在2-3次后，AVplayer不会在ScrollView中显示

Question

我在滚动视图中添加了多个AVPlayer对象。这是第一次这工作正常，但当我回到我以前的观点，并再次回来，我无法看到在scrollView中的AVPlayer对象。

我需要多个AVPlayer的矩阵来显示我的视频的缩略图。

请尽快帮我

在此先感谢。

Answer 1

我有一个类似的问题，并经过大量的搜索后发现AVPLayerItem对象导致此问题。

基本上，当AVPlayer项目离开屏幕时，您需要确保所有内容都已正确释放，然后在屏幕上重新显示所有内容。

随着释放过程的一部分，包括行：

[AVPlayer replaceCurrentItemWithPlayerItem:nil]; 

那排序的非常类似的问题对我来说。

Answer 2

[AVPlayer replaceCurrentItemWithPlayerItem:nil]; 

也解决了我无法立即释放当前播放器项目的问题。 （不能做手工，因为它是由类保留..）

Answer 3

这里是你如何得到10个AVPlayers同时播放，同样的滚动视图，每一次你里面滚动它：

// 
// ViewController.m 
// VideoWall 
// 
// Created by James Alan Bush on 6/13/16. 
// Copyright © 2016 James Alan Bush. All rights reserved. 
// 

#import "ViewController.h" 
#import "AppDelegate.h" 

static NSString *kCellIdentifier = @"Cell Identifier"; 

@interface ViewController() { 
    dispatch_queue_t dispatchQueueLocal; 
} 

@end 

@implementation ViewController 

- (id)initWithCollectionViewLayout:(UICollectionViewFlowLayout *)layout 
{ 
    if (self = [super initWithCollectionViewLayout:layout]) 
    { 
     [self.collectionView registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:kCellIdentifier]; 
     dispatchQueueLocal = dispatch_queue_create("local session queue", DISPATCH_QUEUE_CONCURRENT); 
    } 
    return self; 
} 

- (void)viewDidLoad { 
    [super viewDidLoad]; 

    [self.collectionView setDataSource:self]; 
    [self.collectionView setContentSize:CGSizeMake(AppDelegate.sharedAppDelegate.width, AppDelegate.sharedAppDelegate.height)]; 
} 


- (void)didReceiveMemoryWarning { 
    [super didReceiveMemoryWarning]; 
} 

- (void)dealloc { 
    [super dealloc]; 
} 

#pragma mark <UICollectionViewDataSource> 

- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView { 
    return 1; 
} 

#pragma mark - UICollectionViewDataSource 

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section { 
    return AppDelegate.sharedAppDelegate.assetsFetchResults.count; 
} 

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath { 

    UICollectionViewCell *cell = (UICollectionViewCell *)[collectionView dequeueReusableCellWithReuseIdentifier:kCellIdentifier forIndexPath:indexPath]; 
    [CATransaction begin]; 
    [CATransaction setCompletionBlock:^{ 
     cell.contentView.layer.sublayers = nil; 
     dispatch_release(dispatchQueueLocal); 
    }]; 
    dispatch_retain(dispatchQueueLocal); 
    dispatch_async(dispatchQueueLocal, ^{ 
     [self drawPlayerLayerForCell:cell atIndexPath:indexPath]; 
    }); 
    [CATransaction commit]; 

    return cell; 
} 

- (void)drawPlayerLayerForCell:(UICollectionViewCell *)cell atIndexPath:(NSIndexPath *)indexPath { 
    void (^drawPlayerLayer)(UICollectionViewCell*, NSIndexPath*) = ^(UICollectionViewCell* cell, NSIndexPath* indexPath) { 
     [AppDelegate.sharedAppDelegate.imageManager requestPlayerItemForVideo:AppDelegate.sharedAppDelegate.assetsFetchResults[indexPath.item] options:nil resultHandler:^(AVPlayerItem * _Nullable playerItem, NSDictionary * _Nullable info) { 
      dispatch_async(dispatch_get_main_queue(), ^{ 
       if(![[info objectForKey:PHImageResultIsInCloudKey] boolValue]) { 
        AVPlayerLayer *playerLayer = [AVPlayerLayer playerLayerWithPlayer:[AVPlayer playerWithPlayerItem:playerItem]]; 
        [playerLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill]; 
        [playerLayer setBorderColor:[UIColor whiteColor].CGColor]; 
        [playerLayer setBorderWidth:1.0f]; 
        [playerLayer setFrame:cell.contentView.bounds]; 

        [cell.contentView.layer addSublayer:playerLayer]; 
        [(AVPlayer *)playerLayer.player play]; 

       } else { 
        [AppDelegate.sharedAppDelegate.imageManager requestImageForAsset:AppDelegate.sharedAppDelegate.assetsFetchResults[indexPath.item] 
                      targetSize:CGSizeMake(AppDelegate.sharedAppDelegate.flowLayout.itemSize.width, AppDelegate.sharedAppDelegate.flowLayout.itemSize.height) 
                     contentMode:PHImageContentModeAspectFill 
                      options:nil 
                     resultHandler:^(UIImage *result, NSDictionary *info) { 
                      dispatch_async(dispatch_get_main_queue(), ^{ 
                       cell.contentView.layer.contents = (__bridge id)result.CGImage; 
                      }); 
                     }]; 
       } 
      }); 
     }]; 
    }; 
    drawPlayerLayer(cell, indexPath); 
} 

@end 

以下是AppDelegate实施文件：

// 
// AppDelegate.m 
// VideoWall 
// 
// Created by James Alan Bush on 6/13/16. 
// Copyright © 2016 James Alan Bush. All rights reserved. 
// 

#import "AppDelegate.h" 
#import "ViewController.h" 

@implementation AppDelegate 

+ (AppDelegate *)sharedAppDelegate 
{ 
    return (AppDelegate *)[[UIApplication sharedApplication] delegate]; 
} 

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { 
    // Override point for customization after application launch 

    self.width = [[UIScreen mainScreen] bounds].size.width/2.0; 
    self.height = [[UIScreen mainScreen] bounds].size.height/4.0; 

    self.window     = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]]; 
    self.window.rootViewController = [self viewController]; 
    self.window.rootViewController.view = self.viewController.view; 


    [self.window makeKeyAndVisible]; 

    return YES; 
} 

- (ViewController *)viewController { 
    ViewController *c = self->_viewController; 
    if (!c) { 
     c = [[ViewController alloc] initWithCollectionViewLayout:[self flowLayout]]; 
     [c.view setFrame:[[UIScreen mainScreen] bounds]]; 
     self->_viewController = c; 
    } 
    return c; 
} 

- (UICollectionViewFlowLayout *)flowLayout { 
    UICollectionViewFlowLayout *v = self->_flowLayout; 
    if (!v) { 
     v = [UICollectionViewFlowLayout new]; 
     [v setItemSize:CGSizeMake(AppDelegate.sharedAppDelegate.width, AppDelegate.sharedAppDelegate.height)]; 
     [v setSectionInset:UIEdgeInsetsMake(0.0, 0.0, 0.0, 0.0)]; 
     [v setMinimumLineSpacing:0.0]; 
     [v setMinimumInteritemSpacing:0.0]; 
     [v setEstimatedItemSize:CGSizeMake(AppDelegate.sharedAppDelegate.width, AppDelegate.sharedAppDelegate.height)]; 
     self->_flowLayout = v; 
    } 
    return v; 
} 

- (PHCachingImageManager *)imageManager { 
    PHCachingImageManager *i = self->_imageManager; 
    if (!i) { 
     i = [[PHCachingImageManager alloc] init]; 
     self->_imageManager = i; 
    } 
    return i; 
} 

- (PHFetchResult *)assetsFetchResults { 
    PHFetchResult *i = self->_assetsFetchResults; 
    if (!i) { 
     PHFetchResult *smartAlbums = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeSmartAlbum subtype:PHAssetCollectionSubtypeSmartAlbumVideos options:nil]; 
     PHAssetCollection *collection = smartAlbums.firstObject; 
     if (![collection isKindOfClass:[PHAssetCollection class]]) 
      return nil; 
     PHFetchOptions *allPhotosOptions = [[PHFetchOptions alloc] init]; 
     allPhotosOptions.sortDescriptors = @[[NSSortDescriptor sortDescriptorWithKey:@"creationDate" ascending:NO]]; 
     i = [PHAsset fetchAssetsInAssetCollection:collection options:allPhotosOptions]; 
     self->_assetsFetchResults = i; 
    } 
    return i; 
} 

- (void)applicationWillResignActive:(UIApplication *)application { 
    // Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state. 
    // Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game. 
} 

- (void)applicationDidEnterBackground:(UIApplication *)application { 
    // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later. 
    // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits. 
} 

- (void)applicationWillEnterForeground:(UIApplication *)application { 
    // Called as part of the transition from the background to the inactive state; here you can undo many of the changes made on entering the background. 
} 

- (void)applicationDidBecomeActive:(UIApplication *)application { 
    // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface. 
} 

- (void)applicationWillTerminate:(UIApplication *)application { 
    // Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:. 
} 

@end 

这些是您需要的唯一两个文件;没有NIB/XIB。