MainActivity.java

package net.anandsingh.movies

import android.net.Uri;
import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.widget.TextView;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

public class MainActivity extends AppCompatActivity {

    TextView text;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        //Text to display response result
        text = (TextView) findViewById(R.id.textView);

        //Executing AsyncTask, passing api as parameter
        new CheckConnectionStatus().execute("http://www.androidinhindi.com/logindemo/login.php");

    }

    //AsyncTask to process network request
    class  CheckConnectionStatus extends AsyncTask<String, Void, String>
    {

        //This method will run on UIThread and it will execute before doInBackground
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            
            //Making text field blank
            text.setText("");
        }

        //This method will run on background thread and after completion it will return result to onPostExecute
        @Override
        protected String doInBackground(String... params) {
            URL url = null;
            try {
                //As we are passing just one parameter to AsyncTask, so used param[0] to get value at 0th position that is URL
                url = new URL(params[0]);
            } catch (MalformedURLException e) {
                e.printStackTrace();
            }
            try {
                HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
                urlConnection.setDoOutput(true);

                //Building URI
                Uri.Builder builder = new Uri.Builder()
                        .appendQueryParameter("username", "admin")
                        .appendQueryParameter("password", "admin");

                //Getting object of OutputStream from urlConnection to write some data to stream
                OutputStream outputStream = urlConnection.getOutputStream();

                //Writer to write data to OutputStream
                BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream,"UTF-8"));
                bufferedWriter.write(builder.build().getEncodedQuery());
                bufferedWriter.flush();
                bufferedWriter.close();
                outputStream.close();

                urlConnection.connect();

                //Getting inputstream from connection, that is response which we got from server
                InputStream inputStream = urlConnection.getInputStream();
                
                //Reading the response
                BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
                String s = bufferedReader.readLine();
                bufferedReader.close();

                //Returning the response message to onPostExecute method
                return s;
            } catch (IOException e) {
                Log.e("Error: ", e.getMessage(), e);
            }
            return null;
        }

        //This method runs on UIThread and it will execute when doInBackground is completed
        @Override
        protected void onPostExecute(String s) {
            super.onPostExecute(s);
            
            //Setting the response message to textview
            text.setText(s);
        }
    }
}