fix : align of center widget

adjust the align of cetner widget as design

Log: fix the design of center listvie
Issue: linuxdeepin/developer-center#3597
Influence: the appearance of the mainwindow of control center
Change-Id: I0971297d941397c9da8a9d431ebb7ac3be4e5b73

src/frame/mainmodule.cpp

@@ -106,15 +106,18 @@ class MainModulePrivate
             m_view->setGridSize(ListViweItemSize_IconMode);
             m_view->setContentsMargins(0, 0, 0, 0);
             m_view->setSpacing(20);
-            m_view->setAlignment(Qt::AlignCenter);
+            m_view->setAlignment(Qt::AlignHCenter);
 
             while (!m_layout->isEmpty()) {
                 QLayoutItem *item = m_layout->takeAt(0);
                 if (item->widget() && item->widget() != m_view && item->widget() != m_sidebarWidget)
                     delete item->widget();
                 delete item;
             }
-            m_layout->addWidget(m_view);
+            QVBoxLayout *vlayout = new QVBoxLayout;
+            vlayout->addSpacing(20);
+            vlayout->addWidget(m_view);
+            m_layout->addLayout(vlayout);
 
             m_view->setMinimumWidth(0);
             m_view->setMaximumWidth(QWIDGETSIZE_MAX);