Question

How can I create a widget from the Javascript. For example I need to create a simple button or table . I have some thirdaparty
javascripts which draw tables. Now if I want to create GWT widget by using those javascript what should I do first?
How other frameworks like GWTExt,SmartGWT, are using custom Widgets? Are they starting from the scratch or They reuse the
GWT widget functionality? Like if I want to create one table in my own style, do I need to inherit GWT Table?can anybody
give one example or sample code how to create a widget from the javascript? If my questions are wrong please excuse me.

example:

Mytable table = new Mytable(2,3). then it should draw my own table with 2 columns and 3 rows

Answer 1

You are asking a lot of questions here. In your case you should create as much questions in so as you have qustion marks in your original post.

Regarding your first question, look at JSNI.

Edit: So okrasz gave you a number of references to look at. From my side I’ll try to help with your example using JSNI (because you were asking about binding your existing js to GWT).

Let’s say you have your MyTable defined as

<script type="text/javascript">
    MyTable = function(a,b){
        this.a = a;
        this.b = b;
    };
</script>

and your js file is called mytable.js

Now, we need this to be a component. In your .java file in GWT library project create a class like this:

public class MyTable extends JavaScriptObject {
    protected MyTable(){}
    public static native MyTable create(double a, double b) /*-{
        return new MyTable(a,b);
    }-*/;
    public final native double getA() /*-{
        return this.a;
    }-*/;

    public final native double getB() /*-{
        return this.b;
    }-*/;
}

Add your original js file to the resources and add a script node to your gwt.xml module like this:

<module>
  <inherits name="com.google.gwt.core.Core"/>
  <script src="path/to/mytable.js"/>
  <source path="client"/>
  <public path="public"/>
</module>

That’s pretty much it. I might forgot something but you can reference any oss project that does the same thing you need. For instance, take a look at swfupload-gwt project source code.