How to scroll a scrolled composite using mouse wheels in SWT

问题

I would like to know if it is possible to scroll a ScrolledCompositeusing mouse wheels. By default it is not working.

回答1:

Apparently, it is necessary to create mouse wheel listener for your composite. You can use something like this as the basis:

    scrolledComposite = new ScrolledComposite(parent, SWT.H_SCROLL | SWT.V_SCROLL);
    GridData scrollGridData = new GridData(SWT.FILL, SWT.FILL, true, true);
    scrolledComposite.setLayoutData(scrollGridData);
    layout = new GridLayout();
    scrolledComposite.setLayout(layout);

    compositeWrapper = new Composite(scrolledComposite);
    compositeWrapper.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
    compositeWrapper.setLayout(layout);
    scrolledComposite.setExpandHorizontal(true);
    scrolledComposite.setExpandVertical(true);

    scrolledComposite.addListener(SWT.MouseWheel, new Listener() {
            public void handleEvent(Event event) {
                int wheelCount = event.count;
                wheelCount = (int) Math.ceil(wheelCount / 3.0f);
                while (wheelCount < 0) {
                    scrolledComposite.getVerticalBar().setIncrement(4);
                    wheelCount++;
                }

                while (wheelCount > 0) {
                    scrolledComposite.getVerticalBar().setIncrement(-4);
                    wheelCount--;
                }
            }
        });

回答2:

After googling around, I found a simple solution,

scrolledComposite.addListener(SWT.Activate, new Listener() {
  public void handleEvent(Event e) {
    scrolledComposite.setFocus();
  }
});

回答3:

I'm not sure why @AlexanderGavrilov is writing so much code, the following works for me as well:

scrolledComposite.addListener(SWT.MouseWheel, new Listener() {
    public void handleEvent(Event event) {
        scrolledComposite.getVerticalBar().setIncrement(e.count*3);
    }
});

来源：https://stackoverflow.com/questions/23881144/how-to-scroll-a-scrolled-composite-using-mouse-wheels-in-swt

标签

java

swt

mousewheel