JavaFX: Node: Attach data to a control

 

'javafx.scene.Node' class provides 'setUserData' method, it is used to associate some data to UI control, you can retrieve this data later point of time.

 

Syntax

public void setUserData(Object value)

 

Example

button1.setUserData(userData);

 

Let’s write simple program, that count button clicks.

 

ButtonClickCount.java

package com.sample.app.widgets;

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.Label;
import javafx.scene.control.Alert.AlertType;
import javafx.scene.effect.DropShadow;
import javafx.scene.layout.HBox;
import javafx.scene.layout.VBox;
import javafx.scene.paint.Color;
import javafx.scene.text.Font;
import javafx.scene.text.FontPosture;
import javafx.stage.Stage;

public class ButtonClickCount extends Application {

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

    }

    @Override
    public void start(Stage primaryStage) throws Exception {

        HBox hBox1 = new HBox();
        Label label1 = new Label("Demo to count number of clicks");
        label1.setFont(Font.font("Verdana", FontPosture.REGULAR, 45));
        hBox1.getChildren().add(label1);
        hBox1.setPadding(new Insets(20, 20, 20, 20));

        Button button1 = new Button("Click Me");
        button1.setAlignment(Pos.CENTER);
        button1.setFont(Font.font("Verdana", FontPosture.REGULAR, 30));
        button1.setPadding(new Insets(10, 10, 10, 10));
        button1.setUserData(0);

        Button button2 = new Button("Click Count");
        button2.setAlignment(Pos.CENTER);
        button2.setFont(Font.font("Verdana", FontPosture.REGULAR, 30));
        button2.setPadding(new Insets(10, 10, 10, 10));

        HBox hBox2 = new HBox();
        hBox2.setSpacing(10);
        hBox2.setPadding(new Insets(20, 20, 20, 20));
        hBox2.getChildren().addAll(button1, button2);

        button1.setOnAction((event) -> {
            Integer userData = (Integer) button1.getUserData();
            userData += 1;

            button1.setUserData(userData);

        });

        button2.setOnAction((event) -> {
            Integer userData = (Integer) button1.getUserData();

            Alert alert = new Alert(AlertType.INFORMATION);
            alert.setTitle("Count Checker");
            alert.setContentText("You clicked " + userData + " times");

            alert.showAndWait();

        });

        DropShadow dropShadow = new DropShadow();
        dropShadow.setOffsetX(5);
        dropShadow.setOffsetY(5);
        dropShadow.setColor(Color.GRAY);

        VBox vBox = new VBox();
        vBox.getChildren().addAll(hBox1, hBox2);
        vBox.setEffect(dropShadow);

        Scene scene = new Scene(vBox, 900, 500, Color.WHITE);

        primaryStage.setTitle("Button Demo 1");
        primaryStage.setScene(scene);
        primaryStage.show();
    }

}

 

Output

 

 

Click the button ‘Click Me’ n number of times, and click on ‘Click Count’ button to see how many times you clicked.

 

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