Adam, I added
<script src="protovis.js" />
to the .gwt.xml.
No change!
On Jul 20, 4:24 pm, Adam T <[email protected]> wrote:
> Hi,
>
> It might be the case that in both cases your GWT code is loaded and
> executing before the browser has loaded your externally referenced
> JavaScript file. To remove that possiblity, you can place the
> <script> tag you have in the HTML into your module's .gwt.xml
> definition, i.e.
>
> <module>
> <inherits name='com.google.gwt.user.User' />
> <script type="text/javascript" src="protovis.js">
> </module>
>
> With this sett up, the GWT boostrap code should ensure the library
> JavaScript is loaded before your GWT code executes.
>
> //Adam
>
> On 19 Juli, 18:19, wsaleem <[email protected]> wrote:
>
> > I am not a JS developer and use it pretty much by example, so it might
> > be that I am missing something really basic below.
>
> > I have come across problems using JSNI in the following 2 scenarios:
>
> > 1.
> > I use Google Visualization API successfully in JS as follows:
> > ********************
> > HTML file
> > <script type="text/javascript" src="http://www.google.com/jsapi";></
> > script>
> > JS file
> > google.load('visualization', '1', {'packages':['piechart']}); //
> > <== future JSNI problems occur here
> > var chart = new google.visualization.LineChart
> > (document.getElementById('GoogleVisChart'));
> > // other JS commands to draw the chart
> > **********
> > and then try to write a wrapper using GWT JSNI as follows:
> > ********************
> > HTML file
> > <script type="text/javascript" src="http://www.google.com/jsapi";></
> > script>
> > JAVA file
> > class GChart {
> > static { _init(); }
> > private static native void _init() /*-{ // <=== ERROR at this
> > function
> > $wnd.google.load('visualization', '1', {'packages':
> > ['piechart']});
> > }-*/;
>
> > JavaScriptObject gvis;
> > public GChart( String id ) { gvis = _chart( id ); }
> > private native JavaScriptObject _chart( String id ) /*-{
> > return new $wnd.google.visualization.LineChart
> > ($wnd.document.getElementById( id ) );
> > }-*/;
> > // methods to draw the chart through native functions
> > **********
> > The GWT compiler gives the following error for the above code
> > ********************
> > [ERROR] Unable to load module entry point class
> > com.google.gwt.app.testGViz.client.TestGViz (see associated exception
> > for details)
> > java.lang.RuntimeException: Failed to invoke native method:
> > @com.google.gwt.app.testGViz.client.GChart::_init() with 0 arguments.
> > at com.google.gwt.dev.shell.moz.LowLevelMoz.invoke(LowLevelMoz.java:
> > 132)
> > at com.google.gwt.dev.shell.moz.ModuleSpaceMoz.doInvoke
> > (ModuleSpaceMoz.java:98)
> > at
> > com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:
> > 447)
> > at com.google.gwt.dev.shell.ModuleSpace.invokeNativeVoid
> > (ModuleSpace.java:248)
> > at com.google.gwt.dev.shell.JavaScriptHost.invokeNativeVoid
> > (JavaScriptHost.java:107)
> > at com.google.gwt.app.testGViz.client.GChart._init(GChart.java)
> > at com.google.gwt.app.testGViz.client.GChart.<clinit>(GChart.java:7)
> > at com.google.gwt.app.testGViz.client.TestGViz.onModuleLoad
> > (TestGViz.java:21)
> > at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> > at sun.reflect.NativeMethodAccessorImpl.invoke
> > (NativeMethodAccessorImpl.java:39)
> > at sun.reflect.DelegatingMethodAccessorImpl.invoke
> > (DelegatingMethodAccessorImpl.java:25)
> > at java.lang.reflect.Method.invoke(Method.java:597)
> > at com.google.gwt.dev.shell.ModuleSpace.onLoad(ModuleSpace.java:320)
> > at com.google.gwt.dev.shell.BrowserWidget.attachModuleSpace
> > (BrowserWidget.java:329)
> > at com.google.gwt.dev.shell.moz.BrowserWidgetMoz.access$100
> > (BrowserWidgetMoz.java:35)
> > at com.google.gwt.dev.shell.moz.BrowserWidgetMoz
> > $ExternalObjectImpl.gwtOnLoad(BrowserWidgetMoz.java:59)
> > at org.eclipse.swt.internal.gtk.OS._g_main_context_iteration(Native
> > Method)
> > at org.eclipse.swt.internal.gtk.OS.g_main_context_iteration(OS.java:
> > 1428)
> > at
> > org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:2840)
> > at com.google.gwt.dev.GWTShell.pumpEventLoop(GWTShell.java:720)
> > at com.google.gwt.dev.GWTShell.run(GWTShell.java:593)
> > at com.google.gwt.dev.GWTShell.main(GWTShell.java:357)
> > **********
> > Moving the statement in the native _init function to the constructor
> > does not help either. To get it to work, I have to move it out to the
> > HTML file
> > ********************
> > HTML file
> > <script type="text/javascript" src="http://www.google.com/jsapi";></
> > script>
> > <script type="text/javascript">
> > google.load('visualization', '1', {'packages':['piechart']});
> > </script>
> > **********
> > This was also suggested
> > inhttp://groups.google.com/group/Google-Web-Toolkit/browse_thread/threa...
> > Although this works, I do not understand why I could no do the
> > google.load through JSNI.
> > In the meanwhile, this is not an issue as GWT now provides its own
> > wrappers for the Google Visualization API. But, I would still like to
> > understand the error.
>
> > 2.
> > I am trying this time to write a wrapper for another Visualization
> > library, Protovis. An example JS use case is as follows:
> > ********************
> > HTML file
> > <script type="text/javascript" src="protovis.js"></script>
> > JS file
> > var vis = new pv.Panel().canvas("PVis"); // <== future JSNI
> > problems occur at this point
> > var line = vis.add(pv.Line);
> > // add data and attributes to line
> > vis.render();
> > **********
> > I write a GWT wrapper as follows
> > ********************
> > JAVA file
> > class PChart {
> > JavaScriptObject pvis;
> > public PChart( String id ) { pvis = _chart( id ); }
> > private native JavaScriptObject _chart( String id ) /*-{
> > return new $wnd.pv.Panel().canvas( id ); // <=== ERROR at
> > this line
> > } -*/;
> > // other stuff
> > **********
> > The GWT compiler returns the following error at the indicated line
> > ********************
> > com.google.gwt.core.client.JavaScriptException: (TypeError): $wnd.pv
> > has no properties
> > **********
>
> > I do not understand what I am doing wrong. Can someone help me to get
> > this to work?
>
>
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