Add dialog when server is unreachable

app/src/main/res/layout/dialog_server_unreachable.xml

@@ -0,0 +1,11 @@
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:orientation="vertical">
+
+    <TextView
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:gravity="center"
+        android:text="aaaaaa" />
+</LinearLayout>