NSTimer

[NSTimer scheduledTimerWithTimeInterval:1.0target:selfselector:@selector(timerFireMethod:)userInfo:nilrepeats:YES];

 Second = 60;

- (void)timerFireMethod:(NSTimer *)theTimer

{

    SecondNum--;

   if (SecondNum == 0) {

        [theTimerinvalidate];//停止

        NSString *StrSecond = [NSStringstringWithFormat:@"点击获取"];

        [self.BtnGainIdentifyCodesetTitle:StrSecond forState:UIControlStateNormal];

    }else{

        NSString *StrSecond = [NSStringstringWithFormat:@"重新获取%d秒",SecondNum];

        [self.BtnGainIdentifyCodesetTitle:StrSecond forState:UIControlStateNormal];

        ;

    }

    

}