diff --git a/app/src/main/java/com/seafile/seadroid2/ui/WidgetUtils.java b/app/src/main/java/com/seafile/seadroid2/ui/WidgetUtils.java
index 10a00e33a..d8adb347e 100644
--- a/app/src/main/java/com/seafile/seadroid2/ui/WidgetUtils.java
+++ b/app/src/main/java/com/seafile/seadroid2/ui/WidgetUtils.java
@@ -199,18 +199,21 @@ public static void showFile(final BaseActivity activity, File file, boolean isOp
 
         String name = file.getName();
         String suffix = name.substring(name.lastIndexOf('.') + 1).toLowerCase();
-        if (!isOpenWith) {
-            //Open markdown and txt files in MarkdownActivity
-            if ("md".equals(suffix) || "markdown".equals(suffix) || "txt".equals(suffix)) {
-                startMarkdownActivity(activity, file.getPath());
-                activity.overridePendingTransition(0, 0);
-                return;
-            }
+
+        //Open markdown and txt files in MarkdownActivity
+        boolean isTextMime = Utils.isTextMimeType(name);
+        if (isTextMime && !isOpenWith) {
+            startMarkdownActivity(activity, file.getPath());
+            activity.overridePendingTransition(0, 0);
+            return;
         }
 
         String mime = MimeTypeMap.getSingleton().getMimeTypeFromExtension(suffix);
-        if (mime==null)
-            mime = "*/*"; // forces app chooser dialog on unknown type
+        if (mime == null && isTextMime) {
+            mime = "text/*"; // set .md  .markdown .txt file type//
+        } else if (mime == null) {
+            mime = "*/*"; // forces app chooser dialog on unknown type//
+        }
         Intent open = new Intent(Intent.ACTION_VIEW);
         open.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
 
diff --git a/app/src/main/java/com/seafile/seadroid2/ui/fragment/ReposFragment.java b/app/src/main/java/com/seafile/seadroid2/ui/fragment/ReposFragment.java
index 08d9aefcd..cdcb71f61 100644
--- a/app/src/main/java/com/seafile/seadroid2/ui/fragment/ReposFragment.java
+++ b/app/src/main/java/com/seafile/seadroid2/ui/fragment/ReposFragment.java
@@ -252,6 +252,10 @@ public void onClick(DialogInterface dialog, int which) {
             menu.findItem(R.id.delete).setVisible(false);
             menu.findItem(R.id.move).setVisible(false);
         }
+        if (!Utils.isTextMimeType(filename)) {
+            Menu menu = builder.build().getMenu();
+            menu.findItem(R.id.open).setVisible(false);
+        }
         builder.show();
         SeafRepo repo = getDataManager().getCachedRepoByID(repoID);
         if (repo != null && repo.encrypted) {
diff --git a/app/src/main/java/com/seafile/seadroid2/util/Utils.java b/app/src/main/java/com/seafile/seadroid2/util/Utils.java
index 58c048b7a..fb48d69d0 100644
--- a/app/src/main/java/com/seafile/seadroid2/util/Utils.java
+++ b/app/src/main/java/com/seafile/seadroid2/util/Utils.java
@@ -333,19 +333,19 @@ public static boolean isNetworkOn() {
         ConnectivityManager connMgr = (ConnectivityManager)
                 SeadroidApplication.getAppContext().getSystemService(
                         Context.CONNECTIVITY_SERVICE);
-
-        NetworkInfo wifi = connMgr.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
-        if(wifi != null && wifi.isAvailable()
-                && wifi.getDetailedState() == DetailedState.CONNECTED) {
-            return true;
+        NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();
+        if (networkInfo == null) {
+            return false;
         }
-
-        NetworkInfo mobile = connMgr.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);
-        if(mobile != null && mobile.isAvailable()
-                && mobile.getDetailedState() == DetailedState.CONNECTED) {
+        if (networkInfo.getType() == ConnectivityManager.TYPE_MOBILE) {
+            String extraInfo = networkInfo.getExtraInfo();
+            if (!TextUtils.isEmpty(extraInfo)) {
+                return true;
+            }
+        }
+        if (networkInfo.getType() == ConnectivityManager.TYPE_WIFI) {
             return true;
         }
-
         return false;
     }
 
@@ -733,6 +733,15 @@ public final static boolean isValidEmail(CharSequence target) {
         return !TextUtils.isEmpty(target) && android.util.Patterns.EMAIL_ADDRESS.matcher(target).matches();
     }
 
+    public static boolean isTextMimeType(String fileName) {
+        String suffix = fileName.substring(fileName.lastIndexOf('.') + 1).toLowerCase();
+        //file is markdown or  txt
+        if ("md".equals(suffix) || "markdown".equals(suffix) || "txt".equals(suffix)) {
+            return true;
+        }
+        return false;
+    }
+
     private static long lastClickTime;
 
     /**
@@ -849,4 +858,6 @@ public static void hideSystemNavigationBar(Activity activity) {
             decorView.setSystemUiVisibility(uiOptions);
         }
     }
+
+
 }