focused(_:)

Return Value 戻り値

The modified view.

Discussion 議論

Use this modifier to cause the view to receive focus whenever the the condition value is true. You can use this modifier to observe the focus state of a single view, or programmatically set and remove focus from the view.

In the following example, a single TextField accepts a user’s desired username. The text field binds its focus state to the Boolean value usernameFieldIsFocused. A “Submit” button’s action verifies whether the name is available. If the name is unavailable, the button sets usernameFieldIsFocused to true, which causes focus to return to the text field, so the user can enter a different name.

@State private var username: String = ""
@FocusState private var usernameFieldIsFocused: Bool
@State private var showUsernameTaken = false


var body: some View {
    VStack {
        TextField("Choose a username.", text: $username)
            .focused($usernameFieldIsFocused)
        if showUsernameTaken {
            Text("That username is taken. Please choose another.")
        }
        Button("Submit") {
            showUsernameTaken = false
            if !isUserNameAvailable(username: username) {
                usernameFieldIsFocused = true
                showUsernameTaken = true
            }
        }
    }
}

To control focus by matching a value, use the focused(_:equals:) method instead.