NonNull annotations
diff --git a/sample/src/main/java/com/davemorrissey/labs/subscaleview/test/extension/ExtensionCircleFragment.java b/sample/src/main/java/com/davemorrissey/labs/subscaleview/test/extension/ExtensionCircleFragment.java
index cb79bbe..cff6907 100644
--- a/sample/src/main/java/com/davemorrissey/labs/subscaleview/test/extension/ExtensionCircleFragment.java
+++ b/sample/src/main/java/com/davemorrissey/labs/subscaleview/test/extension/ExtensionCircleFragment.java
@@ -1,6 +1,7 @@
 package com.davemorrissey.labs.subscaleview.test.extension;
 
 import android.os.Bundle;
+import android.support.annotation.NonNull;
 import android.support.v4.app.Fragment;
 import android.view.LayoutInflater;
 import android.view.View;
@@ -14,7 +15,7 @@
 public class ExtensionCircleFragment extends Fragment {
 
     @Override
-    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
+    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
         View rootView = inflater.inflate(layout.extension_circle_fragment, container, false);
         rootView.findViewById(id.next).setOnClickListener(new View.OnClickListener() {
             @Override public void onClick(View v) { ((ExtensionActivity) ExtensionCircleFragment.this.getActivity()).next(); }