如何在我的应用程序中实现 UITapGestureRecognizer

Question

我对编程和 Objective C 很陌生。我想知道如何制作一个具有空白屏幕和一分钟计时器的应用程序。你应该尽可能快地点击，只要你可以。我想知道如何在我的代码中实现UITapGestureRecognizer。

Answer 1

这是关于如何在课堂上实现手势识别器的分步指南：

1. 使您的班级符合UIGestureRecognizerDelegate 协议。

2. 实例化手势识别器。例如，要实例化一个UITapGestureRecognizer，我们将这样做：

   UITapGestureRecognizer *tapGestureRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleTapFrom:)];
   

   这里，action 是处理手势的选择器。在这里，我们的选择器 handleTapFrom 看起来像：

   - (void) handleTapFrom: (UITapGestureRecognizer *)recognizer
   {
       //Code to handle the gesture
   }
   

   选择器的参数是手势识别器。我们可以使用这个手势识别器来访问它的属性，例如，我们可以找到手势识别器的状态，比如UIGestureRecognizerStateBegan、UIGestureRecognizerStateEnded等。

3. 在实例化的手势识别器上设置所需的属性。例如，对于UITapGestureRecognizer，我们可以设置属性numberOfTapsRequired和numberOfTouchesRequired。

4. 将手势识别器添加到要检测手势的视图中。在我们的示例代码中（我将分享该代码供您参考），我们将使用以下代码行将手势识别器添加到 imageView：

   [self.imageView addGestureRecognizer:tapGestureRecognizer];
   

5. 将手势识别器添加到视图后，设置手势识别器的委托，即处理所有手势识别器内容的类。在我们的示例代码中，它会是这样的：

   tapGestureRecognizer.delegate = self;
   

   注意：在将手势识别器添加到视图后分配委托。否则不会调用action方法。

Answer 2

Swift 中的示例：

import UIKit

class ViewController: UIViewController {

    @IBOutlet var myUIImageView: UIImageView!

    override func viewDidLoad() {
        super.viewDidLoad()

        let singleTap: UITapGestureRecognizer = UITapGestureRecognizer(target: self, action: "myUIImageViewTapped:")
        singleTap.numberOfTapsRequired = 1
        singleTap.numberOfTouchesRequired = 1
        self.myUIImageView.addGestureRecognizer(singleTap)
        self.myUIImageView.userInteractionEnabled = true
    }

    func myUIImageViewTapped(recognizer: UITapGestureRecognizer) {
        if(recognizer.state == UIGestureRecognizerState.Ended){
            println("myUIImageView has been tapped by the user.")
        }
    }

}

Answer 3

UITapGestureRecognizer *gestureRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(hideKeyboard)];
[self.tableView addGestureRecognizer:gestureRecognizer];
self.tableView.userInteractionEnabled = YES;
gestureRecognizer.cancelsTouchesInView = NO;  // this prevents the gesture recognizers to 'block' touches

Answer 4

适用于 Xcode 11.4、Swift 5

class ViewController: UIViewController {

    @IBOutlet weak var targetView: UIView!
    override func viewDidLoad() {
        super.viewDidLoad()
        let tap = UITapGestureRecognizer(target: self, action: #selector(self.touchCallback(_:)))
        self.targetView.addGestureRecognizer(tap)
    }

    @objc func touchCallback(_ sender: UITapGestureRecognizer? = nil) {
        if(sender?.state == .ended) {
            print("tapped")
        }
    }
}

// If you want to touch start, available touchesBegan
class ViewController: UIViewController {

    @IBOutlet weak var targetView: UIView!
    override func viewDidLoad() {
        super.viewDidLoad()
    }


    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
          for touch in touches {
              let location = touch.location(in: targetView)
              print(location)
          }
      }
}

Answer 5

如果您使用 Swift (iOS9) 和 SpriteKit，请尝试以下操作。

class GameScene: SKScene {
    override func didMoveToView(view: SKView) {
        let singleTap = UITapGestureRecognizer(target:self, action:#selector(self.handleSingleTap:))
        singleTap.numberOfTouchesRequired = 1
        singleTap.addTarget(self, action:#selector(self.handleSingleTap))
        view.userInteractionEnabled = true
        view.addGestureRecognizer(singleTap)
    }
    //event handler
    func handleSingleTap(sender:UITapGestureRecognizer){
        print("tapped")
    }
}