01.轮播图之五 ：一个 imageView也能 作 轮播

这个是最近才写的，本以为实现起来很有难度，需要更高深的理论，

写完之后，才发现自己错误的离谱；

之所以能用一个imageview 实现轮播 基于两点：：：

1. 使用 imageview 的layer 层设置，也就是动用的是imageview的重新绘制---- 这个是视图切换的原因
2. 使用 CATransition 动画 ------ 这个动画模拟了轮播的效果

就是简单：：：

.h 的声明

@interface ImageViewShuffling : UIView

@property (nonatomic,strong)NSArray *array;

@end

.m 实现，和理论解释

@interface ImageViewShuffling ()

@property (nonatomic,strong)UIImageView *imageView;

@property (nonatomic,assign)NSInteger  currentIndex;

@end

@implementation ImageViewShuffling

@synthesize array = _array;

-(instancetype)initWithFrame:(CGRect)frame{

    if (self == [super initWithFrame:frame]) {

        [self addSubview:self.imageView];

    }

    return self;

}

-(void)setArray:(NSArray *)array{

    NSAssert(array.count != , @"传入的滚动数组是 空的");

    _array = array;

    self.imageView.backgroundColor = array.firstObject;

}

-(UIImageView *)imageView{

    if (_imageView == nil) {

        _imageView =[[UIImageView alloc]initWithFrame:CGRectMake(, , self.frame.size.width, self.frame.size.height)];

        _imageView.contentMode = UIViewContentModeScaleAspectFit;

        _imageView.userInteractionEnabled = YES;

 /*
imageview 添加左右滑动的手势
*/

        UISwipeGestureRecognizer *left = [[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(leftSwifAction:)];

        left.direction = UISwipeGestureRecognizerDirectionLeft;

        [_imageView addGestureRecognizer:left];

        UISwipeGestureRecognizer *right = [[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(rigthSwifAction:)];

        right.direction = UISwipeGestureRecognizerDirectionRight;

        [_imageView addGestureRecognizer:right];

    }

    return _imageView;

}
/*
根据手势判断 左右的滑动 判断 显示的index
*/

-(void)rigthSwifAction:(UISwipeGestureRecognizer*)swip{

    self.currentIndex = (self.currentIndex+) % (self.array.count);

    [self changeImageWithIndex:self.currentIndex andDirection:@"right"];

}

-(void)leftSwifAction:(UISwipeGestureRecognizer*)swip{

    self.currentIndex = (self.currentIndex -  + self.array.count)%(self.array.count);

    [self changeImageWithIndex:self.currentIndex andDirection:@"left"];

}


/*
这个是唯一的重点：：
使用 CATransition 添加动画
*/

-(void)changeImageWithIndex:(NSInteger)integer  andDirection:(NSString*)direction{

    self.imageView.backgroundColor = self.array[integer];

    CATransition *transition = [[CATransition alloc]init];

    transition.type = kCATransitionPush;

    if ([direction isEqualToString:@"right"]) {

        transition.subtype = kCATransitionFromLeft;

    }else{// if left

        transition.subtype = kCATransitionFromRight;

    }

    [self.imageView.layer addAnimation:transition forKey:@"direction"];

}

有木有发现，这个实现很简单呀…………

主要是CATransition 动画的功劳…………

调用：：：

-(void)prepareImageViewShuffling{

        ImageViewShuffling *imageViewShuffling = [[ImageViewShuffling alloc]initWithFrame:CGRectMake(, , self.view.frame.size.width -, )];

        [self.view addSubview:imageViewShuffling];;

        imageViewShuffling.array = self.arr;

}