If you sniff the wire just past the wifi access point, how many
requests/responses do you see during this time?
On Mon, Nov 24, 2008 at 2:59 PM, joshv <[EMAIL PROTECTED]> wrote:
>
> My issues is that I am sitting 3 feet from a stable wi-fi access point
> and for minutes on end every single URLConnection attempt will fail.
> I could certainly understand if maybe the first attempt failed, or
> took longer, because I was waiting for the radio to turn on, but 100%
> failure for minutes on end is just weird. There is no good reason for
> it. It should be considered a bug. And even when it does work, it's
> still not 100%, the failure rate is still very high.
>
> This makes for a really crappy application experience, as I simply
> cannot predict when my user will see their data update. I feel like
> there are reliable ways of communicating, as even when my application
> is experiencing errors, I get emails and IMs on the phone, and I can
> browse the internet - so somehow the google apps are able to
> communicate. That's why I am asking if I am doing something wrong or
> if there is some other API I should try. I can try out the Apache
> HTTPComponents, but I am assuming they just wrap the lower level java
> network APIs. I am not sure what benefit I would get.
>
> On Nov 24, 1:44 pm, "Tom Gibara" <[EMAIL PROTECTED]> wrote:
>> I don't know if this is related to what you're experiencing, but it's my
>> understanding that the wifi connections shuts down when the phone sleeps. I
>> believe this is because, unlike the radio, it requires the CPU to be active
>> to maintain the connection.
>> Also, contrary to your view, I think it's not intrinsically a hardware or
>> software problem. It's simply that in the context of mobile phone software,
>> the probability of a connection failure is greater than that you may be used
>> to, and due to the necessary limitations in powering the device, simple
>> solutions (like constantly striving to maintain a wifi connection) aren't an
>> option.
>>
>> Perhaps a better perspective is to see the various data connections (wifi,
>> GPRS, EDGE, 3G etc.) as fallible primitives which you can combine to form a
>> more reliable transport suited to your application's needs.
>>
>> Tom.
>>
>> 2008/11/24 joshv <[EMAIL PROTECTED]>
>>
>>
>>
>> > As I pointed out in my previous post, the polling occurs only when the
>> > application is active and on screen. It starts/stops in onResume/
>> > onPause - so I am not sure how this is going to limit battery life
>> > unless the user forces the application to remain active for hours at a
>> > time.
>>
>> > Could you please explain to me why, with a solid wi-fi signal and
>> > connection to a local access point, my URLConnections would ever throw
>> > an exception unless there is a problem with the remote website? Are
>> > the implementations of these APIs that brittle? Is the hardware
>> > really that flaky?
>>
>> > Are there other APIs that bang on the hardware until it works, without
>> > throwing exceptions? Am I doing something wrong? Or is this level of
>> > unreliability, even over local wi-fi, to be expected?
>>
>> > On Nov 24, 10:58 am, Jean-Baptiste Queru <[EMAIL PROTECTED]> wrote:
>> > > Even with a 10-second pause between the end of a response and the next
>> > > request, you're likely to keep the radio (either cell or wifi) turned
>> > > on all the time, since they tend to stay up for about that long even
>> > > when there's no activity before powering back down. That could limit
>> > > the phone's battery life to as little as 3 or 4 hours (with the screen
>> > > constantly off and the CPU idle most of the time).
>>
>> > > The APIs that you're using are built on top of a foundation that was
>> > > designed for environments where the conditions that trigger exceptions
>> > > were indeed more exceptional than what you're seeing on a device
>> > > indeed. Such is the cost of making Android compatible with APIs that
>> > > developers are likely to be familiar with.
>>
>> > > JBQ
>>
>> > > On Mon, Nov 24, 2008 at 8:51 AM, joshv <[EMAIL PROTECTED]> wrote:
>>
>> > > > The polling happens only while the apps is loaded and displayed on
>> > > > screen. The second the screen turns off or another app is loaded, the
>> > > > polling stops. It's pretty well behaved in that respect. Also, I
>> > > > don't hammer the connection 6 times a minute no matter what - each
>> > > > thread waits for the previous to finish, waits ten seconds, and then
>> > > > attempts to connect.
>>
>> > > > My issue is that URLConnections seem to be so unreliable that
>> > > > Exceptions seem to be the rule, not the exception. This might be
>> > > > something unique to my handset, I only have one, so I can't tell. It
>> > > > certainly doesn't happen in the emulator. I might expect it to happen
>> > > > if I have a marginal 3G or edge connection - but not when the handset
>> > > > is literally 3 feet away from the WiFi access point it's using for a
>> > > > connection.
>>
>> > > > On Nov 24, 10:00 am, "Andrew Stadler" <[EMAIL PROTECTED]> wrote:
>> > > >> If your code is going to access a site every 10 seconds, the radio is
>> > > >> going to, essentially, stay "on" continuously. This is going to have
>> > > >> a significant impact on your users' battery life. Is this definitely
>> > > >> what you want to do?
>>
>> > > >> On Mon, Nov 24, 2008 at 5:17 AM, joshv <[EMAIL PROTECTED]> wrote:
>>
>> > > >> > I am attempting to write an application that regularly polls data
>> > from
>> > > >> > a publicly available website using a URLConnection. The code is
>> > > >> > pretty basic (urlStr contains the URL...)
>>
>> > > >> > URL url = new URL(urlStr);
>> > > >> > URLConnection urlConn = url.openConnection();
>> > > >> > urlConn.setConnectTimeout(5000);
>> > > >> > BufferedReader in = new BufferedReader(new
>> > InputStreamReader
>> > > >> > (urlConn.getInputStream()));
>> > > >> > String line;
>> > > >> > while ((line = in.readLine())!=null) { ....
>>
>> > > >> > Anyway, even when the G1 is connected to the network (verified in
>> > > >> > browser) this block of code will regularly throw
>> > > >> > java.net.SocketException: No route to host,
>> > > >> > java.net.SocketTimeoutException: Socket is not connected (though
>> > this
>> > > >> > is probably because I added a timeout), and many times throw an
>> > > >> > Exception claiming that it could not resolve the hostname in urlStr
>> > -
>> > > >> > oddly the web browser has no such issues resolving the name.
>>
>> > > >> > The above block of code runs every 10 seconds (or longer if the
>> > > >> > previous request takes longer), and I'd guess succeeds approximately
>> > > >> > 25-50% of the time, though it tends to be a bit streaky. When the
>> > > >> > connection succeeds, it take less than a second to connect and
>> > > >> > download the data, it's a very small data set - so the timeout
>> > setting
>> > > >> > should not be an issue.
>>
>> > > >> > The periods of error do not correspond to a loss of connectivity, as
>> > I
>> > > >> > can browser the web at the same time the errors are happening. This
>> > > >> > happens whether connected to local wi-fi or 3G.
>>
>> > > >> > Am I doing something wrong, or is network connectivity on the G1
>> > just
>> > > >> > this flaky?
> >
>
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google
Groups "Android Developers" group.
To post to this group, send email to [email protected]
To unsubscribe from this group, send email to
[EMAIL PROTECTED]
For more options, visit this group at
http://groups.google.com/group/android-developers?hl=en
-~----------~----~----~----~------~----~------~--~---
