Question

我有多个imageview子视图根据我的传入数据进行堆叠。基本上所有这些子视图都根据我的输入数据设置为图像或视频图层。我遇到的问题是播放视频。我可以播放堆叠中的第一个视频，但之后的每个视频都只是第一个视频的声音。我怎么能相应地玩每一个？

通过像Snapchat这样的点击事件来浏览视图。见下文：

@interface SceneImageViewController ()

@property (strong, nonatomic) NSURL *videoUrl;
@property (strong, nonatomic) AVPlayer *avPlayer;
@property (strong, nonatomic) AVPlayerLayer *avPlayerLayer;

@end

@implementation SceneImageViewController

- (void)viewDidLoad {

[super viewDidLoad];

self.mySubviews = [[NSMutableArray alloc] init];
self.videoCounterTags = [[NSMutableArray alloc] init];

int c = (int)[self.scenes count];
c--;
NSLog(@"int c = %d", c);
self.myCounter = [NSNumber numberWithInt:c];


for (int i=0; i<=c; i++) {

    //create imageView
    UIImageView *imageView =[[UIImageView alloc] initWithFrame:CGRectMake(0, 0, self.view.bounds.size.width, self.view.bounds.size.height)];
    [imageView setUserInteractionEnabled:YES]; // <--- This is very important
    imageView.tag = i;                        // <--- Add tag to track this subview in the view stack
    [self.view addSubview:imageView];
    NSLog(@"added image view %d", i);


    //get scene object
    PFObject *sceneObject = self.scenes[i];


    //get the PFFile and filetype
    PFFile *file = [sceneObject objectForKey:@"file"];
    NSString *fileType = [sceneObject objectForKey:@"fileType"];



    //check the filetype
    if ([fileType  isEqual: @"image"])
    {
        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^{
        //get image
        NSURL *imageFileUrl = [[NSURL alloc] initWithString:file.url];
        NSData *imageData = [NSData dataWithContentsOfURL:imageFileUrl];
            dispatch_async(dispatch_get_main_queue(), ^{
        imageView.image = [UIImage imageWithData:imageData];
            });
        });

    }

    //its a video
    else
    {
        // the video player
        NSURL *fileUrl = [NSURL URLWithString:file.url];

        self.avPlayer = [AVPlayer playerWithURL:fileUrl];
        self.avPlayer.actionAtItemEnd = AVPlayerActionAtItemEndNone;

        self.avPlayerLayer = [AVPlayerLayer playerLayerWithPlayer:self.avPlayer];
        //self.avPlayerLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;

        [[NSNotificationCenter defaultCenter] addObserver:self
                                                 selector:@selector(playerItemDidReachEnd:)
                                                     name:AVPlayerItemDidPlayToEndTimeNotification
                                                   object:[self.avPlayer currentItem]];

        CGRect screenRect = [[UIScreen mainScreen] bounds];

        self.avPlayerLayer.frame = CGRectMake(0, 0, screenRect.size.width, screenRect.size.height);
        [imageView.layer addSublayer:self.avPlayerLayer];

        NSNumber *tag = [NSNumber numberWithInt:i+1];

        NSLog(@"tag = %@", tag);

        [self.videoCounterTags addObject:tag];

        //[self.avPlayer play];
    }



}



UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(viewTapped:)];

[self.view bringSubviewToFront:self.screen];

[self.screen addGestureRecognizer:tapGesture];


}


 - (void)viewTapped:(UIGestureRecognizer *)gesture{

NSLog(@"touch!");

[self.avPlayer pause];

int i = [self.myCounter intValue];
NSLog(@"counter = %d", i);



for(UIImageView *subview in [self.view subviews]) {

    if(subview.tag== i) {

        [subview removeFromSuperview];
    }
}

if ([self.videoCounterTags containsObject:self.myCounter]) {
    NSLog(@"play video!!!");
    [self.avPlayer play];
}

if (i == 0) {
    [self.avPlayer pause];
    [self.navigationController popViewControllerAnimated:NO];
}


i--;
self.myCounter = [NSNumber numberWithInt:i];


NSLog(@"counter after = %d", i);





}

Answer 1

看看你设置myCounter变量的方式。它被设置一次，在点击视图之前永远不会改变，然后将其设置为场景计数-1。

此外，尝试查看您设置为_avPlayer指针var的方式。它总是被设置，一遍又一遍，似乎在for循环中你想要存储引用，而不是简单地将相同的指针更新为场景集合中最新的值。

另外，来自Apple的documentation：

您可以使用相同的AVPlayer对象创建任意数量的播放器图层。只有最近创建的播放器图层才会在屏幕上实际显示视频内容。

所以，有可能因为你使用相同的AVPlayer对象来创建所有这些AVPlayer图层，所以你永远不会看到任何一个以上的实际视频图层。

Answer 2

Brooks Hanes所说的是正确的，你一直在压倒飞机。这就是我建议你做的事情：

将点击手势添加到imageView而不是屏幕（或者使用UIButton代替更简洁的方法）：

UIImageView *imageView =[[UIImageView alloc] initWithFrame:CGRectMake(0, 0, self.view.bounds.size.width, self.view.bounds.size.height)];
[imageView setUserInteractionEnabled:YES]; // <--- This is very important
imageView.tag = i;                        // <--- Add tag to track this subview in the view stack
[self.view addSubview:imageView];
NSLog(@"added image view %d", i);
UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:imageView action:@selector(viewTapped:)];
[imageView addGestureRecognizer:tapGesture];

通过这种方式，您可以在viewTapped:方法中获取所按下图片的标记，如下所示：gesture.view.tag而不是使用myCounter。

要让视频正常工作，您可以为每个视频创建一个新的AVPlayer，但这可能会使内存变得非常昂贵。更改视频时，更好的方法是使用AVPlayerItem并切换AVPlayer＆＃39; AVPlayerItem。

所以在for循环中执行类似的操作self.videoFiles属于NSMutableDictionary属性：

           // the video player
            NSNumber *tag = [NSNumber numberWithInt:i+1];
            NSURL *fileUrl = [NSURL URLWithString:file.url];
          //save your video file url paired with the ImageView it belongs to.
           [self.videosFiles setObject:fileUrl forKey:tag];
// you only need to initialize the player once.
            if(self.avPlayer == nil){
                AVAsset *asset = [AVAsset assetWithURL:fileUrl];
                AVPlayerItem *item = [[AVPlayerItem alloc] initWithAsset:asset];
                self.avPlayer = [[AVPlayer alloc] initWithPlayerItem:item];
                self.avPlayer.actionAtItemEnd = AVPlayerActionAtItemEndNone;
                [[NSNotificationCenter defaultCenter] addObserver:self
                    selector:@selector(playerItemDidReachEnd:)
                name:AVPlayerItemDidPlayToEndTimeNotification
                object:[self.avPlayer currentItem]];
            }
            // you don't need to keep the layer as a property 
            // (unless you need it for some reason 
            AVPlayerLayer* avPlayerLayer = [AVPlayerLayer playerLayerWithPlayer:self.avPlayer];
            avPlayerLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;

            CGRect screenRect = [[UIScreen mainScreen] bounds];                
            avPlayerLayer.frame = CGRectMake(0, 0, screenRect.size.width, screenRect.size.height);
            [imageView.layer addSublayer:avPlayerLayer];
            NSLog(@"tag = %@", tag);                
            [self.videoCounterTags addObject:tag];

现在在viewTapped：

 if ([self.videoCounterTags containsObject:gesture.view.tag]) { 

  NSLog(@"play video!!!");
    AVAsset *asset = [AVAsset assetWithURL:[self.videoFiles objectForKey:gesture.view.tag]];
    AVPlayerItem *item = [[AVPlayerItem alloc] initWithAsset:asset];
    self.avPlayer replaceCurrentItemWithPlayerItem: item];
    [self.avLayer play];
}

或者使用self.videoFiles，然后根本不需要self.videoCounterTags：

 NSURL* fileURL = [self.videoFiles objectForKey:gesture.view.tag];
 if (fileURL!=nil) {    
     NSLog(@"play video!!!");
     AVAsset *asset = [AVAsset assetWithURL:fileURL];
     AVPlayerItem *item = [[AVPlayerItem alloc] initWithAsset:asset];
     self.avPlayer replaceCurrentItemWithPlayerItem: item];
     [self.avLayer play];
 }

这是它的要点。

播放叠加的视频

2 个答案: