NSTimer用法

NSTimer 可以精确控制50 - 100ms 的时间，如何Timer 处理函数比较耗时，真实的间隔时间可以比预设时间长，core function framework 也提供相似的对象, CFRunLoopTimerRef, 而且CFRunLoopTimerRef 可以 和NSTimer 相互替换

NSTimer class

Creating Timer

1. scheduledTimerWithTimeInterval:invocation:repeats:

>> 最短间隔时间0.1 millisecond

2. scheduledTimerWithTimeInterval:target:selector:userInfo:repeats

3. timerWithTimerInterval:invocation:repeats:

4. timerWithTimerInterval:target:selector:userInfo:repeats:

5. initWithFireDate:interval:target:selector:userInfo:repeats:

Firing a Timer

1. fire

Stopping a Timer

1. invalidate

Information for Timer

1. isValid

2. fireDate

3. setFireDate

4. timeInterval

5. userInfo

example：

[NSTimer scheduledTimerWithTimeInterval:2.0 target:self selector:@selector(func:) userInfo:nil repeats:NO];

[NSTimer scheduledTimerWithTimeInterval:2.0 target:self selector:@selector(func:) userInfo:nil repeats:YES];

//stop timer

[myTimer invalidate];

myTimer = nil;

NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(TimeElapse:) userInfo:nil repeats:YES];

-(void) TimeElapse:(id) sender

{

//do something here
}