Mousemove handler

gwt

Can we add a listener for mouse move events on the main document in GWT? I'm not sure how to do this and if whatever I do add will interfere with other parts of GWT (like drag and drop?). In javascript I do this:

window.onload = function() { 
  document.onmousemove = function(e) { 
      alert("the mouse was moved!"); 
  }; 
}

I'm just not sure where to start, GWT got a bit confusing for me since the new stuff was introduce in 2.0 (I used to use 1.4),

Thanks

Best Answer

I'm not sure why you'd want to monitor the movement of the mouse in the whole window, but a quick and dirty solution would be to wrap everything in a FocusPanel and add a handler via addMouseMoveHandler(MouseMoveHandler handler) (check the other interfaces that FocusPanel implements - there's quite a lot of them :)). AFAICT, this shouldn't conflict with anything else (drag&drop is not part of GWT, BTW ;)) - unless you start to mess around with the event itself (like stop propagating it) or something.

Related Solutions

Javascript – Using SVG in GWT

I don't entirely understand why, but the createElementNS JavaScript method allows you to create and correctly format xhtml within html.

Because there is no equivalent in explorer, GWT does not implement createElementNS, but you can with a quick native method :

private static native Element createElementNS(final String ns, 
        final String name)/*-{
    return document.createElementNS(ns, name);
}-*/;

It makes sense to put this into an SVGPanel class.

import com.google.gwt.user.client.Element;
import com.google.gwt.user.client.ui.ComplexPanel;

public class SVGPanel extends ComplexPanel{

    private static final String SVG_NAMESPACE = "http://www.w3.org/2000/svg";

    public SVGPanel() {
        setElement(createElementNS(SVG_NAMESPACE, "svg"));
        showcaseSVG(); //Demonstrate that SVG works! Inexplicably!
    }

    private void showcaseSVG(){
        Element svgElement = createElementNS(SVG_NAMESPACE, "circle");
        svgElement.setAttribute("cx", "50");
        svgElement.setAttribute("cy", "50");
        svgElement.setAttribute("r", "30");
        getElement().appendChild(svgElement);
    }
}

This should produce some simple SVG when added to your program. Congratulations! You are now sticking it to the xhtml man.

Making a simple overlay class

You need to give an Element to appendChild. So just make your overlay class extend Element instead of JavaScriptObject.

public class SVGPanel extends Element {

Note that Element is a subclass of JavaScriptObject.

Best Answer

Related Solutions

Javascript – Using SVG in GWT

Making a simple overlay class

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