基础动画

+(CAKeyframeAnimation *)zoomAnimation{
    
    //动画大小
    CAKeyframeAnimation *animation = [CAKeyframeAnimation animation];
    animation.keyPath = @"transform";
    NSMutableArray *values = [NSMutableArray array];
    [values addObject:[NSValue valueWithCATransform3D:CATransform3DMakeScale(0, 0, 1.0)]];
    [values addObject:[NSValue valueWithCATransform3D:CATransform3DMakeScale(1.2, 1.2, 1.0)]];
    [values addObject:[NSValue valueWithCATransform3D:CATransform3DMakeScale(1.0, 1.0, 1.0)]];
    animation.duration = 0.3;//动画执行时间
    animation.keyTimes = @[@(0.0), @(0.2), @(1.0)]; //每一帧用的时间比
    [animation setValues:values];
    animation.autoreverses=NO;//不重复
    animation.repeatCount=0;
    animation.removedOnCompletion = NO; //执行动画后不要移除
    animation.fillMode = kCAFillModeForwards; //保持最新
    return animation;
    
}