diff --git a/build.gradle b/build.gradle
index 9788666..d371af7 100644
--- a/build.gradle
+++ b/build.gradle
@@ -12,7 +12,7 @@ buildscript {
     ]
 
     repositories {
-        jcenter()
+        mavenCentral()
         google()
     }
     dependencies {
diff --git a/example/src/main/java/co/paystack/example/MainActivity.java b/example/src/main/java/co/paystack/example/MainActivity.java
index 5b8901d..7588db6 100644
--- a/example/src/main/java/co/paystack/example/MainActivity.java
+++ b/example/src/main/java/co/paystack/example/MainActivity.java
@@ -211,6 +211,13 @@ public void beforeValidate(Transaction transaction) {
                 updateTextViews();
             }
 
+            @Override
+            public void showLoading(Boolean isProcessing) {
+                if (isProcessing) {
+                    Toast.makeText(MainActivity.this, "Processing...", Toast.LENGTH_LONG).show();
+                }
+            }
+
             @Override
             public void onError(Throwable error, Transaction transaction) {
                 // If an access code has expired, simply ask your server for a new one
diff --git a/paystack/src/main/java/co/paystack/android/Paystack.java b/paystack/src/main/java/co/paystack/android/Paystack.java
index 7c7aaa6..1002b90 100644
--- a/paystack/src/main/java/co/paystack/android/Paystack.java
+++ b/paystack/src/main/java/co/paystack/android/Paystack.java
@@ -82,7 +82,7 @@ private interface BaseCallback {
     public interface TransactionCallback extends BaseCallback {
         void onSuccess(Transaction transaction);
         void beforeValidate(Transaction transaction);
-
+        void showLoading(Boolean isProcessing);
         void onError(Throwable error, Transaction transaction);
     }
 
diff --git a/paystack/src/main/java/co/paystack/android/TransactionManager.java b/paystack/src/main/java/co/paystack/android/TransactionManager.java
index bf6faf4..fb874de 100644
--- a/paystack/src/main/java/co/paystack/android/TransactionManager.java
+++ b/paystack/src/main/java/co/paystack/android/TransactionManager.java
@@ -66,6 +66,7 @@ class TransactionManager {
         @Override
         public void onResponse(Call<TransactionApiResponse> call, Response<TransactionApiResponse> response) {
             handleApiResponse(response.body());
+            transactionCallback.showLoading(false);
         }
 
         @Override
@@ -166,6 +167,7 @@ private void chargeWithAvs(Address address) {
         HashMap<String, String> fields = address.toHashMap();
         fields.put("trans", transaction.getId());
         try {
+            this.transactionCallback.showLoading(true);
             Call<TransactionApiResponse> call = apiService.submitCardAddress(fields);
             call.enqueue(serverCallback);
         } catch (Exception e) {
@@ -175,20 +177,23 @@ private void chargeWithAvs(Address address) {
     }
 
     private void validateChargeOnServer() throws KeyManagementException, NoSuchAlgorithmException, KeyStoreException {
+        this.transactionCallback.showLoading(true);
         HashMap<String, String> params = validateRequestBody.getParamsHashMap();
         Call<TransactionApiResponse> call = apiService.validateCharge(params);
         call.enqueue(serverCallback);
     }
 
     private void reQueryChargeOnServer() throws KeyManagementException, NoSuchAlgorithmException, KeyStoreException {
+        this.transactionCallback.showLoading(true);
         Call<TransactionApiResponse> call = apiService.requeryTransaction(transaction.getId());
         call.enqueue(serverCallback);
     }
 
     private void initiateChargeOnServer() throws KeyManagementException, NoSuchAlgorithmException, KeyStoreException {
-
+        this.transactionCallback.showLoading(true);
         Call<TransactionApiResponse> call = apiService.charge(chargeRequestBody.getParamsHashMap());
         call.enqueue(serverCallback);
+
     }
 
     private void handleApiResponse(TransactionApiResponse transactionApiResponse) {
@@ -275,6 +280,7 @@ public void onTick(long millisUntilFinished) {
 
     private void notifyProcessingError(Throwable t) {
         setProcessingOff();
+        transactionCallback.showLoading(false);
         transactionCallback.onError(t, transaction);
     }