iOS动画－－基础

动画

所谓动画就是使一幅图像“活”起来的过程。当眼睛看到多张图片连续快速的切换时，就会被认为是一段连续播放的动画。
实验证明:动画和电影的画面刷新率为24帧/s,即每秒放映24幅画面，则人眼看到的是连续的画面效果。

CoreAnimation

CoreAnimation分为三大类，分别是CAPropertyAnimation（属性动画）、CAAnimationGroup（动画组）、CATransition（转场动画）。

属性动画

CAPropertyAnimation：属性动画的基类（通过可动画属性进行动画设置），不能直接使用。

CABasicAnimation：基础动画，通过属性修改进行动画参数控制，只有初始状态和结束状态(两个关键帧)。

CAKeyframeAnimation：关键帧动画，同样是通过属性进行动画参数控制，但是同基础动画不同的是它可以有多个状态控制。

动画组

CAAnimationGroup：动画组，动画组是一种组合模式设计，可以通过动画组来进行所有动画行为的统一控制，组中所有动画效果可以并发执行。

转场动画

CATransition：转场动画，主要通过滤镜进行动画效果设置。

CoreAnimation实例

CABasicAnimation

CABasicAnimation *scaleAnimation = [CABasicAnimation animationWithKeyPath:@"transform.scale"];
scaleAnimation.duration=5.0f;
scaleAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
scaleAnimation.fromValue = @(1);
scaleAnimation.toValue = @(1.5);
scaleAnimation.fillMode = kCAFillModeForwards;
scaleAnimation.removedOnCompletion = NO;
[_aniView.layer addAnimation:scaleAnimation forKey:@"transformscale"];

CABasicAnimation

CAKeyframeAnimation

CAKeyframeAnimation *keyframeAnimation=[CAKeyframeAnimation animationWithKeyPath:@"position"];

NSValue *key1=[NSValue valueWithCGPoint:_aniView.layer.position];
NSValue *key2=[NSValue valueWithCGPoint:CGPointMake(100,100)];
NSValue *key3=[NSValue valueWithCGPoint:CGPointMake(200,100)];
NSValue *key4=[NSValue valueWithCGPoint:CGPointMake(200,500)];
NSArray *values=@[key1,key2,key3,key4];
keyframeAnimation.values=values;
keyframeAnimation.duration=8.0;
keyframeAnimation.beginTime=CACurrentMediaTime();
[_aniView.layer addAnimation:keyframeAnimation forKey:@"KCKeyframeAnimation_Position"];

CAKeyframeAnimation

CAAnimationGroup

-(void)groupAnimation{
    CAAnimationGroup *animationGroup=[CAAnimationGroup animation];
    
    CABasicAnimation *basicAnimation=[self rotationAnimation];
    CAKeyframeAnimation *keyframeAnimation=[self translationAnimation];
    animationGroup.animations=@[basicAnimation,keyframeAnimation];
    
    animationGroup.delegate=self;
    animationGroup.duration=10.0;
    animationGroup.beginTime=CACurrentMediaTime();
    
    [_aniView.layer addAnimation:animationGroup forKey:nil];
}

-(CABasicAnimation *)rotationAnimation{
    CABasicAnimation *basicAnimation=[CABasicAnimation animationWithKeyPath:@"transform.rotation.z"];
    CGFloat toValue=M_PI_2*3;
    basicAnimation.toValue=[NSNumber numberWithFloat:M_PI_2*3];
    
    basicAnimation.autoreverses=true;
    basicAnimation.repeatCount=HUGE_VALF;
    basicAnimation.removedOnCompletion=NO;
    
    [basicAnimation setValue:[NSNumber numberWithFloat:toValue] forKey:@"KCBasicAnimationProperty_ToValue"];
    
    return basicAnimation;
}

-(CAKeyframeAnimation *)translationAnimation{
    CAKeyframeAnimation *keyframeAnimation=[CAKeyframeAnimation animationWithKeyPath:@"position"];
   
    NSValue *key1=[NSValue valueWithCGPoint:_aniView.layer.position];
    NSValue *key2=[NSValue valueWithCGPoint:CGPointMake(100,100)];
    NSValue *key3=[NSValue valueWithCGPoint:CGPointMake(200,100)];
    NSValue *key4=[NSValue valueWithCGPoint:CGPointMake(200,500)];
    NSArray *values=@[key1,key2,key3,key4];
    keyframeAnimation.values=values;
    
    [keyframeAnimation setValue:[NSValue valueWithCGPoint:_aniView.layer.position] forKey:@"KCKeyframeAnimationProperty_EndPosition"];
    
    return keyframeAnimation;
}

CAAnimationGroup

CATransition

CATransition *animation = [CATransition animation];
animation.duration = 5.0f;
animation.timingFunction = UIViewAnimationCurveEaseInOut;
animation.type = kCATransitionMoveIn;
animation.subtype = kCATransitionFromTop;
[_aniView.layer addAnimation:animation forKey:nil];

transition

基础部分就先讲到这了，下一篇开始将讲下较复杂、炫酷的动画实现。