Hmm, after searching I'll bet it has something to do with the iframe that GWT embeds. According to w3schools, "the browser creates one window object for the HTML document, and one additional window object for each frame." Weirdly, an Array object in one window isn't the same as one in another: http://groups.google.com/group/google-web-toolkit/browse_thread/thread/9d82fa9a8d87832/4d9d9f703be6ee45?lnk=gst&q=jsni+array#4d9d9f703be6ee45
The Flex library probably tests the array somewhere when deserializing it. I'd be very interested to hear how you worked around the problem, Alain. On May 24, 1:27 pm, Alain Ekambi <[email protected]> wrote: > I did had the same problem while working on gwt4air Flex API. > Let me see if i can find the solution > > Best, > > Alain > > 2011/5/24 Debug Desperado <[email protected]> > > > > > I'm trying to wrap a javascript library (Cytoscape Web: > >http://cytoscapeweb.cytoscape.org/documentation) that exposes methods > > for interacting with a Flash object built with Flex. The library is > > designed very well, consisting of a single javascript Visualisation > > object and several member functions. These functions usually take > > JSON-like objects as arguments, and I'm encountering an error when I > > construct the object within a JSNI method. The Flash player error is > > "Error #1034: Type Coercion failed: cannot convert Object@3cf6821 to > > Array." > > > Here is my class that extends JavaScriptObject and wraps the library's > > Visualisation object: > > > public class Visualization extends JavaScriptObject{ > > protected Visualization(){} > > > public static final native Visualization create()/*-{ > > var div_id = "cytoscapeweb"; > > > var options = { > > // where you have the Cytoscape Web SWF > > swfPath: "swf/CytoscapeWeb", > > // where you have the Flash installer SWF > > flashInstallerPath: "swf/playerProductInstall" > > }; > > > var vis = new $wnd.org.cytoscapeweb.Visualization(div_id, > > options); > > return vis; > > }-*/; > > > /* BROKEN: Causes the Flash error #1034 */ > > public final native void draw()/*-{ > > > var network_json = { > > data: { > > nodes: [ { id: "1" }, { id: "2" } ], > > edges: [ { id: "2to1", target: "1", source: "2" } ] > > } > > }; > > > this.draw({network: network_json}); > > }-*/; > > } > > > Whenever I call the draw function using a javascript object as an > > argument, I get the error #1034 type conversion problem. However, the > > library has an alternate method for encoding a graph using an XML > > string, and passing the string literal works! > > > /* Passing a string literal works fine. No error with this method > > */ > > public final native void draw()/*-{ > > var xml = '\ > > <graphml>\ > > <key id="label" for="all" attr.name="label" > > attr.type="string"/>\ > > <key id="weight" for="node" attr.name="weight" > > attr.type="double"/>\ > > <graph edgedefault="directed">\ > > <node id="1">\ > > <data key="label">A</data>\ > > <data key="weight">2.0</data>\ > > </node>\ > > <node id="2">\ > > <data key="label">B</data>\ > > <data key="weight">1.5</data>\ > > </node>\ > > <node id="3">\ > > <data key="label">C</data>\ > > <data key="weight">1.0</data>\ > > </node>\ > > <edge source="1" target="2">\ > > <data key="label">A to B</data>\ > > </edge>\ > > <edge source="1" target="3">\ > > <data key="label">A to C</data>\ > > </edge>\ > > </graph>\ > > </graphml>\ > > '; > > > this.draw({network: xml}); > > }-*/; > > > Furthermore, I tried hard-coding the javascript object in the <head> > > section of the HTML file, and it ends up working just fine, too > > (referenced with the $wnd variable)! > > > public final native void draw()/*-{ > > this.draw({network: $wnd.network_json}); > > }-*/; > > > Note, however, that if I redefine the $wnd.network_json variable > > within the JSNI method, the same error rears its ugly head. > > > In summary, the flash object seems to not agree with me passing it an > > object that I create through a JSNI method. Whenever the object is > > hard-coded into the HTML page, there are no errors; copy-pasting the > > exact same object into a JSNI method results in an odd error about > > converting the object into Array. I've traced through the code with > > FireBug, and the object referenced seems fine to me. I don't really > > have any way to debug the Flex application, so I'm at a loss to see > > what it's complaining about. To me it just seems peculiar that it > > only fails when created through a JSNI method. Any help with this > > brain-teaser would be kindly appreciated! > > > -- > > You received this message because you are subscribed to the Google Groups > > "Google Web Toolkit" group. > > To post to this group, send email to [email protected]. > > To unsubscribe from this group, send email to > > [email protected]. > > For more options, visit this group at > >http://groups.google.com/group/google-web-toolkit?hl=en. > > -- > > GWT API for non Java based > platformshttp://code.google.com/p/gwt4air/http://www.gwt4air.appspot.com/ -- You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-web-toolkit?hl=en.
