iphone定时器方法

最新推荐文章于 2016-11-29 17:24:46 发布

原创最新推荐文章于 2016-11-29 17:24:46 发布 · 133 阅读

0 ·

CC 4.0 BY-SA版权

iphone 专栏收录该内容

197 篇文章

订阅专栏

本文介绍如何使用iPhone上的NSTimer创建定时任务。通过scheduledTimerWithTimeInterval方法可以设置目标对象、触发间隔、回调方法等参数实现重复或一次性触发的任务。示例展示了如何启动及停止定时器。

iphone定时器方法

scheduledTimerWithTimeInterval:target:selector:userInfo:repeats:

Creates and returns a new NSTimer object and schedules it on the current run loop in the default mode.

+ (NSTimer *)scheduledTimerWithTimeInterval:(NSTimeInterval)seconds target:(id)target selector:(SEL)aSelectoruserInfo:(id)userInfo repeats:(BOOL)repeats

Parameters

seconds

The number of seconds between firings of the timer. If seconds is less than or equal to 0.0, this method chooses the nonnegative value of 0.1 milliseconds instead.

target

The object to which to send the message specified by aSelector when the timer fires. The target object is retained by the timer and released when the timer is invalidated.

aSelector

The message to send to target when the timer fires. The selector must have the following signature:

- (void)timerFireMethod:(NSTimer*)theTimer

The timer passes itself as the argument to this method.

userInfo

The user info for the timer. The object you specify is retained by the timer and released when the timer is invalidated. This parameter may be nil.

repeats

If YES, the timer will repeatedly reschedule itself until invalidated. If NO, the timer will be invalidated after it fires.

Return Value

A new NSTimer object, configured according to the specified parameters.

Discussion

After seconds seconds have elapsed, the timer fires, sending the messageaSelector to target.

定义定时器例子:

	NSTimer *timer=[NSTimer scheduledTimerWithTimeInterval:0.01 
										   target:self 
										 selector:@selector(showTime) 
										 userInfo:nil 
										  repeats:YES];

结束定时器例子：

[timer invalidate];