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

Why does Android bond even when asked not to bond?

I have developed an application on an on-board device which allows a smartphone to be able to connect in secure BLE.
Everything works fine but I notice that every time I do a "pairing" via an Android smartphone, that the smartphone "bonds" the device even though I specified in the request that I did not want bondage. I don't have this problem on IOS.
Here are the requests that are sent by my on-board device to the smartphone:
Security request
Pairing response
Is it possible that Android does not support "pairing only"? If it is paired, it does a "boding" automatically even if it has received a request asking it not to do a bond?
Thank you

"Non-bondable mode" is mandatory to support in the Bluetooth Core specification. If Android makes a permanent bond, even though you say to not bond in the "Pairing response", it's a bug in Android. Please file a bug report to Android Open Source Project (AOSP).

Mobile Phones confused about BLE pairing

We have an IoT device that has an onboard BLE chip (Anaren A20737A) that the user can control from their mobile phone. At times, the phone will pair with the device (or at least report that it is paired), but will not receive any data, and all commands appear to be ignored by the device. Connecting the logger to the device, we can see that it believes that it is sending out messages correctly, and that it is paired with the phone. The solution appears to be forgetting the BLE pairing from the Bluetooth settings on the phone, and sometimes restarting the phone as well. No changes to the IoT device appear to have any impact, the only thing that works is forgetting the pairing from the phone's settings. This problem has occurred on both iPhone and Android (separate code bases).
EDIT
The problem is seen on iOS 7.0 and multiple versions of android from at least 4.4 onward.
Logging the data out from the chip we see it drop the connection and start advertising. About 1 in 10 times, the phone seems to believe that it has a connection with the device, but the logs on the device show that it is still in advertising mode.
Has anyone else ever seen this issue?

Android Service And Lenovo

I'm trying to make App that will communicate with Bluetooth device. i have a service which set connection, get data from Bluetooth & collect it to int array, and sent users settings to device. Then when App ask for new Data service return array.When user change some data in App it sent it to Service and service sent it back to bluetooth*. I have tested this app on Sony Z, HTC, Samsung Tab2 - it works fine... But on ZTE, and Lenovo i have problems! The main problem that this devices have slow speed on reading socket.getInputStream(); too slow... i have a great delay... with data reading. And the App Crashes.
Why it so?
I think, i ll try to make to Threads in Service for get and sent data... but on devices Sony HTC Samsung.. it works fine! By the way Samsung have only 500 mb RAM (damaged) ZTE Blade and Lenovo Tablet must be more faster!

Android app polls bluetooth devices and freezes after 80min

Together with a sub-company we try to develop an android app which simulates an automotive HMI system. There is a functionality to changes the color-theme in case of connected mobile-phone (via Bluetooth). In general this is working: If a known paired phone is in range the theme switches... if the phone loses connection the theme switches back...
Problem: Currently the app polls the paired bluetooth devices for every second and checks if a known phone is paired.
After ~1h and 20min (+/- 5min) the app freezes (reproducible).
Our sub-company told us, that the reason is a problem in android bluetooth device - A timer overflows and android refuses the requests of the app after this time. Thats the reason, that the app freezes.
I´m not familiar with android development and I have to believe in this statements.
Could you tell me if there are other possibilities?
Is it necessary to poll the bluetooth device? Is there nothing like an system event which could be used?
Is this problem (refused bluetooth pooling after defined time) known?
Hint: The problem occurs only with power supply. In battery usage the app runs till battery is empty (longer than 80min).
Samsung Galaxy Tab Pro with android 4.4 (same problem with android 4.3)
It would be nice if anybody is able to help.
Many thanks