GWT：TextField的拖放事件？(GWT: Drag&Drop Event for TextField?)

 我想知道如何监听TextField的drop事件。 我需要拦截那些事件才能进行价值检查。 
 
 我写了一个扩展的TextBox ，它触发了TextChangeEvents 。 但是当我将文本放入文本字​​段时，我没有调用onBrowserEvent(Event event)方法。 
 
 任何提示？ 
 
public class ExtendedTextBox extends TextBox {

    /**
     * Creates an empty extended text box.
     */
    public ExtendedTextBox() {
        super();

        // Catch the browser events.
        sinkEvents(Event.ONKEYUP);
        sinkEvents(Event.ONPASTE);

    }

    @Override
    public void onBrowserEvent(Event event) {
        super.onBrowserEvent(event);
        System.out.println(event.getTypeInt());

        switch (event.getTypeInt()) {
            case Event.ONKEYUP:
            case Event.ONPASTE: {
            // Fire the event after the text box shows the new data.
            Scheduler.get().scheduleDeferred(new ScheduledCommand() {

                @Override
                public void execute() {
                    fireEvent(new TextChangeEvent(ExtendedTextBox.this.getText()));
                }
            });
            break;
        }
        default:
        }
    }

    /**
     * Add a given {@link TextChangeEventHandler} to the widget.
     * 
     * @param handler
     *            the handler
     * @return {@link HandlerRegistration} used to remove the handler
     */
    public HandlerRegistration addTextChangeEventHandler(TextChangeEventHandler handler) {
        return addHandler(handler, TextChangeEvent.TYPE);
    }
}

I wonder how it is possible to listen for the drop event for a TextField. I need to intercept that events in order to do value checks. 
 
I wrote an extended TextBox, which fires TextChangeEvents. But when i drop a text into the text field, I don't get a call for the onBrowserEvent(Event event) method.
 
Any hint?
 
public class ExtendedTextBox extends TextBox {

    /**
     * Creates an empty extended text box.
     */
    public ExtendedTextBox() {
        super();

        // Catch the browser events.
        sinkEvents(Event.ONKEYUP);
        sinkEvents(Event.ONPASTE);

    }

    @Override
    public void onBrowserEvent(Event event) {
        super.onBrowserEvent(event);
        System.out.println(event.getTypeInt());

        switch (event.getTypeInt()) {
            case Event.ONKEYUP:
            case Event.ONPASTE: {
            // Fire the event after the text box shows the new data.
            Scheduler.get().scheduleDeferred(new ScheduledCommand() {

                @Override
                public void execute() {
                    fireEvent(new TextChangeEvent(ExtendedTextBox.this.getText()));
                }
            });
            break;
        }
        default:
        }
    }

    /**
     * Add a given {@link TextChangeEventHandler} to the widget.
     * 
     * @param handler
     *            the handler
     * @return {@link HandlerRegistration} used to remove the handler
     */
    public HandlerRegistration addTextChangeEventHandler(TextChangeEventHandler handler) {
        return addHandler(handler, TextChangeEvent.TYPE);
    }
}

原文：https://stackoverflow.com/questions/15553983