flutter_blue
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pauldemarco
How to find out if we're already connected to a device?
When my app start, I need to know if I'm already connected to a device. How can I do that using flutter_blue, I couldn't find the function anywhere.
What I do is keep track of the connected devices in the Flutter app itself. So when you are connected you just set a boolean to true.
Even better is to use this (also used in the Flutter Blue example):
deviceStateSubscription = device.onStateChanged().listen((s) {
setState(() {
deviceState = s;
});
});
This will set deviceState to either of 4 states.
Then simply write a isConnected bool in your code:
bool get isConnected => (deviceState == BluetoothDeviceState.connected);
When the device you are connected to disconnects the deviceState should automatically be updated by the onStateChanged() stream.
When your Flutter app disconnects make sure you hard code deviceState = BluetoothDeviceState.disconnected; in your code. When you disconnect the deviceState = s; part may never be called again because device may already be null or the deviceStateSubscription is already cancelled or null (depending on your code).
As far as I can tell, the only way to know about connected devices is to keep track of it from the .connect() on? I don't see any way to pull already connected devices, via FlutterBlue or the platform. .scan() seems to skip connected ones as well.
I'm needing this too. Using version 0.6.0+1. The connect() function returns void. How to check if the connection succeded?
I'm using the code below. But, it would be better if connect() returned the status.
void _connect(BluetoothDevice device) async {
_stopScan();
await device.connect();
List<BluetoothDevice> connectedDevices = await flutterBlue.connectedDevices;
if(connectedDevices.contains(device)) {
Navigator.pushReplacementNamed(context, '/home');
}
}
I've two devices connected to my Galaxy Tab S3 but using @LastMonopoly snippet the connected devices list is always empty even if it is not the truth
@enricobenedos FlutterBlue.instance.connectedDevices will give u devices connected using FlutterBlue, not all Bluetooth-connected devices
So just to be clear, there is no way to get a list of the already connected devices to the phone prior to FlutterBlue being initialized? I am curious about what the limitations are that are stopping this from happening.
Just wondering as well if there is a way to know currently connected device NOT connected using flutter_blue.
I have the same issue! For security reasons there're bluetooth devices that don't broadcast themselves, but only connect to devices and don't let anyone find that device.
Some day I want to look into this, I don't understand why it isn't what we expect as I see in Logcat that android is correctly reporting the connected devices. I also don't understand why people aren't crying about this more, it's kind of a big deal if you actually need to connect to a device for your usecase
No solution for years?! hmm, I also looking for it, my app need to listen if the phone auto connect to a device (which already connected before).
Maybe it's worthwhile to raise this same ticket in the flutter_blue_plus repository as it is actively being maintained by the community since flutter_blue is not.
