Example app

Practice tracker

Reuse a score display with your own counting rules.

Run this example

Stop the app and save your current Main and helpers outside src/. Copy the files shown below into the listed destinations in your standalone starter, creating resource folders when needed. Replace Main and the listed helpers. Keep the zero/ framework folder and build files. If an older downloaded kit does not have these examples, use the source shown here.

examples/practice/Main.java → src/main/java/Main.java
examples/shared/ScoreDisplay.java → src/main/java/ScoreDisplay.java

Run App to rebuild. These examples run in VS Code, in a separate JavaFX window.

Open related lesson

Read the source

practice/Main.java

import javafx.geometry.Insets;
import javafx.scene.control.Button;
import javafx.scene.layout.VBox;
import zero.SimpleApp;

/** A second app reuses the exact same ScoreDisplay class. */
public class Main extends SimpleApp {
    private int completed;
    private ScoreDisplay score;

    @Override public void settings() {
        title("Practice tracker");
        size(420, 240);
    }

    @Override public void setup() {
        score = new ScoreDisplay("Completed");
        Button add = new Button("Completed an exercise");
        Button reset = new Button("Reset");
        add.setOnAction(event -> completeExercise());
        reset.setOnAction(event -> resetProgress());
        VBox screen = new VBox(12, score.view(), add, reset);
        screen.setPadding(new Insets(20));
        show(screen);
    }

    private void completeExercise() {
        completed++;
        score.setScore(completed);
    }

    private void resetProgress() {
        completed = 0;
        score.setScore(completed);
    }

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

shared/ScoreDisplay.java

import javafx.scene.Node;
import javafx.scene.control.Label;

/** An ordinary class: the app owns the number; this object displays it. */
public class ScoreDisplay {
    private final Label label;
    private final String caption;

    public ScoreDisplay() {
        this("Score");
    }

    public ScoreDisplay(String caption) {
        this.caption = caption;
        label = new Label(caption + ": 0");
    }

    public void setScore(int points) {
        label.setText(caption + ": " + points);
    }

    public Node view() {
        return label;
    }
}