iOS 手势

    1.如果一个控件继承于 UIControl，那么它将不需要手势
    2.所有控件都可以添加手势
    [控件 addGestureRecognizer: ]
    3.iOS 系统提供的手势有哪些
 
    UITapGestureRecognizer 点击
    UISwipeGestureRecognizer 轻扫
    UIPanGestureRecognizer 拖动
    UIRotationGestureRecognizer 旋转
    UIPinchGestureRecognizer 捏合
    UILongPressGestureRecognizer 长按
 
    4.iOS 自定义的手势都是具有相同的父类  UIGestureRecognizer
    5.UIGestureRecognizer 这个手势父类是如何封装？
    
    UIGestureRecognizer  这个父类可以看做一个抽象类，并不具备手势的具体功能，但是它提供了子类共有的初始化方法、属性、代理
    <共有的初始化方法>
    - (instancetype)initWithTarget:(nullable id)target action:(nullable SEL)action 
 
    <2>手势的状态  state
    <3>手势是否有效 enable
    <4>代理 delegate
    <5>被添加手势的 view

手势.gif

/** 图片 */
@property (nonatomic,strong) UIImageView *imageView;
/** 数组 */
@property (nonatomic,strong) NSArray *images;
/** 图片张数 */
@property int count;

     _count = 0;
     _images = @[[UIImage imageNamed:@"00"],[UIImage imageNamed:@"01"],[UIImage imageNamed:@"02"]];
     _imageView = [[UIImageView alloc] initWithFrame:CGRectMake([UIScreen mainScreen].bounds.size.width / 2 - 50, [UIScreen mainScreen].bounds.size.height / 2 -100, 100, 200)];
     _imageView.image = _images[_count];
     _imageView.contentMode = UIViewContentModeScaleAspectFit;
     [self.view addSubview:_imageView];

• 手势需要开启用户交互

    //手势需要开启用户交互
    _imageView.userInteractionEnabled = YES;

点击手势

• 单击手势

    //单击手势
    UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(singleTapAction:)];
    [_imageView addGestureRecognizer:singleTap];

• 双击手势 添加 numberOfTapsRequired属性 能判断点击次数

    UITapGestureRecognizer *doubleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(doubleTapAction:)];
    //判断点击次数
    doubleTap.numberOfTapsRequired = 2;
    [singleTap requireGestureRecognizerToFail:doubleTap];
    [_imageView addGestureRecognizer:doubleTap];

• 三击手势

    UITapGestureRecognizer *threeTop = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(TapGestureAction:)];
    threeTop.numberOfTapsRequired = 3;
    [doubleTap requireGestureRecognizerToFail:threeTop];
    [_imageView addGestureRecognizer:threeTop];

• 点击事件方法

    -(void)TapGestureAction:(UITapGestureRecognizer *)sender
    {
        if (sender.numberOfTapsRequired == 1) {
            NSLog(@"单击");
    }
        else if (sender.numberOfTapsRequired == 2) {
            NSLog(@"双击");
    }
        else
    {
            NSLog(@"三击");
    }
    }

轻扫手势

• 向左轻扫

    UISwipeGestureRecognizer *leftSwipe = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipeAction:)];
    leftSwipe.direction = UISwipeGestureRecognizerDirectionLeft; //左
    [_imageView addGestureRecognizer:leftSwipe];

• 向右轻扫

    UISwipeGestureRecognizer *rightSwipe = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipeAction:)];
    rightSwipe.direction = UISwipeGestureRecognizerDirectionRight;
    [_imageView addGestureRecognizer:rightSwipe];

• 轻扫手势（左右）的事件方法

-(void)swipeAction:(UISwipeGestureRecognizer *)sender
{
    switch (sender.direction) {
        case UISwipeGestureRecognizerDirectionLeft:
        {
            NSLog(@"向左轻扫");
            if (_count > _images.count - 2) {
                
                //扫到最右一张弹出警示框
                UIAlertController *alertController = [UIAlertController alertControllerWithTitle:nil message:@"最后一张" preferredStyle:UIAlertControllerStyleAlert];
                
                UIAlertAction *sure = [UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault handler:nil];
                
                [alertController addAction:sure];
                [self presentViewController:alertController animated:YES completion:nil];
                
                break;
            }
            [UIView beginAnimations:nil context:nil];
            [UIView setAnimationDuration:1.0f];
            [UIView setAnimationTransition:UIViewAnimationTransitionCurlDown forView:_imageView cache:YES];
            [UIView commitAnimations];
            
            
               _imageView.image = _images[++_count];
        }
            break;
            case UISwipeGestureRecognizerDirectionRight:
        {
            NSLog(@"向右轻扫");
            if (_count < _images.count - 2) {
                UIAlertController *alertController = [UIAlertController alertControllerWithTitle:nil message:@"第一张" preferredStyle:UIAlertControllerStyleAlert];
                
                UIAlertAction *sure = [UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault handler:nil];
                
                [alertController addAction:sure];
                [self presentViewController:alertController animated:YES completion:nil];
                
                break;
            }
            [UIView beginAnimations:nil context:nil];
            [UIView setAnimationDuration:1.0f];
            [UIView setAnimationTransition:UIViewAnimationTransitionCurlDown forView:_imageView cache:YES];
            [UIView commitAnimations];
            
            _imageView.image = _images[--_count];
        }
        default:
            break;
    }
}

拖动手势

• 拖动

    UIPanGestureRecognizer *panGesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(panGestureAction:)];
    [_imageView addGestureRecognizer:panGesture];

• 拖动事件方法

-(void)panGestureAction:(UIPanGestureRecognizer *)sender
{
    NSLog(@"拖动");
    //转换坐标系
   CGPoint point = [sender translationInView:self.view];
    _imageView.center = CGPointMake(_imageView.center.x + point.x, _imageView.center.y + point.y);
    [sender setTranslation:CGPointZero inView:self.view];
}

旋转手势

• 旋转

    UIRotationGestureRecognizer *rotationGestur = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(rotationAction:)];
    [_imageView addGestureRecognizer:rotationGestur];

• 旋转事件方法

    -(void)rotationAction:(UIRotationGestureRecognizer *)sender
    {
        NSLog(@"旋转");
        _imageView.transform = CGAffineTransformMakeRotation(sender.rotation);
    }

捏合手势

• 捏合

    UIPinchGestureRecognizer *pinchGesture = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(pinchGestureAction:)];
    [_imageView addGestureRecognizer:pinchGesture];

• 捏合事件方法

-(void)pinchGestureAction:(UIPinchGestureRecognizer *)sender
{
    NSLog(@"捏合");
    _imageView.transform = CGAffineTransformMakeScale(sender.scale,sender.scale);
}

长按事件

• 长按

    UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPressAction:)];
    [_imageView addGestureRecognizer:longPress];

• 长按事件方法

-(void)longPressAction:(UILongPressGestureRecognizer *)sender
{
    NSLog(@"长按");
    
    if (sender.state == UIGestureRecognizerStateBegan) {
        
        UIAlertController *alertController = [UIAlertController alertControllerWithTitle:nil message:nil preferredStyle:UIAlertControllerStyleActionSheet];
        
        UIAlertAction *cancle = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {
            
        }];
        [alertController addAction:cancle];
        
        
        UIAlertAction *savePhoto = [UIAlertAction actionWithTitle:@"保存到相册" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
            
            UIImageWriteToSavedPhotosAlbum(_imageView.image, self, @selector(image:didFinishSavingWithError:contextInfo:), NULL);
            
        }];
        [alertController addAction:savePhoto];
        
        
        UIAlertAction *openPhoto = [UIAlertAction actionWithTitle:@"打开相册" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
            
            UIImagePickerController *picker = [[UIImagePickerController alloc] init];
            //资源类型为打开相册
            picker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
            picker.delegate = self;
            //选择后的图片可以被编辑
            picker.allowsEditing = YES;
            
            [self presentViewController:picker animated:YES completion:nil];
            
        }];
        [alertController addAction:openPhoto];
        
        
        UIAlertAction *turnonCamer = [UIAlertAction actionWithTitle:@"打开相机" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
            
            UIImagePickerController *picker = [[UIImagePickerController alloc] init];
            picker.sourceType = UIImagePickerControllerSourceTypeCamera;
            picker.delegate = self;
            picker.allowsEditing = YES;
            
            [self presentViewController:picker animated:YES completion:nil];
        }];
        [alertController addAction:turnonCamer];
        
        [self presentViewController:alertController animated:YES completion:^{
            
        }];
    }
}

• 保存照片的事件方法

- (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo
{
    NSString *msg = nil;
    if (!error) {
        msg = @"保存成功";
    }
    else
    {
        msg = @"图片保存失败";
    }
    
    NSLog(@"%@",msg);
    
}

• 打开相册和打开相机的事件方法

    -(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info
    {
    //打开相机
    if (picker.sourceType == UIImagePickerControllerSourceTypeCamera) {
        
        _imageView.image = info[@"UIImagePickerControllerEditedImage"];
    }
    //打开相册
    else
    {
        NSLog(@"info = %@",info);
        //获取永华编辑之后的图片
        _imageView.image = info[@"UIImagePickerControllerEditedImage"];
       
    }
    [self dismissViewControllerAnimated:YES completion:nil];
    }