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Android Studio – How to use HttpURLConnection in an Android app?

I have a problem in my Android app.
I use a login portal generated by an activity Login Activity, and I want to send username and password to my web API. So I created a java class who use HttpURLConnection for contacting my API. This class was tested (with Netbeans) and everything work perfectly !
But when I call my function who connecting at the API in my Android app, nothing, any request is send. I added Internet permission in androidManifest, always nothing

androidManifest.xml :

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.ben.myapp">
    <!-- Autorisation -->
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
.....
</manifest>

My java class :

public static String verifyLoginAndGetData (String userMail, String userPassword) throws IOException  {
           URL urlGetRequest = new URL("http://my.api.com/index?param1...");
           // HTTP Connexion
            HttpURLConnection apiConnexion = (HttpURLConnection) urlGetRequest.openConnection();
            // Method
            apiConnexion.setRequestMethod("GET");

            try {
                // Response code
                int responseCode = apiConnexion.getResponseCode();

                if (responseCode == HttpURLConnection.HTTP_OK) {
                    // Read the response
                    BufferedReader in = new BufferedReader(new InputStreamReader(apiConnexion.getInputStream()));
                    StringBuffer response = new StringBuffer();
                    while ((inputLine = in.readLine()) != null) {
                        response.append(inputLine);
                    }
                    in.close();

                    // Return response
                    return response.toString();

                } else {
                    return "false";
                }

            } finally {
                apiConnexion.disconnect();
            }

        } catch (Exception e){
            Log.i("Exception", e.toString());
            return "false";
        }

Where I call this function :

public class LoginDataSource {
     public Result<LoggedInUser> login(String username, String password) {
          String resultAPI = my_class.verifyLoginAndGetData(username, password);
     }
}

variables username and password are not empty.

what am I supposed to use ? Or what i should do ?

Thank you for helping me 🙂

BenjaminFB

Tags:

2

Answers


  1. Chosen as BEST ANSWER
    0

    Yes it work !!
    I did what @code-demon told me to do :
    Add at the Manifest

    android:usesCleartextTraffic="true"

    And use thred but I couldn't get any value back from API response, so I did research and came across it: stackoverflow post.
    Finally I developed that :

    ExecutorService executor = Executors.newSingleThreadExecutor();
Callable<String> callable = new Callable<String>() {
      @Override
      public String call() throws IOException {
            // Call my API get function
            return verifyLoginAndGetData(username, password);
      }
};
Future<String> future = executor.submit(callable);
executor.shutdown();
// Get in String, the API response
String resultAPI = future.get();

  2. 0

    First of all have this run on a separate thread from the ui if not done already,for this id do this

    new Thread(new Runnable() {
                @Override
                public void run() {
                    try {
                        Log.e("Download ",verifyLoginAndGetData("username","password"));
                    } catch (IOException e) {
                        Log.e("Exception ",""+e.getMessage());
                    }


                }
            }).start();

    • Next thing.am not sure about the api you are dealing with however id
      recommend using a network config file to allow cleartext traffic to
      your site if it uses cleartext traffic and specify it on your application in manifest.

    • Another thing, remember the internet permission on your manifest

    Other than that,for me this works with the google url http://www.google.com using get

      public static String verifyLoginAndGetData (String userMail, String userPassword) throws IOException {
    URL urlGetRequest = new URL("http://www.google.com");
    // HTTP Connexion
    HttpURLConnection apiConnexion = (HttpURLConnection) urlGetRequest.openConnection();
    // Method
    apiConnexion.setRequestMethod("GET");

    try {
        // Response code
        int responseCode = apiConnexion.getResponseCode();

        if (responseCode == HttpURLConnection.HTTP_OK) {
            // Read the response
            BufferedReader in = new BufferedReader(new InputStreamReader(apiConnexion.getInputStream()));
            StringBuffer response = new StringBuffer();
            String inputLine = null;

            while ((inputLine = in.readLine()) != null) {
                response.append(inputLine);
            }
            in.close();

            // Return response
            return response.toString();

        } else {
            return "false";
        }

    } finally {
        Log.e("Disconnection", "e.toString()");
        apiConnexion.disconnect();
    }


}

    To return data to another class or to the activity thread, yo can use a handler or interface .below is how i would use an interface

      interface data_inter{
    void onDataReceived(String data);
}
data_inter inter=new data_inter() {
    @Override
    public void onDataReceived(String data) {
        Log.e("Downloaded: ",data);
        Toast.makeText(cntx,"Downloaded: "+data,Toast.LENGTH_LONG).show();
        ((EditText)findViewById(R.id.focuser)).setText("Downloaded: "+data);
    }
};
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    cntx=this;
    new Thread(new Runnable() {
        @Override
        public void run() {
            try {
                String responce=verifyLoginAndGetData("","");
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        inter.onDataReceived(responce);
                    }
                });

            } catch (IOException e) {
                Log.e("Exception ",""+e.getMessage());
            }


        }
    }).start();}
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