GUI-Frames

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					           GUI-Frames

A GUI for a Java program can be created by
       extending the class JFrame.

   The JFrame class holds the basic GUI
              functionality.

You extend this class by adding the functions
         your application needs..
             JFrames
• The JFrame class.

• Extending the JFrame class

• The paint() method.

• The drawString() method.
             JFrames
• Graphical Components that make
  up the Graphical User Interface.

• Listener methods that receive the
  events and respond to them.
• Application methods that do useful
  work for the user.
             1st Frame Prog1
•   import java.awt.*;
•   import javax.swing.*;
•   public class TestFrame1
•   {
•     public static void main ( String[] args )
•     {
•       JFrame frame = new JFrame ("Test Frame 1");
•       frame.setSize(200,100);
•       frame.setVisible( true );
• }
• }
1 Is this program an applet
        or Application?
  2. What will be the output
       for this program?
               JFrames
• The program is an application. It is
  not called by a Web browser.

• It has a main() method where it starts
  running
• import java.awt.*; // 1. import the application
  windowing toolkit
• import javax.swing.*; // 2. import the Swing classes
• public class TestFrame1
• {
•    public static void main ( String[] args ) //// usual
  main() method
• {
•    JFrame frame                  // 4. a reference to the
  object
•       = new JFrame("Test Frame 1"); // 3. construct a
  JFrame object
•    frame.setSize(200,100); // 5. set it to 200 pixels
  wide by 100 high
•    frame.setVisible( true ); }// 6. ask it to become
  visible on the screen
• When the program is running:
• How many objects are there?
• Where is the main() method?
              Answer:


• How many objects are there? One
• Where is the main() method? It is a
  static method of the class TestFrame1
       Ist half of the 2nd program-Frame
• import java.awt.*;
• import javax.swing.*;
• class MyFrame extends JFrame{
  // paint() is called automatically by the system
• // to display your customizations to the
  frame.
• public void paint ( Graphics g ){
•     // draw a String at location x=10 y=50
•     g. drawString ("A MyFrame object", 10,
  50 ); }
• }
         2nd half of the 2nd program
• public class TestFrame2 {
• public static void main ( String[] args ) {
•      MyFrame frame = new MyFrame(); //
  construct a MyFrame object
•    frame. setSize( 150, 100 ); // set it to 150
  wide by 100 high
•    frame.setVisible( true );    // ask it to become
  visible
•    }                    // paint() is indirectly
  called
• }
Fill in the blanks: events,*;, drawString, setSize
WindowAdapter, Systwm.exit, setVisible
•   import java.awt.*;
•   import java.awt.________;
•   import javax.swing.*;
•   class myFrame extends JFrame {
•     public void paint ( Graphics g ) {
•       g._____________ ("Click the close button", 10, 50 );
•     }
•   }
•   class WindowQuitter extends ______________
•   {
•     public void windowClosing( WindowEvent e ) {
•       ____________( 0 );
•     }
•   }
These are 3 sample programs:

				
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posted:4/19/2012
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