Question

Code:

        Display display = new Display();
        RowLayout rowLayout = new RowLayout();

        Shell shell = new Shell(display);
        shell.setLayout(rowLayout);

        Text textArea = new Text(shell, SWT.MULTI | SWT.BORDER | SWT.V_SCROLL | SWT.H_SCROLL);
        textArea.setLayoutData(new RowData(200, 200));


        shell.open();
        while(!shell.isDisposed()) {
            if(display.readAndDispatch()) {
                display.sleep();
            }
        }

        display.dispose();

Problem: Typing in text is dog slow. I literally have to wait 1 – 3 seconds to let the text widget lag behind displaying my text in snail steps. Am i doing something wrong ?

Answer 1

Your readAndDispatch loop is backwards. The documentation for Display#readAndDispatch() states that it:

returns true if there is potentially more work to do, or false if the caller can sleep until another event is placed on the event queue.

Thus, your loop should actually be:

while(! shell.isDisposed())
{
    if(! display.readAndDispatch())
    {
        display.sleep();
    }
}

My understanding of sleep() was that it should be fairly efficient about waking up when there’s a new event to service, but that’s certainly not a guarantee.