howdy, fitz!

how can I help you today?

hello - congrats on book revision - will read through it next week

thanks! another update being generated right now

I am again here to just learn and watch - any way to get emailed the chat files even if I miss session - just for my reference

they are posted to the [cw-android] Google Group, generally

ok cool - so now that you have had time to evaluate 2.3 - you like or so-so - see at CES they announced honeycomb already on Motorola tablet

as a user, Android 2.3 isn't that big of a deal to me at present

particularly since the SIP client doesn't work with my SIP provider

as a developer, there is interesting incremental stuff, plus lots of goodies for game developers

cart before the horse - stuff is moving fast :)

since I'm not a game developer (nor do I play one on TV), the incremental stuff is my focus

now, Android 3.0, based on the video from yesterday, is quite a departure

not quite sure how to put that into context right now

ya same here - games are not my thing

have not had time to look at 3.0 - major direction change?

tough to describe in words

ok will go look - listening to CES verizon - hope they have something to say :)

so I am just hanging to watch chats thanks

OK

howdy, David!

Happy New Year! I want to make a Web Server send data to an Android device (usually client) sometimes. How can I do that?

um

that doesn't make a lot of sense to me

Web servers are typically "pull" models, with clients initiating requests

what do you mean by "send data to an Android device sometimes"?

Whenever the server has an event, it will send the data. I know in terms of Server/Client. But is it possible to use socket?

You are welcome to use Java sockets in Android

Your problem is primarily in the server

and in the "sometimes"

and in the "send data"

Is the socket connection always on? Can the Android handle this?

The server will initiate the sending when it has an alert.

You probably want C2DM or Urban Airship, then

or SMS

rolling your own C2DM equivalent is certainly possible, but handling all scenarios will take quite a bit of time

for example, you need to be careful not to draw too much power

I will implement it too, but it has to go through Google network.

and, you need to deal with socket timeouts

and, you need to deal with network failovers from WiFi to 3G (or back to WiFi)

if you have many developer-months lying around that you don't know what to do with, feel free to give it a shot

what we could use is an open source C2DM clone, so you can host this stuff yourself

alas, I am not aware of one

I see.

C2DM uses Google servers, Urban Airship uses Urban Airship servers

How about HTTP persistent connection?

see notes above about socket timeouts and network failovers

will your advanced book next version cover more on C2DM?

Will it work for my applicaiton?

fitz: it already has a chapter on it, and I do not expect to expand upon it any time soon

David: what is "it"?

That is a good news.

ok thanks

Somepeople suggests a proxy. Will it work?

I mean a proxy on Android.

I have no idea what that suggestion might be referring to, sorry

if you elect to implement your own C2DM-like system, watch the 2010 Google I|O presentation on C2DM

they mention a number of challenges they needed to overcome, that you will need to overcome in your own implementation

Thanks.

also, bear in mind that C2DM does not require -- does not even *want* -- you to send much data

mostly, you send a "tickle" with a pointer to some place to get the real data (e.g., URL to a Web service)

hence, the C2DM message that passes through Google servers does not have to contain any data that Google could somehow use

There is little info on how to send content from App Server over C2DM.

the point is, you *don't* send "content" over C2DM, or Urban Airship for that matter

you send a short notice (handful of bytes) that your client on the device can use to go pull the "content"

e.g., a URL

I see. Thanks I make sense.

It makes sense.

Between C2DM and Urban Airship, which one do you recommend?

I have not used Urban Airship, I just know of it

it has the advantage of working on a couple of platforms, whereas C2DM is Android-only

OTOH, C2DM is free, and Urban Airship is not, IIRC

That is good to know.

On a completely unrelated note, _Android Programming Tutorials_ Version 3.1 will be released in less than an hour

tested on Android 2.3, plus better material on getting Eclipse set up

and the ever-popular errata fixes

nice - thanks for update

you can download the PDF now, unless you bought your Warescription in the past couple of weeks -- last handful of PDFs are being created now

EPUB and Kindle editions will roll out over the next several hours

running out of time -- any last questions?

nope cya

That is all for today.

Thank you.

OK, have a pleasant day!