本文实例为大家介绍了iOS时钟开发过程，供大家参考，具体内容如下

思路就是利用CALayer的隐式动画来实现。因为UIView的非根层也就是手动创建的layer在其属性发生变化时会默认会产生动画效果，这些属性也叫作可动画属性。比如bounds、backgroundColor、position。

时钟里面表盘就是一个UIView，而三根针就是三个手动创建的layer。

先在storyboard上弄一个UIImageView，设置表盘图片

然后在viewDidLoad中初始化三根针，并设置定时器，获取当前时间，将当前时间对应的时针分针秒针分别指向对应的角度。

//// ViewController.m// 时钟效果//// Created by Daniel on 16/4/7.// Copyright © 2016年 Daniel. All rights reserved.// #define kClockWH _clockView.bounds.size.width //一秒钟秒针转多少度#define preSecondA 6 //一分钟分针转多少度#define preMinuteA 6 //一小时时针转多少度#define preHourA 30 //每分钟时针转多少度#define preHourMinute 0.5 //每秒钟分针转多少度#define preMinuteSecond 0.1 #define angle2raditon(a) ((a) / 180.0 * M_PI) #import "ViewController.h" @interface ViewController ()@property (weak, nonatomic) IBOutlet UIImageView *clockView; /** 秒针 */@property(nonatomic, strong) CALayer *secondL; /** 分针 */@property(nonatomic, strong) CALayer *minuteL; /** 时针 */@property(nonatomic, strong) CALayer *hourL; @end @implementation ViewController - (void)viewDidLoad {  [super viewDidLoad];     //添加时针  [self setUpHourLayer];     //添加分针  [self setUpMinuteLayer];    //添加秒针  [self setUpSecondLayer];     //添加定时器  [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(timeChange) userInfo:nil repeats:YES];     //开始运行时就获取时间，这样在启动时就不会有停顿的感觉  [self timeChange];   } - (void)timeChange {     //获取当前系统时间  NSCalendar *calendar = [NSCalendar currentCalendar];     NSDateComponents *cmp = [calendar components:NSCalendarUnitSecond | NSCalendarUnitMinute | NSCalendarUnitHour fromDate:[NSDate date]];     //获取秒  NSInteger second = cmp.second;     //获取分  NSInteger minute = cmp.minute;     //获取小时  NSInteger hour = cmp.hour;     //计算秒针转多少度  CGFloat secondA = second * preSecondA;     //计算分针转多少度  CGFloat minuteA = minute * preMinuteA + second * preMinuteSecond;     //计算时针转多少度  CGFloat hourA = hour * preHourA + minute * preHourMinute;     //旋转秒针  _secondL.transform = CATransform3DMakeRotation(angle2raditon(secondA), 0, 0, 1);     //旋转分针  _minuteL.transform = CATransform3DMakeRotation(angle2raditon(minuteA), 0, 0, 1);     //旋转时针  _hourL.transform = CATransform3DMakeRotation(angle2raditon(hourA), 0, 0, 1);   } #pragma mark - 初始化时针- (void)setUpHourLayer {     CALayer *hourL = [CALayer layer];     //设置秒针背景色  hourL.backgroundColor = [UIColor blackColor].CGColor;     //设置秒针锚点  hourL.anchorPoint = CGPointMake(0.5, 1);     //设置秒针锚点在父控件的位置  hourL.position = CGPointMake(kClockWH * 0.5, kClockWH * 0.5);     hourL.cornerRadius = 4;     //设置秒针bounds  hourL.bounds = CGRectMake(0, 0, 4, kClockWH * 0.5 - 40);     //把秒针添加到clockView图层上  [_clockView.layer addSublayer:hourL];     _hourL = hourL;   }  #pragma mark - 初始化分针- (void)setUpMinuteLayer {     CALayer *minuteL = [CALayer layer];     //设置秒针背景色  minuteL.backgroundColor = [UIColor blackColor].CGColor;     //设置秒针锚点  minuteL.anchorPoint = CGPointMake(0.5, 1);     //设置秒针锚点在父控件的位置  minuteL.position = CGPointMake(kClockWH * 0.5, kClockWH * 0.5);     minuteL.cornerRadius = 4;     //设置秒针bounds  minuteL.bounds = CGRectMake(0, 0, 4, kClockWH * 0.5 - 20);     //把秒针添加到clockView图层上  [_clockView.layer addSublayer:minuteL];     _minuteL = minuteL;   } #pragma mark - 初始化秒针- (void)setUpSecondLayer {     CALayer *secondL = [CALayer layer];     //设置秒针背景色  secondL.backgroundColor = [UIColor redColor].CGColor;     //设置秒针锚点  secondL.anchorPoint = CGPointMake(0.5, 1);     //设置秒针锚点在父控件的位置  secondL.position = CGPointMake(kClockWH * 0.5, kClockWH * 0.5);        //设置秒针bounds  secondL.bounds = CGRectMake(0, 0, 1.5, kClockWH * 0.5 - 20);     //把秒针添加到clockView图层上  [_clockView.layer addSublayer:secondL];     _secondL = secondL;   }  @end

效果图：

以上就是本文的全部内容，希望对大家学习IOS程序设计有所帮助。