How to implement PayUmonney in Android & how to create a Hash key in local because I don't know how to create in server - performance

Question

public void PayuMonney(){
**JAVA
this method i am using in my code but it's not done
here i am use payumonney code given to Documentation https://payumobile.gitbook.io/sdk-integration/android/payucheckoutpro. i trying too much but the toast appear in "invalid Hash"**
PayUPaymentParams.Builder builder = new PayUPaymentParams.Builder();
builder.setAmount(mAmount)
.setIsProduction(true)
.setProductInfo(mProductInfo)
.setKey(mMerchantKey)
.setPhone(mPhoneNumber)
.setTransactionId(mTXNId)
.setFirstName(mFirstName)
.setEmail(mEmailId)
.setSurl("https://www.payumoney.com/mobileapp/payumoney/success.php")
.setFurl("https://www.payumoney.com/mobileapp/payumoney/failure.php");
**Optional can contain any additional PG params**
PayUPaymentParams payUPaymentParams = builder.build();
***here i am calling Payuminney checkout process Sample code***
PayUCheckoutPro.open(
this,
payUPaymentParams,
new PayUCheckoutProListener() {
#Override
public void onPaymentSuccess(Object response) {
//Cast response object to HashMap
HashMap<String,Object> result = (HashMap<String, Object>) response;
String payuResponse = (String)result.get(PayUCheckoutProConstants.CP_PAYU_RESPONSE);
String merchantResponse = (String) result.get(PayUCheckoutProConstants.CP_MERCHANT_RESPONSE);
}
#Override
public void onPaymentFailure(Object response) {
//Cast response object to HashMap
HashMap<String,Object> result = (HashMap<String, Object>) response;
String payuResponse = (String)result.get(PayUCheckoutProConstants.CP_PAYU_RESPONSE);
String merchantResponse = (String) result.get(PayUCheckoutProConstants.CP_MERCHANT_RESPONSE);
}
#Override
public void onPaymentCancel(boolean isTxnInitiated) {
}
#Override
public void onError(ErrorResponse errorResponse) {
*//code give some error toast here i the onError fuction*
String errorMessage = errorResponse.getErrorMessage();
Toast.makeText(FinalPlaceOrderActivity.this, errorMessage, Toast.LENGTH_SHORT).show();
}
#Override
public void setWebViewProperties(#Nullable WebView webView, #Nullable Object o) {
*//For setting webview properties, if any. Check Customized Integration section for more details on this*
}
#Override
public void generateHash(HashMap<String, String> valueMap, PayUHashGenerationListener hashGenerationListener) {
String hashName = valueMap.get(PayUCheckoutProConstants.CP_HASH_NAME);
String hashData = valueMap.get(PayUCheckoutProConstants.CP_HASH_STRING);
if (!TextUtils.isEmpty(hashName) && !TextUtils.isEmpty(hashData)) {
*//Do not generate a hash from local, it needs to be calculated from server-side only. Here, hashString contains hash created from your server side.
//here i am call the server file where generate a hash*
StringRequest OrderPlace = new StringRequest(Request.Method.POST, "url link", new Response.Listener() {
#Override
public void onResponse(String response) {
//here i am get hash from the server
System.out.println(response);
String merchandHsh = response;
HashMap<String, String> dataMap = new HashMap<>();
dataMap.put(hashName, merchandHsh);
hashGenerationListener.onHashGenerated(dataMap);
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(getApplicationContext(), "We can't process this time..", Toast.LENGTH_SHORT).show();
}
}
) {
#Nullable
#Override
protected Map<String, String> getParams() throws AuthFailureError {
Map<String, String> map = new HashMap<String, String>();
map.put("key", mMerchantKey);
map.put("texID", mTXNId);
map.put("amount", mAmount);
map.put("productname", mProductInfo);
map.put("name", mFirstName);
map.put("email", mEmailId);
return map;
}
};
Volley.newRequestQueue(FinalPlaceOrderActivity.this).add(OrderPlace);
}
}
}
);
}
but the toast appears a "Hash invalid". this method I am using in my code but it's not done
here I am using the pay money code given to Documentation https://payumobile.gitbook.io/sdk-integration/android/payucheckoutpro. I trying too much but the toast appears in "invalid Hash"
How to implement PayUmonney in Android & how to create a Hash key in local because I don't know how to create in server