1

私はavfoundationビデオプレーヤー内でビデオをループしています：

NSString *loopPath = @"SubView/introCycle";
NSURL *fileURL = [[NSBundle mainBundle] URLForResource:loopPath withExtension:@"mp4"];
AVURLAsset *asset = [AVURLAsset URLAssetWithURL:fileURL options:nil];
NSString *tracksKey = @"tracks";
[asset loadValuesAsynchronouslyForKeys:@[tracksKey] completionHandler:^{
    // The completion block goes here.
    //NSLog(@"asset loaded asynchronously completed!");

    // Completion handler block.
    dispatch_async(dispatch_get_main_queue(),

                   ^{
                       NSError *error;
                       AVKeyValueStatus status = [asset statusOfValueForKey:tracksKey error:&error];

                       if (![self avPlayer] && status == AVKeyValueStatusLoaded) {
                           if(![self playerItem]){
                               self.playerItem = [AVPlayerItem playerItemWithAsset:asset];
                               [self.playerItem addObserver:self forKeyPath:@"status" options:0 context:AVMoviePlayerViewControllerStatusObservationContext];
                               self.avPlayer.actionAtItemEnd = AVPlayerActionAtItemEndNone;
                               [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(playerItemDidReachEnd:)
                                                                     name:AVPlayerItemDidPlayToEndTimeNotification
                                                                     object:[self.avPlayer currentItem]];
                           }
                           self.avPlayer = [AVPlayer playerWithPlayerItem:self.playerItem];
                           [self.VideoLoopView setPlayer:self.avPlayer];
                       }

                       else {
                           // You should deal with the error appropriately.
                           NSLog(@"The asset's tracks were not loaded:\n%@", [error localizedDescription]);
                       }
                   });
}];

ループの終わりに、次のメソッドはビデオを再開します

int countRounds = 0;
- (void)playerItemDidReachEnd:(NSNotification *)notification {
    *//block 1 - this is what we like*
    if (notification.object == self.playerItem) {

        countRounds++;

        [self.playerItem seekToTime:kCMTimeZero];
        [self.avPlayer play];

        }
    }
    *// block 2 - this we don't like*
    else {
        NSInteger reason = [[notification.userInfo objectForKey:AVPlayerItemDidPlayToEndTimeNotification] integerValue];
        NSLog(@"reason: %i", reason);
    }
    NSLog(@"playerItemDidReachEnd, starting round %i", countRounds);
}

これは正常に動作します。ブロック1のみが実行されます。ログショー

MainView did load 
playerItemDidReachEnd, starting round 1 
playerItemDidReachEnd, starting round 2 
...

次に、別のビューをロードして、ビデオループビューに戻ります。メインビューを離れるとき

- (void)viewDidDisappear:(BOOL)animated
{ 
    [[NSNotificationCenter defaultCenter]   removeObserver:self
                                            name:AVPlayerItemDidPlayToEndTimeNotification
                                            object:[self.avPlayer currentItem]];
    [self.avPlayer pause];
    self.avPlayer = nil;
    self.playerItem = nil;


    [super viewDidDisappear:animated];
    NSLog(@"MainView DidDisappear");
}

メインビューをリロードすると、ビデオがリロードされ、ループが正常に再生されます。しかし、ループの最後に、ブロック1とブロック2の両方が実行され、ログに記録されます。

MainView did load (from old log above)
playerItemDidReachEnd, starting round 1 *(from old log above)*
playerItemDidReachEnd, starting round 2 *(from old log above)*
MainView DidDisappear   *(leaving the main view and loading a new one)*
MainView did load *(coming back to main view)*
reason: 0 *(block 2 is executed, triggered by what exactly? WHERE DOES THIS COME FROM?)*
playerItemDidReachEnd, starting round 2
playerItemDidReachEnd, starting round 3 *(this comes from block 1 - we like)*
reason: 0
playerItemDidReachEnd, starting round 3
playerItemDidReachEnd, starting round 4
reason: 0
playerItemDidReachEnd, starting round 4
playerItemDidReachEnd, starting round 5

したがって、ループの最後に、playerItemDidReachEndメソッドが2回トリガーされます。何故ですか？これはどこから来たのですか？

4

1 に答える 1

7

を使用して、間違った通知からのトリガーを回避できます。

if (notification.object == self.playerItem) ...
于 2012-09-02T17:46:08.170 に答える