在这个块中强烈捕获自我可能会导致一个保留循环 [英] capturing self strongly in this block is likely to lead to a retain cycle

问题描述

如何在 xcode 中避免此警告.这是代码片段:

How can I avoid this warning in xcode. Here is the code snippet:

[player(AVPlayer object) addPeriodicTimeObserverForInterval:CMTimeMakeWithSeconds(0.1, 100)
queue:nil usingBlock:^(CMTime time) {
    current+=1;

    if(current==60)
    {
        min+=(current/60);
        current = 0;
    }

    [timerDisp(UILabel) setText:[NSString stringWithFormat:@"%02d:%02d",min,current]];///warning occurs in this line
}];

推荐答案

这里对 self 的捕获是随着你对 self.timerDisp 的隐式属性访问而来的——你不能从 self 强烈保留的块中引用 self 或 self 上的属性.

The capture of self here is coming in with your implicit property access of self.timerDisp - you can't refer to self or properties on self from within a block that will be strongly retained by self.

您可以通过在访问块内的 timerDisp 之前创建对 self 的弱引用来解决此问题:

You can get around this by creating a weak reference to self before accessing timerDisp inside your block:

__weak typeof(self) weakSelf = self;
[player addPeriodicTimeObserverForInterval:CMTimeMakeWithSeconds(0.1, 100)
                                     queue:nil
                                usingBlock:^(CMTime time) {
                                                current+=1;

                                                if(current==60)
                                                {
                                                    min+=(current/60);
                                                    current = 0;
                                                }

                                                 [weakSelf.timerDisp setText:[NSString stringWithFormat:@"%02d:%02d",min,current]];
                                            }];

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