我收到了以下错误,但奇怪的是,只有当我使用分页在我的tableview上滚动,加载第二组帖子,而不是我尝试移出新视图控制器, 如果我只加载帖子的第一页,并移出到另一个视图控制器,则没有崩溃:
Terminating app due to uncaught exception 'NSInternalInconsistencyException',
reason: 'An instance 0x170212330 of class AVPlayerItem was deallocated while key
value observers were still registered with it.
Current observation info: <NSKeyValueObservationInfo 0x174820360> (
<NSKeyValueObservance 0x174244290: Observer: 0x101c76c00, Key path:
playbackBufferEmpty, Options: <New: YES, Old: NO, Prior: NO> Context: 0x0,
Property: 0x174243ea0>
<NSKeyValueObservance 0x1754583c0: Observer: 0x101c76c00, Key path:
playbackLikelyToKeepUp, Options: <New: YES, Old: NO, Prior: NO> Context: 0x0,
Property: 0x174243f60>
我的手机上有一个播放器,这是我的视图控制器代码:
- (UITableViewCell *)tableView:(UITableView *)tableViewSelected cellForRowAtIndexPath:(NSIndexPath *)indexPath {
NSString *identifier = @"postCell";
PostCell* updateCell = [tableViewSelected dequeueReusableCellWithIdentifier:identifier];
dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0ul);
dispatch_async(queue, ^{
dispatch_sync(dispatch_get_main_queue(), ^{
NSLog(@"ADD VIDEO PLAYER and PLAY VIDEO");
NSString* videoString = [NSString stringWithFormat:@"%@%@%@",UrlBase,PostVideos,post.video];
NSString* expandedPath = [videoString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSURL *videoURL = [NSURL URLWithString:expandedPath];
NSLog(@"URL : %@",videoURL);
updateCell.videoItem = [AVPlayerItem playerItemWithURL:videoURL];
[updateCell.videoItem addObserver:updateCell forKeyPath:@"playbackBufferEmpty" options:NSKeyValueObservingOptionNew context:nil];
[updateCell.videoItem addObserver:updateCell forKeyPath:@"playbackLikelyToKeepUp" options:NSKeyValueObservingOptionNew context:nil];
updateCell.videoPlayer = [AVPlayer playerWithPlayerItem:updateCell.videoItem];
updateCell.avLayer = [AVPlayerLayer playerLayerWithPlayer:updateCell.videoPlayer];
updateCell.videoPlayer.actionAtItemEnd = AVPlayerActionAtItemEndNone;
[[NSNotificationCenter defaultCenter] addObserver:updateCell selector:@selector(itemDidBufferPlaying:) name:AVPlayerItemPlaybackStalledNotification object:nil];
[[NSNotificationCenter defaultCenter] addObserver:updateCell selector:@selector(itemDidFinishPlaying:) name:AVPlayerItemDidPlayToEndTimeNotification object:[updateCell.videoPlayer currentItem]];
updateCell.avLayer.frame = updateCell.picture.bounds;
[updateCell.videoView.layer addSublayer:updateCell.avLayer];
[updateCell.avLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill];
if(indexPath.row==0){
[updateCell.videoPlayer play];
}
});
});
return updateCell;
}
我在添加第二页时可以看到的唯一区别是:
在执行常规表视图加载时,我执行:
[_tableView reloadData];
在同一个表格视图中加载第二页时,我会这样做:
[_tableView beginUpdates];
[_tableView insertRowsAtIndexPaths:[[GlobalSingleton sharedInstance] indexPathsToInsert] withRowAnimation:UITableViewRowAnimationTop];
[_tableView endUpdates];
比我的手机还要:
- (void)prepareForReuse{
[self removePlayer];
}
- (void) dealloc {
[self removePlayer];
}
-(void)removePlayer{
@try{
[self.videoItem removeObserver:self forKeyPath:@"playbackBufferEmpty"];
[self.videoItem removeObserver:self forKeyPath:@"playbackLikelyToKeepUp"];
[[NSNotificationCenter defaultCenter] removeObserver:self name:AVPlayerItemPlaybackStalledNotification object:nil];
[[NSNotificationCenter defaultCenter] removeObserver:self name:AVPlayerItemDidPlayToEndTimeNotification object:nil];
NSLog(@"remove Observer!");
// [avLayer.player pause];
}
@catch (NSException * e) {
NSLog(@"Exception: %@", e);
}
@finally {
NSLog(@"finally");
[self.avLayer removeFromSuperlayer];
self.playIV.hidden = YES;
self.videoActivity.hidden = YES;
self.videoView.hidden = YES;
self.videoItem = nil;
self.avLayer = nil;
self.videoPlayer = nil;
}
}
insertRowsAtIndexPaths是否可能导致单元格永远不会被释放?我无法找到让观察员注册的可能性。
答案 0 :(得分:0)
在使用insertRowsAtIndexPaths时,不会调用prepareForReuse,因此我在将新视频项添加到Cell之前,通过取消注册cellForRowAtIndexPath上的观察者来解决它:
- (UITableViewCell *)tableView:(UITableView *)tableViewSelected cellForRowAtIndexPath:(NSIndexPath *)indexPath {
NSString *identifier = @"postCell";
PostCell* updateCell = [tableViewSelected dequeueReusableCellWithIdentifier:identifier];
dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0ul);
dispatch_async(queue, ^{
dispatch_sync(dispatch_get_main_queue(), ^{
NSString* videoString = [NSString stringWithFormat:@"%@%@%@",UrlBase,PostVideos,post.video];
NSString* expandedPath = [videoString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSURL *videoURL = [NSURL URLWithString:expandedPath];
/** SOLUTION STARTS HERE **/
@try{
[self.videoItem removeObserver:self forKeyPath:@"playbackBufferEmpty"];
[self.videoItem removeObserver:self forKeyPath:@"playbackLikelyToKeepUp"];
[[NSNotificationCenter defaultCenter] removeObserver:self name:AVPlayerItemPlaybackStalledNotification object:nil];
[[NSNotificationCenter defaultCenter] removeObserver:self name:AVPlayerItemDidPlayToEndTimeNotification object:nil];
}
@catch (NSException * e) {
NSLog(@"Exception: %@", e);
}
@finally {
NSLog(@"finally");
}
/** SOLUTION ENDS HERE **/
updateCell.videoItem = [AVPlayerItem playerItemWithURL:videoURL];
[updateCell.videoItem addObserver:updateCell forKeyPath:@"playbackBufferEmpty" options:NSKeyValueObservingOptionNew context:nil];
[updateCell.videoItem addObserver:updateCell forKeyPath:@"playbackLikelyToKeepUp" options:NSKeyValueObservingOptionNew context:nil];
updateCell.videoPlayer = [AVPlayer playerWithPlayerItem:updateCell.videoItem];
updateCell.avLayer = [AVPlayerLayer playerLayerWithPlayer:updateCell.videoPlayer];
updateCell.videoPlayer.actionAtItemEnd = AVPlayerActionAtItemEndNone;
[[NSNotificationCenter defaultCenter] addObserver:updateCell selector:@selector(itemDidBufferPlaying:) name:AVPlayerItemPlaybackStalledNotification object:nil];
[[NSNotificationCenter defaultCenter] addObserver:updateCell selector:@selector(itemDidFinishPlaying:) name:AVPlayerItemDidPlayToEndTimeNotification object:[updateCell.videoPlayer currentItem]];
updateCell.avLayer.frame = updateCell.picture.bounds;
[updateCell.videoView.layer addSublayer:updateCell.avLayer];
[updateCell.avLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill];
if(indexPath.row==0){
[updateCell.videoPlayer play];
}
});
});
return updateCell;
}