SWT StyledText - auto highlight (or autoselect)

Question

I am using SWT StyledText to populate the responses to my queries in my plugin. I learnt how to autoscroll to the bottom, but couldn't figure out the correct way to auto select the last entry. I have managed to do this in an un-optimized way, i.e updating the background of all the previous lines to white and then highlighting the latest added line, but there has to be a better way to do this.

Here is my code:

rspST.append(rsp + "\n");     ** //<--- Appending the new response to the styledText **
rspST.setTopIndex(rspST.getLineCount() - 1);     ** //<-- Scroll to bottom**

for(int i=0; i<rspST.getLineCount() - 2; i++)   ** //Setting the background of previous entries to white**
{
    rspST.setLineBackground(i, 1,rspST.getDisplay().getSystemColor(SWT.COLOR_WHITE));
}
rspST.setLineBackground(rspST.getLineCount() - 2,
    1,rspST.getDisplay().getSystemColor(SWT.COLOR_GRAY));    ** Setting the background of the last line added to gray**

Thanks!

Answer 1

This code will select the last line added by clicking the Button:

private static int lineNr = 0;

public static void main(String[] args)
{
    Display display = new Display();
    Shell shell = new Shell(display);
    shell.setLayout(new GridLayout(1, false));

    final StyledText text = new StyledText(shell, SWT.BORDER);
    text.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));

    Button button = new Button(shell, SWT.PUSH);
    button.setText("Add new line");
    button.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
    button.addListener(SWT.Selection, new Listener()
    {
        @Override
        public void handleEvent(Event arg0)
        {
            /* Get the start position of the new text */
            int start = text.getText().length();

            /* Create the new line */
            String newText = "Line: " + lineNr++ + "\n";

            /* Add it */
            text.append(newText);

            /* Determine the end of the new text */
            int end = start + newText.length();

            /* Set the selection */
            text.setSelection(start, end);
        }
    });

    shell.pack();
    shell.setSize(600, 400);
    shell.open();
    while (!shell.isDisposed())
    {
        if (!display.readAndDispatch())
            display.sleep();
    }
    display.dispose();
}

This is what it looks like: