alert(_:isPresented:actions:message:)

Discussion 議論

In the example below, a button conditionally presents an alert depending upon the value of a bound Boolean variable. When the Boolean value is set to true, the system displays an alert with an “OK” action.

struct LoginView: View {
    @Binding var didFail: Bool
    var body: some View {
        LoginForm(didFail: $didFail)
            .alert(
                Text("An error occurred."), isPresented: $didFail
            ) {
                Button("OK") {
                    // Handle acknowledgement.
                }
            } message: {
                Text("Please ensure your credentials are correct.")
            }
    }
}

All actions in an alert dismiss the alert after the action runs. The default button is shown with greater prominence. You can influence the default button by assigning it the defaultAction keyboard shortcut.

The system may reorder the buttons based on their role and prominence.

If no actions are present, the system includes a standard “OK” action. No default cancel action is provided. If you want to show a cancel action, use a button with a role of cancel.

On iOS, tvOS, and watchOS, alerts only support controls with labels that are Text. Passing any other type of view results in the content being omitted.

Only unstyled text is supported for the message.