如何设置SwiftUI的文本字段字符限制? [英] How to set textfield character limit SwiftUI?

问题描述

我正在使用SwiftUi版本2进行应用程序开发.我遇到了SwiftUI中可用的文本字段的问题.我不想再使用UITextField.我想限制TextField中的字符数.我进行了很多搜索，找到了与此相关的答案，但这些答案不适用于SwiftUI版本2.

I'm using SwiftUi version 2 for my application development. I'm facing issue with textfield available in SwiftUI. I don't want to use UITextField anymore. I want to limit the number of Characters in TextField. I searched a lot and i find some answer related to this but those answer doesn't work for SwiftUI version 2.

class textBindingManager: ObservableObject{
    let characterLimit: Int
    @Published var phoneNumber = "" {
        didSet {
            if phoneNumber.count > characterLimit && oldValue.count <= characterLimit {
                phoneNumber = oldValue
            }            
        }
    }
    init(limit: Int = 10) {
        characterLimit = limit
    }    
}

---

struct ContentView: View {
    @ObservedObject var textBindingManager = TextBindingManager(limit: 5)        
    var body: some View {
        TextField("Placeholder", text: $textBindingManager.phoneNumber)
    }
}

推荐答案

无需在发布的属性上使用didSet.您可以在TextField中添加修饰符，并将字符串值限制为其前缀(限制为字符数):

No need to use didSet on your published property. You can add a modifier to TextField and limit the string value to its prefix limited to the character limit:

import SwiftUI

struct ContentView: View {
    @ObservedObject var textBindingManager = TextBindingManager(limit: 5)
    var body: some View {
        TextField("Placeholder", text: $textBindingManager.phoneNumber)
            .padding()
            .onChange(of: textBindingManager.phoneNumber, perform: editingChanged)
    }
    func editingChanged(_ value: String) {
        textBindingManager.phoneNumber = String(value.prefix(textBindingManager.characterLimit))
    }
}

---

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

---

class TextBindingManager: ObservableObject {
    let characterLimit: Int
    @Published var phoneNumber = ""
    init(limit: Int = 10){
        characterLimit = limit
    }
}

这篇关于如何设置SwiftUI的文本字段字符限制?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！