(keitai-l) Re: Moving work to the docomo event Thread

Hi Trent,

I'm fairly certain there's nothing like the invokeLater() in the doja API.  I
guess you've tried some kind of non-threadsafe method?  You say you can't
safely update the UI from the HTTP thread.  What's happening?  blocking?  I'm
no thread guru, so I really don't know.  How about passing your HTTP thread a
reference to the UI button, so that it can call the setText() directly?  or
maybe vice-versa, so the button can kill the HTTP thread.

Hope I didn't confuse you anymore.  Let me know what you come up with, as I may
need it myself someday.  Good luck!

--jason


--- Trent Hill <Trent.Hill@bullant.com.au> wrote:
> Hi Jason,
> 
> > What exactly are you trying to do?
> 
> It's quite simple really - my application has created a thread. Some time 
> later, this thread needs to update the user interface eg. to change the text
> 
> on a label. Now, as far as I know the nttdocomo.ui library is not thread
> safe 
> ie. it is only safe to call Label.setText from the event handling thread. So
> 
> I somehow need to execute the necessary code on the ui thread.
> 
> If I were using C/Win32 I'd use PostMessage(...)
> If I were using Java/Swing I'd use SwingUtilities.invokeLater(...)
> If I were using Java/Midp I'd use Display.callSerially(...)
> 
> I can find anything like this in the com.nttdocomo.ui library.
> 
> > Can you give a pseudo-code example?
> 
> Of course.. this is not my real application but here's a similar example:
> 
> Imagine you had a ui with a button and a label. When the user clicks the
> button, a stock quote is downloaded from an HTTP server and displayed on
> the label.
> 
> Now, the HTTP download is blocking and I do not want to block the main event
> 
> handling thread while the download is occurring eg. I may want a cancel 
> button to be available during the download attempt. Therefore, I must create
> 
> a second thread to handle the HTTP download. When the download succeeds, I 
> need to update the label from the event handling thread to be thread safe.
> 
> So, in pseudo code:
> 
>   // Event handling thread:
>   method handleEvent(event, arg)
>   {
>     if (event == buttonClick)
>     {
>       // create new thread to download quote
>       new Thread(downloadQuote)
>     }
>     else if (event == dataReceived)
>     {
>       // display the new quote
>       myLabel.setText(arg)
>     }
>   }
> 
> 
>   // Network thread:
>   method downloadQuote
>   {
>     openHttpConnection(myUrl)
>     quote = downloadData() // <- long blocking operation
>     closeHttpConnection()
> 
>     // somehow notify event handling thread since I cannot safely update
>     // the ui from this thread
>     sendMessage(handleEvent, dataReceived, quote) // *** <- how to do this??
>   }
> 
> I hope this makes some sense to you. Any assistance would be appreciated.
> 
> Thanks, Trent.
> 
> --
> Trent Hill
> Software Engineer
> Gravana Pty Ltd (trading as Bullant Software)
> 
> 
> 
> 
> This mail was sent to address jasonpollard@yahoo.com
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