Sunday, March 1, 2009

GWT - Javascript to GWT calls

JavaScipt and GWT interoperation are base on JSNI (JavaScript Native Interface)




Note: A JSNI comment block begins with the exact token /*-{ and ends with the exact token }-*/.


Here is an example of JSNI in GWT



public static native void alert(String msg) /*-{

$wnd.alert(msg);

}-*/;

Tips: When accessing the browser's window and document objects from JSNI, you must reference them as $wnd and $doc, respectively.


JSNI's param-signature follows Java data type declaration


For example myMethod(IFLjava/lang/String;)(); refers to this methoda has 3 parameters of Integer, Float and String


Consider the following which generate a HTML code, register a JS method and provide a call back



Add genHtml() to a Panel. Ie, panel.setHtml(genHtml()); If you onClick to the link, it will call onLinkClicked. This way, you can interact with your GWT application



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