Android example for integrating captcha in android example

Google’s reCAPTCHA android example.  Integrating captcha in android example on an android app. Android Kotlin tutorial about integrating Google’s safetynet reCAPTCHA in your apps with the tutorial example. Also explained how to validate the token on a server using PHP Rest-API.

First You need to check our kotlin tutorial for  Google’s reCAPTCHA example on android-kotlin.

( https://galleonsoft.com/android-kotlin-tutorial-safetynet-recaptcha/ )

You need to replace only Kotlin code with java. so here I’m showing only Java program/Code. First, you need to understand and learn our previous post of Android Kotlin tutorial about integrating Google’s safety net reCAPTCHA in your apps with a tutorial example.

Follow the step of getting SafetyNet Site Key and Secret And Create new android project. and after setup Gradle code you need to set design as well.

After you can see set Kotlin code step It means all done for java android app.

1. Follow this step for Java Android example for integrating Google’s reCAPTCHA.

Create a new class named ApiPostHelper.java This Object/Class for POST API. Also, it helps in others projects. This class required for HttpURLConnection Method. You can use alternatively Volley, Retrofit, etc.

2. Create Java Class  ApiPostHelper.java and put the below code.

 
ApiPostHelper.java

package com.galleonsoft.safetynetrecaptcha;

import android.util.Log;

import java.io.BufferedReader;
import java.io.BufferedWriter;
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;

/**
 * Author: JIGAR PATEL.
 * Tutorial_URL: https://galleonsoft.com/tutorial/
 */
 
public class ApiPostHelper {


    // Send Parameters method
    public static String SendParams(String reqURL, HashMap<String, String> postDataParams) {

        URL gsUrl;
        StringBuilder response = new StringBuilder();
        String resultString = "";
        try {
            gsUrl = new URL(reqURL);

            HttpURLConnection conn = (HttpURLConnection) gsUrl.openConnection();
            conn.setReadTimeout(7000);
            conn.setConnectTimeout(7000);
            conn.setRequestMethod("POST");
            conn.setDoInput(true);
            conn.setDoOutput(true);

            // For Post encoded Parameters
            OutputStream os = conn.getOutputStream();
            BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(os, "UTF-8"));
            writer.write(getPostDataString(postDataParams));
            writer.flush();
            writer.close();
            os.close();

            int responseCode = conn.getResponseCode();
            Log.i("responseCode: ", responseCode + "");
            if (responseCode == HttpsURLConnection.HTTP_OK) {
                String line;
                BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream()));
                while ((line = br.readLine()) != null) {
                    response.append(line);
                }

                // convert content stream to a String
                resultString = response.toString();
            } else {
                resultString = "";
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

        return resultString;

    }


    // Collect Params from HashMap and encode with url.
    private static String getPostDataString(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();
    }

}

3. Create Android Java AppCompatActivity as reCAPTCHA_Activity.java and put the below code. (It’s your Activity activity class you need to  declare in the manifest)

 
reCAPTCHA_Activity.java

package com.galleonsoft.safetynetrecaptcha;

import android.annotation.SuppressLint;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.v7.app.ActionBar;
import android.support.v7.app.AppCompatActivity;
import android.text.TextUtils;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.widget.Toast;

import com.google.android.gms.common.api.ApiException;
import com.google.android.gms.common.api.CommonStatusCodes;
import com.google.android.gms.safetynet.SafetyNet;
import com.google.android.gms.safetynet.SafetyNetApi;
import com.google.android.gms.tasks.OnFailureListener;
import com.google.android.gms.tasks.OnSuccessListener;

import org.json.JSONException;
import org.json.JSONObject;

import java.util.HashMap;


public class reCAPTCHA_Activity extends AppCompatActivity {

    private static final String TAG = "reCAPTCHA_Activity";

    // TODO: replace the reCAPTCHA KEY with yours
    private static final String SAFETY_NET_API_KEY = "6LdYZFoUAAAAAAXxuGh0OAnQ_8moTpkzhEtcqARB";

    // TODO: replace the SERVER API URL with yours
    private static final String VERIFY_ON_API_URL_SERVER = "http://apps.galleonsoft.com/api-example/safetynet-recaptcha-verfication.php";

    EditText et_message;
    LinearLayout linearLayoutForm;
    TextView Tv_Message;
    Button btn_send;

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

        ActionBar actionBar = getSupportActionBar();
        if (actionBar != null)
            actionBar.setTitle(getString(R.string.feedback));

        et_message = findViewById(R.id.et_message);
        linearLayoutForm = findViewById(R.id.linearLayoutForm);
        Tv_Message = findViewById(R.id.Tv_Message);
        btn_send = findViewById(R.id.btn_send);

        btn_send.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                CheckSafetynetreCAPTCHA();
            }
        });

    }


    public void CheckSafetynetreCAPTCHA() {

        final String feedback = et_message.getText().toString().trim();
        // checking for empty text message
        if (TextUtils.isEmpty(feedback)) {
            Toast.makeText(getApplicationContext(), "Enter feedback!", Toast.LENGTH_LONG).show();
            return;
        }

        // Showing SafetyNet reCAPTCHA dialog
        SafetyNet.getClient(this).verifyWithRecaptcha(SAFETY_NET_API_KEY)
                .addOnSuccessListener(this, new OnSuccessListener<SafetyNetApi.RecaptchaTokenResponse>() {
                    @Override
                    public void onSuccess(SafetyNetApi.RecaptchaTokenResponse response) {
                        Log.d(TAG, "onSuccess");

                        if (!response.getTokenResult().isEmpty()) {

                            // Received reCaptcha token and This token still needs to be validated on
                            // the server using the SECRET key api.
                            new verifyTokenFromServer(response.getTokenResult(), feedback).execute();
                            Log.i(TAG, "onSuccess: " + response.getTokenResult());
                        }
                    }
                })
                .addOnFailureListener(this, new OnFailureListener() {
                    @Override
                    public void onFailure(@NonNull Exception e) {
                        if (e instanceof ApiException) {
                            ApiException apiException = (ApiException) e;
                            Log.d(TAG, "SafetyNet Error: " + CommonStatusCodes.getStatusCodeString(apiException.getStatusCode()));
                        } else {
                            Log.d(TAG, "Unknown SafetyNet error: " + e.getMessage());
                        }
                    }
                });
    }

    /**
     * Verifying the captcha token on the server
     * Server makes call to https://www.google.com/recaptcha/api/siteverify
     * with SECRET Key and SafetyNet token.
     */
    @SuppressLint("StaticFieldLeak")
    private class verifyTokenFromServer extends AsyncTask<String, String, String> {

        String sToken;
        String msg;

        public verifyTokenFromServer(String token, String message) {
            this.sToken = token;
            this.msg = message;
        }

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

        @Override
        protected String doInBackground(String... args) {

            // object to hold the information, which is sent to the server
            HashMap<String, String> hashMap = new HashMap<>();
            hashMap.put("recaptcha-response", sToken);
            // Optional params you can use like this
            // hashMap.put("feedback-message", msg);

            // Send the recaptcha response token and receive a Result in return
            return ApiPostHelper.SendParams(VERIFY_ON_API_URL_SERVER, hashMap);
        }

        @Override
        protected void onPostExecute(String result) {

            if (result == null)
                return;

            Log.i("onPost::: ", result);
            try {
                JSONObject jsonObject = new JSONObject(result);
                boolean success = jsonObject.getBoolean("success");
                String message = jsonObject.getString("message");

                if (success) {
                    // reCaptcha verified successfully.
                    linearLayoutForm.setVisibility(View.GONE);
                    Tv_Message.setVisibility(View.VISIBLE);
                } else {
                    Toast.makeText(getApplicationContext(), message, Toast.LENGTH_LONG).show();
                }

            } catch (JSONException e) {
                e.printStackTrace();
                Log.i("Error: ", e.getMessage());
            }

        }
    }

}

4. ☻ Don’t forget to change SAFETY_NET_API_KEY and VERIFY_ON_API_URL_SERVER  on “reCAPTCHA_Activity.kt” Kotlin class file replace the value with yours.

Please follow below link for server verification.

reCAPTCHA Token on Server API 

You can download our source code for captcha in android example. If you have any issues, queries or any suggestions please comment at below.

Enjoy the tutorial for Android example about integrating Google’s reCAPTCHA in app. Use this latest tutorial and share it. ?