Question

Tip Calculator App & Order

• Using NetBeans create a new JavaFX project with two classes TipCalculator (the JavaFX class) and Order

• Create the Tip Calculator as follows:
  • Start with an Order class with two instance variables, item a String and price a double; include two constructors, a no-parameter constructor that passes default values empty String and zero (0) to the second constructor which then calls the set methods for item and price; the set method for price validates that price is greater than zero (0); include get methods for both instance variables; there is no need for a toString() method
  • Instantiate ten objects from the Order class in the start() method of the JavaFX application from which two ObservableList objects should be instantiated: (a) an ObservableList of Strings populated from the get method for the “item” field; and (b) an ObservableList of Doubles (use the wrapper class as the sub type to instantiate) populated from the get method for the “price” field
  • The JavaFX form will consist of (a) a ListView of Strings from the ObservableList of “items”; (b) a Slider that represents tip percentage as an int between 15% and 25% (show the current value of the “tip percent” slider in a matching Label); (c) a Button that is clicked to calculate the “total bill”; and (d) a “result” Label
  • Include an event handler method for the Button that calculates the “total bill” as follows: the “price” field from the ObservableList that matches the selected “item” from the ListView (the user may purchase only one item at a time) times sales tax (8.625%) plus the tip which is the matching “price” from the ObservableList times the percentage from the Slider; display with text labels in the “result” Label the selected “item”, its matching “price”, the sales tax, the amount of the “tip” and the “total bill”
• Use a combination of layout objects, as well as font and color formatting to create a pleasing, professional looking form window

• Provide full documentation using the Javadoc standard and based upon the downloaded sample files for the unit

Answer 1

import javafx.application.Application;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.collections.*;
import javafx.scene.layout.*;
import javafx.event.*;
import javafx.stage.Stage;

// Allows the user to enter a meal amount and select a tip rate.
public class Tips extends Application {

    private TextField tfMeal = new TextField();
    private TextField tfTip = new TextField();
    private TextField tfTotal = new TextField();
    private ComboBox cbTips;
    private ObservableList<String> tip_rates =
            FXCollections.observableArrayList (
                    "0.05", "0.10",
                    "0.15", "0.18",
                    "0.20", "0.22",
                    "0.25", "0.30");

    @Override
    // Override the start method in the Application class
    public void start(Stage primaryStage) {

        VBox pane = new VBox(5);

        tfMeal.setPrefColumnCount(10);
        tfTip.setPrefColumnCount(5);
        tfTotal.setPrefColumnCount(10);

// Compmo box for tip rates
        cbTips = new ComboBox(tip_rates);
        cbTips.setVisibleRowCount(4);
        cbTips.setValue(tip_rates.get(4));

        pane.getChildren().addAll(new Label("Amount: "), tfMeal, new Label("Tip rates: "), cbTips);

        HBox hBox = new HBox(5);
        Button btCalculate = new Button("Calculate Tip");

        hBox.setAlignment(Pos.CENTER);
        hBox.getChildren().addAll(btCalculate, new Label("Tip: "), tfTip, new Label("Total: "), tfTotal);
        // tip and total are display only fields
        tfTip.setEditable(false);
        tfTotal.setEditable(false);

        BorderPane borderPane = new BorderPane();
        borderPane.setCenter(pane);
        borderPane.setBottom(hBox);
        BorderPane.setAlignment(hBox, Pos.TOP_CENTER);

        // Create a scene and place it in the stage
        Scene scene = new Scene(borderPane, 375, 150);
        primaryStage.setTitle("Tip calculator"); // Set the stage title
        primaryStage.setScene(scene); // Place the scene in the stage
        primaryStage.show(); // Display the stage

        btCalculate.setOnAction(new EventHandler<ActionEvent>() {

            public void handle(ActionEvent e) {
                // this statement gets the tip rate
                double tiprt = Double.parseDouble(cbTips.getValue().toString());
                double tfMealVal = Double.parseDouble(tfMeal.getText().toString());
                double rslt = tfMealVal*tiprt;
                double totalAmnt = rslt+tfMealVal;
                tfTip.setText(Double.toString(rslt));
                tfTotal.setText(Double.toString(totalAmnt));

            }
        });

    }

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