Receiving data from Arduino using bluetooth

I am trying to build a block of code using the MIT APP inventor. I want to read sensor values from my Arduino and display the result on the mobile app. I succeeded in coming out with the code to establish the Bluetooth connection. Now I am stocked at getting the code for the sensor reading.
The infrared Sensor reads either 0 or 1.
Should change the background color in the app to read when it reads 1, and green when it reads 0.
Here is my Arduino code

Here is my app interface

Here is my block of code

I am building an app using the MIT app inventor. The app receives information from the infrared sensor connected to the microcontroller (Arduino)
If the sensor detects a presence it changes the background color from green to red (shown on the app).