class AVPlayerItem was deallocated while key value observers were still registered - uitableview

Question

I'm getting the following error, but the strange thing is that it only happens when I do a scroll on my tableview using the pagination, loading a second set of posts, and than I try to move out to new view controller,
if I load only the first page of posts, and move out to another view controller, there is no crash:
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>
I have a player on my cell, here is my code for view controller:
- (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;
}
And the only difference I can see from adding a second page is:
When doing regular table view load I do:
[_tableView reloadData];
When loading a second page on the same table view I do:
[_tableView beginUpdates];
[_tableView insertRowsAtIndexPaths:[[GlobalSingleton sharedInstance] indexPathsToInsert] withRowAnimation:UITableViewRowAnimationTop];
[_tableView endUpdates];
Than on my Cell I do:
- (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;
}
}
Is it possible that insertRowsAtIndexPaths is causing the cells to never be dealloc? I can't find how its possible to have the observers registered.

Answer 1

Somehow when using the insertRowsAtIndexPaths, the prepareForReuse is not been called, so I resolved it by unregistering the observers on the cellForRowAtIndexPath before adding a new videoItem to the Cell:
- (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;
}