Hi James,

After a bit more digging on BLE related issues in Android 4.3/4.4, I’ve found that, anecdotally, the Bluetooth stack in those OS versions may have issues with connectivity if you attempt read/write activities immediately post-connection. In light of this, I implemented a test fix in which a thread sleep for 10 seconds was added right after BluetoothGatt.GATT_SUCCESS and before startSingleMeterActivity in the ScanActivity class. The result was a dramatic improvement in the connection success rate. In fact, I would say my LG Volt running Android 4.4.2 now connects with a 90% success rate as opposed to less than 10% if the meter activity is started immediately after GATT_SUCCESS. Empirically, a delay of less than 5 seconds makes no improvement for my phone, so I’ve stuck with a 10 second delay.

My recommendation for a fix is as follows: add either a thread sleep or an activity timer delay between GATT_SUCCESS and starting the meter activity for all instances in which a connection is established or refreshed. Make this sleep / delay setting active by default if the host is running Android 4.3/4.4, and allow the user to toggle the delay and configure its length. A thread sleep might not be appropriate if the app is designed to connect to multiple meters simultaneously, so I think the final implementation will need to be optimized.

Although there is still a connectivity issue with an intermittent crash-on-connect (especially after multiple connect/disconnects), this basic fix transforms the meter from unusable to stable for my LG Volt. I would like to know if this can help anyone else running Android 4.3/4.4 improve the reliability of establishing a connection with their meter.

By the way, thanks for your hard work! I’ll try to pitch in with Android development wherever I can.