給按鈕加倒計時的代碼

1、聲明屬性

{    
  NSInteger _timerNo;   
  NSTimer *_timer;
}

2、在viewDidLoad中設(shè)置按鈕初狀態(tài)

self.Btn.titleLabel.text = @" 獲取驗證碼";
[self.Btn setTitle:@" 獲取驗證碼" forState:UIControlStateDisabled];
[self.Btn setBackgroundColor:[UIColor lightGrayColor] forState:UIControlStateDisabled];

3、在按鈕觸發(fā)方法中觸發(fā)倒計時計時器

if (returnCode != 0) {
         [_timer invalidate];
         self.Btn.enabled = YES;
         NSString *msg = responseObj[@"msg"];
         [MBProgressHUD showError:msg];
  }else{
          [self startSendAuthcode:sender];//若剛開始搭界面，假數(shù)據(jù) 先放這個方法就行
  }

4、添加計時器

//發(fā)送驗證碼
-(void)startSendAuthcode:(UIButton *)btn{  //計時器    
      _timerNo = 60;    
      btn.enabled = NO;    
      _timer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(timerAction:) userInfo:nil repeats:YES];    
      [[NSRunLoop mainRunLoop] addTimer:_timer forMode:NSDefaultRunLoopMode];
}
//定時器
- (void)timerAction:(NSTimer *)timer{
        _timerNo--;
        self.Btn.titleLabel.text = [NSString stringWithFormat:@"(%zd)重新驗證",_timerNo];
        [self.Btn setTitle:[NSString stringWithFormat:@"(%zd)重新驗證",_timerNo] forState:UIControlStateDisabled];
        if (_timerNo == 0) {        
            [timer invalidate];
            self.Btn.enabled = YES;
            self.Btn.titleLabel.text = @"(60)重新驗證";
            [self.Btn setTitle:@"(60)重新驗證" forState:UIControlStateDisabled];
         }
}