Basic Steps: Java Simple AWT Swing On Notepad++

Sunday, May 12, 2013

Java Simple AWT Swing On Notepad++

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copy and paste the following code into a Notepad++ window

import java.awt.Color;
import java.awt.Graphics;
import java.awt.GridLayout;
import java.awt.Container;
 
import javax.swing.JFrame;
import javax.swing.JPanel;
 
public class Draw4Ovals extends JPanel {
 
  Color color;
 
  public Draw4Ovals(Color color) {    
    this.color = color;
    this.setBackground(Color.BLACK);
    this.setOpaque(true);    //needed to ensure panel background is set
  }
 
  public void paintComponent(Graphics g) {
    super.paintComponent(g);    //needed to ensure that panel background is set
    int width = getWidth();
    int height = getHeight();
    g.setColor(color);
    g.fillOval(0, 0, width, height);
  }
 
  public static void main(String args[]) {
    JFrame frame = new JFrame("Oval Sample");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 
    Container content = frame.getContentPane();
    content.setBackground(new Color(180,230,255));    
    content.setLayout(new GridLayout(2, 2, 5 ,5));
    Color colors[] = { Color.RED, Color.BLUE, Color.GREEN, Color.YELLOW };
    for(Color c: colors) {
      Draw4Ovals panel = new Draw4Ovals(c);     
      content.add(panel);
    }
    //validate must be done on the component that has the .add() and the layoutManager
    content.validate();    
    frame.setSize(300, 200);
    frame.setLocation(50,100);
    frame.setVisible(true);    
  }
}

Save this file as “Draw4Ovals.java”. Upper-case is important. Once it is saved, you’ll see that Notepad++ does syntax highlighting.
Select the Macros menu, then click on the Java-compile macro near the bottom. The results should look like this: .
Now select the macro “Java-run”. You should see this:
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If, in addition, you want to test an applet,

paste the following code
save it as “TestApplet.java”
run “Java-compile”
run “Java-applet-HTML”

now either view the file in a browser, or else run “Java-applet-viewer”

import java.awt.*; 
import java.awt.event.*; 
// import java.applet.Applet; 
import javax.swing.*;
 
public class TestApplet extends JApplet implements ActionListener { 
 Button b; 
 JLabel jl;
 public void init(){ 
  setLayout(new FlowLayout()); 
  b = new Button("push me"); 
  b.addActionListener(this); 
  add(b);
  jl = new JLabel("Welome to my applet");
  add(jl);
 } 
 
 public void actionPerformed(ActionEvent e){ 
  jl.setText("You clicked?");  
 }
}

Note: ♦Applets are no longer used as much as other types of web-programming.
♦The Java-applet-HTML script just makes a very simple HTML page. If you want to put an applet in a webpage, you should actually make a decent webpage.