002-内容层动画

一、Core Animation核心动画

1.特点

1）Core Animation来自iOS的QuartzCore.framework框架

2）直接作用于CALayer图层上，而非UIView上

3）Core Animation的执行过程在后台，不阻塞主线程

4）可以利用CALayer绝大多数属性制作高级动画效果

2.核心动画类结构

二、CABasicAnimation

1.动画效果

可以让CALayer的属性值从某一个值渐变到另一个值

2.属性&方法

1）指定CALayer的属性名

　　@property(nullable, copy) NSString *keyPath;

2）初始化方法

　　+ (instancetype)animationWithKeyPath:(nullable NSString *)path;

3）CALayer的属性动画起始值

　　@property(nullable, strong) id fromValue;

4）CALayer的属性动画终止值

　　@property(nullable, strong) id toValue;

5）CALayer的属性动画的累加值

　　@property(nullable, strong) id byValue;

3.代码实例

1）位置动画：position、transform.translation.x、transform.translation.y、transform.translation.z

#pragma mark - 界面
- (void)initUI
{
    self.view.backgroundColor = [UIColor whiteColor];
    
    // btn
    _btn = [UIButton buttonWithType:UIButtonTypeSystem];
    _btn.frame = CGRectMake(20, 100, self.view.bounds.size.width - 20 * 2, 45);
    [_btn setTitle:@"动画" forState:UIControlStateNormal];
    [_btn addTarget:self action:@selector(btnClick:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:_btn];
}

#pragma mark - 点击事件
- (void)btnClick:(UIButton *)sender
{
    CABasicAnimation *basicAnimation = [[CABasicAnimation alloc] init];
    // anchorPoint默认为(0.5, 0.5)，那么position默认就是中点
    basicAnimation.keyPath = @"position";
    basicAnimation.toValue = [NSValue valueWithCGPoint:CGPointMake(_btn.center.x, _btn.center.y + 200)];
    basicAnimation.duration = 2.0;
    basicAnimation.fillMode = kCAFillModeForwards;
    basicAnimation.removedOnCompletion = NO;
    [_btn.layer addAnimation:basicAnimation forKey:nil]; // key:动画标识
}

2）缩放动画：transform.scale、transform.scale.x、transform.scale.y

#pragma mark - 界面
- (void)initUI
{
    self.view.backgroundColor = [UIColor whiteColor];
    
    // btn
    _btn = [UIButton buttonWithType:UIButtonTypeSystem];
    _btn.frame = CGRectMake(20, 100, self.view.bounds.size.width - 20 * 2, 45);
    _btn.backgroundColor = [UIColor redColor];
    _btn.tintColor = [UIColor whiteColor];
    [_btn setTitle:@"动画" forState:UIControlStateNormal];
    [_btn addTarget:self action:@selector(btnClick:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:_btn];
}

#pragma mark - 点击事件
- (void)btnClick:(UIButton *)sender
{
    CABasicAnimation *basicAnimation = [[CABasicAnimation alloc] init];
    basicAnimation.keyPath = @"transform.scale.x";
    basicAnimation.toValue = @0.5;
    basicAnimation.duration = 2.0;
    basicAnimation.fillMode = kCAFillModeForwards;
    basicAnimation.removedOnCompletion = NO;
    [_btn.layer addAnimation:basicAnimation forKey:nil]; // key:动画标识
}

3）旋转动画：transform.rotation

#pragma mark - 界面
- (void)initUI
{
    self.view.backgroundColor = [UIColor whiteColor];
    
    // btn
    _btn = [UIButton buttonWithType:UIButtonTypeSystem];
    _btn.frame = CGRectMake(20, 100, self.view.bounds.size.width - 20 * 2, 45);
    _btn.backgroundColor = [UIColor redColor];
    _btn.tintColor = [UIColor whiteColor];
    [_btn setTitle:@"动画" forState:UIControlStateNormal];
    [_btn addTarget:self action:@selector(btnClick:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:_btn];
}

#pragma mark - 点击事件
- (void)btnClick:(UIButton *)sender
{
    CABasicAnimation *basicAnimation = [[CABasicAnimation alloc] init];
    basicAnimation.keyPath = @"transform.rotation";
    basicAnimation.toValue = @(M_PI / 4.0);
    basicAnimation.duration = 2.0;
    basicAnimation.fillMode = kCAFillModeForwards;
    basicAnimation.removedOnCompletion = NO;
    [_btn.layer addAnimation:basicAnimation forKey:nil]; // key:动画标识
}

4）淡入淡出动画：opacity

#pragma mark - 界面
- (void)initUI
{
    self.view.backgroundColor = [UIColor whiteColor];
    
    // btn
    _btn = [UIButton buttonWithType:UIButtonTypeSystem];
    _btn.frame = CGRectMake(20, 100, self.view.bounds.size.width - 20 * 2, 45);
    _btn.backgroundColor = [UIColor redColor];
    _btn.tintColor = [UIColor whiteColor];
    [_btn setTitle:@"动画" forState:UIControlStateNormal];
    [_btn addTarget:self action:@selector(btnClick:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:_btn];
}

#pragma mark - 点击事件
- (void)btnClick:(UIButton *)sender
{
    CABasicAnimation *basicAnimation = [[CABasicAnimation alloc] init];
    basicAnimation.keyPath = @"opacity";
    basicAnimation.toValue = @0.2;
    basicAnimation.duration = 2.0;
    basicAnimation.fillMode = kCAFillModeForwards;
    basicAnimation.removedOnCompletion = NO;
    [_btn.layer addAnimation:basicAnimation forKey:nil]; // key:动画标识
}

三、CAKeyframeAnimation