SwiftUI TextEditor にプレースホルダーを設定する

PlaceHolderTextEditor.swift

import SwiftUI

struct PlaceHolderTextEditor: View {
    var placeholderText: String
    @State var text: String
    
    var body: some View {
        ZStack(alignment: .topLeading) {
            if text.isEmpty {
                Text(placeholderText)
                    .foregroundColor(Color(UIColor.placeholderText))
                    .padding(.leading, 5)
                    .padding(.top, 24)
            }
            TextEditor(text: $text)
                .padding(.top)
        }
        .onAppear() {
            //⚠️ NOTE: UITextView の　backgroundColor　を変更しておかないと、placeholderText が表示されない
            UITextView.appearance().backgroundColor = .clear
        }
        .onDisappear() {
            UITextView.appearance().backgroundColor = nil
        }
    }
}

PlaceHolderTextEditorSampleApp.swift

import SwiftUI

@main
struct PlaceHolderTextEditorSampleApp: App {
    var body: some Scene {
        WindowGroup {
            PlaceHolderTextEditor(placeholderText: "Placeholder Text", text: "")
        }
    }
}