IOS 设置定时器

IOS 设置定时器  自动滚动视图 定时发送坐标信息 即时显示 时钟

NSTimer *timer;

- (void)start

{//1second 调用一次

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

}

-(NSString *)updateClock:(NSTimer *)theTimer //精确到分系统时间

{

    NSDate * senddate=[NSDate date];

    NSDateFormatter *dateformatter=[[NSDateFormatter alloc] init];

    //  [dateformatter setDateFormat:@"ss:SS"];//hh:mm:ss:SSS

    [dateformatter setDateFormat:@"hh:mm"];

    NSString * locationString=[dateformatter stringFromDate:senddate];

   // NSLog(@"==%@==",locationString);

    label_System_hour.text=locationString;

    return locationString;

}

- (void)stop

{

    [timer invalidate];

    timer = nil;

}