开发iOS时钟的案例

//
// 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