iOS - 在图像视图上点击手势问题

Posted 2023-02-27

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【中文标题】iOS - 在图像视图上点击手势问题【英文标题】：iOS - Tap Gesture issue on image view 【发布时间】：2016-01-25 04:09:01 【问题描述】：

我正在慢慢完成 Apple 的 Swift 学习开发，但我的点击手势一直遇到问题。我重新创建了项目编号，所有结果都相同。

我在图像视图中添加了一个点击手势，这应该会从我的计算机打开照片库。什么都没有发生。

当我从 Apple 下载并运行示例文件时，一切正常。当我将代码从 Apple 复制并粘贴到我的时，再次没有任何反应。我已经经历了我能做的所有事情，但我觉得我错过了一些东西。

这是我的代码。苹果的代码如下：

import UIKit

class ViewController: UIViewController, UITextFieldDelegate, UIImagePickerControllerDelegate, UINavigationControllerDelegate 

    // MARK: Properties
    @IBOutlet weak var nameTextField: UITextField!
    @IBOutlet weak var mealNameLabel: UILabel!
    @IBOutlet weak var photoImageView: UIImageView!

    override func viewDidLoad() 
        super.viewDidLoad()

        // handle the text fields user input through delegate callbacks
        nameTextField.delegate = self

    

    override func didReceiveMemoryWarning() 
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    

    // MARK: UITextFieldDelegate
    func textFieldShouldReturn(textField: UITextField) -> Bool 
       // Hide the Keyboard
        textField.resignFirstResponder()
        return true

    
    func textFieldDidEndEditing(textField: UITextField) 
        mealNameLabel.text = textField.text
    

    // MARK: UIImagePickerControllerDelegate

    func imagePickerControllerDidCancel(picker: UIImagePickerController) 
        // dismiss the picker if user cancels
        dismissViewControllerAnimated(true, completion: nil)
    

    func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : AnyObject]) 
        // The info dictionary contains multiple representations of the image, and this uses the original.
        let selectedImage = info[UIImagePickerControllerOriginalImage] as! UIImage

        // Set the photoviewimage to be the selected image
        photoImageView.image = selectedImage

        // Dismiss the picker
        dismissViewControllerAnimated(true, completion: nil)
    

    // MARK: Actions

    @IBAction func selectImageFromPhotoLibrary(sender: UITapGestureRecognizer) 
        // Hide the Keyboard
        nameTextField.resignFirstResponder()

        // UIImagePickerController is a view controller that lets a user pick media from their photo library.
        let imagePickerController = UIImagePickerController()

        // Only Allow pictures to be selected and not taken
        imagePickerController.sourceType = .PhotoLibrary

        // make sure the viewcontroller is notified when the user selects an image
        imagePickerController.delegate = self

        presentViewController(imagePickerController, animated: true, completion: nil)

    

    @IBAction func setDefaultLabelText(sender: UIButton) 
        mealNameLabel.text = "Default Text"

这是苹果的代码：

import UIKit

class ViewController: UIViewController, UITextFieldDelegate, UIImagePickerControllerDelegate, UINavigationControllerDelegate 
    // MARK: Properties

    @IBOutlet weak var nameTextField: UITextField!
    @IBOutlet weak var mealNameLabel: UILabel!
    @IBOutlet weak var photoImageView: UIImageView!

    override func viewDidLoad() 
        super.viewDidLoad()

        // Handle the text field’s user input through delegate callbacks.
        nameTextField.delegate = self
    

    // MARK: UITextFieldDelegate

    func textFieldShouldReturn(textField: UITextField) -> Bool 
        // Hide the keyboard.
        textField.resignFirstResponder()
       return true
    

    func textFieldDidEndEditing(textField: UITextField) 
        mealNameLabel.text = textField.text
    

    // MARK: UIImagePickerControllerDelegate
    func imagePickerControllerDidCancel(picker: UIImagePickerController) 
        // Dismiss the picker if the user canceled.
        dismissViewControllerAnimated(true, completion: nil)
    

    func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : AnyObject]) 
        // The info dictionary contains multiple representations of the image, and this uses the original.
        let selectedImage = info[UIImagePickerControllerOriginalImage] as! UIImage

        // Set photoImageView to display the selected image.
        photoImageView.image = selectedImage

        // Dismiss the picker.
        dismissViewControllerAnimated(true, completion: nil)
    

    // MARK: Actions
    @IBAction func selectImageFromPhotoLibrary(sender: UITapGestureRecognizer) 
        // Hide the keyboard.
        nameTextField.resignFirstResponder()

        // UIImagePickerController is a view controller that lets a user pick media from their photo library.
        let imagePickerController = UIImagePickerController()

        // Only allow photos to be picked, not taken.
        imagePickerController.sourceType = .PhotoLibrary

        // Make sure ViewController is notified when the user picks an image.
        imagePickerController.delegate = self

        presentViewController(imagePickerController, animated: true, completion: nil)
    

    @IBAction func setDefaultLabelText(sender: UIButton) 
        mealNameLabel.text = "Default Text"

来自 Anbu 的工作代码

import UIKit

class ViewController: UIViewController, UITextFieldDelegate, UIImagePickerControllerDelegate, UINavigationControllerDelegate  


    // MARK: Properties
    @IBOutlet weak var nameTextField: UITextField!
    @IBOutlet weak var mealNameLabel: UILabel!
    @IBOutlet weak var photoImageView: UIImageView!



    override func viewDidLoad() 
        let tapgesture = UITapGestureRecognizer(target: self, action: Selector("imagepressed"))
        photoImageView.userInteractionEnabled = true
        photoImageView.addGestureRecognizer(tapgesture)

        super.viewDidLoad()

        // handle the text fields user input through delegate callbacks
        nameTextField.delegate = self

    

    override func didReceiveMemoryWarning() 
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    

    // MARK: UITextFieldDelegate
    func textFieldShouldReturn(textField: UITextField) -> Bool 
       // Hide the Keyboard
        textField.resignFirstResponder()
        return true

    
    func textFieldDidEndEditing(textField: UITextField) 
        mealNameLabel.text = textField.text
    

    // MARK: UIImagePickerControllerDelegate

    func imagePickerControllerDidCancel(picker: UIImagePickerController) 
        // dismiss the picker if user cancels
        dismissViewControllerAnimated(true, completion: nil)
    

    func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : AnyObject]) 
        // The info dictionary contains multiple representations of the image, and this uses the original.
        let selectedImage = info[UIImagePickerControllerOriginalImage] as! UIImage

        // Set the photoviewimage to be the selected image
        photoImageView.image = selectedImage

        // Dismiss the picker
        dismissViewControllerAnimated(true, completion: nil)
    

    // MARK: Actions


    func imagepressed () 
        nameTextField.resignFirstResponder()

        // UIImagePickerController is a view controller that lets a user pick media from their photo library.
        let imagePickerController = UIImagePickerController()

        // Only Allow pictures to be selected and not taken
        imagePickerController.sourceType = .PhotoLibrary

        // make sure the viewcontroller is notified when the user selects an image
        imagePickerController.delegate = self

        presentViewController(imagePickerController, animated: true, completion: nil)
    



/*    @IBAction func selectImageFromPhotoLibrary(sender: UITapGestureRecognizer) 
        let tapgesture = UITapGestureRecognizer(target: self, action: Selector("imagepressed"))
        photoImageView.userInteractionEnabled = true
        photoImageView.addGestureRecognizer(tapgesture)

        // Hide the Keyboard
        nameTextField.resignFirstResponder()

        // UIImagePickerController is a view controller that lets a user pick media from their photo library.
        let imagePickerController = UIImagePickerController()

        // Only Allow pictures to be selected and not taken
        imagePickerController.sourceType = .PhotoLibrary

        // make sure the viewcontroller is notified when the user selects an image
        imagePickerController.delegate = self

        presentViewController(imagePickerController, animated: true, completion: nil)

    
   */

    @IBAction func setDefaultLabelText(sender: UIButton) 
        mealNameLabel.text = "Default Text"

【问题讨论】：

点击手势识别器在哪里？您是否在情节提要/XIB 中为您的视图控制器添加了轻触识别器？如果您还没有将点击手势识别器添加到 storyboard/xib，然后将 action 方法连接到 selectImageFromPhotoLibrary。点击手势被添加到情节提要到 ImageView 上，然后通过拖放连接到 //Mark: Actions with the UITapGesture 下 【参考方案1】：

我发现解决此问题的最简单方法是在图像视图的属性编辑器中单击“启用用户交互”复选框。 Screenshot

【讨论】：

本质上，此错误来自“添加膳食照片”部分中缺少指令 #12：“在属性检查器中，找到交互字段并选中启用用户交互复选框。您需要此功能稍后让用户与图像视图进行交互。” 在将“Tap Gesture Recognizer”控制器与“Image View”控制器连接之前，您必须检查真正的“User Interaction Enabled”。【参考方案2】：

喜欢

原因，UIImageview userInteraction默认为false，需要手动开启

第一步

let tapGesture = UITapGestureRecognizer(target:self, action:Selector("imagePressed"))
photoImageView.userInteractionEnabled = true // this line is important
photoImageView.addGestureRecognizer(tapGesture)

第二步

func imagePressed()

//do  Your action here  whatever you want

【讨论】：

我会在哪里添加这个？这就是我一直在想的（至少沿着这些思路，因为我不想给自己太多的功劳）但苹果开发者并没有在任何地方展示这一点。在 viewdidload 上调用这个 Andu，我尝试了几个不同的位置来放置代码，但均未成功。请随时像对待我两岁的儿子一样对待我，并让我知道将代码放在哪里。另外，我是否只需复制并粘贴基金 selectuserimagefromlibrary 下的代码并将其粘贴到 func imagepressed() 中？谢谢安布！我能够让它工作并感谢帮助！我已经添加了上面的工作代码。【参考方案3】：

您的代码非常好。问题出在故事板中的 UIImageView 上。 user interaction 选项未选中。

因此，您只需在情节提要中启用此选项即可。

转到您的故事板。

选择您的 UIImageView（您将其命名为 photoimageview）

现在在“属性检查器”中查找user interaction enabled，它应该被“选中”

现在运行你的项目，它就可以工作了。

【讨论】：

【参考方案4】：

您在哪里为图像视图添加了UITapGestureRecognizer？如果您在 Storyboard 中添加它，您是否将其连接到选择器 selectImageFromPhotoLibrary:？

【讨论】：

点击手势被添加到情节提要到 ImageView 上，然后通过拖放连接到 //Mark: Actions with the UITapGesture 下

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