Thread: how to use the keyboard up,down,right,left

Hi, i am making a simple program that uses Graphics and this is the first time that i used this Graphics,now what i want is to move the circle inside in my JFrame and controlled by the arrow up,down,left and right.

How can i accomplished this.?

import java.util.*;
import java.awt.*;
import javax.swing.*;
 
 
public class TestPoint extends JFrame 
{
 
   public TestPoint()
   {
   	     setTitle("Moving circle");
	     setSize(400,400);
	     setVisible(true);
	     setDefaultCloseOperation(EXIT_ON_CLOSE);
 
   }
 
 
	public void paint(Graphics g)
	{
 
 
	    super.paint(g);
 
	    this.setBackground(Color.white);
		g.setColor(Color.RED);
	    g.fillOval(10,100,10,10);
 
 
 
 
	}
 
 
	public static void main(String[]c)
	{
 
		TestPoint t = new TestPoint();
	       t.setBackground(Color.white);
 
 
 
	}
 
}

Originally Posted by Norm

You will need to use a keylistener or key binding so the program will know when one of the keys is pressed and can react to it.

Hi thank you for the reply, can you please show me example just only to move my circle i really don't have idea on it...this is my first time to use the keylistener i hope you can help me norm.

I would suggest that you use Key Bindings since this is a Swing program, and there's a great tutorial on how to use Key Bindings in the Java tutorials. This will likely help get you started.

Originally Posted by curmudgeon

I would suggest that you use Key Bindings since this is a Swing program, and there's a great tutorial on how to use Key Bindings in the Java tutorials. This will likely help get you started.

hi, thank you for the reply, but i was confuse by the example.how do i control it the circle to move?

Originally Posted by Norm

Change its x,y location so when the paint method is called it will be drawn at a new location.

Do you have a snippet on this,can you please show me.

Hi, I am having problem on my code it says cannot find symbol

in this part of code

int condition = JComponent.WHEN_IN_FOCUSED_WINDOW;
InputMap inputMap = getInputMap(condition);
ActionMap actionMap = getActionMap();

inputMap.put(keyStroke.getKeyStroke(KeyEvent.vk_up _right),"up");
getActionMap().put("up",up);

import java.util.*;
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
 
 
 
public class TestPoint extends JFrame 
{
 
  int x = 10;
  int y=100;	
   public TestPoint()
   {
 
   	  int condition = JComponent.WHEN_IN_FOCUSED_WINDOW;
      InputMap inputMap = getInputMap(condition);
      ActionMap actionMap = getActionMap();
   	     setTitle("My Ball");
	     setSize(400,400);
	     setVisible(true);
	     setDefaultCloseOperation(EXIT_ON_CLOSE);
 
	    Action up = new AbstractAction(){
	    	public void actionPerformed(ActionEvent e){	    		
	    		y++;
	    		repaint();
	    	}
	    };
 
 
   	    inputMap.put(keyStroke.getKeyStroke(KeyEvent.vk_up_right),"up");
   	    getActionMap().put("up",up);
 
   }
 
 
	public void paint(Graphics g)
	{
	    super.paint(g);
 
	    this.setBackground(Color.white);
		g.setColor(Color.RED);
	    g.fillOval(x,y,10,10);
 
	}
 
 
 
	public static void main(String[]c)
	{ 
		TestPoint t = new TestPoint();
	    t.setBackground(Color.white);
 
	}
 
 
}