SWT文字侦听器

Question

I have a Text in SWT:

final Text textArea = new Text(parent, SWT.MULTI | SWT.WRAP | SWT.V_SCROLL);
textArea.setVisible(false);
textArea.setEditable(false);
textArea.setEnabled(false);
textArea.setText("Scheduler Info");

I have a listener. Once the listener is fired, I would like some data to overwrite again and again in the text area. Is there anyway I can retain the "Scheduler Info" Header in the text area. I do not want the first line to be overwritten. I want the rest of the area to be overwritten.

Answer 1

There are two ways you can do this:

1. Just use Text#setText(String) with your new String and prepend the original string.
2. Select everything after the original string and Text#insert(String) your new stuff.

Here is an example with both methods:

private static final String INITIAL_TEXT = "Scheduler Info";

public static void main(String[] args)
{
    final Display display = new Display();
    final Shell shell = new Shell(display);
    shell.setText("StackOverflow");
    shell.setLayout(new FillLayout());

    final Text text = new Text(shell, SWT.MULTI | SWT.WRAP | SWT.V_SCROLL);
    text.setEditable(false);
    text.setEnabled(false);
    text.setText(INITIAL_TEXT);

    Button replace = new Button(shell, SWT.PUSH);
    replace.setText("Replace");
    replace.addListener(SWT.Selection, new Listener()
    {
        private int counter = 1;
        @Override
        public void handleEvent(Event arg0)
        {
            String replace = INITIAL_TEXT;

            for(int i = 0; i < counter; i++)
                replace += "\nLine " + i;

            text.setText(replace);

            counter++;
        }
    });

    Button insert = new Button(shell, SWT.PUSH);
    insert.setText("Insert");
    insert.addListener(SWT.Selection, new Listener()
    {
        private int counter = 1;
        @Override
        public void handleEvent(Event arg0)
        {
            text.setSelection(INITIAL_TEXT.length(), text.getText().length());

            String newText = "";

            for(int i = 0; i < counter; i++)
                newText += "\nLine " + i;

            text.insert(newText);

            counter++;
        }
    });

    shell.pack();
    shell.setSize(shell.computeSize(SWT.DEFAULT, SWT.DEFAULT).x, 300);
    shell.open();

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