如何在下一页上更改AVAsset的URL并在没有内存问题iOS的情况下转到上一页

2 回答

• 0

  您将不得不添加逻辑来查看控制器2的viewWillDisappear方法以停止和释放AVPlayer，并移动创建AVPlayer的逻辑并启动它来播放viewWillAppear（这样当您弹出视图控制器3并返回查看时控制器2你可以再次播放视图控制器2的视频 . ）

  你如何做到这一点取决于你如何管理AVPlayer . 发布设置AVPlayer的VC2代码，并在VC2的层次结构中安装其回放层 . （编辑原始问题以包含该信息 . 不要在评论中发布代码 . 这几乎是不可读的 . ）

  回复于 2024-05-04T07:09:11+08:00
• 0

  这是我为scenario3做的事情：

  -(void)goToNextPage
  {
  //This stops the video....
   [player replaceCurrentItemWithPlayerItem:nil];
  }
  

  现在我正在创建一个委托 . 所以现在VC2充当VC3的委托 . 所以当我在VC3上时，我编写了一个代码来生成一个新的Url，并将其传递给VC2中的一个属性 .

  所以我得出结论，只要VC2加载到内存中，我就不需要在VC2中解除分配AVPlayer . 同时，也不需要删除与之关联的观察者 .

  这是AVPlayer及其观察者的完整演示 . 我相信它将帮助每个开始使用AVFoundation和观察者的人 .

  // VC1

  -(IBAction)gotoPlayer:(id)sender
  {
  
    PlayerViewController *playerVC = [self.storyboard instantiateViewControllerWithIdentifier:@"PlayerViewController"];
    [self.navigationController pushViewController:playerVC animated:YES];
  }
  

  //VC2.h

  @interface PlayerViewController : UIViewController<ChangeUrlDelegate>
  @property (nonatomic,strong) NSURL *url;
  
  -(void)playWithURL:(NSURL*)url_;
  
  @end
  

  //VC2.m

  -(void)viewDidLoad
  {
      [self setPlayerDataOnPageArrival];
  }
  
  
  -(void)viewDidAppear:(BOOL)animated
  {
   if(self.url)
      [self playWithURL:self.url];
   else{
        NSString *path = [[NSBundle mainBundle]pathForResource:@"sample_mpeg4" ofType:@"mp4"];
        PlayerSource *source_ = [[PlayerSource alloc]initWithURL:[[NSURL alloc] initFileURLWithPath:path]];
        [self playWithURL:source_.sourceURL];
      }
  }
  
  
  -(void)dealloc
  {
  
    NSLog(@"In playerViewController dealloc");
    [playerItem_ removeObserver:self forKeyPath:@"status"];
    [player_ removeTimeObserver:self.timeObserver];
    [[NSNotificationCenter defaultCenter]removeObserver:self   name:self.itemEndObserver object:playerItem_];
  }
  
  
  #pragma mark ChangeURLViewController delegate methods
  
  -(void)newURL:(NSURL *)url_
  {
    self.url = url_;
  }
  
  
  #pragma mark player methods
  
  -(void)setPlayerDataOnPageArrival{
  
  NSString *path = [[NSBundle mainBundle]pathForResource:@"sample_mpeg4" ofType:@"mp4"];
  PlayerSource *source_ = [[PlayerSource alloc]initWithURL:[[NSURL alloc] initFileURLWithPath:path]];
  self.url = source_.sourceURL;
  asset_ = [AVAsset assetWithURL:self.url];
  
  playerItem_ = [AVPlayerItem playerItemWithAsset:asset_];
  NSLog(@"observer added");
  [playerItem_ addObserver:self forKeyPath:@"status" options:0 context:nil];
  
  player_ = [AVPlayer playerWithPlayerItem:playerItem_];
  playerLayer = [AVPlayerLayer playerLayerWithPlayer:player_];
  
  }
  
  
  -(void)playWithURL:(NSURL*)url_{
  
  [playerLayer setFrame:self.playerView.frame];
  
  if(self.playerView.layer.sublayers.count == 0)
      [self.playerView.layer addSublayer:playerLayer];
  else{
  
      AVPlayerItem *newPlayerItem_ = [AVPlayerItem playerItemWithURL:url_];
      [player_ replaceCurrentItemWithPlayerItem:newPlayerItem_];
  
      NSLog(@"rate--->%f",player_.rate);
      if(player_.rate == 0 && player_.status == 1)
          player_.rate = 1;
      }
  }
  
  
  -(void)addPlayerItemTimeObserver{
  
  CMTime interval = CMTimeMakeWithSeconds(0.01,NSEC_PER_SEC);
   //   __weak PlayerViewController *weakSelf = self;
      self.timeObserver = [player_ addPeriodicTimeObserverForInterval:interval queue:dispatch_get_main_queue() usingBlock:^(CMTime time) {
  
      //NSLog(@"in addPlayerItemTimeObserver");
  
      CGFloat currentTime = CMTimeGetSeconds(time);
      NSLog(@"currentTime--->%f",currentTime);
      }];
  }
  
  
  -(void)addItemEndObserverForPlayerItem{
  
  //When playback completes,an AVPlayerItem posts a notification called "AVPlayerItemDidPlayToEndTimeNotification"
  
  self.itemEndObserver = AVPlayerItemDidPlayToEndTimeNotification;
  
  [[NSNotificationCenter defaultCenter]addObserverForName:self.itemEndObserver object:nil queue:NULL usingBlock:^(NSNotification * _Nonnull note) {
  
      NSLog(@"in item end observer");
      }];
  }
  
  
  
  #pragma mark player status observer
  
  -(void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary<NSString *,id> *)change context:(void *)context{
  
  NSLog(@"In observer");
  
  if (playerItem_.status == AVPlayerItemStatusReadyToPlay) {
  
      NSLog(@"success");
      [self addPlayerItemTimeObserver];
      [self addItemEndObserverForPlayerItem];
      [player_ play];
  }
  
  else if(player_.status == AVPlayerItemStatusFailed){
  
      NSLog(@"failed");
  }
  
  else if(player_.status == AVPlayerItemStatusUnknown){
  
      NSLog(@"Unknown");
      }  
  }
  
  #pragma mark action methods
  
  -(IBAction)goToNextPage:(id)sender{
  
  [player_ replaceCurrentItemWithPlayerItem:nil];
  ChangeURLViewController *changeUrlVC_ = [self.storyboard instantiateViewControllerWithIdentifier:@"ChangeURLViewController"];
  changeUrlVC_.delegate=self;
  self.url = nil;
  [self.navigationController pushViewController:changeUrlVC_ animated:YES];
  
  }
  
  
  -(IBAction)changeURL:(id)sender{
  
  NSString *path = [[NSBundle mainBundle]pathForResource:@"sample_mpeg4" ofType:@"mp4"];
  PlayerSource *source_ = [[PlayerSource alloc]initWithURL:[[NSURL alloc] initFileURLWithPath:path]];
  [self playWithURL:source_.sourceURL];
  }
  

  //VC3.h

  @protocol ChangeUrlDelegate <NSObject>
  
    -(void)newURL:(NSURL*)url_;
  
  @end
  
  @interface ChangeURLViewController : UIViewController
  
    @property (weak,nonatomic) id <ChangeUrlDelegate> delegate;
  
  @end
  

  //VC3.m

  -(void)dealloc{
  
      NSLog(@"In changeURL dealloc");
  }
  
  -(IBAction)changeURLAction:(id)sender{
  
       NSString *path = [[NSBundle mainBundle]pathForResource:@"sample_mpeg4" ofType:@"mp4"];
      PlayerSource *source_ = [[PlayerSource alloc]initWithURL:[[NSURL alloc] initFileURLWithPath:path]];
      NSLog(@"delegate---->%@",self.delegate);
      [self.delegate newURL:source_.sourceURL];
      [self.navigationController popViewControllerAnimated:YES];
  
      }
  

  注意：请注意，您应该在每个视图控制器中使用dealloc（），并且应该超时调用视图控制器从内存中删除（弹出导航堆栈） .

  回复于 2024-05-04T07:09:11+08:00