1. Java Applet Basics (2)

2. The Body Mass Index Calculator

3. The Applet Skeleton import java.applet.*; import java.awt.*; public class BodyMassApplet extends Applet { }

4. The HTML Page

5. Create the Skeleton Files

6. Control Components Label TextField Button

7. Add a Label Control import java.applet.*; import java.awt.*; public class BodyMassApplet extends Applet { Label myLabel = new Label(“XXXXXXXX”); public void init() { add(myLabel); }

8. Member Variable

9. Add Labels into the Skeleton

10. Add a TextField Control import java.applet.*; import java.awt.*; public class BodyMassApplet extends Applet { TextField myTextField = new TextField(columns); public void init() { add(myTextField); }

11. Add TextFields into the Skeleton

12. Add a Button Control import java.applet.*; import java.awt.*; public class BodyMassApplet extends Applet { Button myButton = new Button(“Text on the Button”); public void init() { add(myButton); }

13. Add Buttons into the Skeleton

14. Handle Action Events import java.awt.event.*; public class BodyMassApplet extends Applet implements ActionListener { Button myButton = new Button(“my button”); public void init() { add(myButton); myButton.addActionListener(this); } public void actionPerformed(ActionEvent e) { //handle the event here }

15. Add the Event Handler

16. Display Text on a Label Control Syntax: myLabel.setText(“the text shown on the label control”);

17. Read Text from a TextField Syntax: myTextField.getText(); E.g. String input; input = myTextField.getText();

18. Read Inputs From all TextFields

19. Math.round(dbl) Rounds a real number into the nearest integer Syntax: integer = Math.round(dbl) Example: double dblIndex; int intIndex; intIndex = Math.round(dblIndex); Question: what’s the difference between Math.round(dbl) and (int)dbl?

20. Round the Body Index