Make Function Block In Kotlin

I appreciate that this may have already been answered but I'm unable to find a solution that works for me. Tl;dr: How do make a function block? I have the following BLE-related co

Solution 1:

The onDescriptorWrite() method might be helpful. You should already be overriding it.

Try the following:

privatevar canContinue = false;

overridefunonServicesDiscovered(gatt: BluetoothGatt, status: Int) { //gatt shouldn't be null, so the null-safe ? isn't needed
    loopAsync(gatt);
}

overridefunonDescriptorWrite(gatt: BluetoothGatt, descriptor: BluetoothGattDescriptor, status: Int) {
    canContinue = true; //allow the loop to continue once a descriptor is written
}

privatefunloopAsync(gatt: BluetoothGatt) {
    async { //Run it async
        gatt.services.forEach { gattService -> //Kotlin has a handy Collections.forEach() extension function
            gattService.characteristics.forEach { gattChar -> //Same for this oneif (gattChar.uuid.toString().contains(ADC_SAMPLESET_0) && !subscribed_0) {
                    subscribed_0 = true

                    gatt.setCharacteristicNotification(gattChar, true)

                    val descriptor = gattChar.getDescriptor(
                            UUID.fromString(BleNamesResolver.CLIENT_CHARACTERISTIC_CONFIG)
                    }
                    descriptor.value = BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE
                    gatt.writeDescriptor(descriptor)
                    while(!canContinue); //wait until canContinue becomes true and then continue
                }
            }
        }
    }
}

This is a little hacky. There is probably a way to do this with recursion, but the nested for loops make that tricky.

Solution 2:

It's not really a question of Kotlin. BluetoothGatt is an Async API with callbacks (as is often true of Bluetooth, because of the nature of it), and you can't easily use language features to hide that aspect of it.

It's probably possible to write a facade on top of BluetoothGatt that is blocking, but doing a good job of it would be a fair amount of work, and I wouldn't really recommend it.