毫无疑问,这是一个广泛的问题,但在使用SwiftUI TextEditor控件时,是否可以通过iOS的UndoManager撤销或重做文本输入?我已经到处寻找,但未能找到任何关注此工作流组合(SwiftUI + TextEditor + UndoManager)的资源。考虑到TextEditor相对不成熟,我想知道这是否根本不可能,或者需要一些工作来促进。任何指导都将不胜感激!
毫无疑问,这是一个广泛的问题,但在使用SwiftUI TextEditor控件时,是否可以通过iOS的UndoManager撤销或重做文本输入?我已经到处寻找,但未能找到任何关注此工作流组合(SwiftUI + TextEditor + UndoManager)的资源。考虑到TextEditor相对不成熟,我想知道这是否根本不可能,或者需要一些工作来促进。任何指导都将不胜感激!
不可否认,这有点像是一个hack,并且与SwiftUI的风格不太相符,但它确实有效。基本上,在UITextView:UIViewRepresentable中声明一个绑定到UndoManager的绑定。您的UIViewRepresentable将把该绑定设置为UITextView提供的UndoManager。然后,您的父视图就可以访问内部的UndoManager了。以下是一些示例代码。重做也可以工作,尽管此处未显示。
struct MyTextView: UIViewRepresentable {
/// The underlying UITextView. This is a binding so that a parent view can access it. You do not assign this value. It is created automatically.
@Binding var undoManager: UndoManager?
func makeUIView(context: Context) -> UITextView {
let uiTextView = UITextView()
// Expose the UndoManager to the caller. This is performed asynchronously to avoid modifying the view at an inappropriate time.
DispatchQueue.main.async {
undoManager = uiTextView.undoManager
}
return uiTextView
}
func updateUIView(_ uiView: UITextView, context: Context) {
}
}
struct ContentView: View {
/// The underlying UndoManager. Even though it looks like we are creating one here, ultimately, MyTextView will set it to its internal UndoManager.
@State private var undoManager: UndoManager? = UndoManager()
var body: some View {
NavigationView {
MyTextView(undoManager: $undoManager)
.toolbar {
ToolbarItemGroup(placement: .navigationBarTrailing) {
Button {
undoManager?.undo()
} label: {
Image(systemName: "arrow.uturn.left.circle")
}
Button {
undoManager?.redo()
} label: {
Image(systemName: "arrow.uturn.right.circle")
}
}
}
}
}
}
import SwiftUI
import PlaygroundSupport
class Model: ObservableObject {
@Published var active = ""
func registerUndo(_ newValue: String, in undoManager: UndoManager?) {
let oldValue = active
undoManager?.registerUndo(withTarget: self) { target in
target.active = oldValue
}
active = newValue
}
}
struct TextView: UIViewRepresentable {
@Binding var text: String
func makeUIView(context: Context) -> UITextView {
let textView = UITextView()
textView.autocapitalizationType = .sentences
textView.isSelectable = true
textView.isUserInteractionEnabled = true
return textView
}
func updateUIView(_ uiView: UITextView, context: Context) {
uiView.text = text
}
}
struct ContentView: View {
@ObservedObject private var model = Model()
@Environment(\.undoManager) var undoManager
@State var text: String = ""
var body: some View {
ZStack (alignment: .bottomTrailing) {
// Testing TextView for undo & redo functionality
TextView(text: Binding<String>(
get: { self.model.active },
set: { self.model.registerUndo($0, in: self.undoManager) }))
HStack{
// Testing TextField for undo & redo functionality
TextField("Enter Text...", text: Binding<String>(
get: { self.model.active },
set: { self.model.registerUndo($0, in: self.undoManager) })).padding()
Button("Undo") {
withAnimation {
self.undoManager?.undo()
}
}.disabled(!(undoManager?.canUndo ?? false)).padding()
Button("Redo") {
withAnimation {
self.undoManager?.redo()
}
}.disabled(!(undoManager?.canRedo ?? false)).padding()
}.background(Color(UIColor.init(displayP3Red: 0.1, green: 0.3, blue: 0.3, alpha: 0.3)))
}.frame(width: 400, height: 400, alignment: .center).border(Color.black)
}
}
PlaygroundPage.current.setLiveView(ContentView())