Prevent null pointer exception

app/src/main/java/cy/agorise/crystalwallet/views/CryptoNetBalanceViewHolder.java

@@ -125,8 +125,10 @@ public class CryptoNetBalanceViewHolder extends RecyclerView.ViewHolder {
         preferedCurrencySetting.observe((LifecycleOwner)this.itemView.getContext(), new Observer<GeneralSetting>() {
             @Override
             public void onChanged(@Nullable GeneralSetting generalSetting) {
+                if(generalSetting != null){
                     preferredCurrency = generalSetting.getValue();
                 }
+            }
         });
 
     }