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Add final use cases and implementation details for AddItem().

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git-svn-id: file:///srv/svn/repos/haiku/trunk/current@1006 a95241bf-73f2-0310-859d-f6bbb57e9c96
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jrand
2002-09-10 03:30:21 +00:00
parent 6cf8d733aa
commit 9eb78d12d6
1 changed files with 57 additions and 5 deletions
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docs/develop/app/usecases/BDeskbarUseCases.html
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@@ -1,5 +1,5 @@
<HTML> <HTML>
<!-- $Id: BDeskbarUseCases.html,v 1.3 2002/09/09 04:18:20 jrand Exp $ --> <!-- $Id: BDeskbarUseCases.html,v 1.4 2002/09/10 03:30:21 jrand Exp $ -->
<HEAD> <HEAD>
<TITLE>BDeskbar Use Cases and Implementation Details</TITLE> <TITLE>BDeskbar Use Cases and Implementation Details</TITLE>
</HEAD> </HEAD>
@@ -23,7 +23,7 @@ The document has the following sections:</P>
<P>The BDeskbar class is a simple class for getting information from the deskbar and for modifying <P>The BDeskbar class is a simple class for getting information from the deskbar and for modifying
it from your application. The best source of source of information for the BDeskbar interface can be found it from your application. The best source of source of information for the BDeskbar interface can be found
<A HREF="file:///boot/beos/documentation/Be%20Book/The%20Application%20Kit/MessageQueue.html">here in the Be Book</A>. <A HREF="file:///boot/beos/documentation/Be%20Book/Deskbar/Deskbar.html">here in the Be Book</A>.
</P> </P>
<A NAME="usecases"></A><H2>BDeskbar Use Cases:</H2> <A NAME="usecases"></A><H2>BDeskbar Use Cases:</H2>
@@ -38,9 +38,23 @@ BDeskbar instance creates a connection to the deskbar in order to get and change
deskbar is closed. However any change to the deskbar's state made through the BDeskbar instance deskbar is closed. However any change to the deskbar's state made through the BDeskbar instance
persists.</P></LI> persists.</P></LI>
<LI><P><B>Add Item 1:</B> </P></LI> <LI><P><B>Add Item 1:</B> The AddItem() member function can be used to take a passed in pointer to
a BView and send it to the deskbar for inclusion in its shelf. This BView must be archivable
and must be exported by the application (for details on how to do this,
<A HREF="http://bedriven.be-in.org/articles/replicant/III_027-stepping%20up%20to%20the%20deskbar.html">this article</A>
may help). The item will be added and the id of the new item will be passed back to the caller
through a pointer to an int32.</P></LI>
<LI><P><B>Add Item 2:</B> </P></LI> <LI><P><B>Add Item 2:</B> The AddItem() member function can be used to add an item to the deskbar
shelf by passing a pointer to an entry_ref. The file pointed to by this entry_ref should be
an addon that exports the symbol "BView *instantiate_deskbar_item()". This entry point is used to
get a BView which it can display in the shelf. More information on this mechanism can be found in
the <A HREF="file:///boot/beos/documentation/Be%20Book/Release%20Notes/Deskbar.html">Deskbar Release Notes</A>
but not in the Be Book proper. The item id of the added item is passed back in an int32 pointer
provided by the caller. NOTE: The source code for the deskbar found in
<A HREF="http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/opentracker/opentracker/deskbar/StatusView.cpp?rev=1.5&content-type=text/vnd.viewcvs-markup">TReplicantTray::LoadAddon()</A>
indicates that it also looks for a symbol called "BView *instantiate_deskbar_entry(image_id, entry_ref *)"
first, but there is no documentation on this.</P></LI>
<LI><P><B>Remove Item 1:</B> The RemoveItem() member function takes an integer id and removes it <LI><P><B>Remove Item 1:</B> The RemoveItem() member function takes an integer id and removes it
from the deskbar shelf if it exists. The member returns B_OK at all times (unless the deskbar is from the deskbar shelf if it exists. The member returns B_OK at all times (unless the deskbar is
@@ -127,6 +141,44 @@ here:</P>
itself.</P> itself.</P>
<H3>AddItem:</H3>
<P>The AddItem() member sends the following message to the deskbar to add an item from an
archived BView:</P>
<PRE>
BMessage theMsg;
BMessage viewMsg;
theView.Archive(&amp;viewMsg); // This takes the target BView to place in the shelf and archives it into viewMsg
theMsg.what = 'icon'
theMsg.AddMessage("view", &amp;viewMsg); // This puts the archived view in the viewMsg and puts it in the message to the deskbar
</PRE>
<P>Or, the AddItem() member sends the following message to the deskbar to add an item from a file
that exports the "BView *instantiate_deskbar_item(void)" function:</P>
<PRE>
BMessage theMsg;
theMsg.what = 'adon'
theMsg.AddRef("addon", &amp;theAddonRef); // This is the addon which contains the hook function to get the view to add
</PRE>
<P>The /boot/app/Pulse application exports the necessary symbol for this mechanism to work and
is a good candidate to test with.</P>
<P>In either case, the deskbar responds with a message which looks like:</P>
<PRE>
BMessage theMsg;
theMsg.AddInt32("id", theID); // This is the id of the new item
</PRE>
<P>Note that in both cases, the deskbar does not set the what code of the reply. Checking the
source code for
<A href="http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/opentracker/opentracker/deskbar/BarWindow.cpp?rev=1.2&content-type=text/vnd.viewcvs-markup">TBarWindow::AddItem()</A>
confirms this.
<H3>HasItem:</H3> <H3>HasItem:</H3>
<P>The HasItem() member sends the following message to the deskbar:</P> <P>The HasItem() member sends the following message to the deskbar:</P>
@@ -175,7 +227,7 @@ theMsg.AddInt32("id", theID); // This is the id corresponding to the nam
<P>Note that the deskbar does not set the what code of the reply. Checking the source code <P>Note that the deskbar does not set the what code of the reply. Checking the source code
for for
<A href="http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/opentracker/opentracker/deskbar/BarWindow.cpp?rev=1.2&content-type=text/vnd.viewcvs-markup">TBarWindow::ItemExists()</A> <A href="http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/opentracker/opentracker/deskbar/BarWindow.cpp?rev=1.2&content-type=text/vnd.viewcvs-markup">TBarWindow::ItemInfo()</A>
confirms this.</P> confirms this.</P>