diff --git a/src/loginwindow.cpp b/src/loginwindow.cpp
index 5cd734b..1aec43c 100644
--- a/src/loginwindow.cpp
+++ b/src/loginwindow.cpp
@@ -100,7 +100,6 @@ void LoginWindow::initUi()
     m_pVMainLayout->addSpacerItem(new QSpacerItem(20,20,QSizePolicy::Minimum,QSizePolicy::Expanding));
 
 	initUserList();
-    SQLHelper::Open();
 }
 
 void LoginWindow::init()
diff --git a/src/main.cpp b/src/main.cpp
index bb61b90..ade262d 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -3,6 +3,7 @@
 #include "loginwindow.h"
 #include "InputObject.h"
 #include <QQmlApplicationEngine>
+#include <src/db/SQLHelper.h>
 
 int main(int argc, char *argv[])
 {
@@ -25,23 +26,21 @@ int main(int argc, char *argv[])
 
 	//a.installEventFilter(obj);
     InputObject *obj = new InputObject();
-
 	a.installEventFilter(obj);
-
-    needLogin:
-    LoginWindow l;
-    l.showFullScreen();
-
-
+    SQLHelper::Open();
     MainWindow w;
+    w.showFullScreen();
+    LoginWindow l;
+    needLogin:
+    l.showFullScreen();
     int rec =  l.exec();
     if (rec !=QDialog::Accepted )
     {
         goto needLogin;
     }
 //    l.deleteLater();
+    w.centerWidgetShow();
 
-    w.showFullScreen();
 
     return a.exec();
 }
diff --git a/src/mainwindow.cpp b/src/mainwindow.cpp
index 75ac857..0304de1 100644
--- a/src/mainwindow.cpp
+++ b/src/mainwindow.cpp
@@ -131,9 +131,18 @@ MainWindow::MainWindow(QWidget *parent) :
         msgDialog->hide();
     });
     DeviceManager::Default()->initDevice();
+    centerWidgetHide();
 }
 
 MainWindow::~MainWindow()
 {
     delete ui;
 }
+
+void MainWindow::centerWidgetHide() {
+    ui->centralWidget->hide();
+}
+
+void MainWindow::centerWidgetShow() {
+    ui->centralWidget->show();
+}
diff --git a/src/mainwindow.h b/src/mainwindow.h
index 1642914..122aab6 100644
--- a/src/mainwindow.h
+++ b/src/mainwindow.h
@@ -14,7 +14,8 @@ class MainWindow : public QMainWindow
 public:
     explicit MainWindow(QWidget *parent = nullptr);
     ~MainWindow();
-
+    void centerWidgetHide();
+    void centerWidgetShow();
 private:
     Ui::MainWindow *ui;
     GUIMessageDialog* msgDialog = nullptr;