diff --git a/app/src/main/java/com/supwisdom/conferencecheck/activity/MainActivity.java b/app/src/main/java/com/supwisdom/conferencecheck/activity/MainActivity.java
index c55ea5d..1294aa3 100644
--- a/app/src/main/java/com/supwisdom/conferencecheck/activity/MainActivity.java
+++ b/app/src/main/java/com/supwisdom/conferencecheck/activity/MainActivity.java
@@ -51,7 +51,7 @@
     private Bitmap bitmap;
 
     private Pos pos;
-    private String qrcode_url = "";
+    private String qrcode_url = ""; // 
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {