Runtime Error: "Attempt to invoke virtual method 'java.lang.Class java.lang.Obje

[L Yim]

I am testing Arduino HC-05 Bluetooh Led On/Off with App Inventor 2. I am getting Runtime Error. 

Please help!

Pressing any of the sending text buttons. (It turned the Led On or Off OK.)

However, immediately I got from Companion or from App, Runtime Error.

"Attempt to invoke virtual method 'java.lang.Class java.lang.Object.getClass()' on a null object reference"

I am using Android 5.1.1 Nexus 4 mobile phone and Arduino UNO. (With Windows & Linux. Using more than 1 browsers.)

image 2 is part of image 1.

Much appreciated. Thank you.

[Abraham Getzler]

The Timer event is calling procedure doReceive.

But I don't see it in your Downloaded Blocks Image.

Maybe that is a dead procedure reference?

ABG

[L Yim]

Thanks Abraham. No wonder it was working previously.

I accidentally disabled the block.

I have now also made some modifications.

It is working fine now. No more Runtime Error.

Attached the revised blocks.