Controlling multiple TextAreas with one ScrollBar

Question

Hello,
Fairly new to java so you may have to excuse my lack of java knowledge!
I would like to create a Frame with three TextAreas, side-by-side, controlled by a single ScrollBar.
I thought it would be fairly easy. Just add the three TextAreas to a Panel then add a ScrollPane to the Panel. If that is the right way, how can you make the TextArea as high as the number of rows. Think I've seen some example using Swing but I'm using AWT.
I've provided some example code if it helps:
import java.awt.*;
public class MyExample extends Frame
  TextArea field1 = new TextArea("", 0, 0, TextArea.SCROLLBARS_NONE);
  TextArea field2 = new TextArea("", 0, 0, TextArea.SCROLLBARS_NONE);
  TextArea field3 = new TextArea("", 0, 0, TextArea.SCROLLBARS_NONE);
  MyExample()
    super("My Example");
    this.setSize(800, 500);
    new BorderLayout();
    //enter any data into all three text areas
    for (int i = 0; i < 150; i++)
      field1.append(i+"\n");
      field2.append(i+"\n");
      field3.append(i+"\n");
   /** Any method here to make the TextAreas the maximum height (so the TextAreas
   *   are too large for the Panel and need the scrollbar!). I have tried setSize,
   *   setMinimumSize, setMaximumSize, setRows and prob more but cannot get any
   *   to work!?!
    // create panel and add the three text areas
    Panel centerPanel = new Panel(new GridLayout(1,3));
    centerPanel.add(field1);
    centerPanel.add(field2);
    centerPanel.add(field3);
    //create a scroll pane and add the panel to control
    ScrollPane scrollPane = new ScrollPane(ScrollPane.SCROLLBARS_ALWAYS);
    scrollPane.add(centerPanel);
    // add scroll pane to frame
    add("Center", scrollPane);
}Any help is appreciated!
Dave

Answer 1

Hai dave,
try the below program in which i set the panel size by calculating the textarea size. To caluculate the number of lines in the text area-field1:
1. store the value of field1 in a string
2. find the number of '\n' -end line characters
this gives the number of lines in the text area-field1
then set the height of the panel equivalent to the height of field1 by using the calculated number of lines * 15( a single line takes 15"-i am not certain but it is OK).
import java.awt.*;
public class MyExample extends Frame
TextArea field1 = new TextArea("", 0, 0, TextArea.SCROLLBARS_NONE);
TextArea field2 = new TextArea("", 0, 0, TextArea.SCROLLBARS_NONE);
TextArea field3 = new TextArea("", 0, 0, TextArea.SCROLLBARS_NONE);
public MyExample()
super("My Example");
this.setSize(800, 500);
new BorderLayout();
//enter any data into all three text areas
for (int i = 0; i < 300; i++)
field1.append(i+"\n");
field2.append(i+"\n");
field3.append(i+"\n");
/** Any method here to make the TextAreas the maximum height (so the TextAreas
* are too large for the Panel and need the scrollbar!). I have tried setSize,
* setMinimumSize, setMaximumSize, setRows and prob more but cannot get any
* to work!?!
**/int k=0;
String str=field1.getText();
/*my for loop to calculate number of lines in the string which holds value of TextArea-field1*/
for(int j=0;j<str.length();j++){
     if(str.charAt(j)=='\n')k++;
System.out.println(String.valueOf(k));
Panel centerPanel = new Panel(new GridLayout(1,3));
centerPanel.add(field1);
centerPanel.add(field2);
centerPanel.add(field3);
Dimension dim=field1.getPreferredSize();
ScrollPane scrollPane = new ScrollPane(ScrollPane.SCROLLBARS_ALWAYS);
scrollPane.add(centerPanel);
//the scroll bar of mouse can't work!(?)
centerPanel.setPreferredSize(new Dimension(780,k*15));
add("Center", scrollPane);
setVisible(true);
public static void main(String args[]){
     new MyExample();
* if you still have problem then post but expects my reply after atleast 2 days:i am busy