UIScrollView 阻止运行循环?

问题描述

我在同一个 viewController 上实现了 NSTimer(repeats) 和 UITableView.

I implemented a NSTimer(repeats) and UITableView on the same viewController.

不知何故，当我滚动 tableView 时，运行循环似乎停止触发 NSTimer.UITextView 也是如此，它也是 UIScrollView 的子类.

Somehow, when I scroll through the tableView, the run loop seems to stop firing the NSTimer. The same goes for UITextView, which is also a subclass of UIScrollView.

我可以知道这里发生了什么吗?

May I know what is happening here?

推荐答案

定时器停止触发的原因是滚动时run loop切换到UITrackingRunLoopMode，默认没有添加定时器那种模式.您可以在启动计时器时手动执行此操作:

The reason that the timer stops firing is that the run loop switches to UITrackingRunLoopMode during scrolling and the timer is not added by default to that mode. You can do that manually when you start the timer:

NSTimer *timer = [NSTimer timerWithTimeInterval:1.0 target:self selector:@selector(timerFired:) userInfo:nil repeats:YES];
NSRunLoop *runloop = [NSRunLoop currentRunLoop];
[runloop addTimer:timer forMode:NSRunLoopCommonModes];
[runloop addTimer:timer forMode:UITrackingRunLoopMode];