Help to make nsIWebProgressListener work

steve lu Thu, 21 Oct 2004 08:24:52 -0700

Hi,

I have read all the previous threads on nsIWebProgressListener.

I have included the Interface of nsISupportsWeakReference, nsIObserver, and nsIWebProgressListener.

I have put AddProgressListener into the Observe() routine upon "xpcom-startup".

still, the xpcom object crashes inside of AddProgressListener() with error msg saying "pure virtual function".

My code set up is as follows:

(1) Gecko SDK 1.7.3 with xpcomglue.lib and xpcom.lib linked in

(2) Test with Mozilla 1.7.3 and Firfox 0.9x

----------------------------------------------------------------------------------------------------------

Here is what is inside of my observe() code:

if (strcmp(aTopic, "xpcom-startup") == 0)
{
  nsCOMPtr<nsIServiceManager> servMan;
  nsresult rv = NS_GetServiceManager(getter_AddRefs(servMan));
  if (NS_FAILED(rv))
   return NS_OK;

  nsCOMPtr<nsIWebProgress> progress;
  rv = servMan->GetServiceByContractID( "@mozilla.org/docloaderservice;1",
         NS_GET_IID(nsIWebProgress),
         getter_AddRefs(progress));

  if (NS_SUCCEEDED(rv))
  {
   if (progress)
    progress->AddProgressListener(NS_STATIC_CAST(nsIWebProgressListener*,this),
         nsIWebProgress::NOTIFY_STATE_DOCUMENT);
  }
}

----------------------------------------------------------------------------------------------------------

I have provided the impl for 4 interfaces

NS_IMPL_ISUPPORTS4(MyComponent,
       IMyComponent,
       nsIWebProgressListener,
                   nsIObserver,
                   nsISupportsWeakReference)

----------------------------------------------------------------------------------------------------------

Here is the MyComponentRegistration code:

nsresult rv;
nsCOMPtr<nsIServiceManager> servman = do_QueryInterface((nsISupports*)aCompMgr, &rv);

if (NS_FAILED(rv))
return rv;

nsCOMPtr<nsICategoryManager> catman;
rv = servman->GetServiceByContractID( NS_CATEGORYMANAGER_CONTRACTID,
NS_GET_IID(nsICategoryManager),
getter_AddRefs(catman));

if (NS_FAILED(rv))
return rv;

char *previous = nsnull;
rv = catman->AddCategoryEntry("xpcom-startup",
       MY_COMPONENT_CLASSNAME,
       MY_COMPONENT_CONTRACTID,
       PR_TRUE,
       PR_TRUE,
       &previous);

if (NS_FAILED(rv))
return rv;

if (previous)
nsMemory::Free(previous);

return rv;

----------------------------------------------------------------------------------------------------------

Any help is appreciated

Thanks,

Steve Lu

Help to make nsIWebProgressListener work

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