Ok, comencé con el enfoque @sas, pero necesitaba que realmente se viera y se sintiera como un campo de texto de varias líneas con ajuste de contenido, etc. Esto es lo que tengo. Espero que sea útil para alguien más ... Usé Xcode 11.1.
El campo MultilineTextField personalizado proporcionado tiene:
1. ajuste de contenido
2. enfoque automático
3. marcador de posición
4. en la confirmación
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
textField.backgroundColor = UIColor.clear
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
}
}
}
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)
.background(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 = ""
static var testBinding = Binding<String>(get: { test }, set: {
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