How can I get text to wrap in a UILabel (via UIViewRepresentable) without having a fixed width?

问题

Setting lineBreakMode to byWordWrapping and set numberOfLines to 0 does not seem to be sufficient:

struct MyTextView: UIViewRepresentable {
    func makeUIView(context: Context) -> UILabel {
        let label = UILabel()
        label.lineBreakMode = .byWordWrapping
        label.numberOfLines = 0
        label.text = "Here's a lot of text for you to display. It won't fit on the screen."
        return label
    }

    func updateUIView(_ view: UILabel, context: Context) {
    }
}

struct MyTextView_Previews: PreviewProvider {
    static var previews: some View {
        MyTextView()
            .previewLayout(.fixed(width: 300, height: 200))
    }
}

The text does not wrap, regardless of which setting I use for lineBreakMode. The canvas preview and live preview both look like this:

The closest I've gotten is setting preferredMaxLayoutWidth, which does cause the text to wrap, but there doesn't seem to be a value that means "whatever size the View is".

回答1:

Possible solution is to declare the width as a variable on MyTextView:

struct MyTextView: UIViewRepresentable {

    var width: CGFloat

    func makeUIView(context: Context) -> UILabel {
        let label = UILabel()
        label.lineBreakMode = .byWordWrapping
        label.numberOfLines = 0
        label.preferredMaxLayoutWidth = width
        label.text = "Here's a lot of text for you to display. It won't fit on the screen."
        return label
    }

    func updateUIView(_ view: UILabel, context: Context) {
    }
}

and then use GeometryReader to findout how much space there is avaible and pass it into the intializer:

struct ExampleView: View {

    var body: some View {
        GeometryReader { geometry in
            MyTextView(width: geometry.size.width)
        }
    }
}

来源：https://stackoverflow.com/questions/58469001/how-can-i-get-text-to-wrap-in-a-uilabel-via-uiviewrepresentable-without-having