGravity = AVLayerVideoGravityResize;
  [superLayer addSublayer:self.playerLayer];
}
- (void)initLoopPlayers:(CALayer *)superLayer{
  self.player = [[AVQueuePlayer alloc] init];
  self.playerLayer = [AVPlayerLayer playerLayerWithPlayer:self.player];
  self.playerLayer.videoGravity = AVLayerVideoGravityResize;
  [superLayer addSublayer:self.playerLayer];
}
-(void)fof_play{
  [self.player play];
}
-(void)fof_pause{
  [self.player pause];
}
#pragma mark - Observe
-(void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary*)change context:(void *)context{
  if ([keyPath isEqualToString:@"status"]) {
    AVPlayerItem *item = (AVPlayerItem *)object;
    AVPlayerItemStatus status = [[change objectForKey:@"new"] intValue]; // 獲取更改后的狀態(tài)
    if (status == AVPlayerItemStatusReadyToPlay) {
      _duration = item.duration;//只有在此狀態(tài)下才能獲取，不能在AVPlayerItem初始化后馬上獲取
      NSLog(@"準(zhǔn)備播放");
      if (self.blockStatusReadyPlay) {
        self.blockStatusReadyPlay(item);
      }
    } else if (status == AVPlayerItemStatusFailed) {
      if (self.blockStatusFailed) {
        self.blockStatusFailed();
      }
      AVPlayerItem *item = (AVPlayerItem *)object;
      NSLog(@"%@",item.error);
      NSLog(@"AVPlayerStatusFailed");
    } else {
      self.blockStatusUnknown();
      NSLog(@"%@",item.error);
      NSLog(@"AVPlayerStatusUnknown");
    }
  }else if ([keyPath isEqualToString:@"tracking"]){
    NSInteger status = [change[@"new"] integerValue];
    if (self.blockTracking) {
      self.blockTracking(status);
    }
    if (status) {//正在拖動
      [self.player pause];
    }else{//停止拖動
    }
  }else if ([keyPath isEqualToString:@"loadedTimeRanges"]){
    NSArray *array = _playItem.loadedTimeRanges;
    CMTimeRange timeRange = [array.firstObject CMTimeRangeValue];//本次緩沖時間范圍
    CGFloat startSeconds = CMTimeGetSeconds(timeRange.start);
    CGFloat durationSeconds = CMTimeGetSeconds(timeRange.duration);
    NSTimeInterval totalBuffer = startSeconds + durationSeconds;//緩沖總長度
    double progress = totalBuffer/CMTimeGetSeconds(_duration);
    if (self.blockLoadedTimeRanges) {
      self.blockLoadedTimeRanges(progress);
    }
    NSLog(@"當(dāng)前緩沖時間：%f",totalBuffer);
  }else if ([keyPath isEqualToString:@"playbackBufferEmpty"]){
    NSLog(@"緩存不夠，不能播放！");
  }else if ([keyPath isEqualToString:@"playbackLikelyToKeepUp"]){
    if (self.blockPlaybackLikelyToKeepUp) {
      self.blockPlaybackLikelyToKeepUp([change[@"new"] boolValue]);
    }
  }
}
-(void)setUrl:(NSURL *)url{
  _url = url;
  [self.player replaceCurrentItemWithPlayerItem:self.playItem];
}
-(AVPlayerItem *)playItem{
  _playItem = [[AVPlayerItem alloc] initWithURL:_url];
  //監(jiān)聽播放器的狀態(tài)，準(zhǔn)備好播放、失敗、未知錯誤
  [_playItem addObserver:self forKeyPath:@"status" options:NSKeyValueObservingOptionNew context:nil];
  //  監(jiān)聽緩存的時間
  [_playItem addObserver:self forKeyPath:@"loadedTimeRanges" options:NSKeyValueObservingOptionNew context:nil];
  //  監(jiān)聽獲取當(dāng)緩存不夠，視頻加載不出來的情況：
  [_playItem addObserver:self forKeyPath:@"playbackBufferEmpty" options:NSKeyValueObservingOptionNew context:nil];
  //  用于監(jiān)聽緩存足夠播放的狀態(tài)
  [_playItem addObserver:self forKeyPath:@"playbackLikelyToKeepUp" options:NSKeyValueObservingOptionNew context:nil];
  [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(private_playerMovieFinish) name:AVPlayerItemDidPlayToEndTimeNotification object:nil];
  return _playItem;
}
- (void)private_playerMovieFinish{
  NSLog(@"播放結(jié)束");
  if (self.blockPlayToEndTime) {
    self.blockPlayToEndTime();
  }
  if (_loop) {//默認(rèn)提供一個循環(huán)播放的功能
    [self.player pause];
    CMTime time = CMTimeMake(1, 1);
    __weak typeof(self)this = self;
    [self.player seekToTime:time completionHandler:^(BOOL finished) {
      [this.player play];
    }];
  }
}
-(void)dealloc{
  NSLog(@"-----銷毀-----");
}
@end

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