gui: Convert UI to use Fragments

Change-Id: I7269604a1da72e6b22f4bbac31c1f5561660ccf5
Refs: #2646, #2667
diff --git a/app/src/main/res/layout/fragment_main.xml b/app/src/main/res/layout/fragment_main.xml
new file mode 100644
index 0000000..9fa4afa
--- /dev/null
+++ b/app/src/main/res/layout/fragment_main.xml
@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:orientation="vertical"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    style="@style/default_linear_layout_padding"
+    >
+
+    <TextView
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:text="@string/pref_category_title_general"
+        style="?android:listSeparatorTextViewStyle"
+        />
+
+    <Switch
+        android:id="@+id/nfd_start_stop_switch"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_gravity="center_horizontal"
+        android:text="@string/checking_on_nfd"
+        />
+
+</LinearLayout>
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