Saturday, March 28, 2009

Introduction to GWT for Developers

Yesterday I presented a session on GWT at ETE 2009. Both the slides and demonstration files for the GWT presentation are available for download.

8 comments:

Matt Barnes said...

A nice introduction to GWT. I'm reading through it now and am finding it very useful.

Thanks.

balaji said...

Hi Hanson,

Thank you so much for the presentation. Its very helpful for beginners. I have gone through your book too. its really fantastic.
I need a clarification, In GWT, is it possible to get the uploading file size(like 10kbs etc)

Thanks & Regards
Venkat Raman

Robert Hanson said...

Venkat,

Glad you found the presentation and book helpful.

No, you can't get the file size... at least not on the client side. What you can do is upload the file and have the server return the size to the client.

Another way would be to not use the standard HTML upload functionality. You could for instance write an applet (or Google for one), and I am not sure but Google Gears may have some functionality that could help.

In any case, the client-side is very limited unless you use some sort of plug-in.

balaji said...

Hi Hanson,

Thank you for your quick reply. I have planned to check the file size in server side. That can be done easily and quickly. In Java with the use of File method we can get the length of the file.

Anyway, I am really happy to have reply from you.

Thanks & Regards,
Venkat

balaji said...

Hi Hanson,

I have completed the work with the server side for image upload and everything goes pretty well with GWT. I have created a chat application as per the guide from your book, It works fine without any problem.

I need a help from you for the chat application. The pop-up chat window appears at the bottom of the screen and if you scroll upwards or downwards its fixed at the same place and its hiding other contents, I need to have chat interface like what he have in gmail. is it possible to do it.

Please help.

Regards,
Venkat

balaji said...

Hi Hanson,

Is it possible to create chat windows behaviors as in Google chat, i have created a chat application as in the book but it stick on to one position and its while scrolling up and downwards..

Please help.

Venkat

Robert Hanson said...

I did a quick Google search on how to detect scrolling with JS and came up with this tutorial.

http://codepunk.hardwar.org.uk/ajs02.htm

It seems that there is no way to listen for this event, so you just need to continually poll.

When the tutorial mentions "polling", "setInterval", or "clearInterval", replace that with the GWT Timer class.

http://google-web-toolkit.googlecode.com/svn/javadoc/1.5/com/google/gwt/user/client/Timer.html

When the tutorial discusses "document.body.scrollTop", "window.pageYOffset", and others, replace that with the methods from the GWT Window class (e.g. Window.getScrollTop()).

http://google-web-toolkit.googlecode.com/svn/javadoc/1.5/com/google/gwt/user/client/Window.html

balaji said...

Hey Hanson,

I missed your reply to my previous question. yes I tried those but its not working fine. So I have created a button to minimize and maximize restored the window accordingly.

Thank you so much for the reply.

Regards,
Venkat