BleManager | ble library and sample | Networking library

I'm learning iOS vs OSX BLE.
I notice that I can't instantiate CBCentralManager in iOS because of:

I am a new in Bluetooth connection and I want to add second device in my iOS project. I already have one device, and the new device is very similar with first one, but little bit deferent. I have one process for the two devices, and I did not change a lot of code, just created all value for the new device. My all devices have different name and identifier, first device is working fine.

For creating UUID values, I used UUID generator (https://www.guidgenerator.com/online-guid-generator.aspx).

I have the following function in my Fragment -

i used bluetooth low energy in my mobile app with react-native . and i want to just find other mobile devices, so i can't find any other mobile phone and theirs supported bluetooth low-energy , but i find my Smartwatch , well my question is bluetooth low energy can find other mobile phone or is just for Accessory?

and what are you advicing me to find other mobile phone .

my code

I'm looking at the open source Bluefruit code as an example, specifically the BleManager class that is the interface with the CBCentralManager. I've emailed the author and they didn't respond:

Bluefruit BleManager class

It looks like the class is designed in a singleton architecture ("shared" on line 23) and so is constructed lazily when the first "BleManager.connect() is called elsewhere in the code.

What confuses me is in the init(), there's a semaphore "wait" function:

I am seeing some strange behaviour on a Pixel 4XL (Android 11). My foreground service's onTaskRemoved is being called unexpectedly. This doesn't occur on any other devices but I don't have any other Android 11 devices and the emulator can't do BLE.

My app uses an ongoing BLE connection to communicate with another non-android device. A foreground service is used to ensure the program remains active to receive BLE communications from the device.

It doesn't always happen but in most cases (75% of the time) after pressing home (swiping up from the bottom of the screen on a Pixel 4XL) this will cause the foreground service's onTaskRemoved to be called.

Opening a different activity in my app (i.e. an activity other than MainActivity) is almost guaranteed to make this occur.

Opening settings from the notification bar then swiping home still triggers this to occur, so it can't be that I'm accidentally killing the app since I'm swiping up when the settings app is in focus.

From my understanding, this method is only supposed to be triggered when the user terminates the app by swiping it in the task switcher.

If I go back to the task switcher, after the service was killed, my app is still available and showing the last activity opened and it's state. Switching to it resumes to the correct place, so the app itself must not have been terminated. The phone is plugged in an charging so it shouldn't be and doze/sleeping functions. This can occur within 60 seconds of launching the app, it's not a 30 minute thing.

What on earth could be going on here? The only thing I can think of is that it's not considered a foreground service for some reason. There are no errors in logcat at or around the time of the onTaskRemoved. I am not calling onTaskRemoved myself anywhere in code.

I've tried following the dumpsys in this post but it seems to be different and I couldn't find any of the references mentioned.

The notification itself is listed like this:

I am trying to return data from the BlueTooth device after connected because to use the read and write function, need some data. Example data name, overflowServiceUUIDs, solicitedServiceUUIDs, mtu, rssi... and many others. Because if I want to read or write I need some attributes. I am using the library react-native-ble-plx.

After the device connected I lost some values.

I am having issues running some asynchronous code in a bluetooth RN app.

I am trying to create a listener function that does the following: connect to a device (using an async function), log that I have connected, then disconnect from the device (using an async function).

This listener function is provided as a parameter to a bluetooth low energy (ble) device scan function:

I'm developing an App in Swift 5 that connects to a wereable device that measure body information (temperature, heart rate, etc.)

For measure this information, I have to write a Data object in one characteristic of the device (and recieve the information in other characteristic with notifications activated), and now i have to measure it every 30 minutes, so i have to create a timer with repeata every 30 minutes to execute that "write" in the BLE characteristic. (All the options in Capabilities are already activated - bluetooth-central, bluetooth-peripheral, background-processing, background-fetch)

I've read a lot of topics in Stackoverflow and there are people that says that you can't write to BLE in background and other that say that you can.

Before to implement all the posibilities i've read: ¿It's possbile to execute every 30 minutos a task to connect to a device, set notification to true to one characteristic, and write a Data object in one characteristic in Background Mode?

If the response is "Yes", is there any code that I have to implement apart from the corresponding bluetooth methods that already work in the foreground?

I've not attach my BLEManager class (centralManager) because is the "standard" from the Apple Documentation, but if you need, ask me and I'll attatch it.

Thank u all!