I am currently working on an app which requires a Bluetooth laser meter. So i tried a few lines of code and went through a loads of failures. The last error I get is an NPE because i try to access the array returned by getUuids(). I also tried to connect the app to my airPods and everything worked well. I am at minSdk 27 and targetSdk 31 All bluetooth permissions (bluetooth, bluetooth_admin) are granted.
the fact is, the laser thing requires an app to work and i wonder if the constructor could have blocked some functionalities. if so, i'll look to buy another one from another brand, if someone could provide me a link to buy a device working for my app. Here's my bluetooth connect code (pretty generic I guess)
I also tried the static UUID suggested in this post but i now get this socket error which (i think) mean the uuid's not working either:
BluetoothAdapter blueAdapter = BluetoothAdapter.getDefaultAdapter();
if (blueAdapter != null) {
if (blueAdapter.isEnabled()) {
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.BLUETOOTH) != PackageManager.PERMISSION_GRANTED) {
Const.requestAllAppPermissions(this);
return;
}
Set<BluetoothDevice> bondedDevices = blueAdapter.getBondedDevices();
if (bondedDevices.size() > 0) {
Object[] devices = bondedDevices.toArray();
BluetoothDevice device = (BluetoothDevice) devices[0];
System.out.println(device.getName());
if (device.fetchUuidsWithSdp()) {
ParcelUuid[] uuids = device.getUuids();
BluetoothSocket socket = null;
try {
//socket = device.createRfcommSocketToServiceRecord(uuids[0].getUuid());
socket = device.createRfcommSocketToServiceRecord(
UUID.fromString("00001101-0000-1000-8000-00805f9b54fb"));
socket.connect();
} catch (IOException e) {
e.printStackTrace();
}
}
//outputStream = socket.getOutputStream();
// inStream = socket.getInputStream();
} else {
}
} else {
System.out.println("bluetooth disabled");
}
} else {
System.out.println("No bluetooth built-in");
}
here's the static UUID stacktrace:
W/BluetoothAdapter: getBluetoothService() called with no BluetoothManagerCallback
W/System.err: java.io.IOException: read failed, socket might closed or timeout, read ret: -1
W/System.err: at android.bluetooth.BluetoothSocket.readAll(BluetoothSocket.java:920)
W/System.err: at android.bluetooth.BluetoothSocket.readInt(BluetoothSocket.java:934)
W/System.err: at android.bluetooth.BluetoothSocket.connect(BluetoothSocket.java:494)
W/System.err: at com.adici.activities.PlanActivity.lambda$defButton$13$com-adici-activities-PlanActivity(PlanActivity.java:409)
W/System.err: at com.adici.activities.PlanActivity$$ExternalSyntheticLambda10.onClick(Unknown Source:2)
W/System.err: at android.view.View.performClick(View.java:7346)
W/System.err: at android.view.View.performClickInternal(View.java:7312)
W/System.err: at android.view.View.access$3200(View.java:846)
W/System.err: at android.view.View$PerformClick.run(View.java:27794)
W/System.err: at android.os.Handler.handleCallback(Handler.java:873)
W/System.err: at android.os.Handler.dispatchMessage(Handler.java:99)
W/System.err: at android.os.Looper.loop(Looper.java:214)
W/System.err: at android.app.ActivityThread.main(ActivityThread.java:7100)
W/System.err: at java.lang.reflect.Method.invoke(Native Method)
W/System.err: at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:494)
W/System.err: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:964)
I'm open to any suggestion
