JAVA2EVERYONE: 12/22/08

Java simple counter

Source below will show you, how to create simple counter in java.

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COMPLETE SOURCE CODE FOR : JavaSimpleCounter.java
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import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;

import java.awt.Graphics;
import java.awt.Font;
import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.Color;
import java.awt.Font;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class JavaSimpleCounter extends JLabel implements ActionListener
{
JButton buttonReset=new JButton("RESET");
JButton buttonCount=new JButton("CLICK HERE");
int countValue=0;
JFrame frame;
Font fontForNumber=new Font("Tahoma",Font.BOLD,80);

public JavaSimpleCounter()
{
 frame=new JFrame("JAVA SIMPLE COUNTER");
 frame.setLayout(new BorderLayout());
 JPanel panel=new JPanel();
 panel.setLayout(new GridLayout(1,2));
 buttonCount.addActionListener(this);
 buttonReset.addActionListener(this);
 panel.add(buttonCount);
 panel.add(buttonReset);
 frame.add(this,BorderLayout.CENTER);
 frame.add(panel,BorderLayout.SOUTH);
 frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 frame.setSize(400,200);
 frame.setVisible(true);
}

public void paint(Graphics g)
{
 g.setFont(fontForNumber);
 g.setColor(Color.BLACK);
 g.fillRect(0,0,getSize().width,getSize().height);
 g.setColor(Color.WHITE);
 g.drawString(Integer.toString(countValue),10,80);
}

public void actionPerformed(ActionEvent event)
{
 if(event.getSource()==buttonCount)
 {
  countValue++;
  frame.repaint();
 }

 else if(event.getSource()==buttonReset)
 {
  Graphics panelGraphics=getGraphics();
  panelGraphics.setFont(fontForNumber);
  panelGraphics.setColor(Color.BLACK);
  panelGraphics.fillRect(0,0,getSize().width,getSize().height);
  panelGraphics.setColor(Color.RED);
  panelGraphics.drawString(Integer.toString(0),10,80);
  countValue=0;
  frame.repaint();
 }
}

public static void main(String[]args)
{
 JavaSimpleCounter jsc=new JavaSimpleCounter();
}
}

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JUST COMPILE AND EXECUTE IT
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Remove component from JFrame during runtime

Source code below will show you, how to remove component from a JFrame during program runtime. Component that will be use in source code below is a group of JButton.

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COMPLETE SOURCE CODE FOR : RemoveComponentOnJFrameAtRuntime.java
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import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JButton;
import javax.swing.JOptionPane;

import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.Component;

import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;

public class RemoveComponentOnJFrameAtRuntime extends JFrame implements ActionListener
{
JPanel panel;

public RemoveComponentOnJFrameAtRuntime()
{
 super("Remove component on JFrame during runtime");
 setLayout(new BorderLayout());

 panel=new JPanel();
 panel.setLayout(new FlowLayout());

 JButton button1=new JButton("BUTTON 1");
 JButton button2=new JButton("BUTTON 2");
 JButton button3=new JButton("BUTTON 3");
 JButton button4=new JButton("BUTTON 4");
 JButton button5=new JButton("BUTTON 5");

 panel.add(button1);
 panel.add(button2);
 panel.add(button3);
 panel.add(button4);
 panel.add(button5);

 add(panel,BorderLayout.CENTER);

 JButton removeButton=new JButton("Click here to remove button");
 removeButton.addActionListener(this);

 add(removeButton,BorderLayout.SOUTH);

 setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 setSize(500,500);
 setVisible(true);
}

public void actionPerformed(ActionEvent event)
{
 Component[]storeAllButtonInPanel=panel.getComponents();

 if(storeAllButtonInPanel.length!=0)
 {
  panel.remove(storeAllButtonInPanel.length-1);
  panel.revalidate();
  validate();
  repaint();
 }

 else
 {
  JOptionPane.showMessageDialog(this,"No button to remove");
 }
}

public static void main(String[]args)
{
 RemoveComponentOnJFrameAtRuntime rcojfat=new RemoveComponentOnJFrameAtRuntime();
}
}

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JUST COMPILE AND EXECUTE IT
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Java default look and feel

Default look and feel is Metal look and feel. Below is an image that show how Metal look and feel looks like.

Add component on JFrame during runtime

Source code below will show you how to add a component into a JFrame during program runtime. Component that will be use in this program, is JButton.

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COMPLETE SOURCE CODE FOR : AddComponentOnJFrameAtRuntime.java
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import javax.swing.JFrame;
import javax.swing.JButton;
import javax.swing.JPanel;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import java.awt.FlowLayout;
import java.awt.BorderLayout;

public class AddComponentOnJFrameAtRuntime extends JFrame implements ActionListener
{
JPanel panel;

public AddComponentOnJFrameAtRuntime()
{
 super("Add component on JFrame at runtime");
 setLayout(new BorderLayout());
 panel=new JPanel();
 panel.setLayout(new FlowLayout());
 add(panel,BorderLayout.CENTER);
 JButton button=new JButton("CLICK HERE");
 add(button,BorderLayout.SOUTH);
 button.addActionListener(this);
 setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 setSize(500,500);
 setVisible(true);
}

public void actionPerformed(ActionEvent evt)
{
 panel.add(new JButton("Button"));
 panel.revalidate();
 validate();
}

public static void main(String[]args)
{
 AddComponentOnJFrameAtRuntime acojfar=new AddComponentOnJFrameAtRuntime();
}
}

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JUST COMPILE AND EXECUTE IT
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Close JFrame when mouse click release in JFrame

Source code below will create a JFrame. After that, click in the JFrame, hold for a few seconds, and after that release your mouse click. The JFrame that created in this program will be close and this application will terminate.

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COMPLETE SOURCE CODE FOR : CloseJFrameWhenMouseReleased.java
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import javax.swing.JFrame;

import java.awt.event.MouseListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

public class CloseJFrameWhenMouseReleased
{
public static void main(String[]args)
{
 //Create mouse listener that will listen when mouse released in JFrame
 MouseListener ml=new MouseAdapter()
 {
  public void mouseReleased(MouseEvent event)
  {
   //Put JFrame close code here
   System.exit(0);
  }
 };

 //Create JFrame with title ( CLICK ON ME,HOLD FOR A FEW SECOND,RELEASE YOUR CLICK )
 JFrame frame=new JFrame("CLICK ON ME,HOLD FOR A FEW SECOND,RELEASE YOUR CLICK");

 //Add mouse listener to JFrame
 frame.addMouseListener(ml);

 //Set default close operation to JFrame
 frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

 //Set JFrame size to :
 //Width : 700 pixels
 //Height : 400 pixels
 frame.setSize(700,400);

 //Make JFrame visible. So we can see it.
 frame.setVisible(true);
}
}

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JUST COMPILE AND EXECUTE IT
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Close JFrame when cursor exit from JFrame

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COMPLETE SOURCE CODE FOR : CloseJFrameWhenMouseExit.java
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import javax.swing.JFrame;

import java.awt.event.MouseListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

public class CloseJFrameWhenMouseExit
{
public static void main(String[]args)
{
 //Create mouse listener that will listen when cursor exit JFrame
 MouseListener ml=new MouseAdapter()
 {
  public void mouseExited(MouseEvent event)
  {
   //Put JFrame close code here
   System.exit(0);
  }
 };

 //Create JFrame with title ( GET YOUR CURSOR INTO JFRAME, AFTER THAT MOVE IT AWAY )
 JFrame frame=new JFrame("GET YOUR CURSOR INTO JFRAME, AFTER THAT MOVE IT AWAY");

 //Add mouse listener to JFrame
 frame.addMouseListener(ml);

 //Set default close operation to JFrame
 frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

 //Set JFrame size to :
 //Width : 700 pixels
 //Height : 400 pixels
 frame.setSize(700,400);

 //Make JFrame visible. So we can see it.
 frame.setVisible(true);
}
}