Alerts in Javafx do not close when "x" button is pressed - javafx

Question

Hi for a different javafx application I've been testing alerts and the only thing which doesn't work in pressing the "X" button for the alert box.
I have added a code below but if you don't have time to run it here is a GIF of explaining what issue I have with the alertbox:
https://giant.gfycat.com/GeneralUntimelyBluewhale.webm
I am not quite sure how to upload gifs to the actual post so sorry for that.
Is there any way of fixing this issue?
Thanks
import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Alert;
import javafx.scene.control.Button;
import javafx.scene.control.ButtonType;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
public class Playground extends Application {
public static void main(String[] args) {
launch(args);
}
#Override
public void start(Stage primaryStage) {
VBox root = new VBox(100);
root.setPadding(new Insets(10));
root.setAlignment(Pos.CENTER);
Button button = new Button("Alert");
button.setOnAction(event -> {
ButtonType goodButton = new ButtonType("Good");
ButtonType badButton = new ButtonType("Bad");
Alert alert = new Alert(Alert.AlertType.CONFIRMATION, "", goodButton, badButton);
alert.showAndWait();
if (alert.getResult().equals(goodButton)) {
System.out.println("Good");
} else if (alert.getResult().equals(badButton)) {
System.out.println("Bad");
}
});
// Add the buttons to the layout
root.getChildren().addAll(button);
// Show the Stage
primaryStage.setScene(new Scene(root));
primaryStage.show();
}
}

Answer 1

As per the "Dialog Closing Rules" in the Dialog API documentation, the default "X" button works normally only if atleast one of the buttons is of type "CANCEL". So changing any one of your button to ButtonType.CANCEL should close your dialog on click of "X".
If you are not interested in using built in buttons, then you have to explicitly handle the close request of dialog as per your requirement.
ButtonType goodButton = new ButtonType("Good");
ButtonType badButton = new ButtonType("Bad");
Alert alert = new Alert(Alert.AlertType.ERROR,"",goodButton,badButton);
Window window = alert.getDialogPane().getScene().getWindow();
window.setOnCloseRequest(e -> alert.hide());
Optional<ButtonType> result = alert.showAndWait();
result.ifPresent(res->{
if (res.equals(goodButton)) {
System.out.println("Good");
} else if (res.equals(badButton)) {
System.out.println("Bad");
}
});

Answer 2

To add to Sai Dandem's answer, here is the relevant javadoc from Dialog:
...
Dialog Closing Rules
It is important to understand what happens when a Dialog is closed, and also how a Dialog can be closed, especially in abnormal closing situations (such as when the 'X' button is clicked in a dialogs title bar, or when operating system specific keyboard shortcuts (such as alt-F4 on Windows) are entered). Fortunately, the outcome is well-defined in these situations, and can be best summarised in the following bullet points:
JavaFX dialogs can only be closed 'abnormally' (as defined above) in two situations:
When the dialog only has one button, or
When the dialog has multiple buttons, as long as one of them meets one of the following requirements:
The button has a ButtonType whose ButtonBar.ButtonData is of type ButtonBar.ButtonData.CANCEL_CLOSE.
The button has a ButtonType whose ButtonBar.ButtonData returns true when ButtonBar.ButtonData.isCancelButton() is called.
In all other situations, the dialog will refuse to respond to all close requests, remaining open until the user clicks on one of the available buttons in the DialogPane area of the dialog.
If a dialog is closed abnormally, and if the dialog contains a button which meets one of the two criteria above, the dialog will attempt to set the result property to whatever value is returned from calling the result converter with the first matching ButtonType.
If for any reason the result converter returns null, or if the dialog is closed when only one non-cancel button is present, the result property will be null, and the showAndWait() method will return Optional.empty(). This later point means that, if you use either of option 2 or option 3 (as presented earlier in this class documentation), the Optional.ifPresent(java.util.function.Consumer) lambda will never be called, and code will continue executing as if the dialog had not returned any value at all.
Normally, when using AlertType.CONFIRMATION, there would already be a cancel button. However, you're declaring your own buttons in the constructor of your Alert which overrides the default buttons.
Javadoc of Alert(AlertType,String,ButtonType...):
...
By passing in a variable number of ButtonType arguments, the developer is directly overriding the default buttons that will be displayed in the dialog, replacing the pre-defined buttons with whatever is specified in the varargs array.
...
And none of your buttons are a cancel button. Since you don't specify a ButtonData they all have ButtonBar.ButtonData.OTHER.

Answer 3

Alternatively, if you want the close "X" button of the alert window to default to one of the alert buttons you can set its ButtonData type:
ButtonType goodButton = new ButtonType("Good");
ButtonType badButton = new ButtonType("Bad", ButtonBar.ButtonData.CANCEL_CLOSE);
Closing the alert will then be equivalent to pressing the "Bad" button.