Exercise 2: Adding a Toolbar Button That Presents a Modal Sheet — Possible Solution
==========================================================================================

struct NewTaskView: View {
    var body: some View {
        Text("New Task Form")
            .font(.title)
            .padding()
    }
}

struct TaskListView: View {
    @State private var isShowingSheet = false

    let tasks: [Task] = [
        Task(title: "Buy groceries"),
        Task(title: "Finish report"),
        Task(title: "Call dentist"),
        Task(title: "Water plants"),
        Task(title: "Read a chapter")
    ]

    var body: some View {
        NavigationStack {
            List(tasks) { task in
                NavigationLink(task.title, value: task)
            }
            .navigationTitle("Tasks")
            .navigationDestination(for: Task.self) { task in
                TaskDetailView(task: task)
            }
            .toolbar {
                Button("Add") {
                    isShowingSheet = true
                }
            }
            .sheet(isPresented: $isShowingSheet) {
                NewTaskView()
            }
        }
    }
}

HOW IT WORKS: isShowingSheet is a real @State private var, initially
false. Tapping the toolbar's own "Add" Button sets it to true. The
.sheet(isPresented: $isShowingSheet) modifier watches that same real
binding - the moment it becomes true, SwiftUI automatically presents
NewTaskView as a modal sheet floating above the current screen, and
automatically resets isShowingSheet back to false once the user
dismisses it (by swiping down, for instance) - the framework manages
that reset without any extra code needed here.

This is a genuinely different presentation style from the
NavigationLink-based push navigation used for the task rows themselves
- the sheet floats above TaskListView rather than replacing it in the
navigation stack, and there's no back button involved in dismissing it.

ANSWER: Adding @State private var isShowingSheet = false, a toolbar
Button setting it true, and .sheet(isPresented: $isShowingSheet)
presenting NewTaskView correctly shows a modal sheet when "Add" is
tapped, using the exact isPresented pattern covered in the chapter.

WHY THIS WORKS AS AN ANSWER
------------------------------
This correctly wires a Boolean @State flag through a toolbar button
into .sheet(isPresented:), demonstrating the modal-presentation pattern
as a genuinely separate mechanism from the push-navigation already
built in Exercise 1.