NSTimer的用法 IOS

NSTimer *myTimer;

// 1
调用一次

myTimer =[NSTimer
scheduledTimerWithTimeInterval:1.5
target:self
selector:@selector(scrollTimer)userInfo:nil
repeats:NO];

// 2
重复调用

myTimer =[NSTimer
scheduledTimerWithTimeInterval:1.5
target:self
selector:@selector(scrollTimer)userInfo:nil
repeats:YES];

// 3
永久停止定时器
[myTimer
invalidate];

// 4
关闭定时器

[myTimer setFireDate:[NSDate
distantFuture]];

// 5
重新开启定时器

[myTimer setFireDate:[NSDate
distantPast]];

// 6
页面消失的时候关闭定时器，页面再次打开的时候开启定时器
-(void)viewWillAppear:(BOOL)animated
{

//开启定时器
[self.myTimer setFireDate:[NSDate distantPast]];
}
-(void)viewDidDisappear:(BOOL)animated
{

//关闭定时器
[self.myTimer setFireDate:[NSDate distantFuture]];
}