在循环中使用NSTimer

本文介绍了在循环中使用NSTimer的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述 我需要显示一个从30到0的计时器，几次。 （30到0，从30开始，等等）然而，当我把它放在一个for循环，而不是等到定时器无效，开始下一个定时器，循环遍历和几个定时器创建。

如何构成一个等待计时器失效的循环？

- （IBAction）startCountdown：（id）sender {

NSNumber * rounds = [[NSNumber alloc] initWithInt：sliderRounds.value]; for（int i = rounds.intValue; i> 0; i--）{ [self timer]; $ / code $ / $ p

解决方案

您可以使用scheduledTimerWithTimeInterval

[NSTimer scheduledTimerWithTimeInterval：0.5 target：self selector：@selector（handleTimer :) userInfo：nil repeats：NO];

在handleTimer内部创建下一个定时器

I need to show a timer counting down from 30 to 0, several times. (30 to 0, start over at 30, etc) However when I placed it in a for-loop, instead of waiting till the timer invalidates to begin the next timer, the loop iterates through and several timers are created.

How can I form a loop that waits until the timer has invalidated?

- (IBAction)startCountdown:(id)sender {

NSNumber *rounds = [[NSNumber alloc]initWithInt:sliderRounds.value]; for (int i = rounds.intValue; i > 0; i--) { [self timer]; }

解决方案

You can use the scheduledTimerWithTimeInterval

[NSTimer scheduledTimerWithTimeInterval: 0.5 target: self selector: @selector(handleTimer:) userInfo: nil repeats: NO];

And inside the handleTimer you create the next timer