Prompt users to turn on Wifi in Cloud Storage and OPDS Browser (#2650)

* prompt users to turn on Wifi in Cloud Storage and OPDS Browser

frontend/apps/cloudstorage/cloudstorage.lua

@@ -101,6 +101,11 @@ end
 
 function CloudStorage:openCloudServer(url)
     local tbl
+    local NetworkMgr = require("ui/network/manager")
+    if not NetworkMgr:isOnline() then
+        NetworkMgr:promptWifiOn()
+        return
+    end
     if self.type == "dropbox" then
         tbl = DropBox:run(url, self.password)
     elseif self.type == "ftp" then

frontend/ui/widget/opdsbrowser.lua

@@ -353,8 +353,7 @@ end
 
 function OPDSBrowser:getCatalog(feed_url)
     local ok, catalog = pcall(self.parseFeed, self, feed_url)
-    -- prompt users to turn on Wifi if network is unreachable
-    if not ok and catalog and (catalog:find("Network is unreachable") or catalog:find("host or service not provided")) then
+    if not ok and catalog and not NetworkMgr:isOnline() then
         NetworkMgr:promptWifiOn()
         return
     elseif not ok and catalog then