iOS获取验证码倒计时

开始计时调用下面这个方法就可以了。获取验证码的按钮就会开始显示倒计时直到60s后恢复最初状态

[self startTime];

实现代码如下：

定义定时器和时间

@implementation LoginViewController {
    NSTimer *_timer;
    int _waiTime;
}

#pragma mark--开始计时
- (void)startTime {
    
    [_timer invalidate];
    _waiTime = 60;
    [self updateVareyButton];
    _timer = [NSTimer scheduledTimerWithTimeInterval:1.0
                                              target:self
                                            selector:@selector(updateWaitTime)
                                            userInfo:nil
                                             repeats:YES];
}

- (void)updateVareyButton {
    
    NSString *title = @"获取验证码";
    if (_waiTime > 0) {
        title = [NSString stringWithFormat:@"%d秒后重发", _waiTime];
        [self.getVerfyCodeBtn setTitleColor:SecondColor forState:UIControlStateNormal];
        self.getVerfyCodeBtn.userInteractionEnabled = NO;
    }
    [self.getVerfyCodeBtn setTitle:title forState:UIControlStateNormal];
}

- (void)updateWaitTime {
    
    _waiTime = _waiTime - 1;
    [self updateVareyButton];
    if (_waiTime <= 0) {
        [self.getVerfyCodeBtn setTitleColor:MainColor forState:UIControlStateNormal];
        self.getVerfyCodeBtn.userInteractionEnabled = YES;
        [_timer invalidate];
        _timer = nil;
    }
    
}