UIImageView 上的 UIGestureRecognizer

Question

我有一个 UIImageView，我希望能够调整大小和旋转等。

可以将 UIGestureRecognizer 添加到 UIImageView 中吗？

我想将旋转和捏合识别器添加到将在运行时创建的 UIImageView 中。

如何添加这些识别器？

Answer 1

SWIFT 3 示例

override func viewDidLoad() {

    self.backgroundImageView.addGestureRecognizer(
        UITapGestureRecognizer.init(target: self, action:#selector(didTapImageview(_:)))
    )

    self.backgroundImageView.isUserInteractionEnabled = true
}

func didTapImageview(_ sender: Any) {
    // do something
}

无需手势识别器委托或其他必要的实现。

Answer 2

您还可以将点击手势识别器拖动到 Storyboard 中的图像视图。然后通过 Ctrl + 拖动 到代码中创建一个操作。

Answer 3

对于块爱好者，您可以使用 ALActionBlocks 在块中添加手势操作

__weak ALViewController *wSelf = self;
imageView.userInteractionEnabled = YES;
UITapGestureRecognizer *gr = [[UITapGestureRecognizer alloc] initWithBlock:^(UITapGestureRecognizer *weakGR) {
    NSLog(@"pan %@", NSStringFromCGPoint([weakGR locationInView:wSelf.view]));
}];
[self.imageView addGestureRecognizer:gr];

Answer 4

检查 UIImageView 上的 userInteractionEnabled 是否为 YES。然后您可以添加手势识别器。

imageView.userInteractionEnabled = YES;
UIPinchGestureRecognizer *pgr = [[UIPinchGestureRecognizer alloc] 
    initWithTarget:self action:@selector(handlePinch:)];
pgr.delegate = self;
[imageView addGestureRecognizer:pgr];
[pgr release];
:
:
- (void)handlePinch:(UIPinchGestureRecognizer *)pinchGestureRecognizer
{
  //handle pinch...
}

Answer 5

是的，可以将 UIGestureRecognizer 添加到 UIImageView 中。正如另一个答案中所述，记住通过将其 userInteractionEnabled 属性设置为 YES 来启用图像视图上的用户交互非常重要。 UIImageView继承自UIView，UIView的用户交互属性默认设置为YES，但UIImageView的用户交互属性默认设置为NO。

来自 UIImageView 文档：

新的图像视图对象被配置为忽略用户事件
默认。如果你想在自定义子类中处理事件
UIImageView，您必须显式更改
初始化对象后，userInteractionEnabled 属性设置为 YES。

无论如何，关于大部分答案。以下示例展示了如何使用 UIPinchGestureRecognizer、UIRotationGestureRecognizer 和 UIPanGestureRecognizer 创建 UIImageView。

首先，在 viewDidLoad 或您选择的其他方法中，创建一个图像视图，为其提供图像、框架，并启用其用户交互。然后创建三个手势，如下所示。请务必使用他们的委托属性（最有可能设置为 self）。这需要同时使用多个手势。

- (void)viewDidLoad
{
    [super viewDidLoad];

    // set up the image view
    UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"someImage"]];
    [imageView setBounds:CGRectMake(0.0, 0.0, 120.0, 120.0)];
    [imageView setCenter:self.view.center];
    [imageView setUserInteractionEnabled:YES]; // <--- This is very important

    // create and configure the pinch gesture
    UIPinchGestureRecognizer *pinchGestureRecognizer = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(pinchGestureDetected:)];
    [pinchGestureRecognizer setDelegate:self];
    [imageView addGestureRecognizer:pinchGestureRecognizer];

    // create and configure the rotation gesture
    UIRotationGestureRecognizer *rotationGestureRecognizer = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(rotationGestureDetected:)];
    [rotationGestureRecognizer setDelegate:self];
    [imageView addGestureRecognizer:rotationGestureRecognizer];

    // creat and configure the pan gesture
    UIPanGestureRecognizer *panGestureRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(panGestureDetected:)];
    [panGestureRecognizer setDelegate:self];
    [imageView addGestureRecognizer:panGestureRecognizer];


    [self.view addSubview:imageView]; // add the image view as a subview of the view controllers view
}

以下是检测到视图上的手势时将调用的三个方法。在它们内部，我们将检查手势的当前状态，如果它处于开始或更改的 UIGestureRecognizerState 状态，我们将读取手势的缩放/旋转/平移属性，将该数据应用于仿射变换，将仿射变换应用于图像视图，然后重置手势缩放/旋转/平移。

- (void)pinchGestureDetected:(UIPinchGestureRecognizer *)recognizer
{
    UIGestureRecognizerState state = [recognizer state];

    if (state == UIGestureRecognizerStateBegan || state == UIGestureRecognizerStateChanged)
    {
        CGFloat scale = [recognizer scale];
        [recognizer.view setTransform:CGAffineTransformScale(recognizer.view.transform, scale, scale)];
        [recognizer setScale:1.0];
    }
}

- (void)rotationGestureDetected:(UIRotationGestureRecognizer *)recognizer
{
    UIGestureRecognizerState state = [recognizer state];

    if (state == UIGestureRecognizerStateBegan || state == UIGestureRecognizerStateChanged)
    {
        CGFloat rotation = [recognizer rotation];
        [recognizer.view setTransform:CGAffineTransformRotate(recognizer.view.transform, rotation)];
        [recognizer setRotation:0];
    }
}

- (void)panGestureDetected:(UIPanGestureRecognizer *)recognizer
{
    UIGestureRecognizerState state = [recognizer state];

    if (state == UIGestureRecognizerStateBegan || state == UIGestureRecognizerStateChanged)
    {
        CGPoint translation = [recognizer translationInView:recognizer.view];
        [recognizer.view setTransform:CGAffineTransformTranslate(recognizer.view.transform, translation.x, translation.y)];
        [recognizer setTranslation:CGPointZero inView:recognizer.view];
    }
}

最后也是非常重要的是，您需要利用 UIGestureRecognizerDelegate 方法 gestureRecognizer: shouldRecognizeSimultaneouslyWithGestureRecognizer 允许手势同时工作。如果这三个手势是仅有的三个将此类指定为其委托的手势，那么您只需返回 YES 即可，如下所示。但是，如果您有其他手势将此类指定为其委托，则您可能需要向此方法添加逻辑，以确定哪个手势是哪个手势，然后才能允许它们一起工作。

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
    return YES;
}

不要忘记确保您的类符合 UIGestureRecognizerDelegate 协议。为此，请确保您的界面如下所示：

@interface MyClass : MySuperClass <UIGestureRecognizerDelegate>

如果您更喜欢自己使用工作示例项目中的代码，我创建的示例项目包含此代码com/NSPostWhenIdle/GestureImageView">可以在这里找到。

Answer 6

Swift 4.2

myImageView.isUserInteractionEnabled = true
let tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(imageTapped))
tapGestureRecognizer.numberOfTapsRequired = 1
myImageView.addGestureRecognizer(tapGestureRecognizer)

以及点击时：

@objc func imageTapped(_ sender: UITapGestureRecognizer) {
   // do something when image tapped
   print("image tapped")
}

Answer 7

Swift 2.0 解决方案

您可以在同一庄园中创建点击、捏合或滑动手势识别器。下面我将引导您完成 4 个步骤来启动并运行识别器。

4 个步骤

1.) 通过将 UIGestureRecognizerDelegate 添加到您的类签名来继承它。

class ViewController: UIViewController, UIGestureRecognizerDelegate {...}

2.) 控制从图像拖动到 viewController 以创建 IBOutlet：

@IBOutlet weak var tapView: UIImageView!

3.) 在 vi​​ewDidLoad 中添加以下代码：

// create an instance of UITapGestureRecognizer and tell it to run 
// an action we'll call "handleTap:"
let tap = UITapGestureRecognizer(target: self, action: Selector("handleTap:"))
// we use our delegate
tap.delegate = self
// allow for user interaction
tapView.userInteractionEnabled = true
// add tap as a gestureRecognizer to tapView
tapView.addGestureRecognizer(tap)

4.) 创建点击手势识别器时将调用的函数。 （如果您选择，可以排除 = nil）。

func handleTap(sender: UITapGestureRecognizer? = nil) {
    // just creating an alert to prove our tap worked!
    let tapAlert = UIAlertController(title: "hmmm...", message: "this actually worked?", preferredStyle: UIAlertControllerStyle.Alert)
    tapAlert.addAction(UIAlertAction(title: "OK", style: .Destructive, handler: nil))
    self.presentViewController(tapAlert, animated: true, completion: nil)
}

---

您的最终代码应该如下所示：

class ViewController: UIViewController, UIGestureRecognizerDelegate {

    @IBOutlet weak var tapView: UIImageView!

    override func viewDidLoad() {
        super.viewDidLoad()

        let tap = UITapGestureRecognizer(target: self, action: Selector("handleTap:"))
        tap.delegate = self
        tapView.userInteractionEnabled = true
        tapView.addGestureRecognizer(tap)
    }

    func handleTap(sender: UITapGestureRecognizer? = nil) {
        let tapAlert = UIAlertController(title: "hmmm...", message: "this actually worked?", preferredStyle: UIAlertControllerStyle.Alert)
        tapAlert.addAction(UIAlertAction(title: "OK", style: .Destructive, handler: nil))
        self.presentViewController(tapAlert, animated: true, completion: nil)
    }
}

Answer 8

我刚刚使用 swift4 通过在单个视图 UIPinchGestureRecognizer 中添加 3 个手势来完成此操作

1. ：放大和缩小视图。
2. UIRotationGestureRecognizer：旋转视图。
3. UIPanGestureRecognizer：拖动视图。

这是我的示例代码

class ViewController: UIViewController: UIGestureRecognizerDelegate{
      //your image view that outlet from storyboard or xibs file.
     @IBOutlet weak var imgView: UIImageView!
     // declare gesture recognizer
     var panRecognizer: UIPanGestureRecognizer?
     var pinchRecognizer: UIPinchGestureRecognizer?
     var rotateRecognizer: UIRotationGestureRecognizer?

     override func viewDidLoad() {
          super.viewDidLoad()
          // Create gesture with target self(viewcontroller) and handler function.  
          self.panRecognizer = UIPanGestureRecognizer(target: self, action: #selector(self.handlePan(recognizer:)))
          self.pinchRecognizer = UIPinchGestureRecognizer(target: self, action: #selector(self.handlePinch(recognizer:)))
          self.rotateRecognizer = UIRotationGestureRecognizer(target: self, action: #selector(self.handleRotate(recognizer:)))
          //delegate gesture with UIGestureRecognizerDelegate
          pinchRecognizer?.delegate = self
          rotateRecognizer?.delegate = self
          panRecognizer?.delegate = self
          // than add gesture to imgView
          self.imgView.addGestureRecognizer(panRecognizer!)
          self.imgView.addGestureRecognizer(pinchRecognizer!)
          self.imgView.addGestureRecognizer(rotateRecognizer!)
     }

     // handle UIPanGestureRecognizer 
     @objc func handlePan(recognizer: UIPanGestureRecognizer) {    
          let gview = recognizer.view
          if recognizer.state == .began || recognizer.state == .changed {
               let translation = recognizer.translation(in: gview?.superview)
               gview?.center = CGPoint(x: (gview?.center.x)! + translation.x, y: (gview?.center.y)! + translation.y)
               recognizer.setTranslation(CGPoint.zero, in: gview?.superview)
          }
     }

     // handle UIPinchGestureRecognizer 
     @objc func handlePinch(recognizer: UIPinchGestureRecognizer) {
          if recognizer.state == .began || recognizer.state == .changed {
               recognizer.view?.transform = (recognizer.view?.transform.scaledBy(x: recognizer.scale, y: recognizer.scale))!
               recognizer.scale = 1.0
         }
     }   

     // handle UIRotationGestureRecognizer 
     @objc func handleRotate(recognizer: UIRotationGestureRecognizer) {
          if recognizer.state == .began || recognizer.state == .changed {
               recognizer.view?.transform = (recognizer.view?.transform.rotated(by: recognizer.rotation))!
               recognizer.rotation = 0.0
           }
     }

     // mark sure you override this function to make gestures work together 
     func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
         return true
     }

}

如有任何问题，只需输入评论即可。谢谢