iOS 简易钟表实现

效果图：

注意：表盘是一个UIImageView控件，设置image为表盘图片
核心代码：

////  ViewController.m//  时钟////  Created by llkj on 2017/8/29.//  Copyright © 2017年 LayneCheung. All rights reserved.//#import "ViewController.h"//每一秒旋转多少度#define perSecA 6//每一分旋转多少度#define perMinA 6//每一小时旋转多少度#define perHourA 30//每一分时针旋转的度数#define perMinHour 0.5//角度转弧度#define angle2Rad(angle) ((angle) / 180.0 * M_PI)@interface ViewController ()@property (weak, nonatomic) IBOutlet UIImageView *clockView;@property (nonatomic, weak) CALayer *secL;@property (nonatomic, weak) CALayer *minL;@property (nonatomic, weak) CALayer *hourL;@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];    [self setHour];    [self setMin];    [self setSec];    [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(timeChange) userInfo:nil repeats:YES];    [self timeChange];}- (void)timeChange{    //获取当前秒    NSCalendar *cal = [NSCalendar currentCalendar];    NSDateComponents *cmp = [cal components:NSCalendarUnitSecond | NSCalendarUnitMinute | NSCalendarUnitHour fromDate:[NSDate date]];    NSInteger curSec = cmp.second + 1;    NSInteger curMin = cmp.minute;    NSInteger curHour = cmp.hour;    //秒针开始旋转    //计算秒针当前旋转的角度    // angle = 当前多少秒 * 每一秒旋转多少度    CGFloat secA = curSec * perSecA;    //旋转方向是Z轴    self.secL.transform = CATransform3DMakeRotation(angle2Rad(secA), 0, 0, 1);    //分针开始旋转    //计算分针当前旋转的角度    // angle = 当前多少分 * 每一分旋转多少度    CGFloat minA = curMin * perMinA;    self.minL.transform = CATransform3DMakeRotation(angle2Rad(minA), 0, 0, 1);    //时针开始旋转    //计算时针当前旋转的角度    // angle = 当前多少时 * 每一小时旋转多少度    CGFloat hourA = curHour * perHourA + curMin * perMinHour;    self.hourL.transform = CATransform3DMakeRotation(angle2Rad(hourA), 0, 0, 1);}//添加秒针- (void)setSec{    CALayer *secL = [CALayer layer];    secL.bounds = CGRectMake(0, 0, 1, 80);    secL.backgroundColor = [UIColor redColor].CGColor;    //绕着锚点旋转    secL.anchorPoint = CGPointMake(0.5, 1);    secL.position = CGPointMake(self.clockView.bounds.size.width * 0.5, self.clockView.bounds.size.height * 0.5);    [self.clockView.layer addSublayer:secL];    self.secL = secL;}//添加分针- (void)setMin{    CALayer *minL = [CALayer layer];    minL.bounds = CGRectMake(0, 0, 3, 70);    minL.cornerRadius = 1.5;    minL.backgroundColor = [UIColor blackColor].CGColor;    minL.anchorPoint = CGPointMake(0.5, 1);    minL.position = CGPointMake(self.clockView.bounds.size.width * 0.5, self.clockView.bounds.size.height * 0.5);    [self.clockView.layer addSublayer:minL];    self.minL = minL;}//添加时针- (void)setHour{    CALayer *hourL = [CALayer layer];    hourL.bounds = CGRectMake(0, 0, 3, 60);    hourL.backgroundColor = [UIColor blackColor].CGColor;    hourL.anchorPoint = CGPointMake(0.5, 1);    hourL.position = CGPointMake(self.clockView.bounds.size.width * 0.5, self.clockView.bounds.size.height * 0.5);    [self.clockView.layer addSublayer:hourL];    self.hourL = hourL;}- (void)didReceiveMemoryWarning {    [super didReceiveMemoryWarning];    // Dispose of any resources that can be recreated.}@end