constant, prevent possible NPE

src/com/owncloud/android/ui/activity/ShareActivity.java

@@ -65,6 +65,7 @@ public class ShareActivity extends FileActivity
     private static final String TAG_SHARE_FRAGMENT = "SHARE_FRAGMENT";
     private static final String TAG_SEARCH_FRAGMENT = "SEARCH_USER_AND_GROUPS_FRAGMENT";
     private static final String TAG_EDIT_SHARE_FRAGMENT = "EDIT_SHARE_FRAGMENT";
+    private static final String TAG_PUBLIC_LINK = "PUBLIC_LINK";
 
     /// Tags for dialog fragments
     private static final String FTAG_CHOOSER_DIALOG = "CHOOSER_DIALOG";
@@ -295,7 +296,7 @@ public class ShareActivity extends FileActivity
             String link = "";
             for (Object object : result.getData()) {
                 OCShare shareLink = (OCShare) object;
-                if (shareLink.getShareType().name().equalsIgnoreCase("PUBLIC_LINK")) {
+                if (TAG_PUBLIC_LINK.equalsIgnoreCase(shareLink.getShareType().name())) {
                     link = shareLink.getShareLink();
                     break;
                 }