Core Animation之CATransition和CAAnimationGroup

CATransition

• CATransition是CAAnimation的子类，用于做转场动画
• 能为层提供移除屏幕和移入屏幕的动画效果
• UINavigationController就是通过CATransition实现了将控制器的试图推入屏幕的动画效果

转场动画的属性

• type:过渡类型
• subtype：过渡方向
• startProgress：动画起点(在整体动画的百分比)
• endProgress：动画终点(在整体动画的百分比)

    CATransition *anim = [CATransition animation];
    anim.type = @"cube";
    anim.subtype = kCATransitionFromLeft;
    anim.duration = 0.5;
    [_imageView.layer addAnimation:anim forKey:nil];

CAAnimationGroup

• 动画组也是CAAnimation的子类，可以保存一组动画对象
• CAAnimationGroup对象加入层之后，组中所有动画可以同时并发执行

动画组属性

• animations：用来保存一组动画对象的NSArray
• beginTime：动画对象的开始时间。默认是同时运行的

// 旋转
    CABasicAnimation *rotation = [CABasicAnimation animation];

    rotation.keyPath = @"transform.rotation";

    rotation.toValue = @M_PI_2;

    // 位移
    CABasicAnimation *position = [CABasicAnimation animation];

    position.keyPath = @"position";

    position.toValue = [NSValue valueWithCGPoint:CGPointMake(100, 250)];

    // 缩放
    CABasicAnimation *scale = [CABasicAnimation animation];

    scale.keyPath = @"transform.scale";

    scale.toValue = @0.5;

    CAAnimationGroup *group = [CAAnimationGroup animation];

    group.animations = @[rotation,position,scale];

    group.duration = 2;

    // 取消反弹
    group.removedOnCompletion = NO;
    group.fillMode = kCAFillModeForwards;

    [_redView.layer addAnimation:group forKey:nil];