如何在Mac OS的SwiftUI中创建多行文本字段? [英] How do I create a Multi Line Text Field in SwiftUI for MacOS?

问题描述

我正在使用Swift编写我的第一个MacOS应用程序.我需要创建一个允许多个段落的简单可编辑文本框.在HTML中，这将是 textarea .

我了解到iOS 14将包含 TextEditor ，但这不是现在，而且我也不知道MacOS中是否会包含该代码.

我见过许多解决方案都假定使用iOS和UIKit.

我该如何使用SwiftUI和MacOS?

更新

有人建议这个问题与此类似:

  struct TestTextArea:视图{@State private var text =占位符:输入一些文本"var body:some View {VStack {TextArea(文本:$ text).border(彩色.黑色)//文本(文本)//取消注释以查看输入的文本的镜像}.填充()}}struct TextArea:NSViewRepresentable {@Binding var text:字符串func makeNSView(context:Context)->NSScrollView {context.coordinator.createTextViewStack()}func updateNSView(_ nsView:NSScrollView，context:Context){如果让textArea = nsView.documentView为?NSTextView，textArea.string！= self.text {textArea.string = self.text}}func makeCoordinator()->协调员{协调人(文本:$文本)}类协调器:NSObject，NSTextViewDelegate {var文字:Binding< String>init(text:Binding< String>){self.text = 文本}func textView(_ textView:NSTextView，shouldChangeTextIn范围:NSRange，replaceString text:String?)->布尔{推迟 {self.text.wrappedValue =(textView.string as NSString).replacingCharacters(in:range，with:text！)}返回真}fileprivate惰性var textStorage = NSTextStorage()fileprivate惰性var layoutManager = NSLayoutManager()fileprivate惰性var textContainer = NSTextContainer()fileprivate惰性var textView:NSTextView = NSTextView(frame:CGRect()，textContainer:textContainer)fileprivate惰性var scrollview = NSScrollView()func createTextViewStack()->NSScrollView {让contentSize = scrollview.contentSizetextContainer.containerSize = CGSize(width:contentSize.width，height:CGFloat.greatestFiniteMagnitude)textContainer.widthTracksTextView = truetextView.minSize = CGSize(宽度:0，高度:0)textView.maxSize = CGSize(宽度:CGFloat.greatestFiniteMagnitude，高度:CGFloat.greatestFiniteMagnitude)textView.isVerticallyResizable = truetextView.frame = CGRect(x:0，y:0，宽度:contentSize.width，高度:contentSize.height)textView.autoresizingMask = [.width]textView.delegate =自我scrollview.borderType = .noBorderscrollview.hasVerticalScroller = truescrollview.documentView = textViewtextStorage.addLayoutManager(layoutManager)layoutManager.addTextContainer(textContainer)返回scrollview}}} 

I am writing my first MacOS app using Swift. I need to create a simple editable text box which allows multiple paragraphs. In HTML, this would be a textarea.

I gather that iOS 14 will include TextEditor, but that’s not now, and I don’t know whether that will be in MacOS anyway.

Many solutions I have seen presume iOS and UIKit.

How do I do this with SwiftUI and MacOS?

Update

Someone has suggested that the question is similar to this one: How do I create a multiline TextField in SwiftUI?

I have already looked at that question, but:

• The linked question is specifically for iOS, but mine is for MacOS
• The answers, as far as I can tell, are specifically for iOS using UIKit. If someone cares to explain how this answers my MacOS question I would be very interested …

解决方案

Here is some initial demo of component like iOS14 TextEditor.

Demo prepared & tested with Xcode 11.7 / macOS 10.15.6

struct TestTextArea: View {
    @State private var text = "Placeholder: Enter some text"

    var body: some View {
        VStack {
            TextArea(text: $text)
                .border(Color.black)
//            Text(text) // uncomment to see mirror of enterred text
        }.padding()
    }
}

struct TextArea: NSViewRepresentable {
    @Binding var text: String

    func makeNSView(context: Context) -> NSScrollView {
        context.coordinator.createTextViewStack()
    }

    func updateNSView(_ nsView: NSScrollView, context: Context) {
        if let textArea = nsView.documentView as? NSTextView, textArea.string != self.text {
            textArea.string = self.text
        }
    }

    func makeCoordinator() -> Coordinator {
        Coordinator(text: $text)
    }

    class Coordinator: NSObject, NSTextViewDelegate {
        var text: Binding<String>

        init(text: Binding<String>) {
            self.text = text
        }

        func textView(_ textView: NSTextView, shouldChangeTextIn range: NSRange, replacementString text: String?) -> Bool {
            defer {
                self.text.wrappedValue = (textView.string as NSString).replacingCharacters(in: range, with: text!)
            }
            return true
        }

        fileprivate lazy var textStorage = NSTextStorage()
        fileprivate lazy var layoutManager = NSLayoutManager()
        fileprivate lazy var textContainer = NSTextContainer()
        fileprivate lazy var textView: NSTextView = NSTextView(frame: CGRect(), textContainer: textContainer)
        fileprivate lazy var scrollview = NSScrollView()

        func createTextViewStack() -> NSScrollView {
            let contentSize = scrollview.contentSize

            textContainer.containerSize = CGSize(width: contentSize.width, height: CGFloat.greatestFiniteMagnitude)
            textContainer.widthTracksTextView = true

            textView.minSize = CGSize(width: 0, height: 0)
            textView.maxSize = CGSize(width: CGFloat.greatestFiniteMagnitude, height: CGFloat.greatestFiniteMagnitude)
            textView.isVerticallyResizable = true
            textView.frame = CGRect(x: 0, y: 0, width: contentSize.width, height: contentSize.height)
            textView.autoresizingMask = [.width]
            textView.delegate = self

            scrollview.borderType = .noBorder
            scrollview.hasVerticalScroller = true
            scrollview.documentView = textView

            textStorage.addLayoutManager(layoutManager)
            layoutManager.addTextContainer(textContainer)

            return scrollview
        }
    }
}

这篇关于如何在Mac OS的SwiftUI中创建多行文本字段?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！