iOS, network drops when device enters lock screen?

I have an iPhone 4 running iOS 7.1.1 and as soon as my iPhone enters the lock screen the network connection to the SanDisk Wireless Flash Drive is dropped and any media playback that was in progress stops. What this means is that you need to keep the screen active (on) while playing any media files which shouldn’t be necessary as it just runs down the battery on the iOS device.

Note that other network apps don’t have this problem. For example, you can enter the lock screen (turn the iPhone display off) while streaming over either WiFi or 3G/LTE when using services and apps like Pandora and Amazon Music. It seems like the SanDisk WFD app and device should be able to do the same.

Is this something that will be fixed in a future app or firmware update? Without this change the Sandisk WFD can run the battery down on iOS devices much more quickly than it should (when streaming audio or using Airplay for video).

It seems that this might be an intermittent problem, as I’ve had some success in getting the streaming/networking to continue even after the lock screen is activated. So, perhaps this is just a bug that may or may not occur depending upon some condition in either the WFD device or the iPhone.

I’ll update this thread as I learn more.

It looks like some of the intermittent success in being able to enter the locked screen has something to do with the caching that is being done on the media files. That is, you may only need to be connected for a few seconds to the WFD device in order to cache an entire music playlist (which could be 20 or 30 mintues long). Thus, once the media is cached you no longer need the network connection and the playback will continue even if the network connection is dropped.

Interestinly, this means that you can probably play many, many hours of music by just making use of this caching behavior. So, if you have a music playlist that is one hour long you probably only need to be connected to the WFD device for a minute or two after which you can enter the locked screen on the iOS device and then turn the WFD device off (saving the WFD battery). I suspect if you did this carefully you could get an order of magnitude more playback on each battery charge on the WFD. So, for music instead of only 4 hours of playback you might be able to get 40 hour of battery life out of the WFD. This won’t work, however, if you are constantly changing the playlist or trying to skip songs since as soon as you access the WFD app it will notice that the flash disk is no longer attached (and it will then stop playback).

In any case, it still seems like the network connection is being dropped when you enter the lock screen under iOS. There may be some other factors involved here, perhaps under some conditions the network remains active even when in the locked screen mode. I will continue to look at this to see if I can figure out exactly what is wrong. 

So 5 months later, we still have this problem.

When I saw the technical details of this product, I thought it was a perfect solution for me however when actually using it, the story is a bit different.

When the app is open (thus screen on), everything works fine.

But if the screen is off, the app looses the background connection and the music stops.

This is very unfortunate if you want to use your phone only as a music player with the screen off.

I don’t think this is an impossible mission to accomplish, given the fact that other music apps (Deezer, Spotify, etc) can mantain the background process alive.

what version of the app, FW, and iOS version are you running? I have the latest and have never had an issue with loosing connection when the screen is locked. I am actually listening right now and my phone is locked. 

Here is the required info:

iOS version: 8.1.1
Application version: 2.1.0 (111) 32-bit
Firmware: 3.4.1

During my online research, I’ve found this thread:

And after checking my iPhone’s settings, I cannot see any Sandisk app under Background App Refresh list so that I can enable it.

i am running exactly the same versions you are and no issues loosing connection when the screen is locked.