iOS 开发 毫秒计时器

毫秒计时器.gif

项目需要实现一个类似于这样的毫秒计时器功能，原来想着用：毫秒 -> 秒 -> 分钟，分用三个控件，后来做个优化一个控件搞定，简单记录一下。

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• API调用

[_timer setFireDate:[NSDate date]];
[_timer setFireDate:[NSDate distantFuture]];

• 具体代码实现

7B4B4EB592A1B625E540262208B6AF0D.jpg

@interface ViewController () {
    NSInteger _minute;         // 分钟
    NSInteger _second;         // 秒
    NSInteger _millisecond;    // 毫秒
    BOOL _isStop;
}
@property (nonatomic, strong) NSTimer *timer;
@property (weak, nonatomic) IBOutlet UILabel *timeLabel;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    _isStop = YES;
    self.timer = [NSTimer scheduledTimerWithTimeInterval:0.01
                                                  target:self
                                                selector:@selector(startTimer)
                                                userInfo:nil
                                                 repeats:YES];
    // 让定时器暂停
    [_timer setFireDate:[NSDate distantFuture]];
}

- (void)startTimer{
    _millisecond ++;
    if(_millisecond == 100){
        _second ++;
        _millisecond = 0;
    }
    if (_second == 60) {
        _minute ++;
        _second = 0;
    }
    self.timeLabel.text = [NSString stringWithFormat:@"%02ld:%02ld:%02ld", _minute, _second, _millisecond];
}

// 开始/停止
- (IBAction)start:(id)sender {
    UIButton *btn = (UIButton *)sender;
    if (_isStop) {
        [btn setTitle:@"停止" forState:UIControlStateNormal];
        [_timer setFireDate:[NSDate date]];
        _isStop = NO;
    } else {
        [btn setTitle:@"开始" forState:UIControlStateNormal];
        [_timer setFireDate:[NSDate distantFuture]];
        _isStop = YES;
    }
}

// 重置
- (IBAction)reset:(id)sender {
    _millisecond = 0;
    _second = 0;
    _minute = 0;
    self.timeLabel.text = [NSString stringWithFormat:@"%02ld:%02ld:%02ld", _millisecond, _second, _minute];
}

@end