Question

威斯康星州有一个iPad自助服务终端应用程序，可通过HDMI连接到iPad的外接显示器上显示视频。我有一个viewController来管理外部监视器上的视图。当我完成播放视频时，我忽略了MPMoviePlayerController实例。在iOS7中，这可以正常工作，但在iOS8中，我将moviePlayer设置为nil后会出现严重崩溃。

- (void)removeMoviePlayer {
[self.moviePlayerController.view removeFromSuperview];
[self removeMovieNotificationHandlers];
self.moviePlayerController = nil;}

启用Zombies后，我在调试器中收到一条消息：

[MPAVController release]: message sent to deallocated instance

同样，当应用程序在iOS7下运行时，不会发生此崩溃。导致此次崩溃的变化是什么？

Answer 1

经过几天的反复试验后，我发现当MPMoviePlayerPlaybackState为MPMoviePlaybackStatePaused时尝试取消MPMoviePlayerController实例时，应用程序会崩溃。当视频到达结尾时，MPMoviePlayerController发送MPMoviePlaybackDidFinish通知，该通知将回放状态报告为MPMoviePlaybackStatePaused。修复是测试播放状态，如果暂停调用[MPMoviePlayerController stop]。这会将MPMoviePlaybackState更改为MPMoviePlaybackStateStopped，然后您可以在不崩溃的情况下将实例清零。

这次崩溃在iOS 8之前没有发生。代码如下：

-(void)moviePlayBackDidFinish:(NSNotification *)notification {
    [self stopVideo:notification];
}

- (void)stopVideo:(NSNotification *)notification {
    if (self.moviePlayerController) {
        if (self.moviePlayerController.playbackState == MPMoviePlaybackStatePlaying || self.moviePlayerController.playbackState == MPMoviePlaybackStatePaused) {
            [self.moviePlayerController stop];
        }
        [self cleanUpVideo];
    }
}

- (void)cleanUpVideo {
    [self killProgressTimer];

    [UIView animateWithDuration:1.0f animations:^{
        self.closedCaptionLabel.alpha = 0.0f;
        self.moviePlayerController.view.alpha = 0.0f;
        self.backgroundImageView.alpha = 1.0f;
    } completion:^(BOOL finished) {
        [self removeMoviePlayer];
        [self resetClosedCaptions];
        [self.delegate videoDidStop];
    }];
}

- (void)removeMoviePlayer {
    [self.moviePlayerController.view removeFromSuperview];
    [self removeMovieNotificationHandlers];
    self.moviePlayerController = nil;

}

将对象设置为nil iOS7 vs iOS8

1 个答案: