Preventing a NPE

- We're now checking that there is a selected node before trying to use it, and in case there is none we schedule a
retry in DEFAULT_INITIAL_DELAY ms.

graphenej/src/main/java/cy/agorise/graphenej/api/android/NetworkService.java

@@ -229,9 +229,13 @@ public class NetworkService extends Service {
                 .writeTimeout(5, TimeUnit.SECONDS)
                 .build();
         mSelectedNode = nodeProvider.getBestNode();
-        Log.v(TAG,"connect.url: "+ mSelectedNode.getUrl()+", latency: "+mSelectedNode.getLatencyValue());
+        if(mSelectedNode != null){
             Request request = new Request.Builder().url(mSelectedNode.getUrl()).build();
             mWebSocket = client.newWebSocket(request, mWebSocketListener);
+        }else{
+            // If no node could be found yet, schedule a new attempt in DEFAULT_INITIAL_DELAY ms
+            mHandler.postDelayed(mConnectAttempt, DEFAULT_INITIAL_DELAY);
+        }
     }
 
     public long sendMessage(String message){