Fixed multiple pro fragments

app/src/amazon/java/eu/faircode/email/ActivityBilling.java

@@ -80,9 +80,12 @@ public class ActivityBilling extends ActivityBase implements PurchasingListener,
         if (standalone) {
             setContentView(R.layout.activity_billing);
 
+            int count = getSupportFragmentManager().getBackStackEntryCount();
+            if (count == 0) {
                 FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
                 fragmentTransaction.replace(R.id.content_frame, new FragmentPro()).addToBackStack("pro");
                 fragmentTransaction.commit();
+            }
 
             getSupportActionBar().setDisplayHomeAsUpEnabled(true);
 

app/src/fdroid/java/eu/faircode/email/ActivityBilling.java

@@ -98,9 +98,12 @@ public class ActivityBilling extends ActivityBase implements
         if (standalone) {
             setContentView(R.layout.activity_billing);
 
+            int count = getSupportFragmentManager().getBackStackEntryCount();
+            if (count == 0) {
                 FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
                 fragmentTransaction.replace(R.id.content_frame, new FragmentPro()).addToBackStack("pro");
                 fragmentTransaction.commit();
+            }
 
             getSupportActionBar().setDisplayHomeAsUpEnabled(true);
 

app/src/github/java/eu/faircode/email/ActivityBilling.java

@@ -98,9 +98,12 @@ public class ActivityBilling extends ActivityBase implements
         if (standalone) {
             setContentView(R.layout.activity_billing);
 
+            int count = getSupportFragmentManager().getBackStackEntryCount();
+            if (count == 0) {
                 FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
                 fragmentTransaction.replace(R.id.content_frame, new FragmentPro()).addToBackStack("pro");
                 fragmentTransaction.commit();
+            }
 
             getSupportActionBar().setDisplayHomeAsUpEnabled(true);
 
@@ -314,6 +317,7 @@ public class ActivityBilling extends ActivityBase implements
                 Log.unexpectedError(getSupportFragmentManager(), ex);
             }
     }
+
     /*
         private void onPurchaseConsume(Intent intent) {
             billingClient.queryPurchasesAsync(BillingClient.SkuType.INAPP, new PurchasesResponseListener() {

app/src/play/java/eu/faircode/email/ActivityBilling.java

@@ -98,9 +98,12 @@ public class ActivityBilling extends ActivityBase implements
         if (standalone) {
             setContentView(R.layout.activity_billing);
 
+            int count = getSupportFragmentManager().getBackStackEntryCount();
+            if (count == 0) {
                 FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
                 fragmentTransaction.replace(R.id.content_frame, new FragmentPro()).addToBackStack("pro");
                 fragmentTransaction.commit();
+            }
 
             getSupportActionBar().setDisplayHomeAsUpEnabled(true);