Updating canvas through textfield

>>public void paintComponent(Graphics g)

should be

public void paint(Graphics g)

in your canvas

Have just tried that, when I enter in a value and hit enter, the scollbar moves, but te color doesn,t update

Works for me with my correction

Nah, the color doesn't change at all, even tho the scrollbar does.  I have tried it on both JCreator, and from the comand line on my laptop

Well it's got to really - it does for me ;-)  This is what i did

1. Copy-pasted the code as ColourChooser.java
2. Made the change i mentioned
3. Got rid of the import in DrawCanvas and removed 'public' in 'public class'
4. Compiled and ran it

>> Nah, the color doesn't change at all

Of course you'll have to make noticeable changes - a few notches here and there won't make any visible difference

The color changes ok when I move the scrollbar, thats not the problem, I want it to also change if the user enters the number directly into the text field and hits enter. All that happens now if I enter, say 200 into teh textfield and hit enter, teh scrollbar moves ok but the color doesn't change at all

In that case, all i can think is that you're not running the code you posted with my change as i can change the colour fine by typing and hitting enter

Can u paste your code so I can compare, my eyes are going googly looking at it :-(

Sure. Save it elsewhere as ColourChooser.java:

SNIP=========================================================================


import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.awt.Graphics.*;
import java.util.*;

public class ColourChooser extends JFrame implements AdjustmentListener,
            ActionListener {

      // set up the canvas object which will be displayed on a panel called row1
      // the colour will be displayed on this canvas
      JPanel row1 = new JPanel();

      // setting up the individual scrollbars and adding them to a panel called row2
      JPanel row2 = new JPanel();

      Scrollbar sb1 = new Scrollbar(Scrollbar.HORIZONTAL, 0, 0, 1, 255);

      Scrollbar sb2 = new Scrollbar(Scrollbar.HORIZONTAL, 0, 0, 1, 255);

      Scrollbar sb3 = new Scrollbar(Scrollbar.HORIZONTAL, 0, 0, 1, 255);

      // setting up the labels and putting then in a panel called row3
      JPanel row3 = new JPanel();

      JLabel rd = new JLabel("      Red");

      JLabel grn = new JLabel("     Green");

      JLabel bl = new JLabel("     Blue");

      // setting up the textfields that will display the individual colour values
      // and then adding
      // them to a pnel called row4
      JPanel row4 = new JPanel();

      JTextField txt1 = new JTextField(10);

      JTextField txt2 = new JTextField(10);

      JTextField txt3 = new JTextField(10);

      DrawCanvas myCanvas = new DrawCanvas();

      // setting up the container to hold the components (which are in there own
      // panels)
      // and setting up the layout manager (grid layout)
      public ColourChooser() {
            super("Brendan Whelan");
            setSize(350, 100);
            setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            GridLayout layout = new GridLayout(1, 5);
            Container con = getContentPane();
            con.setLayout(layout);
            con.setVisible(true);

            // add the canvas to panel row1 and set the layout for the panel (flow
            // layout)
            // set the size of the canvas to 65 pixels by 65 pixels
            FlowLayout layout1 = new FlowLayout(FlowLayout.CENTER);
            row1.setLayout(layout1);
            row1.add(myCanvas);
            con.add(row1);

            // set up the layout manager for the scrollbars (gridlayout) 1 column wide
            // and 3 rows high
            // add the action listeners to the scrollbars
            GridLayout layout2 = new GridLayout(3, 1);
            row2.setLayout(layout2);
            sb1.addAdjustmentListener(this);
            row2.add(sb1);
            sb2.addAdjustmentListener(this);
            row2.add(sb2);
            sb3.addAdjustmentListener(this);
            row2.add(sb3);
            con.add(row2);

            // set up the layout manager for the labels and add them to them to the
            // container
            GridLayout layout3 = new GridLayout(3, 1);
            row3.setLayout(layout3);
            row3.add(rd);
            row3.add(grn);
            row3.add(bl);
            con.add(row3);

            // set up the layout manager for the textfields and add them to the
            // container
            GridLayout layout4 = new GridLayout(3, 1);
            row4.setLayout(layout4);
            row4.add(txt1);
            txt1.addActionListener(this);
            row4.add(txt2);
            txt2.addActionListener(this);
            row4.add(txt3);
            txt3.addActionListener(this);
            con.add(row4);

      }

      // This method gets the value from the scrollbar & repaints the colour onto
      // the canvas
      public void adjustmentValueChanged(AdjustmentEvent e) {
            // Gets the value from the selected scrollbar
            int r = sb1.getValue();
            int g = sb2.getValue();
            int b = sb3.getValue();
            // Sets the colour on the canvas
            myCanvas.setBackground(new Color(r, g, b));
            myCanvas.repaint();
            // This finds out which of the 3 scrolbars has been selected
            // and adjusts the value accordingly
            Object source = e.getSource();
            int i = ((Scrollbar) source).getValue();
            if (source == sb1) {
                  txt1.setText("" + i);
            } else if (source == sb2) {
                  txt2.setText("" + i);
            } else if (source == sb3) {
                  txt3.setText("" + i);
            }
      }

      public void actionPerformed(ActionEvent e) {

            int r = sb1.getValue();
            int g = sb2.getValue();
            int b = sb3.getValue();
            sb1.setValue(Integer.parseInt(txt1.getText()));
            sb2.setValue(Integer.parseInt(txt2.getText()));
            sb3.setValue(Integer.parseInt(txt3.getText()));
            myCanvas.setBackground(new Color(r, g, b));
            myCanvas.repaint();
      }

      public static void main(String[] args) {

            ColourChooser choose = new ColourChooser();
            choose.setVisible(true);

      }

}

class DrawCanvas extends Canvas

{
      // Variable declarations
      int red, green, blue;

      // int redValue, greenValue, blueValue;

      public DrawCanvas() {
            // set the size of the canvas
            setSize(65, 65);
      }

      public void paint(Graphics g) {
            // set the colour of the canvas
            g.setColor(getBackground());
            g.fillRect(0, 0, getWidth(), getHeight());

      }

      public void setCanvasColor(int red, int green, int blue) {
            // "repaint" the canvas(this will call the paint method)
            setBackground(new Color(red, green, blue));
            repaint();
      }

}

Still not working, even with your code.  I have to nudge the scrollbar a notch and then the canvas displays the correct color, but not when I hit the enter button

(from the directory you put it in)