NSTimer

---------------------------------------NSTimer的用法-------------------------------------------------

wSelf.timeFlag = 60;

            wSelf.timer = [NSTimerscheduledTimerWithTimeInterval:1.0target:selfselector:@selector(timerUp:) userInfo:nilrepeats:YES];

            [[NSRunLoopcurrentRunLoop]addTimer:wSelf.timerforMode:NSRunLoopCommonModes];//有了这句，表格滚动的时候，定时器也不会停止了。

 

            wSelf.sendCode.userInteractionEnabled = NO;

 

- (void)timerUp:(NSTimer*)timer{

    self.timeFlag -- ;

    if (self.timeFlag <= 0) {

        if(self.timer && [self.timer isValid]){// 没用的时候要记得销毁timer 

            [self.timer invalidate];

            self.timer = nil;

        }

        self.sendCode.userInteractionEnabled = YES;

        [self.sendCodesetTitle:NSLocalizedString(@"获取验证码", nil) forState:UIControlStateNormal];

    }else{

        self.sendCode.userInteractionEnabled = NO;

        [self.sendCodesetTitle:[NSStringstringWithFormat:@"%d s",self.timeFlag] forState:UIControlStateNormal];

    }

 

}