Improved error handling for the app

[tusharojha]

Description

Improving error handling inside the app. As of now, all APIs are expecting positive responses but there are several situations in which it might not work. Also, I am covering small cases where the app crashes. Therefore, the PR is going to have a major code change so I thought to create a WIP PR and start working.

Fixes: #63

[tusharojha]

@harchani-ritik I have added more checks (showing toasts to users) and try-catch statements with debug prints. Also, I have added this small chin to show if the app is not able to fetch torrentsList from the rtorrent server.

Also, I would suggest trying out the app changes before merging.

[rj-since-2000]

Hi @tusharojha, a big red label looks a bit odd in the app theme. Maybe you can change it to have a background colour of grey[100] and text colour red. Also add an error icon leading the text.

Now the changes in lib/api/api_requests.dart file has too many checks for the status code 200 from the response and debug print. So instead of checking it manually every-time you can create functions similar to

bool isConnectedToTorrentServer (dynamic response) {
     if (response.statusCode == 200) {
          return true;
     }
     return false;
}

void showNetworkErrorResponse (dynamic response, String value) {
     Fluttertoast.showToast(msg: 'Unable to $value. Please check your network.');
     debugPrint('Error in $value api: [${response.statusCode}] ${response.body}');
}

and optimise repetition of code. Also try to think about other status codes that the torrent server may respond. #64

[buildwithmalik]

The project has been updated extensively in the last 2 years (check wiki for more info). The default branch is now the "main" branch. All issues and pull requests for previous versions are being removed.