如何在 SwiftUI 中自动扩展 NSTextView 的高度？

Question

如何在下面的 NSTextView 上正确实施 NSView 约束，以便它与 SwiftUI .frame() 交互？

目标

一个 NSTextView，它在新行上垂直扩展其框架以强制 SwiftUI 父视图再次呈现（即，扩展文本下方的背景面板 + 下推 VStack 中的其他内容）。父视图已经包装在 ScrollView 中。由于 SwiftUI TextEditor 丑陋且功能不足，我猜其他几个刚接触 MacOS 的人会想知道如何做同样的事情。

更新

@Asperi 指出了埋在另一个线程中的 UIKit 示例。我尝试为 AppKit 调整它，但异步 recalculateHeight 函数中有一些循环。明天我会用咖啡仔细看看它。谢谢阿斯佩里。（无论你是谁，你都是 SwiftUI SO 爸爸。）

问题

下面的 NSTextView 实现可以愉快地编辑，但不符合 SwiftUI 的垂直框架。在水平方向上，所有内容都被遵守，但文本只是继续向下超过垂直高度限制。除非，当将焦点移开时，编辑器会裁剪多余的文本...直到再次开始编辑。

我试过的

作为模型的帖子太多了。下面是一些。我认为我的不足是误解了如何设置约束、如何使用 NSTextView 对象，以及可能想得太多了。

我尝试在下面的代码中同时实现 NSTextContainer、NSLayoutManager 和 NSTextStorage 堆栈，但没有任何进展。
我玩过 GeometryReader 输入，没有骰子。
我已经在 textdidChange() 上打印了 LayoutManager 和 TextContainer 变量，但是我没有看到尺寸随着换行而改变。还尝试监听 .boundsDidChangeNotification / .frameDidChangeNotification。

GitHub: unnamedd MacEditorTextView.swift <- 删除了它的 ScrollView，但在这样做之后无法立即获得文本约束
SO: Multiline editable text field in SwiftUI <- 帮助我了解如何换行，删除了 ScrollView
SO: Using a calculation by layoutManager <- 我的实现不起作用
Reddit: Wrap NSTextView in SwiftUI <- 提示似乎很准确，但缺乏可遵循的 AppKit 知识
SO: Autogrow height with intrinsicContentSize <- 我的实现没有效果
SO: Changing a ScrollView <- 不知道如何推断
Apple NSTextContainer Class
Apple Tracking the Size of a Text View

ContentView.swift

import SwiftUI
import Combine

struct ContentView: View {
    @State var text = NSAttributedString(string: "Testing.... testing...")
    let nsFont: NSFont = .systemFont(ofSize: 20)

    var body: some View {
// ScrollView would go here
        VStack(alignment: .center) {
            GeometryReader { geometry in
                NSTextEditor(text: $text.didSet { text in react(to: text) },
                             nsFont: nsFont,
                             geometry: geometry)
                    .frame(width: 500, // Wraps to width
                           height: 300) // Disregards this during editing
                    .background(background)
            }
           Text("Editing text above should push this down.")
        }
    }

    var background: some View {
        ...
    }

    // Seeing how updates come back; I prefer setting them on textDidEndEditing to work with a database
    func react(to text: NSAttributedString) {
        print(#file, #line, #function, text)
    }

}

// Listening device into @State
extension Binding {

    func didSet(_ then: @escaping (Value) ->Void) -> Binding {
        return Binding(
            get: {
                return self.wrappedValue
            },
            set: {
                then([=10=])
                self.wrappedValue = [=10=]
            }
        )
    }
}

NSTextEditor.swift


import SwiftUI

struct NSTextEditor: View, NSViewRepresentable {
    typealias Coordinator = NSTextEditorCoordinator
    typealias NSViewType = NSTextView

    @Binding var text: NSAttributedString
    let nsFont: NSFont
    var geometry: GeometryProxy

    func makeNSView(context: NSViewRepresentableContext<NSTextEditor>) -> NSTextEditor.NSViewType {
        return context.coordinator.textView
    }

    func updateNSView(_ nsView: NSTextView, context: NSViewRepresentableContext<NSTextEditor>) { }

    func makeCoordinator() -> NSTextEditorCoordinator {
        let coordinator =  NSTextEditorCoordinator(binding: $text,
                                                   nsFont: nsFont,
                                                   proxy: geometry)
        return coordinator
    }
}

class  NSTextEditorCoordinator : NSObject, NSTextViewDelegate {
    let textView: NSTextView
    var font: NSFont
    var geometry: GeometryProxy

    @Binding var text: NSAttributedString

    init(binding: Binding<NSAttributedString>,
         nsFont: NSFont,
         proxy: GeometryProxy) {
        _text = binding
        font = nsFont
        geometry = proxy

        textView = NSTextView(frame: .zero)
        textView.autoresizingMask = [.height, .width]
        textView.textColor = NSColor.textColor
        textView.drawsBackground = false
        textView.allowsUndo = true


        textView.isAutomaticLinkDetectionEnabled = true
        textView.displaysLinkToolTips = true
        textView.isAutomaticDataDetectionEnabled = true
        textView.isAutomaticTextReplacementEnabled = true
        textView.isAutomaticDashSubstitutionEnabled = true
        textView.isAutomaticSpellingCorrectionEnabled = true
        textView.isAutomaticQuoteSubstitutionEnabled = true
        textView.isAutomaticTextCompletionEnabled = true
        textView.isContinuousSpellCheckingEnabled = true
        textView.usesAdaptiveColorMappingForDarkAppearance = true

//        textView.importsGraphics = true // 100% size, layoutManger scale didn't fix
//        textView.allowsImageEditing = true // NSFileWrapper error
//        textView.isIncrementalSearchingEnabled = true
//        textView.usesFindBar = true
//        textView.isSelectable = true
//        textView.usesInspectorBar = true
        // Context Menu show styles crashes


        super.init()
        textView.textStorage?.setAttributedString($text.wrappedValue)
        textView.delegate = self
    }

//     Calls on every character stroke
    func textDidChange(_ notification: Notification) {
        switch notification.name {
        case NSText.boundsDidChangeNotification:
            print("bounds did change")
        case NSText.frameDidChangeNotification:
            print("frame did change")
        case NSTextView.frameDidChangeNotification:
            print("FRAME DID CHANGE")
        case NSTextView.boundsDidChangeNotification:
            print("BOUNDS DID CHANGE")
        default:
            return
        }
//        guard notification.name == NSText.didChangeNotification,
//              let update = (notification.object as? NSTextView)?.textStorage else { return }
//        text = update
    }

    // Calls only after focus change
    func textDidEndEditing(_ notification: Notification) {
        guard notification.name == NSText.didEndEditingNotification,
              let update = (notification.object as? NSTextView)?.textStorage else { return }
        text = update
    }
}

来自 UIKit 线程的快速 Asperi 回答

崩溃

*** Assertion failure in -[NSCGSWindow setSize:], NSCGSWindow.m:1458
[General] Invalid parameter not satisfying: 
   size.width >= 0.0 
&& size.width < (CGFloat)INT_MAX - (CGFloat)INT_MIN 
&& size.height >= 0.0 
&& size.height < (CGFloat)INT_MAX - (CGFloat)INT_MIN


import SwiftUI

struct AsperiMultiLineTextField: View {

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

    @Binding private var text: NSAttributedString
    private var internalText: Binding<NSAttributedString> {
        Binding<NSAttributedString>(get: { self.text } ) {
            self.text = [=13=]
            self.showingPlaceholder = [=13=].string.isEmpty
        }
    }

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

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

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

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

fileprivate struct NSTextViewWrapper: NSViewRepresentable {
    typealias NSViewType = NSTextView

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

    func makeNSView(context: NSViewRepresentableContext<NSTextViewWrapper>) -> NSTextView {
        let textField = NSTextView()
        textField.delegate = context.coordinator

        textField.isEditable = true
        textField.font = NSFont.preferredFont(forTextStyle: .body)
        textField.isSelectable = true
        textField.drawsBackground = false
        textField.allowsUndo = true
        /// Disabled these lines as not available/neeed/appropriate for AppKit
//        textField.isUserInteractionEnabled = true
//        textField.isScrollEnabled = false
//        if nil != onDone {
//            textField.returnKeyType = .done
//        }
        textField.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)
        return textField
    }
    
    func makeCoordinator() -> Coordinator {
        return Coordinator(text: $text, height: $calculatedHeight, onDone: onDone)
    }

    func updateNSView(_ NSView: NSTextView, context: NSViewRepresentableContext<NSTextViewWrapper>) {
        NSTextViewWrapper.recalculateHeight(view: NSView, result: $calculatedHeight)
    }

    fileprivate static func recalculateHeight(view: NSView, result: Binding<CGFloat>) {
/// UIView.sizeThatFits is not available in AppKit. Tried substituting below, but there's a loop that crashes.
//        let newSize = view.sizeThatFits(CGSize(width: view.frame.size.width, height: CGFloat.greatestFiniteMagnitude))

// tried reportedSize = view.frame, view.intrinsicContentSize
        let reportedSize = view.fittingSize
        let newSize = CGSize(width: reportedSize.width, height: CGFloat.greatestFiniteMagnitude)
        if result.wrappedValue != newSize.height {
            DispatchQueue.main.async {
                result.wrappedValue = newSize.height // !! must be called asynchronously
            }
        }
    }


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

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

        func textDidChange(_ notification: Notification) {
            guard notification.name == NSText.didChangeNotification,
                  let textView = (notification.object as? NSTextView),
                  let latestText = textView.textStorage else { return }
            text.wrappedValue = latestText
            NSTextViewWrapper.recalculateHeight(view: textView, result: calculatedHeight)
        }

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

}

Answer 1

解决方案感谢@Asperi 的转换技巧一些事情必须改变：

NSView 也缺少 view.sizeThatFits() 用于提议的边界更改，所以我发现视图的 .visibleRect 可以代替。

错误：

第一次渲染时出现气泡（从较小的垂直方向到适当的大小）。我认为这是由 recalculateHeight() 引起的，它最初会打印出一些较小的值。那里的门控语句停止了这些值，但问题仍然存在。
目前我将占位符文本的插入设置为一个幻数，这应该是根据 NSTextView 的属性来完成的，但我还没有找到任何可用的东西。如果它具有相同的字体，我想我可以在占位符文本前面添加一个 space 或两个并完成它。

希望这可以节省一些其他人制作 SwiftUI Mac 应用程序的时间。

import SwiftUI

// Wraps the NSTextView in a frame that can interact with SwiftUI
struct MultilineTextField: View {

    private var placeholder: NSAttributedString
    @Binding private var text: NSAttributedString
    @State private var dynamicHeight: CGFloat // MARK TODO: - Find better way to stop initial view bobble (gets bigger)
    @State private var textIsEmpty: Bool
    @State private var textViewInset: CGFloat = 9 // MARK TODO: - Calculate insetad of magic number
    var nsFont: NSFont

    init (_ placeholder: NSAttributedString = NSAttributedString(string: ""),
          text: Binding<NSAttributedString>,
          nsFont: NSFont) {
        self.placeholder = placeholder
        self._text = text
        _textIsEmpty = State(wrappedValue: text.wrappedValue.string.isEmpty)
        self.nsFont = nsFont
        _dynamicHeight = State(initialValue: nsFont.pointSize)
    }

    var body: some View {
        ZStack {
            NSTextViewWrapper(text: $text,
                              dynamicHeight: $dynamicHeight,
                              textIsEmpty: $textIsEmpty,
                              textViewInset: $textViewInset,
                              nsFont: nsFont)
                .background(placeholderView, alignment: .topLeading)
                // Adaptive frame applied to this NSViewRepresentable
                .frame(minHeight: dynamicHeight, maxHeight: dynamicHeight)
        }
    }

    // Background placeholder text matched to default font provided to the NSViewRepresentable
    var placeholderView: some View {
        Text(placeholder.string)
            // Convert NSFont
            .font(.system(size: nsFont.pointSize))
            .opacity(textIsEmpty ? 0.3 : 0)
            .padding(.leading, textViewInset)
            .animation(.easeInOut(duration: 0.15))
    }
}

// Creates the NSTextView
fileprivate struct NSTextViewWrapper: NSViewRepresentable {

    @Binding var text: NSAttributedString
    @Binding var dynamicHeight: CGFloat
    @Binding var textIsEmpty: Bool
    // Hoping to get this from NSTextView,
    // but haven't found the right parameter yet
    @Binding var textViewInset: CGFloat
    var nsFont: NSFont

    func makeCoordinator() -> Coordinator {
        return Coordinator(text: $text,
                           height: $dynamicHeight,
                           textIsEmpty: $textIsEmpty,
                           nsFont: nsFont)
    }

    func makeNSView(context: NSViewRepresentableContext<NSTextViewWrapper>) -> NSTextView {
        return context.coordinator.textView
    }

    func updateNSView(_ textView: NSTextView, context: NSViewRepresentableContext<NSTextViewWrapper>) {
        NSTextViewWrapper.recalculateHeight(view: textView, result: $dynamicHeight, nsFont: nsFont)
    }

    fileprivate static func recalculateHeight(view: NSView, result: Binding<CGFloat>, nsFont: NSFont) {
        // Uses visibleRect as view.sizeThatFits(CGSize())
        // is not exposed in AppKit, except on NSControls.
        let latestSize = view.visibleRect
        if result.wrappedValue != latestSize.height &&
            // MARK TODO: - The view initially renders slightly smaller than needed, then resizes.
            // I thought the statement below would prevent the @State dynamicHeight, which
            // sets itself AFTER this view renders, from causing it. Unfortunately that's not
            // the right cause of that redawing bug.
            latestSize.height > (nsFont.pointSize + 1) {
            DispatchQueue.main.async {
                result.wrappedValue = latestSize.height
                print(#function, latestSize.height)
            }
        }
    }
}

// Maintains the NSTextView's persistence despite redraws
fileprivate final class Coordinator: NSObject, NSTextViewDelegate, NSControlTextEditingDelegate {
    var textView: NSTextView
    @Binding var text: NSAttributedString
    @Binding var dynamicHeight: CGFloat
    @Binding var textIsEmpty: Bool
    var nsFont: NSFont

    init(text: Binding<NSAttributedString>,
         height: Binding<CGFloat>,
         textIsEmpty: Binding<Bool>,
         nsFont: NSFont) {

        _text = text
       _dynamicHeight = height
        _textIsEmpty = textIsEmpty
        self.nsFont = nsFont

        textView = NSTextView(frame: .zero)
        textView.isEditable = true
        textView.isSelectable = true

        // Appearance
        textView.usesAdaptiveColorMappingForDarkAppearance = true
        textView.font = nsFont
        textView.textColor = NSColor.textColor
        textView.drawsBackground = false
        textView.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)

        // Functionality (more available)
        textView.allowsUndo = true
        textView.isAutomaticLinkDetectionEnabled = true
        textView.displaysLinkToolTips = true
        textView.isAutomaticDataDetectionEnabled = true
        textView.isAutomaticTextReplacementEnabled = true
        textView.isAutomaticDashSubstitutionEnabled = true
        textView.isAutomaticSpellingCorrectionEnabled = true
        textView.isAutomaticQuoteSubstitutionEnabled = true
        textView.isAutomaticTextCompletionEnabled = true
        textView.isContinuousSpellCheckingEnabled = true

        super.init()
        // Load data from binding and set font
        textView.textStorage?.setAttributedString(text.wrappedValue)
        textView.textStorage?.font = nsFont
        textView.delegate = self
    }

    func textDidChange(_ notification: Notification) {
        // Recalculate height after every input event
        NSTextViewWrapper.recalculateHeight(view: textView, result: $dynamicHeight, nsFont: nsFont)
        // If ever empty, trigger placeholder text visibility
        if let update = (notification.object as? NSTextView)?.string {
            textIsEmpty = update.isEmpty
        }
    }

    func textDidEndEditing(_ notification: Notification) {
        // Update binding only after editing ends; useful to gate NSManagedObjects
        $text.wrappedValue = textView.attributedString()
    }
}

Answer 2

我发现了 unnamedd 创建的很好的要点代码。

https://gist.github.com/unnamedd/6e8c3fbc806b8deb60fa65d6b9affab0

示例用法：

MacEditorTextView(
   text: $text,
   isEditable: true,
   font: .monospacedSystemFont(ofSize: 12, weight: .regular)
)
.frame(minWidth: 300,
       maxWidth: .infinity,
       minHeight: 100,
       maxHeight: .infinity)
.padding(12)
.cornerRadius(8)

如何在 SwiftUI 中自动扩展 NSTextView 的高度？

How to auto-expand height of NSTextView in SwiftUI?

macos

nstextview

swiftui

nsviewrepresentable

如何在下面的 NSTextView 上正确实施 NSView 约束，以便它与 SwiftUI .frame() 交互？

ContentView.swift

NSTextEditor.swift

来自 UIKit 线程的快速 Asperi 回答