iphone - 定时器不重复

Question

我的计时器不重复请帮忙

这是代码

timer = [NSTimer timerWithTimeInterval:1 target:self selector:@selector(doAnimation:) userInfo:nil repeats:YES];
[timer fire];

方法

-(void)doAnimation:(id)Sender
{
}

Answer 1

[timer fire] 手动触发计时器 仅一次 并且实际上并未“启动”计时器。来自docs :

You can use this method to fire a repeating timer without interrupting its regular firing schedule. If the timer is non-repeating, it is automatically invalidated after firing, even if its scheduled fire date has not arrived.

您需要add the timer在开始触发和重复之前的运行循环中:

You must add the new timer to a run loop, using addTimer:forMode:. Then, after seconds seconds have elapsed, the timer fires, sending the message aSelector to target. (If the timer is configured to repeat, there is no need to subsequently re-add the timer to the run loop.)

更简单的方法是执行以下操作:

timer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(doAnimation:) userInfo:nil repeats:YES];

和:

-(void)doAnimation:(NSTimer*)timer
{
}

这automatically schedules计时器并将其添加到运行循环中。以防万一你没有这样做，因为你已经将目标设置为 self 你必须确保方法 doAnimation 是在同一个类中定义的。

NSTimer Class Reference