iOS 7 introduced a new user configuration to disable cellular data for specific apps. It can be configured in "Settings"->"Cellular" and then scrolling down.
You'll find a switch for each installed app and can see how much cellular data it has consumed.
How can I programmatically test if the switch is turned on for my app? Is there an API for that? Can I determine how much data my app has used over cellular?
I'm not asking to get the values for all apps. I'm only interested in my apps usage.
There is no API to detect your download consumption or whether cellular is active for your app.
If your app tries to connect to a website, but cellular is turned off, then iOS may ask the user to turn cellular back on. I'm not exactly sure how that works, but it is probably similar to the iOS 6 "no network connection" alert that would pop up if there is no connection but an app tries to access the internet.
You can check if the current internet connection is over WiFi or Cellular, but if Cellular is disabled you will just be told that there is no network connection.
More details here: iOS Detect 3G or WiFi
You can't check if the cellular data switch is turned on.
The closest thing is that you can check if a specific host is reachable over cellular connection using the SCNetworkReachability kSCNetworkReachabilityFlagsIsWWAN flag.
Additionally, you can enable/disable cellular data for specific connections using the NSURLRequest allowsCellularAccess property.
Reference: https://developer.apple.com/library/ios/documentation/NetworkingInternetWeb/Conceptual/NetworkingOverview/Platform-SpecificNetworkingTechnologies/Platform-SpecificNetworkingTechnologies.html
This answer suggests how data usage can be measured system-wide: iPhone Data Usage Tracking/Monitoring
Related
Is it possible to access internet (using cellular) during WiFi device configuration using Apple's "Wireless Accessory Configuration" feature?
This device would create the WiFi network and we would need to get data from the server while configurating the device.
Specifications:
Would iOS automatically use cellular to connect to the internet if there is no internet connection through WiFi? (But still keeps WiFi connection with device)
Or is it possible to programmatically switch between connections? For example: Get data from device through WiFi, send data to server through cellular, get data from server through cellular and then configurate device through WiFi.
Some other way to accomplish this?
From Apple Developers Forum:
eskimo:
"iOS keeps WWAN active even when Wi-Fi is fully functioning. That’s done because important system services, like push notifications, always run over WWAN where possible.
So, what you’re asking about is the switch of the default route. In general, iOS only switches the default route to Wi-Fi when the Wi-Fi is fully up and running. That means that WWAN should remain the default route during the WAC process."
https://forums.developer.apple.com/thread/46528
Apologizing in advance, I am no 802.11 expert and this is a long winded question...
I am working on an iOS voip client, we use the Cocoaasyncsocket library for our TCP/UDP connections. The app/iDevice is allowed to roam in/out of wifi coverage (for the purposes of this discussion we will assume the app is using wifi only... no cellular connection). We have the appropriate plist settings for backgroundmode (voip, audio) as well as requiring persistent wifi.
We are having a problem that seems particular to Cisco AP's. With the client app in the foreground and roaming out and in of wifi range, we noticed that eventually the iOS device will eventually not automatically rejoin the network. After a great deal of debug the failure to rejoin was noted to have nothing to do with the app. The failure to re-join can ultimately be reproduced by forcing the AP (via config) to deauthenticate the iDevice three times. After the 1st and 2nd deauthentications, the iDevice readily automatically re-joins. But after the 3rd time, iOS does not automatically rejoin the network.
The network will be rejoined if, for example, the iOS email app is put in the foreground.
We were curious if any other VOIP type apps suffered this problem, and ran an experiment with running FaceTime and Skype on the iOS device.
Skype behaved much like our voip app, after the 3rd deauth the connection was lost. Trying to initiate another call resulted in a message to the effect of "must have an internet connection to make a call".
FaceTime did disconnect on the 3rd deauth and failed to automatically rejoin... however, we were able to re-initiate another FaceTime call which caused iOS to rejoin the network and make the call.
We would like to emulate the FaceTime behavior, but so far do not understand what we should be doing differently. To the best of our knowledge, we are properly closing the open sockets when we get disconnected. Is anyone familiar with this issue and have some insight to offer?
If a user decides to not allow an app to access cellular data every time they try to open the app they are shown a warning telling them that cellular data is turned off.
Is there a way in the SDK to stop showing this message or control when / where it is displayed?
The system will show this message if you try to access the Internet when permission has been revoked. To prevent it from appearing, you could use Apple's Reachability code to detect network availability, and only make web calls if the network is available.
See also, this StackOverflow post.
For a GPS tracking app, recording location signals with WIFI turned on results in really imprecise data or data with gaps.
I've used the Reachability queries to detect if wifi is available prior to starting tracking. The problem is that if when that query is made the wifi is enabled but not connected to a network, it shows that the internet is not reachable via wifi, but that's not an indication of if the setting is disabled in the settings app. This means that if the user starts running and a connection is made mid-run, they'll get a location signal from the wifi instead of the GPS or cell network. Consequently the accuracy on those data points can be > 10 meters so I want to skip that point. The issue is that on wifi they'll have a large blank period where their signal wasn't recorded.
So how can I check if wifi is enabled but disconnected?
I've read all the other reachability discussions I could find but this seems to be the one gap with lots of responses incorrectly suggesting that reachability solves this out of the box.
...and I'm not going to require wifi - just alert them to the fact that it is enabled so at some point in their workout their location data might be lost (due to inaccuracy).
It's been quite a while since you asked, but I just came across this one.
It doesn't look like there is any way to do it if you want to obey Apple's rules. sysctl and ioctl won't work because there are no flags which will show you wether WiFi is enabled. For example the flags for "UP" and "RUNNING" will be the same if WiFi is disabled or WiFi is enabled but not connected.
Apple's own WiFi framework uses mach to directly communicate with the kernel and I doubt Apple would allows such code in the AppStore.
This IS possible, but the solution is obscure and ugly. The short answer is that if you see TWO interfaces with the name "awdl0" then WiFi is enabled, just one and it's disabled.
See Better way to detect WiFi enabled/disabled on iOS? for a more complete description and sample code.
G'day Guys,
I've been using the reachability API with reachability status callbacks to determine whether an application is connected over 3G or wifi. It's an application that acts as a voice extension for an existing piece of hardware and as such we're using the VoIP APIs to run in the background and accept calls etc.
Is there a definitive way other than using reachability status callbacks to determine whether you can access a particular IP endpoint or not? I could use an ASIHTTPRequest and then check if it timed out but that may cause potential problems for me in the long run.
I'm not looking for a programmatical answer but more any insights other developers would have on how to manage a roaming between the two in the background if you have a persistent connection. Basically if the device roams over to 3G I need to destroy the session on the device and if it roams back over to Wifi I need to recreate the session.
Any feedback or advice would be welcome.
The Reachability APIs will provide the connection change notifications to your app so that you can know when the connectivity changed from WWAN to wifi. It will not tell you if you've changed from Edge to 3G or LTE unfortunately. The Reachability API also has methods to test reachability to a specific host. So, in your app you can listen for the notifications that the connection method has changed, then when it does change test reachability to your target host and at that time make the decision whether to rebuild the session or leave it intact.