Question

我在我建立的名为MPMoviePlayerController的类中使用MYVideo。这是代码：

#import <MediaPlayer/MediaPlayer.h>
#import "MYVideo.h"

@interface MYVideo()
@property (strong, nonatomic) UIView * viewRef;
@property (strong, nonatomic) NSDictionary * contentData;
@property (strong, nonatomic) MPMoviePlayerController * videoController;
@end

@implementation MYVideo
@synthesize contentData,videoController,viewRef;

- (MYVideo*) initIntoView: (UIView*) view withContent:(NSDictionary*)contentDict{
    self=[super init];
    viewRef=view;
    contentData = contentDict;
    NSString *rawUrl = [[NSString alloc] initWithFormat:@"http://....com/app/%@.mp4", [contentDict objectForKey:@"cnid"]];
    NSURL *videoUrl = [[NSURL alloc]initWithString:rawUrl];
    videoController = [[MPMoviePlayerController alloc] initWithContentURL:videoUrl];
    videoController.movieSourceType=MPMovieSourceTypeFile;
    videoController.view.frame = viewRef.bounds;
    [videoController.view setAutoresizingMask:UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight];
    videoController.controlStyle=MPMovieControlStyleNone; 
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(playbackFinished:)
                                                 name:MPMoviePlayerPlaybackDidFinishNotification
                                               object:videoController];
    [viewRef addSubview:videoController.view];
    return self;
}

- (void) playbackFinished: (NSNotification*) notification {
    NSLog(@"playback finished");
    if(videoController){
        [videoController play];
    }
}

- (void) play: (int) offset {
    videoController.initialPlaybackTime=offset;
    [videoController play];
}

- (void) stop {
    [[NSNotificationCenter defaultCenter] removeObserver:self
                                                    name:@"playbackFinished"
                                                  object:nil];
    if(videoController){
        [videoController stop];
    }
}

- (void) destroy {
    if(videoController){
        [videoController stop];
        [videoController.view removeFromSuperview];
    }
}
@end

我的问题是我偶尔会收到以下错误：

playback finished
-[__NSCFString playbackFinished:]: unrecognized selector sent to instance 0x1664e6a0

我猜这是由MPMoviePlayerController在此视频类发布时触发“playbackFinished”通知引起的。我是否正确地想到了这一点？

事实是，这个MYVideo类应该在播放视频时仍然存在，此错误仅在视频播放时发生，并且在控制台日志中，我的NSLogging“播放完成”立即在崩溃之前。在没有先删除“playbackFinished”观察者的情况下，我也从未关闭过课程。

有人可以告诉我为什么我会遇到这次崩溃吗？

非常感谢。

Answer 1

是的，看起来你没有删除观察者，就像这段代码：

[[NSNotificationCenter defaultCenter] removeObserver:self
                                                name:@"playbackFinished"
                                              object:nil];

应该是：

[[NSNotificationCenter defaultCenter] removeObserver:self
                                                name:@"playbackFinished:"
                                              object:nil];         //  ^

或更好（因为你并不关心所谓的）：

[[NSNotificationCenter defaultCenter] removeObserver:self
                                                name:nil
                                              object:videoController];

另外，如果您在很多地方使用if (videoController) { ... }等测试，则需要尽快确保nil：

- (void)destroy {
    if(videoController){
        [videoController stop];
        [videoController.view removeFromSuperview];
        videoController = nil;   // Add
    }
}

来自MPMoviePlayerController的__NSCFString playbackFinished无法识别的选择器

1 个答案: