Pages

Saturday, 24 December 2016

Chapter 14 Exercise 12, Introduction to Java Programming, Tenth Edition Y. Daniel LiangY.

14.12 (Display a bar chart)
Write a program that uses a bar chart to display the percentages
of the overall grade represented by projects, quizzes, midterm exams,
and the final exam, as shown in Figure 14.46b. Suppose that projects
take 20 percent and are displayed in red, quizzes take 10 percent and
are displayed in blue, midterm exams take 30 percent and are displayed
in green, and the final exam takes 40 percent and is displayed in orange.
Use the MyRec2 class to display the bars. Interested readers may explore
the JavaFX BarChart class for further study.

import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.layout.Pane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;
import javafx.scene.text.Text;
import javafx.stage.Stage;

public class Exercise_12 extends Application {

    // project - 20% - red
    // quizzes - 10% - blue
    // midterm - 30% - green
    // final - 40% - orange
    private static final double WIDTH = 400;
    private static final double HEIGHT = 400;
    private static final double LIMIT_HEIGHT = (HEIGHT / 2);
    private static double[] percent = new double[]{0.20, 0.10, 0.30, 0.40};
    private static String[] titles = new String[] {
            "project - " + String.format("%d%s", (int)(100 * percent[0]), "%"),
            "quizzes - " + String.format("%d%s", (int)(100 * percent[1]), "%"),
            "midterm - " + String.format("%d%s", (int)(100 * percent[2]), "%"),
            "final - "+ String.format("%d%s", (int)(100 * percent[3]), "%")
     };
    private static Color[] colors = new Color[]{Color.RED, Color.BLUE, Color.GREEN, Color.ORANGE};

    @Override
    public void start(Stage primaryStage) {

        Pane pane = new Pane();
        pane.setPadding(new Insets(5, 10, 0, 10));
        Rectangle[] bars = new Rectangle[4];

        for (int i = 0; i < bars.length; i++) {

            bars[i] = new Rectangle(
                    5 + (100 * i), // x
                    LIMIT_HEIGHT - (HEIGHT * percent[i]), // y
                    WIDTH / bars.length - 5, // width
                    HEIGHT * percent[i]); // height
            bars[i].setFill(colors[i]);

            Text text = new Text(5 + (100 * i),LIMIT_HEIGHT - (HEIGHT * percent[i]) - 5,titles[i]);
            pane.getChildren().addAll(text, bars[i]);

        }

        primaryStage.setScene(new Scene(pane, WIDTH + 20, LIMIT_HEIGHT));
        primaryStage.setTitle("Bar graph");
        primaryStage.show();
    }

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

    }



}

No comments :

Post a Comment