效果图

实现思路

• 该示例通过隐式动画实现
• 表盘通过显示在imageView中的一张图片来实现

• 在表盘上绘制（时分秒）三条直线，分别位于不同的图层，且时针位于最下层，秒针位于最上层

  • 设置直线为圆角
  • 直线的一段位于表盘的圆心
  • 通过NSTimer定时器，使不同的图层定时执行对应的动画

实现步骤

• 通过storyboard创建表盘，并拥有它

  @property (weak, nonatomic) IBOutlet UIImageView *clockView;

• 使用三个成员变量来保存时分秒三根表针位于的不同图层

  @property (nonatomic, weak) CALayer *secondLayer;
  @property (nonatomic, weak) CALayer *minuteLayer; @property (nonatomic, weak) CALayer *hourLayer;

• 初始化所用到的常量

  //将旋转角度转换为弧度制
  #define angleToRadion(angle) ((angle) / 180.0 * M_PI)//秒针每秒钟转过的角度
  #define perSecondAngle 6 //分针每分钟转过的角度 #define perMinuteAngle 6 //时针每小时转过的角度 #define perHourAngle 30 //时针每分钟转过的角度 #define perMuniteHourAngle 0.5

• 设置时分秒三根表针

  • 设置时针

    - (void)setUpHourLayer
    {//创建图层CALayer *layer = [CALayer layer];layer.backgroundColor = [UIColor blackColor].CGColor; layer.cornerRadius = 8; 设置图层的锚点 layer.anchorPoint = CGPointMake(0.5, 1); //设置图层的位置和尺寸 layer.position = CGPointMake(kClockWith * 0.5, kClockWith * 0.5); layer.bounds = CGRectMake(0, 0, 5, kClockWith * 0.5 - 44); //将图层添加到父图层中 [self.clockView.layer addSublayer:layer]; self.hourLayer = layer; }

  • 设置分针

    - (void)setUpMinuteLayer
    {CALayer *layer = [CALayer layer];layer.backgroundColor = [UIColor blackColor].CGColor; layer.cornerRadius = 4; //设置锚点 layer.anchorPoint = CGPointMake(0.5, 1); //设置位置和尺寸 layer.position = CGPointMake(kClockWith * 0.5, kClockWith * 0.5); layer.bounds = CGRectMake(0, 0, 3, kClockWith * 0.5 - 34); //将图层添加到父图层中 [self.clockView.layer addSublayer:layer]; self.minuteLayer = layer; }

  • 设置秒针

    - (void)setUpSecondLayer
    {CALayer *layer = [CALayer layer];layer.backgroundColor = [UIColor redColor].CGColor; //设置锚点 layer.anchorPoint = CGPointMake(0.5, 1); //设置位置和尺寸 layer.position = CGPointMake(kClockWith * 0.5, kClockWith * 0.5); layer.bounds = CGRectMake(0, 0, 1, kClockWith * 0.5 - 24); //将图层添加到父图层中 [self.clockView.layer addSublayer:layer]; self.secondLayer = layer; }

• 设置定时器，定时执行动画

  [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(timeChange) userInfo:nil repeats:YES];

• 设置定时器触发时调用的方式，添加动画代码

  - (void)timeChange
  {//获取日历对象NSCalendar *calendar = [NSCalendar currentCalendar];//获取日期组件 NSDateComponents *components = [calendar components:NSCalendarUnitSecond | NSCalendarUnitMinute | NSCalendarUnitHour fromDate:[NSDate date]]; //获取当前的时分秒值 NSInteger second = components.second; NSInteger munite = components.minute; NSInteger hour = components.hour; //计算当前时分秒表针转过的角度（弧度制） CGFloat secondAngle = angleToRadion(second * perSecondAngle); CGFloat muniteAngle = angleToRadion(munite * perMinuteAngle); CGFloat hourAngle = angleToRadion(hour *perHourAngle + munite * perMuniteHourAngle); //修改时分秒表针位于的图层的transform属性，执行隐式动画 self.secondLayer.transform = CATransform3DMakeRotation(secondAngle, 0, 0, 1); self.minuteLayer.transform = CATransform3DMakeRotation(muniteAngle, 0, 0, 1); self.hourLayer.transform = CATransform3DMakeRotation(hourAngle, 0, 0, 1); }