added timer for volume changes

mainwindow.h

@@ -2,6 +2,7 @@
 #define MAINWINDOW_H
 
 #include <QMainWindow>
+#include <QTimer>
 #include "QtNetwork/QNetworkAccessManager"
 
 namespace Ui {
@@ -18,9 +19,6 @@ public:
     explicit MainWindow(QWidget *parent = 0);
     ~MainWindow();
 
-protected:
-    void func();
-
 private slots:
     void on_btn_onoff_clicked();
     void replyFinished(QNetworkReply *reply);
@@ -32,12 +30,15 @@ private:
     Ui::MainWindow *ui;
 
     QString mAddress;
-
+    QTimer mTimer;
     bool mPowered = false;
     int mVolume = 0;
+    const int WAITTIME = 300;
+
 
     void sendCommand(QString cmd);
     void updateUi();
+    void sendVolume();
 };
 
 }