Develop Reference

Android message “Allow <app name> to access <device-name>? (responded OK) continually repeating while app is in use over USB

We have an ultrasound scanner that connects to our app on Android devices via USB or a built-in WiFi mini-router.
When connected over USB, one of our customers randomly gets the message “Allow to access ? [set to OK). Also, an option to “Always open when is connected?” (shouldn’t be related, but tried both on and off). Brand new Samsung Galaxy Android S8 Ultra Tablet.
Unable to duplicate in our offices, even when using the same model ultrasound and same model tablet. As expected, the message only appears on a new Android or after a factory reset. It also runs fine at numerous other customer locations.
Tried (1) Android setting “Allow Notifications” off and on, (2) “Notification Categories” indicates “This app hasn’t sent you any notifications.” (3) WiFi and Bluetooth both off and on, (5) both Android and the app are current, (4) neither Samsung nor Google has had any other suggestions,
Not sure if/how this might factor in. When connecting via the built-in WiFi, any Android or iOS device quickly drops the signal while inside the building, but runs fine in the parking lot or elsewhere. Unfortunately, too many other companies in the building to start shutting off routers, and where this occurred at other locations, changing the WiFi channel in the app, turning off other routers, or resorting to the USB cable always solved it.
Any suggestions much appreciated. Thanks, David

Android ADB not detecting device

There's absolutely heaps of these questions out there, all with a seemingly random assembly of answers that don't really talk about why, and don't offer anything that at least covers ALL of the reasonable approaches.
I'm running ADB on OSX, but I've got other team members using Linux (Ubuntu) and I occasionally use Windows. OS doesn't really seem to matter, so long as the relevant USB driver has been installed on Windows.
I've got a heap of different makes and models of phone that I'm swapping in and out. Sometimes a phone that previously worked stops being recognised by adb devices. So not really specific to a particular phone.
I've got a USB cable that I know works, for several makes/models of phone.
But still, when I get a new phone to try I still have to faff around with it to get it working.
What I'm after is a checklist of sorts, that results in a reasonable chance of success in getting adb devices to work.

So here's what I've found:
Hardware:
Good USB cable - if it works for one phone it will probably
work for others. If it consistently stops working, throw it away and
get another.
Phone/Tablet/Device - Pre-requisites:
Make sure the phone is charged up - at least 30% seems to be a common
minimum.
Get all system updates and app updates done.
Enable Developer Mode. Settings->About phone->Build number - tap 7 times
Computer - the 'turn it off and on again' approach:
This is useful to know, but doesn't generally get things working. It goes like this:
adb kill-server
adb start-server
adb devices
If you don't see your device after adb devices then the above isn't the answer (but it's still good to know).
Phone/Tablet/Device - the 'wipe it and start again' approach:
This is basically clear your current settings and then re-establish them.
In Developer options, under Debugging:
Turn OFF USB debugging (some phones won't let you click this option - thanks LG)
Click/Tap Revoke USB debugging authorizations
Turn ON USB debugging, answer OK to the first dialog
And if you device is already plugged in:
WAIT, for a second prompt asking if you want 'Allow USB debugging' and click 'OK' - not every device will trigger this second prompt straight away, but give it 5 to 10 seconds just in case.
Now, get permission for EVERY use of the USB connection.
Swipe down from the top and tap on the item for USB connection.
Systematically work through every option your device provides and grant permission when asked. Don't do just one option, do ALL of them, including Charge phone.
Having given permission for one of the usages of the USB connection some devices will give permission for everything - but most won't. For the majority you should go through each one and give the permission. Just to add to the confusion some devices will require you to revisit an option a second time before they give you the prompt asking for permission (thanks again LG).
Now try adb devices again. Still nothing? Go back through the USB usage options again from start to finish (I kid you not).
You may still need to reboot the device and/or swap between media transfer and photo transfer to get it showing up on adb devices.
So what if a previously working device stops working? Go through the 'wipe it and start again' approach first. It's likely to be the most effective. but I'd definitely check whether its time to retire the USB cable as well.

Google Glass are bricked - receiving "Home/Camera/Voice stopped unexpectedly" errors

Our research lab has several pair of Google Glass that we've been using in our research. Recently, one pair (that had been sitting in storage) stopped working - we booted them up about a month ago (they hadn't been used since April 2014) and during the boot sequence, we received several "stopped unexpectedly" errors (for Home, Camera, and Voice functions).
We spoke with Google twice on the issue, and they told us:
(1) The Glass likely lost a connection during a software update, so to do a factory reset we'd need the original device that the Glass were tethered to to initiate a factory reset. Sadly, we no longer have this device, so we cannot initiate a factory reset.
(2) The Glass are out of warranty, so they will not offer any further customer service, other than to direct us to StackOverflow. (stings a bit, to be honest)
So, my question ... there has to be a way to manually reset the Glass via USB? Any help or advice from this community would be incredibly helpful!

You can do factory reset in Google Glass by doing this:
Tap the touchpad to activate Glass.
From the Home screen, swipe backward on the touchpad until you see the Settings bundle.
Tap into the Setting bundle and swipe forward until you see the Device Info card.
Tap again and swipe forward until you see Factory Reset.
Another method can be done using Recovery Mode.
To access Recovery Mode, turn off Glass. Hold the camera button, then press the power button once. Continue to hold the camera button for about 10 seconds, and Glass will go into Recovery Mode.
In Recovery Mode, you have the option to:
Reboot normally
Reboot into fast boot (This is mainly used by developers)
Factory reset (Removes your account, pictures, videos, and Glass settings from this device. If your Glass is having issues, this will give you a fresh start. Warning: If your pictures and videos haven’t been synced to Auto Backup, they will be erased. If you want to keep them, connect Glass to your computer using the USB cable and manually transfer the files.)
Sideline from adb (Also for developers)
Check also this thread for more information.

I had a similar issue with 2 pairs I have. I contacted Google support on this and they told me to power them on and leave them close to the last known WiFi access point they were connected to.
This has worked for 1 pair. The other pair still has the same issues. I'll update if I find anything that worked.
Good luck

I have a similar problem. Unfortunately, same boat ... device is out of warranty and turning the device on and update itself using the original Wifi or the paired phone is non-existent. Also seeking any way to refresh the "image" of the OS/program on the device via USB.

Resetting all saved WiFi connections on Android with CM12

I have a rooted Samsung Galaxy S4 with CyanogenMod 12.0 on it.
I had a lot of Wifi connections, about 100, which I restored with Titanium Backup, when I installed CM12.
Then I had the effect, that when entering the area of a known Wifi, the phone didn't connect to this Wifi. Only when I disabled mobile data, the phone connected to the Wifi, after this I could reenable the mobile data and the wifi-connection would now stay connected.
So I deleted in the wifi-manager's list all of them and added the important ones one by one, but the problem persists.
Now I think maybe if I reset the Wifi completely and restore a few connections manually it could work again, but I don't know how to reset Wifi.
It is not done by deleting all Wifi-networks in the manager's list, this didn't help.
How can I reset all Wifi settings to factory default, without resetting the phone to factory, which I absolutely don't want to do?
As I have root, there must be some files or database which I had to delete, but which?
In the settings app list (all apps) I don't find the Wifi-Manager app.
Which app and where is it?
Thank.s
frank

Debugging my android for an issue with wifi

I am new to Android SDK. Maybe someone here can show me how to debug the following problem I have with my Android enabling and keeping the wifi switched on.
I have myself a Samsung Galaxy ACE s5830 which I got just few days back and had found this problem where the phone just displayed error while switching on wifi. I then restarted the phone and found that wifi was working fine. After this I began noticing that the phone occasionally (two or three times a day) got hung up with a blank screen while the keypad is locked (while charging and while idle). When I tried unlocking the keypad, the phone do not respond. I would then have to disconnect the battery or press and hold the power key for 10 seconds to bring my phone back to life. However, I can see that if I switch off wifi, the phone does not get hung up.
I have installed SDK and Dalvik Debug Monitor in my PC but I would like to know how I will be able to debug this issue with the phone connected. Thanks in advance.

If I understand correctly, this issue occurs when you are on a charger with wifi active and the device goes to sleep.
You might attempt to understand the issue by connecting the phone to your computer via usb and leaving "adb logcat" or its DDMS-window equivalent running, and see if anything interesting is shown if it dies. But you may just get buried in extraneous messages until you have some real familiarity with what is normal (lots of weird errors/warnings all the time) and what isn't. After a restart you can look at things like /proc/last_kmsg
Incidentally, if the problem happens on the mains charger but not when connected to the pc (just connected, SD card not mounted and DDMS not running), that could suggest the culprit is electrical noise from the charger.
Or you could attempt to work around it. Some devices have in their settings menu an option to stay "on" whenever connected to a charger.
I believe that you could also write an application which listens for ACTION_BATTERY_CHANGED intents, detects that you have gone on the charger, finds out if wifi is on, and if it is acquires a wakelock. You'd also look for going off the charger or disabling wifi, at which point you would release the wakelock.