How to integrate paytm in android using php?

Question

I have tried to integrate paytm using php. I followed this url for implementing paytm https://www.simplifiedcoding.net/paytm-integration-android-example/ . Then downloaded sample code of them to try. Changed all credential like MID, callback url and channel iD, etc. When running on device it open buying screen when tapping on buy button it takes to some time to load and show oops "Oops! Payment failed"

In android console i am able to get order id. Here is the code of constants.java

 package simplifiedcoding.net.paytmpaymentsample;

/**
* Created by Belal on 1/10/2018.
*/

public class Constants {

public static final String M_ID = "xxxxx301208461"; //Paytm Merchand Id 
we got it in paytm credentials
public static final String CHANNEL_ID = "WAP"; //Paytm Channel Id, got it in 
paytm credentials
public static final String INDUSTRY_TYPE_ID = "Retail"; //Paytm industry type 
got it in paytm credential

public static final String WEBSITE = "APP_STAGING";
public static final String CALLBACK_URL = 
"https://pguat.paytm.com/paytmchecksum/paytmCallback.jsp";


}

here is the code API.java

   package simplifiedcoding.net.paytmpaymentsample;

import retrofit2.Call;
import retrofit2.http.Field;
import retrofit2.http.FormUrlEncoded;
import retrofit2.http.POST;

 /**
 * Created by Belal on 1/10/2018.
 */

 public interface Api {

    //this is the URL of the paytm folder that we added in the server
  //make sure you are using your ip else it will not work
  String BASE_URL = "http://10.208.1.229/paytm/";

   @FormUrlEncoded
   @POST("generateChecksum.php")
   Call<Checksum> getChecksum(
        @Field("MID") String mId,
        @Field("ORDER_ID") String orderId,
        @Field("CUST_ID") String custId,
        @Field("CHANNEL_ID") String channelId,
        @Field("TXN_AMOUNT") String txnAmount,
        @Field("WEBSITE") String website,
        @Field("CALLBACK_URL") String callbackUrl,
        @Field("INDUSTRY_TYPE_ID") String industryTypeId
   );

  }

MainActivity.java code

    package simplifiedcoding.net.paytmpaymentsample;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
 import android.widget.TextView;
 import android.widget.Toast;

 import com.paytm.pgsdk.PaytmOrder;
 import com.paytm.pgsdk.PaytmPGService;
 import com.paytm.pgsdk.PaytmPaymentTransactionCallback;

import java.util.HashMap;
 import java.util.Map;

 import retrofit2.Call;
import retrofit2.Callback;
 import retrofit2.Response;
import retrofit2.Retrofit;
import retrofit2.converter.gson.GsonConverterFactory;

//implementing PaytmPaymentTransactionCallback to track the payment result.
 public class MainActivity extends AppCompatActivity implements 
 PaytmPaymentTransactionCallback {

//the textview in the interface where we have the price
TextView textViewPrice;

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

    //getting the textview
    textViewPrice = findViewById(R.id.textViewPrice);


    //attaching a click listener to the button buy
    findViewById(R.id.buttonBuy).setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {

            //calling the method generateCheckSum() which will generate the paytm checksum for payment
            generateCheckSum();
        }
    });

}

private void generateCheckSum() {

    //getting the tax amount first.
    String txnAmount = textViewPrice.getText().toString().trim();

    //creating a retrofit object.
    Retrofit retrofit = new Retrofit.Builder()
            .baseUrl(Api.BASE_URL)
            .addConverterFactory(GsonConverterFactory.create())
            .build();

    //creating the retrofit api service
    Api apiService = retrofit.create(Api.class);

    //creating paytm object
    //containing all the values required
    final Paytm paytm = new Paytm(
            Constants.M_ID,
            Constants.CHANNEL_ID,
            txnAmount,
            Constants.WEBSITE,
            Constants.CALLBACK_URL,
            Constants.INDUSTRY_TYPE_ID
    );

    //creating a call object from the apiService
    Call<Checksum> call = apiService.getChecksum(
            paytm.getmId(),
            paytm.getOrderId(),
            paytm.getCustId(),
            paytm.getChannelId(),
            paytm.getTxnAmount(),
            paytm.getWebsite(),
            paytm.getCallBackUrl(),
            paytm.getIndustryTypeId()
    );

    //making the call to generate checksum
    call.enqueue(new Callback<Checksum>() {
        @Override
        public void onResponse(Call<Checksum> call, Response<Checksum> response) {

            //once we get the checksum we will initiailize the payment.
            //the method is taking the checksum we got and the paytm object as the parameter
            initializePaytmPayment(response.body().getChecksumHash(), paytm);
        }

        @Override
        public void onFailure(Call<Checksum> call, Throwable t) {

        }
    });
}

private void initializePaytmPayment(String checksumHash, Paytm paytm) {

    //getting paytm service
    PaytmPGService Service = PaytmPGService.getStagingService();

    //use this when using for production
    //PaytmPGService Service = PaytmPGService.getProductionService();

    //creating a hashmap and adding all the values required
    Map<String, String> paramMap = new HashMap<>();
    paramMap.put("MID", Constants.M_ID);
    paramMap.put("ORDER_ID", paytm.getOrderId());
    paramMap.put("CUST_ID", paytm.getCustId());
    paramMap.put("CHANNEL_ID", paytm.getChannelId());
    paramMap.put("TXN_AMOUNT", paytm.getTxnAmount());
    paramMap.put("WEBSITE", paytm.getWebsite());
    paramMap.put("CALLBACK_URL", paytm.getCallBackUrl());
    paramMap.put("CHECKSUMHASH", checksumHash);
    paramMap.put("INDUSTRY_TYPE_ID", paytm.getIndustryTypeId());


    //creating a paytm order object using the hashmap
    PaytmOrder order = new PaytmOrder(paramMap);

    //intializing the paytm service
    Service.initialize(order, null);

    //finally starting the payment transaction
    Service.startPaymentTransaction(this, true, true, this);

}

//all these overriden method is to detect the payment result accordingly
@Override
public void onTransactionResponse(Bundle bundle) {

    Toast.makeText(this, bundle.toString(), Toast.LENGTH_LONG).show();
}

@Override
public void networkNotAvailable() {
    Toast.makeText(this, "Network error", Toast.LENGTH_LONG).show();
}

@Override
public void clientAuthenticationFailed(String s) {
    Toast.makeText(this, s, Toast.LENGTH_LONG).show();
}

@Override
public void someUIErrorOccurred(String s) {
    Toast.makeText(this, s, Toast.LENGTH_LONG).show();
}

@Override
public void onErrorLoadingWebPage(int i, String s, String s1) {
    Toast.makeText(this, s, Toast.LENGTH_LONG).show();
}

  @Override
  public void onBackPressedCancelTransaction() {
      Toast.makeText(this, "Back Pressed", Toast.LENGTH_LONG).show();
  }

   @Override
  public void onTransactionCancel(String s, Bundle bundle) {
    Toast.makeText(this, s + bundle.toString(), Toast.LENGTH_LONG).show();
  }
 }

Answer 1

For paytm integration there is 4 step process that you should follow. Some misleading information is given in Paytm Official documentation but you can follow this reference tutorial for lastest Paytm SDK integration 2019 .

1. Add Paytm Dependency
2. Add Runtime Permission & Paytm Activity
3. Get Merchant ID & Secret Key
4. Upload Checksum Files on Server
5. Generate Paytm Checksum
6. Start Paytm Payment Transaction

Add paytm dependency

   // paytm dependency
implementation('com.paytm:pgplussdk:1.2.3') {
   transitive = true;
}

Add runtime permission

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

Also add this line in main Activity class

if (ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.READ_SMS) != PackageManager.PERMISSION_GRANTED) {
          ActivityCompat.requestPermissions(MainActivity.this, new String[]{Manifest.permission.READ_SMS, Manifest.permission.RECEIVE_SMS}, 101);
      }

To Generate Paytm Checksum you first need to know Order id must be unique on every transaction even in test model transaction.

1. Order id and customer ID must be generate from Your Server only.
2. For testing model you can manually give order id and customer id.

The flow of android code is as follow -

Main Activity – get order id and customer id from App UI.

Pass order id and customer id to another activity name as checksum.java

get checksum from URL by passing param.

  String url ="https://www.blueappsoftware.com/payment/payment_paytm/generateChecksum.php";
        String varifyurl = "https://pguat.paytm.com/paytmchecksum/paytmCallback.jsp";
                           // "https://securegw-stage.paytm.in/theia/paytmCallback?ORDER_ID"+orderId;

 String param=
                "MID="+mid+
                "&ORDER_ID=" + orderId+
                "&CUST_ID="+custid+
                "&CHANNEL_ID=WAP&TXN_AMOUNT=100&WEBSITE=WEBSTAGING"+
                        "&CALLBACK_URL="+ varifyurl+"&INDUSTRY_TYPE_ID=Retail";

start paytm transaction by calling

 Service.startPaymentTransaction(checksum.this, true, true,
                    checksum.this  );

Please read this reference tutorial for complete process