TCP Communication with Android via wifi

Question

I will be creating an Android app to control the brightness of a LED. For this, I will want the Raspberry Pi and Android Phone to communicate with one another via Wifi. I don't need the RPI3 access point to be a working internet, as long as it allows the android to connect via wifi.

Steps to be involved (Correct me if I'm wrong):

1. Set up Raspberry Pi as Access Point.
2. Set up Raspberry Pi as TCP Server to listen for connections.
3. Connect Android phone (TCP Client) to Raspberry Pi via wifi to the access point and send socket connection over.
4. Send data from Android phone to Raspberry Pi.

I'm pretty much done with the Android App working as a client, however not sure about setting up the TCP server on the Raspberry Pi..

Is this what I am looking for? I do not need the RPI3 to be a wifi repeater or able to go to internet, all I want is to set it up as an access point. https://www.raspberrypi.org/documentation/configuration/wireless/access-point.md

Are there any examples for setting up the TCP Server?

I am very new to this, please help!

Answer 1

I managed to do it.

Yes, I first set up the RPI as a standalone network wireless access point.

Then, I wrote a program in C to set up RPI as a TCP Server to listen for connections from my Android phone with the Geany ide.

Here is the tutorial I used to help me with the C programming. TCP Socket Tutorial

Answer 2

The easiest way to set up a TCP listener on your Pi is probably to use netcat.

netcat -l -p 8080

makes netcat listen at port 8080. If you connect to that port from your Android device, you will see what is sent in the terminal on your Pi.