Disable MouseWheel in a SWT composite

问题

I created a composite using the following constructor:

Composite scrolledComposite =
    new Composite(parent, SWT.V_SCROLL | SWT.H_SCROLL);

Each time I use the mouse wheel, the vertical scroll value is changed.

I know that is the default behavior, but I need to disable it. I tried to removeMouseWheelListener from the composite, but it seems that this is a native call. This is the stacktrace that could help to understand my problem.

回答1:

You can add a Filter to the Display that listens for SWT.MouseWheel events. Here is an example for Text, but it works identically for Composite:

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

    // This text is not scrollable
    final Text text = new Text(shell, SWT.MULTI | SWT.BORDER | SWT.WRAP | SWT.V_SCROLL);
    text.setLayoutData(new GridData(GridData.FILL_BOTH));

    text.setText("a\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\n");

    // This is the filter that prevents it
    display.addFilter(SWT.MouseWheel, new Listener()
    {
        @Override
        public void handleEvent(Event e)
        {
            // Check if it's the correct widget
            if(e.widget.equals(text))
                e.doit = false;
            else
                System.out.println(e.widget);
        }
    });

    // This text is scrollable
    final Text otherText = new Text(shell, SWT.MULTI | SWT.BORDER | SWT.WRAP | SWT.V_SCROLL);
    otherText.setLayoutData(new GridData(GridData.FILL_BOTH));

    otherText.setText("a\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\n");

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

This will prevent scrolling in the first Text, but it will work in the second one.

---

Note that you have to click inside the text before trying to scroll, because otherwise it would not be the focus control.

来源：https://stackoverflow.com/questions/18613729/disable-mousewheel-in-a-swt-composite