Android Question Bluetooth SPP Pairing Fails

[Dane du Plooy]

I have a project using BT SPP. If I try pair to a device (ESP32) from the B4A app (using simply Serial.Connect) then it apparently pairs (listed in the "paired" list in Android BT Settings), but I cannot connect to it (either from the B4A app or from a separate terminal app). If however I pair from Android BT Settings then it works fine and I can connect from both B4A and the terminal app. How can I get devices to pair properly from B4A?

 

[Erel]

The pairing process happens automatically by the OS. It is not something that your app controls.

 

[Dane du Plooy]

So an Android Studio app would presumably have the same problem? I was just wondering whether there was some setting - manifest or otherwise - which was causing an issue. Seems odd that there would be this problem. Claude AI suggests doing the pairing process manually first, then delaying to "give the stack time to populate the SDP cache", then trying to connect. I'll experiment further when I have time.

 

[Erel]

You can call any API you like from B4A with JavaObject or inline Java.

The problem that you are describing is not standard. In most cases a pairing request appears and it simply works.

 

[Dane du Plooy]

OK thanks Erel . For reference, this is on a Samsung S25 Ultra (Android 16). I haven't run thorough tests with other devices yet.