Add delay for network connection checking based on pull request #190.

Many thanks to franglais12 .

src/extension.js

@@ -353,6 +353,11 @@ const OpenweatherMenuButton = new Lang.Class({
             this._network_monitor_connection = undefined;
         }
 
+        if (this._timeoutCheckConnectionState)
+            Mainloop.source_remove(this._timeoutCheckConnectionState);
+
+        this._timeoutCheckConnectionState = undefined;
+
         if (this._settingsC) {
             this._settings.disconnect(this._settingsC);
             this._settingsC = undefined;
@@ -506,17 +511,27 @@ const OpenweatherMenuButton = new Lang.Class({
     },
 
     _checkConnectionState: function() {
+        if (this._timeoutCheckConnectionState) {
+            Mainloop.source_remove(this._timeoutCheckConnectionState);
+            this._timeoutCheckConnectionState = undefined;
+        }
+
+        let interval = 1250;
+        this._oldConnected = this._connected;
+        this._connected = false;
+
+        this._timeoutCheckConnectionState = Mainloop.timeout_add(interval, Lang.bind(this, function() {
             let url = this.getWeatherProviderURL();
             let address = Gio.NetworkAddress.parse_uri(url, 80);
             let cancellable = Gio.Cancellable.new();
-        this._oldConnected = this._connected;
-        this._connected = false;
             try {
                 this._network_monitor.can_reach_async(address, cancellable, Lang.bind(this, this._asyncReadyCallback));
             } catch (err) {
                 let title = _("Can not connect to %s").format(url);
                 log(title + '\n' + err.message);
             }
+            return false;
+        }));
     },
 
     _asyncReadyCallback: function(nm, res) {