iOS学习笔记-074.CALayer04——隐式动画

CALayer04——隐式动画

一、基本介绍

每一个UIView内部都默认关联着一个CALayer，我们可用称这个Layer为Root Layer（根层）

所有的非Root Layer，也就是手动创建的CALayer对象，都存在着隐式动画

什么是隐式动画？
当对非Root Layer的部分属性进行修改时，默认会自动产生一些动画效果
而这些属性称为Animatable Properties(可动画属性)

列举几个常见的Animatable Properties：bounds：用于设置CALayer的宽度和高度。修改这个属性会产生缩放动画backgroundColor：用于设置CALayer的背景色。修改这个属性会产生背景色的渐变动画position：用于设置CALayer的位置。修改这个属性会产生平移动画

可以通过动画事务(CATransaction)关闭默认的隐式动画效果

[CATransaction begin];[CATransaction setDisableActions:YES];//[CATransaction setAnimationDuration:5];self.myview.layer.position = CGPointMake(10, 10);[CATransaction commit];

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二、时钟案例

2.1 需要完成的效果图

2.2 代码

////  ViewController.m//  03_UIView67_时钟////  Created by 杞文明 on 17/6/11.//  Copyright © 2017年 杞文明. All rights reserved.//#import "ViewController.h"//每一秒旋转的度数#define perSecA 6//每一分旋转的度数#define perMinA 6//每一小时旋转的度数#define perHourA 30//每一分,时针旋转的度数#define perMinHour 0.5#define angle2Rad(angle) ((angle) / 180.0 * M_PI)@interface ViewController ()@property (weak, nonatomic) IBOutlet UIImageView *clockView;/** 当前的秒针 */@property (nonatomic, weak)   CALayer *secL;/** 当前的分针 */@property (nonatomic, weak)   CALayer *minL;/** 当前的针针 */@property (nonatomic, weak)   CALayer *hourL;@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];    [self initHourPointer];    [self initMinPointer];    [self initSecPointer];    //创建定时器    [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(timeChange) userInfo:nil repeats:YES];    [self timeChange];}//初始化时针-(void)initHourPointer{    _hourL = [self createPointer:CGSizeMake(4, 50) withColor:[UIColor blueColor]];}//初始化分针-(void)initMinPointer{    _minL = [self createPointer:CGSizeMake(3, 70) withColor:[UIColor blackColor]];}//初始化秒针-(void)initSecPointer{    _secL = [self createPointer:CGSizeMake(1, 80) withColor:[UIColor redColor]];}//创建指针-(CALayer*)createPointer:(CGSize)size  withColor: (UIColor*) backColor{    CALayer * pointer = [CALayer layer];    pointer.bounds = CGRectMake(0, 0, size.width, size.height);    pointer.backgroundColor = backColor.CGColor;    pointer.anchorPoint = CGPointMake(0.5, 0.9);    pointer.position = CGPointMake(_clockView.bounds.size.width*0.5, _clockView.bounds.size.height*0.5);    [_clockView.layer addSublayer:pointer];    return pointer;}//时间改变-(void)timeChange{    //获取时间    NSCalendar *cal = [NSCalendar currentCalendar];    NSDateComponents *cmp = [cal components:(NSCalendarUnitHour|NSCalendarUnitMinute|NSCalendarUnitSecond) fromDate:[NSDate date]];    NSInteger curSec = cmp.second;    NSInteger curMin = cmp.minute;    NSInteger curHour = cmp.hour;    NSLog(@"                    %ld : %ld : %ld",curHour,curMin,curSec);    //计算秒针的位置    CGFloat secA = curSec * perSecA;    _secL.transform = CATransform3DMakeRotation(angle2Rad(secA), 0, 0, 1);    //计算分钟位置    CGFloat minA = curMin * perMinA;    _minL.transform = CATransform3DMakeRotation(angle2Rad(minA), 0, 0, 1);    //计算时钟位置    CGFloat hourA = curHour * perHourA + curMin * perMinHour;    _hourL.transform = CATransform3DMakeRotation(angle2Rad(hourA), 0, 0, 1);}@end