How to get dynamic Text height for a ScrollView with SwiftUI

Question

this gives me dynamic text height correctly

import SwiftUI
struct ContentView : View {
    var body: some View {
        List {
            Text("This is some very long text can we can see scrolls past two lines ").lineLimit(nil)   
        }
    }
}

#if DEBUG
struct ContentView_Previews : PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}
#endif

But the following truncates the Text. How do i get dynamic height with the following?

import SwiftUI
struct ContentView : View {
    var body: some View {
        GeometryReader { reader in
            ScrollView {
                Text("This is some very long text can we can see scrolls past two lines ")
                    .lineLimit(nil)
                    .frame(width: reader.size.width)
            }
        }
    }
}
#if DEBUG
struct ContentView_Previews : PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}
#endif

Answer 1

您需要使用fixedSize修饰符来防止截断。在你的情况下，它就像：

Text("This is some very long text can we can see scrolls past two lines ")
 .lineLimit(nil)
 .fixedSize(horizontal: false, vertical: true) //** It keeps 'width size' and expands 'height size'
 .frame(width: reader.size.width)

Answer 2

import SwiftUI

struct ContentView : View {

    let veryLongText = "Very long text..."
    let fontName = "System Font"
    let fontSize: Length = 12

    var body: some View {
        GeometryReader { geometry in
            ScrollView {
                Text(veryLongText)
                    .lineLimit(nil)
                    .font(.custom(fontName, size: fontSize))
                    .frame(width: geometry.size.width, height: veryLongText.textHeightFrom(width: geometry.size.width, fontName: fontName, fontSize: fontSize))
            }
        }
        .padding(.horizontal, 0.5 * fontSize)
    }
}

extension String {

    func textHeightFrom(width: CGFloat, fontName: String = "System Font", fontSize: CGFloat = .systemFontSize) -> CGFloat {

        #if os(macOS) 

        typealias UXFont = NSFont
        let text: NSTextField = .init(string: self)
        text.font = NSFont.init(name: fontName, size: fontSize)

        #else

        typealias UXFont = UIFont
        let text: UILabel = .init()
        text.text = self
        text.numberOfLines = 0

        #endif

        text.font = UXFont.init(name: fontName, size: fontSize)
        text.lineBreakMode = .byWordWrapping
        return text.sizeThatFits(CGSize.init(width: width, height: .infinity)).height
    }
}

Answer 3

可能是一个ScrollView错误。老实说，我不确定为什么您的代码不起作用，但您可以使用以下方法获得所需的结果：

struct ContentView : View {
    var body: some View {
        GeometryReader { reader in
            ScrollView(alwaysBounceVertical: true) {
                ZStack(alignment: .top) {
                    Color.clear.edgesIgnoringSafeArea(.all)
                    Text("This is some very long text can we can see scrolls past two lines ")
                        .lineLimit(nil)
                }.frame(width: reader.size.width, height: reader.size.height)
            }
        }
    }
}

我添加alwaysBounceVertical到滚动视图，以便您可以看到视图滚动。但这没有必要。