Add a GUIMessageDialog class.

src/guimessagedialog.h

@@ -0,0 +1,30 @@
+#ifndef GUIMESSAGEDIALOG_H
+#define GUIMESSAGEDIALOG_H
+
+#include <QDialog>
+#include <QList>
+namespace Ui {
+class GUIMessageDialog;
+}
+
+class GUIMessageDialog : public QDialog
+{
+    Q_OBJECT
+
+public:
+    explicit GUIMessageDialog(QWidget *parent = nullptr);
+    ~GUIMessageDialog();
+    void showMessage(QString msg);
+    void showExitButton();
+    void startLoading();
+    void stopLoading();
+protected:
+    void timerEvent(QTimerEvent* event) override ;
+private:
+    Ui::GUIMessageDialog *ui;
+    QList<QString> frame;
+    int frameIndex=0;
+    int timerID = -1;
+};
+
+#endif // GUIMESSAGEDIALOG_H