Unit 3 Graphical User Interface (GUI) Dr. Magdi AMER

Java library has a class JFrame that implements the methods necessary to create a window on any operating system (Windows, Mac and UNIX). JFrame is generic. It does not have the features that we need (labels, buttons, etc). In real life, when we have a factory and we want to modify it’s product, we do not destroy the factory and build a new one, we simply add the machines that we need. Dr. Magdi Amer2 JFrame

Similarly, in OOP, when we want to modify the behavior of a class, we extend the class. This means that we take all the method of the class into the new one (without having to write the code again) so we can modify a method or add a new method. Dr. Magdi Amer3 Extending JFrame

Dr. Magdi Amer4 Simple Window

A window must extend the class JFrame. JFrame handle all the complexity of creating a window on any OS (remember same java code runs on any operating system. setSize ( 400, 140 ); – Creates a window width = 400, height = 140 setVisible( true ); – Makes the window visible. Dr. Magdi Amer5 Simple Window

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To add a title to the window, we use the code – super(title); – This code uses the constructor of the parent class JFrame. – Calling the constructor of the parent class is a good programming practice, and it may be sometimes necessary. Dr. Magdi Amer7 Simple Window

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GridLayout layout = new GridLayout(4,1);  Creates a layout of 4 rows and 1 column. Container c = getContentPane(); c.setLayout(layout );  Gets the main container of the window and assign to it the grid container Dr. Magdi Amer9 Advanced Window

JPanel p1 = new JPanel(); JPanel p2 = new JPanel(); JPanel p3 = new JPanel(); JPanel p4 = new JPanel(); c.add(p1); c.add(p2); c.add(p3); c.add(p4);  Creates 4 panels (containers) and place them on the window. Each will be placed on a new row. Dr. Magdi Amer10 Advanced Window

p1.add(new JLabel("First")); p2.add(new JLabel("Second")); p3.add(new JLabel("Third")); p4.add(new JLabel("Forth"));  Creates 4 labels and put each label on a panel. Dr. Magdi Amer11 Advanced Window

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JPanel p4 = new JPanel(); c.add(p4); p4.add(new JButton(“Forth")); When a button is placed on a panel  It takes its best fit size c.add(new JButton(“Third")); When a button is placed directly on the window  It expands to take all of the area Dr. Magdi Amer13 Advanced Window

Dr. Magdi Amer14 Event Based System

Dr. Magdi Amer15 Event Based System

this.addWindowListener(new MyWindowAdaptor()); Place an event listener to listen to events generated by the window. If we are interested in handling a specific event, we implement the method that handles this event. Public class MyWindowAdaptor extends WindowAdapter WindowAdapter  class responsible for handling all events of a window public void windowClosing(WindowEvent event) { System.exit(0); } Handles the window closing event and closes the application Dr. Magdi Amer16 Event Based System

Dr. Magdi Amer17 Handling the events of a button

Dr. Magdi Amer18 Handling the events of a button

TextFieldHandler handler = new TextFieldHandler(this); button.addActionListener(handler); Creates an event handler that is associated with a button public class TextFieldHandler implements ActionListener { protected MyFrame myFrame; public TextFieldHandler(MyFrame myFrame) { super(); this.myFrame = myFrame; } Creates an action listener and stores a reference to the window that it controls. Dr. Magdi Amer19 Handling the events of a button

public void actionPerformed(ActionEvent e) { String txt = myFrame.text1.getText(); JOptionPane.showMessageDialog(null, txt); } } Reads the text entered in the text field and displays the text in a popup. Dr. Magdi Amer20 Handling the events of a button

Dr. Magdi Amer21 Building Rich Interface

Dr. Magdi Amer22 Handling the events of a text field

Dr. Magdi Amer23 Handling the events of a text field

Dr. Magdi Amer24 Using a radio button

Dr. Magdi Amer25 Handling the events of a Radio Button

Dr. Magdi Amer26 Using a check box

Dr. Magdi Amer27 Handling the events of a check box

Dr. Magdi Amer28 Using a combo box

Dr. Magdi Amer29 Handling the events of a combo box

Dr. Magdi Amer30 Using Menus

Dr. Magdi Amer31 Using CardLayout

Dr. Magdi Amer32 Creating Panels

Dr. Magdi Amer33 Handling a menu event

Dr. Magdi Amer34 Handling a menu event

Dr. Magdi Amer35 2D Graphics