set initial focus to window

QTProject/mainwindow.cpp

@@ -53,7 +53,7 @@ MainWindow::MainWindow(QWidget *parent) :
 
     this->setCentralWidget(m_centralWidget);
     m_centralWidget->setFocusPolicy(Qt::StrongFocus);
-
+    m_centralWidget->setFocus();
     //  showMaximized();
 }