如何在SwiftUI中创建多行TextField？

Question

我一直在尝试在SwiftUI中创建多行TextField，但是我不知道怎么做。

这是我目前拥有的代码：

struct EditorTextView : View {
    @Binding var text: String

    var body: some View {
        TextField($text)
            .lineLimit(4)
            .multilineTextAlignment(.leading)
            .frame(minWidth: 100, maxWidth: 200, minHeight: 100, maxHeight: .infinity, alignment: .topLeading)
    }
}

#if DEBUG
let sampleText = """
Very long line 1
Very long line 2
Very long line 3
Very long line 4
"""

struct EditorTextView_Previews : PreviewProvider {
    static var previews: some View {
        EditorTextView(text: .constant(sampleText))
            .previewLayout(.fixed(width: 200, height: 200))
    }
}
#endif

但这是输出：

Answer 1

iOS 14 - 原生 SwiftUI

它被称为 TextEditor

struct ContentView: View {
    @State var text: String = "Multiline \ntext \nis called \nTextEditor"

    var body: some View {
        TextEditor(text: $text)
    }
}

动态生长高度：

如果您希望它随着您的输入而增长，请将其嵌入到 a 中ZStack，Text如下所示：

iOS 13 - 使用 UITextView

您可以在 SwiftUI 代码中使用本机 UITextView 使用此结构：

struct TextView: UIViewRepresentable {
    
    typealias UIViewType = UITextView
    var configuration = { (view: UIViewType) in }
    
    func makeUIView(context: UIViewRepresentableContext<Self>) -> UIViewType {
        UIViewType()
    }
    
    func updateUIView(_ uiView: UIViewType, context: UIViewRepresentableContext<Self>) {
        configuration(uiView)
    }
}

用法

struct ContentView: View {
    var body: some View {
        TextView() {
            $0.textColor = .red
            // Any other setup you like
        }
    }
}

好处：

• 支持iOS 13
• 与遗留代码共享
• 经过多年的考验 UIKit
• 完全可定制
• 原版的所有其他好处 UITextView

Answer 2

更新：虽然Xcode11 beta 4现在支持TextView，但我发现换行UITextView仍然是使可编辑多行文本生效的最佳方法。例如，TextView具有显示故障，其中文本在视图内部无法正确显示。

原始（测试版1）答案：

现在，您可以包装UITextView以创建一个composable View：

import SwiftUI
import Combine

final class UserData: BindableObject  {
    let didChange = PassthroughSubject<UserData, Never>()

    var text = "" {
        didSet {
            didChange.send(self)
        }
    }

    init(text: String) {
        self.text = text
    }
}

struct MultilineTextView: UIViewRepresentable {
    @Binding var text: String

    func makeUIView(context: Context) -> UITextView {
        let view = UITextView()
        view.isScrollEnabled = true
        view.isEditable = true
        view.isUserInteractionEnabled = true
        return view
    }

    func updateUIView(_ uiView: UITextView, context: Context) {
        uiView.text = text
    }
}

struct ContentView : View {
    @State private var selection = 0
    @EnvironmentObject var userData: UserData

    var body: some View {
        TabbedView(selection: $selection){
            MultilineTextView(text: $userData.text)
                .tabItemLabel(Image("first"))
                .tag(0)
            Text("Second View")
                .font(.title)
                .tabItemLabel(Image("second"))
                .tag(1)
        }
    }
}

#if DEBUG
struct ContentView_Previews : PreviewProvider {
    static var previews: some View {
        ContentView()
            .environmentObject(UserData(
                text: """
                        Some longer text here
                        that spans a few lines
                        and runs on.
                        """
            ))

    }
}
#endif

Answer 3

@Meo Flute 的回答很棒！但它不适用于多级文本输入。并结合@Asperi 的回答，这是修复的问题，我还添加了对占位符的支持，只是为了好玩！

struct TextView: UIViewRepresentable {
    var placeholder: String
    @Binding var text: String

    var minHeight: CGFloat
    @Binding var calculatedHeight: CGFloat

    init(placeholder: String, text: Binding<String>, minHeight: CGFloat, calculatedHeight: Binding<CGFloat>) {
        self.placeholder = placeholder
        self._text = text
        self.minHeight = minHeight
        self._calculatedHeight = calculatedHeight
    }

    func makeCoordinator() -> Coordinator {
        Coordinator(self)
    }

    func makeUIView(context: Context) -> UITextView {
        let textView = UITextView()
        textView.delegate = context.coordinator

        // Decrease priority of content resistance, so content would not push external layout set in SwiftUI
        textView.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)

        textView.isScrollEnabled = false
        textView.isEditable = true
        textView.isUserInteractionEnabled = true
        textView.backgroundColor = UIColor(white: 0.0, alpha: 0.05)

        // Set the placeholder
        textView.text = placeholder
        textView.textColor = UIColor.lightGray

        return textView
    }

    func updateUIView(_ textView: UITextView, context: Context) {
        textView.text = self.text

        recalculateHeight(view: textView)
    }

    func recalculateHeight(view: UIView) {
        let newSize = view.sizeThatFits(CGSize(width: view.frame.size.width, height: CGFloat.greatestFiniteMagnitude))
        if minHeight < newSize.height && $calculatedHeight.wrappedValue != newSize.height {
            DispatchQueue.main.async {
                self.$calculatedHeight.wrappedValue = newSize.height // !! must be called asynchronously
            }
        } else if minHeight >= newSize.height && $calculatedHeight.wrappedValue != minHeight {
            DispatchQueue.main.async {
                self.$calculatedHeight.wrappedValue = self.minHeight // !! must be called asynchronously
            }
        }
    }

    class Coordinator : NSObject, UITextViewDelegate {

        var parent: TextView

        init(_ uiTextView: TextView) {
            self.parent = uiTextView
        }

        func textViewDidChange(_ textView: UITextView) {
            // This is needed for multistage text input (eg. Chinese, Japanese)
            if textView.markedTextRange == nil {
                parent.text = textView.text ?? String()
                parent.recalculateHeight(view: textView)
            }
        }

        func textViewDidBeginEditing(_ textView: UITextView) {
            if textView.textColor == UIColor.lightGray {
                textView.text = nil
                textView.textColor = UIColor.black
            }
        }

        func textViewDidEndEditing(_ textView: UITextView) {
            if textView.text.isEmpty {
                textView.text = parent.placeholder
                textView.textColor = UIColor.lightGray
            }
        }
    }
}

像这样使用它：

struct ContentView: View {
    @State var text: String = ""
    @State var textHeight: CGFloat = 150

    var body: some View {
        ScrollView {
            TextView(placeholder: "", text: self.$text, minHeight: self.textHeight, calculatedHeight: self.$textHeight)
            .frame(minHeight: self.textHeight, maxHeight: self.textHeight)
        }
    }
}

Answer 4

目前，最好的解决方案是使用我创建的名为TextView 的包。

您可以使用 Swift Package Manager（在 README 中解释）安装它。它允许切换编辑状态和大量自定义（也在自述文件中详细说明）。

下面是一个例子：

import SwiftUI
import TextView

struct ContentView: View {
    @State var input = ""
    @State var isEditing = false

    var body: some View {
        VStack {
            Button(action: {
                self.isEditing.toggle()
            }) {
                Text("\(isEditing ? "Stop" : "Start") editing")
            }
            TextView(text: $input, isEditing: $isEditing)
        }
    }
}

在该示例中，您首先定义两个@State变量。一个用于文本，TextView 在输入时写入文本，另一个用于isEditingTextView的状态。

TextView 在被选中时会切换isEditing状态。当您单击按钮时，还会切换isEditing状态，该状态将显示键盘并在 时选择 TextView true，并在 时取消选择 TextView false。

Answer 5

有了Text()你可以做到这一点使用.lineLimit(nil)，并且该文档表明，这应该为之工作TextField()过。但是，我可以确认这目前无法正常工作。

我怀疑有一个错误-建议您向“反馈助手”提交报告。我已经做到了，ID是FB6124711。

Answer 6

SwiftUI 有TextEditor，它类似于TextField但提供了包含多行的长格式文本输入：

var body: some View {
    NavigationView{
        Form{
            Section{
                List{
                    Text(question6)
                    TextEditor(text: $responseQuestion6).lineLimit(4)
                    Text(question7)
                    TextEditor(text:  $responseQuestion7).lineLimit(4)
                }
            }
        }
    }
}

Answer 7

这将UITextView包装在Xcode 11.0 beta 6中（仍在Xcode 11 GM种子2上运行）：

import SwiftUI

struct ContentView: View {
     @State var text = ""

       var body: some View {
        VStack {
            Text("text is: \(text)")
            TextView(
                text: $text
            )
                .frame(minWidth: 0, maxWidth: .infinity, minHeight: 0, maxHeight: .infinity)
        }

       }
}

struct TextView: UIViewRepresentable {
    @Binding var text: String

    func makeCoordinator() -> Coordinator {
        Coordinator(self)
    }

    func makeUIView(context: Context) -> UITextView {

        let myTextView = UITextView()
        myTextView.delegate = context.coordinator

        myTextView.font = UIFont(name: "HelveticaNeue", size: 15)
        myTextView.isScrollEnabled = true
        myTextView.isEditable = true
        myTextView.isUserInteractionEnabled = true
        myTextView.backgroundColor = UIColor(white: 0.0, alpha: 0.05)

        return myTextView
    }

    func updateUIView(_ uiView: UITextView, context: Context) {
        uiView.text = text
    }

    class Coordinator : NSObject, UITextViewDelegate {

        var parent: TextView

        init(_ uiTextView: TextView) {
            self.parent = uiTextView
        }

        func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
            return true
        }

        func textViewDidChange(_ textView: UITextView) {
            print("text now: \(String(describing: textView.text!))")
            self.parent.text = textView.text
        }
    }
}

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

Answer 8

我只是尝试使用lineLimit（）在GM的Xcode版本11.0（11A419c）中使用swiftui创建多行文本字段。它仍然不起作用。我不敢相信苹果还没有解决这个问题。多行文本字段在移动应用程序中相当普遍。

Answer 9

好的，我从@sas方法开始，但是实际上需要它看起来和感觉像内容适合的多行文本字段，等等。这就是我所得到的。希望对其他人有所帮助。使用过Xcode 11.1。

提供的自定义MultilineTextField具有：
1.适合内容
2.自动对焦
3.占位符
4.提交时

import SwiftUI
import UIKit

fileprivate struct UITextViewWrapper: UIViewRepresentable {
    typealias UIViewType = UITextView

    @Binding var text: String
    @Binding var calculatedHeight: CGFloat
    var onDone: (() -> Void)?

    func makeUIView(context: UIViewRepresentableContext<UITextViewWrapper>) -> UITextView {
        let textField = UITextView()
        textField.delegate = context.coordinator

        textField.isEditable = true
        textField.font = UIFont.preferredFont(forTextStyle: .body)
        textField.isSelectable = true
        textField.isUserInteractionEnabled = true
        textField.isScrollEnabled = false
        if nil != onDone {
            textField.returnKeyType = .done
        }

        textField.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)
        return textField
    }

    func updateUIView(_ uiView: UITextView, context: UIViewRepresentableContext<UITextViewWrapper>) {
        if uiView.text != self.text {
            uiView.text = self.text
        }
        if uiView.window != nil, !uiView.isFirstResponder {
            uiView.becomeFirstResponder()
        }
        UITextViewWrapper.recalculateHeight(view: uiView, result: $calculatedHeight)
    }

    fileprivate static func recalculateHeight(view: UIView, result: Binding<CGFloat>) {
        let newSize = view.sizeThatFits(CGSize(width: view.frame.size.width, height: CGFloat.greatestFiniteMagnitude))
        if result.wrappedValue != newSize.height {
            DispatchQueue.main.async {
                result.wrappedValue = newSize.height // !! must be called asynchronously
            }
        }
    }

    func makeCoordinator() -> Coordinator {
        return Coordinator(text: $text, height: $calculatedHeight, onDone: onDone)
    }

    final class Coordinator: NSObject, UITextViewDelegate {
        var text: Binding<String>
        var calculatedHeight: Binding<CGFloat>
        var onDone: (() -> Void)?

        init(text: Binding<String>, height: Binding<CGFloat>, onDone: (() -> Void)? = nil) {
            self.text = text
            self.calculatedHeight = height
            self.onDone = onDone
        }

        func textViewDidChange(_ uiView: UITextView) {
            text.wrappedValue = uiView.text
            UITextViewWrapper.recalculateHeight(view: uiView, result: calculatedHeight)
        }

        func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
            if let onDone = self.onDone, text == "\n" {
                textView.resignFirstResponder()
                onDone()
                return false
            }
            return true
        }
    }

}

struct MultilineTextField: View {

    private var placeholder: String
    private var onCommit: (() -> Void)?

    @Binding private var text: String
    private var internalText: Binding<String> {
        Binding<String>(get: { self.text } ) {
            self.text = $0
            self.showingPlaceholder = $0.isEmpty
        }
    }

    @State private var dynamicHeight: CGFloat = 100
    @State private var showingPlaceholder = false

    init (_ placeholder: String = "", text: Binding<String>, onCommit: (() -> Void)? = nil) {
        self.placeholder = placeholder
        self.onCommit = onCommit
        self._text = text
        self._showingPlaceholder = State<Bool>(initialValue: self.text.isEmpty)
    }

    var body: some View {
        UITextViewWrapper(text: self.internalText, calculatedHeight: $dynamicHeight, onDone: onCommit)
            .frame(minHeight: dynamicHeight, maxHeight: dynamicHeight)
            .overlay(placeholderView, alignment: .topLeading)
    }

    var placeholderView: some View {
        Group {
            if showingPlaceholder {
                Text(placeholder).foregroundColor(.gray)
                    .padding(.leading, 4)
                    .padding(.top, 8)
            }
        }
    }
}

#if DEBUG
struct MultilineTextField_Previews: PreviewProvider {
    static var test:String = ""//some very very very long description string to be initially wider than screen"
    static var testBinding = Binding<String>(get: { test }, set: {
//        print("New value: \($0)")
        test = $0 } )

    static var previews: some View {
        VStack(alignment: .leading) {
            Text("Description:")
            MultilineTextField("Enter some text here", text: testBinding, onCommit: {
                print("Final text: \(test)")
            })
                .overlay(RoundedRectangle(cornerRadius: 4).stroke(Color.black))
            Text("Something static here...")
            Spacer()
        }
        .padding()
    }
}
#endif

Answer 10

SwiftUI TextView(UIViewRepresentable) 具有以下可用参数：fontStyle、isEditable、backgroundColor、borderColor 和 border Width

TextView(文本：self.$viewModel.text，fontStyle：.body，isEditable：true，backgroundColor：UIColor.white，borderColor：UIColor.lightGray，borderWidth：1.0).padding()

文本视图（UIViewRepresentable）

struct TextView: UIViewRepresentable {

@Binding var text: String
var fontStyle: UIFont.TextStyle
var isEditable: Bool
var backgroundColor: UIColor
var borderColor: UIColor
var borderWidth: CGFloat

func makeCoordinator() -> Coordinator {
    Coordinator(self)
}

func makeUIView(context: Context) -> UITextView {

    let myTextView = UITextView()
    myTextView.delegate = context.coordinator

    myTextView.font = UIFont.preferredFont(forTextStyle: fontStyle)
    myTextView.isScrollEnabled = true
    myTextView.isEditable = isEditable
    myTextView.isUserInteractionEnabled = true
    myTextView.backgroundColor = backgroundColor
    myTextView.layer.borderColor = borderColor.cgColor
    myTextView.layer.borderWidth = borderWidth
    myTextView.layer.cornerRadius = 8
    return myTextView
}

func updateUIView(_ uiView: UITextView, context: Context) {
    uiView.text = text
}

class Coordinator : NSObject, UITextViewDelegate {

    var parent: TextView

    init(_ uiTextView: TextView) {
        self.parent = uiTextView
    }

    func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
        return true
    }

    func textViewDidChange(_ textView: UITextView) {
        self.parent.text = textView.text
    }
  }
}

Answer 11

只是想分享我的UITextView解决方案，而不是协调员。我注意到 SwiftUI 调用时UITextView.intrinsicContentSize没有告诉它应该适合什么宽度。默认情况下UITextView，假设它具有无限的宽度来布局内容，因此如果它只有一行文本，它将返回适合该一行所需的大小。

为了解决这个问题，只要视图的宽度发生变化，我们就可以子类化UITextView并使固有尺寸无效，并在计算固有尺寸时考虑宽度。

struct TextView: UIViewRepresentable {

  var text: String

  public init(_ text: String) {
    self.text = text
  }

  public func makeUIView(context: Context) -> UITextView {
    let textView = WrappedTextView()
    textView.backgroundColor = .clear
    textView.isScrollEnabled = false
    textView.textContainerInset = .zero
    textView.textContainer.lineFragmentPadding = 0
    textView.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)
    textView.setContentHuggingPriority(.defaultHigh, for: .vertical)
    return textView
  }

  public func updateUIView(_ uiView: UITextView, context: Context) {
    uiView.text = text
  }
}

class WrappedTextView: UITextView {

  private var lastWidth: CGFloat = 0

  override func layoutSubviews() {
    super.layoutSubviews()
    if bounds.width != lastWidth {
      lastWidth = bounds.width
      invalidateIntrinsicContentSize()
    }
  }

  override var intrinsicContentSize: CGSize {
    let size = sizeThatFits(
      CGSize(width: lastWidth, height: UIView.layoutFittingExpandedSize.height))
    return CGSize(width: size.width.rounded(.up), height: size.height.rounded(.up))
  }
}