I am currently working on a GWT project and it now needs to used by an external JavaScript file. I am creating a test prototype right now to ensure both sides are working properly.
When I run and compile, I see the console logs in the browser from the events being called. However, the GWT java methods are not being called.
After trying many scenarios, I also noticed that if I remove the $entry wrapper from the exportStaticMethods(), the opposite occurs. I see the System.outs being called in my java code, however the console logs from the JavaScript in the browser are not being called.
I am trying to figure what is causing the behavior and if there is a small missing piece I overlooked.
I have already reviewed the GWT JSNI documentation for calling a Java method from js and tried to find a solution from other related questions on StackOverflow.
GWT and Java side
I have gone into the onModuleLoad() method of my EntryPoint class and added a static method called exportStaticMethods(). I also created the PokePingClass.java file listed below.
EntryPointClass.java
public class EntryPointClass implements EntryPoint {
@Override public void onModuleLoad() {
exportStaticMethods();
// load application here.
}
public static native void exportStaticMethods() /*-{
$wnd.pingApp = $entry((function) {
@com.application.PokePingClass::pingApp()();
});
$wnd.pokeApp = $entry((function) {
@com.application.PokePingClass::pokeApp()();
});
}-*/
}
PokePingClass.java
public class PokePingClass {
public static void pokeApp() {
System.out.println("pokeApp() called");
}
public static void pingApp() {
System.out.println("pingApp() called");
}
}
HTML and js
In the .html file of the project, I added a hidden div element of id 'pokePing', as well as the pokeping.js file.
<html>
<head>
.
. <!-- other stuff -->
.
<script type='text/javascript' src='pokeping.js</script>
</head>
<body>
.
. <!-- other stuff -->
.
<div id="pokePing" style="visibility: hidden;"></div>
</body>
</html>
pokeping.js
$(document).ready(function) {
var $pp = $('#pokePing');
var pokeApp = function() {
console.log("app handling poke event");
window.parent.pokeApp();
}
var pingApp = function() {
console.log("app handling ping event");
window.parent.pingApp();
}
$pp.trigger('pokeApp');
$pp.trigger('pingApp');
}
I found a similar post but the key was to actually return the method calls in the JSNI functions. After that, all works well.