HTTP GET and POST Requests

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Step 1:
Open  activity_main.xml file and copy the below code.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.prasad.getpostrequestex.MainActivity">

    <Button
        android:id="@+id/getRequest"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="50dp"
        android:background="@color/colorPrimary"
        android:padding="8dp"
        android:text="Get Request"
        android:textAllCaps="false"
        android:textColor="#ffffff"
        android:textSize="18dp" />

    <Button
        android:id="@+id/postRequest"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/getRequest"
        android:layout_centerHorizontal="true"
        android:layout_margin="30dp"
        android:background="@color/colorPrimary"
        android:padding="8dp"
        android:text="Post Request"
        android:textAllCaps="false"
        android:textColor="#ffffff"
        android:textSize="18dp" />
</RelativeLayout>

Step 2:
Create ConnectionDetector.java class to check Internet connection and copy below code.

package com.prasad.getpostrequestex.background;

import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;

public class ConnectionDetector {
  

 
    /**
     * Checking for all possible internet providers
     * **/
    public static  boolean isConnectingToInternet(Context _context){
        ConnectivityManager connectivity = (ConnectivityManager) _context.getSystemService(Context.CONNECTIVITY_SERVICE);
          if (connectivity != null)
          {
              NetworkInfo[] info = connectivity.getAllNetworkInfo();
              if (info != null)
                  for (int i = 0; i < info.length; i++)
                      if (info[i].getState() == NetworkInfo.State.CONNECTED)
                      {
                          return true;
                      }
 
          }
          return false;
    }
}

Step 3:
Create ServiceResponse.java model class to store success or failure response and copy below code.

package com.prasad.getpostrequestex.background;


public class ServiceResponse {


    private boolean isSuccessOrFail;
    private String jsonResponse;


    public void setIsSuccessOrFail(boolean isSuccessOrFail) {
        this.isSuccessOrFail = isSuccessOrFail;
    }

    public boolean isSuccessOrFail() {
        return isSuccessOrFail;
    }



    public String getJsonResponse() {
        return jsonResponse;
    }

    public void setJsonResponse(String jsonResponse) {
        this.jsonResponse = jsonResponse;
    }


    public ServiceResponse(boolean isSuccessOrFail, String jsonResponse) {
        this.isSuccessOrFail = isSuccessOrFail;
        this.jsonResponse = jsonResponse;
    }


}

Step 4:
Create WebServiceCallBack.java interface to return response to activity class and copy below code.

package com.prasad.getpostrequestex.background;

public interface WebServiceCallBack {

    void onResponseReceived(Object response);


}

Step 5:
Create WebServiceAsyncTask.java class to call background assync task and copy below code.

package com.prasad.getpostrequestex.background;

import android.app.ProgressDialog;
import android.content.Context;
import android.os.AsyncTask;

import java.util.HashMap;


public class WebServiceAsyncTask extends AsyncTask<Object, Void, Object> {

    private ProgressDialog pDialog;
    private Context context;
    private WebServiceCallBack webServiceListener;
    private String requestUrl;
    private HashMap<String, String> extraParams;
    private int requestType;
    private boolean showProgressBar;


    public WebServiceAsyncTask(Context context, WebServiceCallBack webServiceListener, String requestUrl, HashMap<String, String> extraParams, int requestType, boolean showProgressBar) {
        this.context = context;
        this.webServiceListener = webServiceListener;

        this.requestUrl = requestUrl;
        this.extraParams = extraParams;
        this.requestType = requestType;
        this.showProgressBar = showProgressBar;


    }


    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        if (showProgressBar) {
            showProgressDialog();
        }
    }

    @Override
    protected Object doInBackground(Object[] params) {

        synchronized (this) {

            boolean networkStatus = ConnectionDetector.isConnectingToInternet(context);
            ServiceResponse serviceResponse = null;

            if (networkStatus) {
                HttpWebServiceHandler serviceHandler = new HttpWebServiceHandler();

                if (requestType == 1) {
                    serviceResponse = serviceHandler.getServiceCall(requestUrl, extraParams);
                } else if (requestType == 2) {
                    serviceResponse = serviceHandler.postServiceCall(requestUrl, extraParams);
                }

            } else {
                serviceResponse = new ServiceResponse(false, HttpWebServiceHandler.NoNetWorkErrorMSG);
            }


            return serviceResponse;
        }

    }


    @Override
    protected void onPostExecute(Object reponse) {
        super.onPostExecute(reponse);

        try {

            webServiceListener.onResponseReceived(reponse);
            if (showProgressBar) {
                dismissProgressDialog();
                showProgressBar = false;
            }


        } catch (final IllegalArgumentException e) {

        } catch (final Exception e) {

        } finally {
            pDialog = null;
        }


    }


    public void showProgressDialog() {

        pDialog = new ProgressDialog(context);
        pDialog.setMessage("Please wait...");
        pDialog.setCancelable(false);

        if (!pDialog.isShowing())
            pDialog.show();
    }

    public void dismissProgressDialog() {
        if (pDialog != null && pDialog.isShowing())
            pDialog.dismiss();

    }
}

Step 6:
Create HttpWabServiceHandler.java class file to call Get and Post requests and copy below code.

package com.prasad.getpostrequestex.background;

import android.util.Log;

import org.json.JSONObject;

import java.io.BufferedInputStream;
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.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
import java.util.HashMap;
import java.util.Map;

import javax.net.ssl.HttpsURLConnection;

public class HttpWebServiceHandler {

    static String response = null;
    public static final String NoNetWorkErrorMSG = "No Internet Connection !!!";

    public static final String ServerErrorMSG = "Error in Connection !!!";


    private static JSONObject jsonObj;

    public HttpWebServiceHandler() {

    }

    // Get Request using HttpURLConnection  Code
    public ServiceResponse getServiceCall(String requestURL, HashMap<String, String> params) {

        InputStream inputStream = null;
        HttpURLConnection conn = null;
        ServiceResponse serviceResponse = null;
        String newRequestURL = "";

        try {

            if (params != null) {
                newRequestURL = requestURL + getQueryString(params);
            } else {
                newRequestURL = requestURL;
            }

            URL url = new URL(newRequestURL);
            Log.i("URL ", newRequestURL);

            conn = (HttpURLConnection) url.openConnection();
                 /* optional request header */
            conn.setRequestProperty("Content-Type", "application/json");

                /* optional request header */
            conn.setRequestProperty("Accept", "application/json");
            conn.setReadTimeout(500000);
            conn.setConnectTimeout(500000);
                /* for Get request */
            conn.setRequestMethod("GET");
            int statusCode = conn.getResponseCode();

                /* 200 represents HTTP OK */
            if (statusCode == HttpsURLConnection.HTTP_OK) {

                inputStream = new BufferedInputStream(conn.getInputStream());
                response = convertInputStreamToString(inputStream);
                Log.i("Response", response);
                serviceResponse = new ServiceResponse(true, response);

            } else {
                response = ServerErrorMSG;
                serviceResponse = new ServiceResponse(false, response);
            }

        } catch (Exception e) {

            e.printStackTrace();
            response = ServerErrorMSG;
            serviceResponse = new ServiceResponse(false, response);

        } finally {

            if (conn != null)
                conn.disconnect();
        }

        //  Log.i("RESPONSE", response);
        return serviceResponse; // return response

    }


    // POST Request using HttpURLConnection  Code

    public ServiceResponse postServiceCall(String requestURL, HashMap<String, String> postDataParams) {
        InputStream inputStream = null;
        URL url;
        ServiceResponse serviceResponse = null;
        HttpURLConnection conn = null;
        try {

            String postParams = getQueryString(postDataParams);
            url = new URL(requestURL);
            conn = (HttpURLConnection) url.openConnection();
            conn.setReadTimeout(500000);
            conn.setConnectTimeout(500000);
            conn.setRequestMethod("POST");
            conn.setDoInput(true);
            conn.setDoOutput(true);
            conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");

            OutputStream os = conn.getOutputStream();
            BufferedWriter writer = new BufferedWriter(
                    new OutputStreamWriter(os, "UTF-8"));
            writer.write(postParams);
            writer.flush();
            writer.close();
            os.close();
            int responseCode = conn.getResponseCode();

            if (responseCode == HttpsURLConnection.HTTP_OK) {

                inputStream = new BufferedInputStream(conn.getInputStream());
                response = convertInputStreamToString(inputStream);
                serviceResponse = new ServiceResponse(true, response);
                Log.i("Response", response);

            } else {

                response = ServerErrorMSG;
                serviceResponse = new ServiceResponse(false, response);
            }

        } catch (Exception e) {

            e.printStackTrace();
            response = ServerErrorMSG;
            serviceResponse = new ServiceResponse(false, response);

        } finally {

            if (conn != null)
                conn.disconnect();
        }

        return serviceResponse;

    }

    private String convertInputStreamToString(InputStream inputStream) throws IOException {

        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));

        String line = "";
        String result = "";

        while ((line = bufferedReader.readLine()) != null) {
            result += line;
        }

            /* Close Stream */
        if (null != inputStream) {
            inputStream.close();
        }

        return result;
    }


    private String getQueryString(HashMap<String, String> params) throws UnsupportedEncodingException {
        StringBuilder result = new StringBuilder();
        boolean first = true;
        for (Map.Entry<String, String> entry : params.entrySet()) {
            if (first)
                first = false;
            else
                result.append("&");

            result.append(URLEncoder.encode(entry.getKey(), "UTF-8"));
            result.append("=");
            result.append(URLEncoder.encode(entry.getValue(), "UTF-8"));
        }

        return result.toString();
    }


}

Step 7:
Open MainActivity.java class file and copy below code.

package com.prasad.getpostrequestex;


import android.content.Context;
import android.content.DialogInterface;
import android.os.Bundle;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;

import com.prasad.getpostrequestex.background.ServiceResponse;
import com.prasad.getpostrequestex.background.WebServiceAsyncTask;
import com.prasad.getpostrequestex.background.WebServiceCallBack;

import java.util.HashMap;

public class MainActivity extends AppCompatActivity implements WebServiceCallBack {

    private Button getRequestBtn, postRequestBtn;

    private int serviceRequest = 1;
    private String url;

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

        initControls();
    }

    private void initControls() {

        getRequestBtn = (Button) findViewById(R.id.getRequest);
        postRequestBtn = (Button) findViewById(R.id.postRequest);

        getRequestBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                getRequestCall();

            }
        });

        postRequestBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                postRequestCall();

            }
        });
    }

    private void getRequestCall() {

        serviceRequest = 1;
        url = "http://androidexample.com/media/webservice/JsonReturn.php"; //Replace with your url
        WebServiceAsyncTask loginAsyncTask = new WebServiceAsyncTask(this, this, url, null, 1, true);
        loginAsyncTask.execute();

    }

    private void postRequestCall() {

        serviceRequest = 2;
        url = ""; //Replace with your url
        // if you want pass parameters,use hash map like below
        HashMap<String, String> params = new HashMap<String, String>();
//                params.put("userName", userName);
//                params.put("password", password);

        WebServiceAsyncTask loginAsyncTask = new WebServiceAsyncTask(this, this, url, params, 2, true);
        loginAsyncTask.execute();

    }

    @Override
    public void onResponseReceived(Object response) {

        try {

            ServiceResponse serviceResponse = (ServiceResponse) response;
            String jsonResponse = serviceResponse.getJsonResponse();

            if (serviceResponse.isSuccessOrFail()) {

                //Get Request response
                if (serviceRequest == 1) {

                    //As per response parse json object

                } else if (serviceRequest == 2) {
                    //Post Request response

                    //As per response parse json object
                }


            } else {
                showAlertDialog(this, jsonResponse);
            }

        } catch (NullPointerException e) {
            e.printStackTrace();
        }


    }

    public static void showAlertDialog(Context context, String message) {

        new AlertDialog.Builder(context)
                .setTitle(context.getResources().getString(R.string.app_name))
                .setCancelable(false)
                .setMessage(message)
                .setPositiveButton("OK", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {

                    }
                })
                .show();
    }
}

Step 8:
Open AndroidManifest.xml file and add the internet permissions.

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.prasad.getpostrequestex">

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

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>