addPeriodicTimeObserverForInterval 调用额外时间

Question

我有一个 4 秒视频 ( NSTimeInterval duration = CMTimeGetSeconds(self.playerItem.asset.duration)= 4)的 AVPlayer 。

我想通过更改更新用户界面：

self.periodicTimeObserver = [self.player addPeriodicTimeObserverForInterval:CMTimeMake(1, 1) queue:dispatch_get_main_queue() usingBlock:^(CMTime time) {

    [weakSelf currentTimeDidChange:CMTimeGetSeconds(time)];

}];

但由于某些原因，我收到了对 UI 的额外调用：

- (void)currentTimeDidChange:(NSTimeInterval)currentTime {
    NSLog(@"timePassed %f, total: %f", currentTime, self.duration);
}

日志：

2015-07-23 13:47:07.412   timePassed 0.000000, total: 4.000000
2015-07-23 13:47:07.448   timePassed 0.002814, total: 4.000000
2015-07-23 13:47:07.450   timePassed 0.005481, total: 4.000000
2015-07-23 13:47:08.447   timePassed 1.001473, total: 4.000000
2015-07-23 13:47:09.446   timePassed 2.001612, total: 4.000000
2015-07-23 13:47:10.446   timePassed 3.002021, total: 4.000000
2015-07-23 13:47:11.446   timePassed 4.002139, total: 4.000000
2015-07-23 13:47:12.445   timePassed 5.001977, total: 4.000000
2015-07-23 13:47:12.492   timePassed 5.046618, total: 4.000000

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Answer 1

您需要确保您没有多次调用periodicTimeObserver，因此请编写此代码

if (self.periodicTimeObserver == nil){
self.periodicTimeObserver = [self.player addPeriodicTimeObserverForInterval:CMTimeMake(1, 1) queue:dispatch_get_main_queue() usingBlock:^(CMTime time) {

    [weakSelf currentTimeDidChange:CMTimeGetSeconds(time)];

}];
}

然后一旦您的视频播放完毕就删除观察者

[player removeTimeObserver:self.periodicTimeObserver];
self.periodicTimeObserver = nil;