macOS 13.2下UITextField点击后错位问题求助

问题说明 #

原本设置为居中对齐的UITextField，在macOS 13.2系统中以“My Mac(Designed for iPad)”方式构建运行时，点击文本框后文本会向左偏移；但在iPad设备上运行完全正常，Xcode 14.1和14.2版本均存在此现象。

复现代码 #

import UIKit

class ViewController: UIViewController {
    
    let textField: UITextField = {
        let textField = UITextField()
        textField.translatesAutoresizingMaskIntoConstraints = false
        textField.backgroundColor = .green
        textField.textAlignment = .center
        textField.text = "Hello, World"
        return textField
    }()
    

    override func viewDidLoad() {
        super.viewDidLoad()
        
        view.addSubview(textField)
        
        NSLayoutConstraint.activate([
            textField.widthAnchor.constraint(equalToConstant: 200),
            textField.heightAnchor.constraint(equalToConstant: 50),
            textField.centerXAnchor.constraint(equalTo: view.centerXAnchor),
            textField.centerYAnchor.constraint(equalTo: view.centerYAnchor)
        ])
        
    }
}

解决方法 #

这是macOS上iPad App兼容模式的UIKit已知bug，可通过以下两种方式修复：

方式一：自定义UITextField子类强制保持对齐 #

创建自定义子类，在文本框获取/失去焦点时强制重置居中对齐：

import UIKit

class CenteredTextField: UITextField {
    override func becomeFirstResponder() -> Bool {
        let success = super.becomeFirstResponder()
        self.textAlignment = .center
        return success
    }
    
    override func resignFirstResponder() -> Bool {
        let success = super.resignFirstResponder()
        self.textAlignment = .center
        return success
    }
}

将原代码中的UITextField替换为CenteredTextField即可生效。

方式二：监听编辑状态通知重置对齐 #

在ViewController中添加通知监听，响应文本框编辑状态变化：

override func viewDidLoad() {
    super.viewDidLoad()
    
    view.addSubview(textField)
    
    // 监听编辑开始/结束通知
    NotificationCenter.default.addObserver(
        self,
        selector: #selector(resetTextAlignment),
        name: UITextField.textDidBeginEditingNotification,
        object: textField
    )
    NotificationCenter.default.addObserver(
        self,
        selector: #selector(resetTextAlignment),
        name: UITextField.textDidEndEditingNotification,
        object: textField
    )
    
    NSLayoutConstraint.activate([
        textField.widthAnchor.constraint(equalToConstant: 200),
        textField.heightAnchor.constraint(equalToConstant: 50),
        textField.centerXAnchor.constraint(equalTo: view.centerXAnchor),
        textField.centerYAnchor.constraint(equalTo: view.centerYAnchor)
    ])
}

@objc private func resetTextAlignment() {
    textField.textAlignment = .center
}

// 页面销毁时移除通知监听
deinit {
    NotificationCenter.default.removeObserver(self)
}

效果验证 #

两种方法均能确保文本框在点击编辑和失去焦点时，始终保持文本居中对齐，解决macOS兼容模式下的偏移问题。

内容的提问来源于stack exchange，提问作者Denny