• 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

literally, all i need help with is the last part with the event handler, here is my code:

package tipcalculator;

/** * * @author */ public class Order { String item; double price; public Order() { this("",0.0); } public Order(String item, Double price) { setItem(item); setPrice(price); } /** * updates value of item * @param item */ public void setItem(String item) { this.item = item; } /** * updates value of price * @param price */ public void setPrice(double price) { if(price > 0) { this.price = price; } } public String getItem() { return item; } public double getPrice() { return price; } }

package tipcalculator;

import java.text.DecimalFormat; import javafx.application.Application; import javafx.scene.input.MouseEvent; import javafx.collections.ObservableList; import javafx.collections.FXCollections; import javafx.geometry.HPos; import javafx.geometry.Insets; import javafx.geometry.Pos; import javafx.scene.Scene; import javafx.scene.control.Button; import javafx.scene.control.Label; import javafx.scene.control.ListView; import javafx.scene.layout.VBox; import javafx.scene.layout.GridPane; import javafx.stage.Stage; import javafx.scene.control.Slider; import javafx.scene.layout.FlowPane;

/** * * @author */ public class TipCalculator extends Application { private DecimalFormat twoDecimals; private Label lblHeader; private Label lblResults; private Label lblTip; private Label lblTipHeader; private Slider sliderTip; private ObservableList items; private ObservableList prices; private FlowPane flowTip; private ListView listView; private VBox vBoxListView; private VBox vBoxResults; private VBox vBoxSlider; private VBox vBoxSliderResults; private Button btnCalculate; @Override public void start(Stage primaryStage) { twoDecimals = new DecimalFormat("0.00"); //making the header lblHeader = new Label("Tip Calculator"); lblHeader.setMinWidth(900); lblHeader.setAlignment(Pos.CENTER); lblHeader.setStyle("-fx-font-family: 'Times New Roman'; -fx-font-size: 28px; -fx-text-fill: white; -fx-background-color: rgb(0, 0, 0); -fx-font-weight: bold;"); //instantiating 10 objects from order class Order order1 = new Order("object1", 1.0); Order order2 = new Order("object2", 2.0); Order order3 = new Order("object3", 3.0); Order order4 = new Order("object4", 4.0); Order order5 = new Order("object5", 5.0); Order order6 = new Order("object6", 6.0); Order order7 = new Order("object7", 7.0); Order order8 = new Order("object8", 8.0); Order order9 = new Order("object9", 9.0); Order order10 = new Order("object10", 10.0); //instantiating two observable list objects items = FXCollections.observableArrayList(order1.getItem(),order2.getItem(), order3.getItem(),order4.getItem(),order5.getItem(),order6.getItem(),order7.getItem(), order8.getItem(),order9.getItem(),order10.getItem() ); prices = FXCollections.observableArrayList(order1.getPrice(),order2.getPrice(), order3.getPrice(), order4.getPrice(), order5.getPrice(),order6.getPrice(),order7.getPrice(), order8.getPrice(),order9.getPrice(),order10.getPrice() ); //creating the list view from "items" listView = new ListView(items); //.setOnMouseClicked( e -> updateSelectedItems(e) ); vBoxListView = new VBox(listView); vBoxListView.setPadding( new Insets(10) ); vBoxListView.setPrefWidth(300); vBoxListView.setPrefHeight(100); listView.setOnMouseClicked( e -> updateSelectedItem(e) ); //creating the slider for the tip percentage lblTipHeader = new Label ("tip Percentage"); sliderTip = new Slider(15.0, 25.0, 10.0); sliderTip.setShowTickMarks(false); sliderTip.setShowTickLabels(true); sliderTip.setMajorTickUnit(5.0); sliderTip.setMinorTickCount(4); sliderTip.setPrefWidth(350); lblTip = new Label( twoDecimals.format( sliderTip.getValue() ) ); flowTip = new FlowPane(sliderTip, lblTip); flowTip.setHgap(10); vBoxSlider = new VBox(7, lblHeader, flowTip); vBoxSlider.setMinWidth(400); vBoxSlider.setPadding( new Insets(10) ); sliderTip.setOnMouseDragged( e -> updateTipSlider(e) ); //creating the calculate buttton lblResults = new Label("tip:"); btnCalculate = new Button("Calculate tip"); btnCalculate.setStyle("-fx-background-color: black; -fx-font-weight: bold; -fx-text-fill: white;"); //btnCalculate.setOnAction( e -> handleClickAction(e) );

vBoxResults = new VBox(35, lblResults, btnCalculate); vBoxResults.setPadding( new Insets(15) ); vBoxResults.setPrefWidth(175); vBoxResults.setStyle("-fx-background-color: cornsilk; -fx-border-color: black; -fx-border-radius: 10;"); GridPane grid = new GridPane();

grid.addRow(0, lblHeader); GridPane.setColumnSpan(lblHeader, 2); GridPane.setHalignment(lblHeader, HPos.CENTER); grid.addRow(1, vBoxListView, vBoxResults,vBoxSlider); Scene scene = new Scene(grid, 1000, 200); primaryStage.setTitle("Book Viewer"); primaryStage.setResizable(false); primaryStage.setScene(scene); primaryStage.show(); }

//event handler to update values for slider private void updateTipSlider(MouseEvent e) { lblTip.setText( twoDecimals.format( sliderTip.getValue() ) ); } private void updateSelectedItem(MouseEvent e) { int index = listView.getSelectionModel().getSelectedIndex(); lblResults.setText( prices.get(index).toString() ); } /** * @param args the command line arguments */ public static void main(String[] args) { launch(args); } }