如何实现点击UIView时唤起键盘并使UITextField进入编辑状态

嘿，我明白你想实现的效果：点击主View时弹出键盘，让用户能在searchBar里输入，但现在遇到了UIView没法成为第一响应者的问题。这其实是因为UIView默认不支持成为第一响应者，而且你的目标其实不是让View成为第一响应者，而是让UITextField激活来弹出键盘。下面一步步帮你搞定：

问题根源 #

UIView的canBecomeFirstResponder()默认返回false，所以你调用self.view.becomeFirstResponder()是不会生效的。而且我们真正需要的是让searchBar成为第一响应者，这样键盘才会弹出并允许输入。

解决方案步骤 #

• 调整点击手势的逻辑：不需要让View成为第一响应者，点击View时直接让searchBar激活即可，同时修正isKeyboardShowing的初始值（一开始键盘是隐藏的，所以应该设为false）。
• 修正过时的键盘通知API：iOS 13之后，UIKeyboardWillShow这类通知名已经被弃用，改用UIResponder.keyboardWillShowNotification更稳妥。

修改后的完整代码 #

import UIKit

class ViewController: UIViewController, UITextFieldDelegate {
    @IBOutlet weak var searchBar: UITextField!
    // 初始值改为false，符合键盘默认隐藏的状态
    var isKeyboardShowing: Bool = false
    var viewTapped: UITapGestureRecognizer = UITapGestureRecognizer()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        searchBar.bottomAnchor.constraint(equalTo: self.view.bottomAnchor, constant: -500).isActive = true
        viewTapped = UITapGestureRecognizer(target: self, action: #selector(viewWasTapped))
        self.view.addGestureRecognizer(viewTapped)
        
        // 使用适配新版本iOS的通知名
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: UIResponder.keyboardWillShowNotification, object: nil)
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide), name: UIResponder.keyboardWillHideNotification, object: nil)
        
        searchBar.delegate = self
    }
    
    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        // 初始状态让searchBar失去第一响应者，确保键盘隐藏
        self.searchBar.resignFirstResponder()
        
        print("Can the view be the first responder: \(self.view.canBecomeFirstResponder)")
        print("the searchbar is the first responder: \(searchBar.isFirstResponder)")
        print("the view is the first responder: \(self.view.isFirstResponder)")
    }
    
    @objc func viewWasTapped(){
        print("The view was tapped")
        if isKeyboardShowing {
            // 键盘显示时，点击View收起键盘
            view.endEditing(true)
        } else {
            // 键盘隐藏时，点击View激活searchBar弹出键盘
            searchBar.becomeFirstResponder()
        }
    }
    
    @objc func keyboardWillShow(notification: NSNotification) {
        print("keyboardWillShow")
        isKeyboardShowing = true
    }
    
    @objc func keyboardWillHide(notification: NSNotification){
        print("keyboardWillHide")
        isKeyboardShowing = false
    }
    
    // 可选：添加return键收起键盘的逻辑，提升用户体验
    func textFieldShouldReturn(_ textField: UITextField) -> Bool {
        textField.resignFirstResponder()
        return true
    }
}

关键改动说明 #

• 修正isKeyboardShowing初始值，匹配键盘默认隐藏的状态
• 在viewWasTapped的else分支直接调用searchBar.becomeFirstResponder()，激活输入框并弹出键盘
• 更新键盘通知名称，避免使用过时API
• 新增textFieldShouldReturn代理方法，支持用户点击return键快速收起键盘

这样修改后，点击主View时就会弹出键盘并让searchBar处于可输入状态，再次点击View则收起键盘，完美实现你的需求！

内容的提问来源于stack exchange，提问作者TheRedCamaro3.0 3.0