ios手势复习值之换图片-转场动画（纯代码）

目标：实现通过手势进行图片的切换   通过左扫右扫 来实现（纯代码）

添加三个属性 1uiImageView 用来显示图片的view 

　　　　　　2 index 用来表示图片的索引

　　　　　　3 ISLeft 判断是不是向左滑  

下边是详细的代码：

- (void)viewDidLoad {
    [super viewDidLoad];
    self.index = 0;
    self.ISLeft = YES;
    _imageView = [[UIImageView alloc]initWithFrame:self.view.frame];
   // _imageView.backgroundColor = [UIColor redColor];
    _imageView.contentMode = UIViewContentModeScaleAspectFit;//合适的大小
    
    self.imageView.image = [UIImage imageNamed:[NSString stringWithFormat:@"%ld.png",_index]];
    
    [self.view addSubview:_imageView];
    
    
    //用户交互设置
    self.imageView.userInteractionEnabled = YES;

    //添加扫动得手势
    UISwipeGestureRecognizer *swipL = [[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(swip:)];
    swipL.direction = UISwipeGestureRecognizerDirectionLeft;
    [self.imageView addGestureRecognizer:swipL];
    
    
    UISwipeGestureRecognizer *swipR = [[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(swip:)];
    swipR.direction = UISwipeGestureRecognizerDirectionRight;
    [self.imageView addGestureRecognizer:swipR];
    
}

设置转场动画 ：在手势里边进行实现 

手势的实现以及转场动画：

-(void)swip:(UISwipeGestureRecognizer *)sender

{

    if(sender.direction == UISwipeGestureRecognizerDirectionLeft)

    {

        if(self.index>=0)

        {

            if(self.index>0)

            {

                self.index--;

            }

            else

                

            {

                self.index =3;

            }

            self.ISLeft = YES;

        }

    }

    else

    {

        self.ISLeft = NO;

        if(self.index<3)

        {

            self.index++;

            if(self.index ==3)

            {

                self.index =0;

            }

        }

    }

    

    //转场动画

    CATransition *trans = [[CATransition alloc]init];
  //转场动画的类型
    trans.type =@"push";
    //判断是不是向左滑
    if(self.ISLeft)

    {

        trans.subtype = kCATransitionFromTop;

    }

    else

    {

        trans.subtype = kCATransitionFromBottom;

    }

    trans.duration = 0.5f;

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

    //切换图画

    self.imageView.image = [UIImage imageNamed:[NSString stringWithFormat:@"%ld",_index]];

    

}