Add a class called DeviceManager to manage ShimLib operation.

src/device/DeviceManager.h

@@ -0,0 +1,32 @@
+//
+// Created by Krad on 2021/10/12.
+//
+
+#ifndef GUI_DEVICEMANAGER_H
+#define GUI_DEVICEMANAGER_H
+
+#include <QObject>
+class DeviceManager:public QObject {
+    Q_OBJECT
+
+public:
+    static DeviceManager* Default(){
+        static DeviceManager manager;
+        return &manager;
+    }
+    void setDeviceErrorCallBack();
+    void initDevice();
+
+protected:
+    void timerEvent(QTimerEvent* event) override ;
+
+private:
+    void processScan(const char * json);
+    int timerID = -1;
+    int lastStatus=-1;
+    bool previewing = false;
+    bool errorOccured = false;
+};
+
+
+#endif //GUI_DEVICEMANAGER_H