DialogPane

DialogPane is the main container used inside a dialog window in JavaFX. It controls:

• the message/content
• the header
• the buttons at the bottom
• optional graphics/icons

Usually you do not create a DialogPane directly. Instead, it is automatically used by classes like:

• Alert
• Dialog
• TextInputDialog

Example with Alert:

Alert alert = new Alert(Alert.AlertType.INFORMATION);

alert.setTitle("Information");
alert.setHeaderText("Download Complete");
alert.setContentText("The file was saved successfully.");

alert.showAndWait();

Internally, that alert contains a DialogPane.

You can access and customize it:

DialogPane pane = alert.getDialogPane();

Example:

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Alert;
import javafx.scene.control.ButtonType;
import javafx.scene.control.DialogPane;
import javafx.scene.layout.Region;
import javafx.stage.Stage;

public class DialogPaneExample extends Application {

    @Override
    public void start(Stage stage) {

        Alert alert = new Alert(Alert.AlertType.CONFIRMATION);

        alert.setTitle("Delete File");
        alert.setHeaderText("Are you sure?");
        alert.setContentText("This action cannot be undone.");

        DialogPane pane = alert.getDialogPane();

        // Change minimum size
        pane.setMinHeight(Region.USE_PREF_SIZE);

        // Add custom CSS style
        pane.setStyle("-fx-font-size: 14px;");

        alert.showAndWait().ifPresent(result -> {
            if (result == ButtonType.OK) {
                System.out.println("User clicked OK");
            }
        });
    }

    public static void main(String[] args) {
        launch();
    }
}

Main parts of a DialogPane:

pane.setHeaderText("Header");
pane.setContentText("Message");
pane.getButtonTypes().add(ButtonType.OK);

You can also add your own custom content:

TextField nameField = new TextField();

DialogPane pane = new DialogPane();
pane.setHeaderText("Enter your name");
pane.setContent(nameField);

Example using Dialog directly:

Dialog<String> dialog = new Dialog<>();

dialog.setTitle("User Input");

DialogPane pane = dialog.getDialogPane();

pane.setHeaderText("Enter your username");

TextField textField = new TextField();
pane.setContent(textField);

pane.getButtonTypes().addAll(ButtonType.OK, ButtonType.CANCEL);

dialog.setResultConverter(button -> {
    if (button == ButtonType.OK) {
        return textField.getText();
    }
    return null;
});

dialog.showAndWait().ifPresent(name ->
        System.out.println("Hello " + name));

FXML example:

<DialogPane xmlns:fx="http://javafx.com/fxml">
    <headerText>
        Example Header
    </headerText>

    <content>
        <Label text="This is inside the dialog"/>
    </content>

    <buttonTypes>
        <ButtonType fx:constant="OK"/>
        <ButtonType fx:constant="CANCEL"/>
    </buttonTypes>
</DialogPane>

Important methods:

pane.setHeaderText(...);
pane.setContentText(...);
pane.setContent(node);
pane.getButtonTypes();
pane.lookupButton(ButtonType.OK);

lookupButton(...) lets you get the actual button and modify it:

Button okButton = (Button) pane.lookupButton(ButtonType.OK);
okButton.setDisable(true);

This is useful if you want the OK button disabled until the user enters valid text.