Python Flask server connection with Android app - https://android.jlelse.eu/handmade-backend-for-android-app-using-python-flask-framework-b173ba2bb3aa

gistfile1.py

# development way
if __name__ == '__main__':
    app.run()
    
## server on http://127.0.0.1:5000/
## (invisible across the network) won't work on other device, other than development machine

# suggested way
if __name__ == '__main__':
    app.run(host='0.0.0.0', port=5000)
    
## server on http://0.0.0.0:5000/
## visible across the network
## BaseUrl for Android http://<your ip address>:5000/blah/blah

# hackiest way (not preferred)
if __name__ == '__main__':
    app.run(host='<your ip address>')
    
## server on http://<your ip address>:5000/
## visible across the network
## BaseUrl for Android http://<your ip address>:5000/blah/blah
## whereas port=5000