[FIXED] Cannot connect to localhost API from Android app

Issue

I am new to Django. I have created an API named http://127.0.0.1:8000/api/update/1/ and it works perfectly in the browser and on the Postman app.

However, when I am trying to access the API from the Android app it is returning NULL.

The Android code works when the API is the following:

http://newsapi.org/v1/articles?source=bbc-news&sortBy=top&apiKey=8190df9eb51445228e397e4185311a66

However, it does not work when the API is the following, even if the following API works just fine from my browser running in the same PC and from the Postman application.

http://127.0.0.1:8000/api/update/1/

I am attaching the code where API call is made.

protected String doInBackground(String... args) {
    String xml = "";
    String api = "http://127.0.0.1:8000/api/update/1/"; // returns NULL works in Postman app and in the browser
    // String api = "http://newsapi.org/v1/articles?source=bbc-news&sortBy=top&apiKey=8190df9eb51445228e397e4185311a66"; // works in all places
    String urlParameters = "";
    xml = Function.excuteGet(api, urlParameters);
    return  xml;
}

Can anyone help me with this?

Solution

If you are testing your application from a real android device then you need to put the IP address of your PC while you are trying to connect to your Django server through APIs. And yes, you need to be in the same network as well. So you need to check the following things.

1. Make sure that the PC (where you are running the server) and the Android device (where you are testing your application) are in the same network (connected with same Wifi network maybe).

2. Make sure you are connecting to the IP address of your PC where the server is running. For example, right now, the IP address of your PC is 192.168.0.100. Then, you need to connect to this IP address and call your API like the following.

   http://192.168.0.100:8000/api/update/1/
   

3. Make sure you are accepting requests to the port 8000 in your PC. Check your Firewall configuration if it is blocking any incoming requests to the 8000 port. If it is found blocking, then please allow an incoming request to the 8000 port using the following.

   sudo ufw allow 8000/tcp
   

If there is nothing which is helping you, then please check your Android code to check if the API calling is okay. I would strongly recommend using Volley for API calls suggested in developers documentation.

Last, but not the least, please check if you have necessary permission in your AndroidManifest.xml file. You need to add the following permission to grant your application to use the internet.

<uses-permission android:name="android.permission.INTERNET" /> 
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

Answered By - Reaz Murshed