修复导航栏自定义导航部件没有居中的问题 (#388)

qfluentwidgets/components/navigation/navigation_bar.py

@@ -269,13 +269,13 @@ class NavigationBar(QWidget):
         """ insert widget to layout """
         if position == NavigationItemPosition.TOP:
             widget.setParent(self)
-            self.topLayout.insertWidget(index, widget, 0, Qt.AlignTop)
+            self.topLayout.insertWidget(index, widget, 0, Qt.AlignTop | Qt.AlignHCenter)
         elif position == NavigationItemPosition.SCROLL:
             widget.setParent(self.scrollWidget)
-            self.scrollLayout.insertWidget(index, widget, 0, Qt.AlignTop)
+            self.scrollLayout.insertWidget(index, widget, 0, Qt.AlignTop | Qt.AlignHCenter)
         else:
             widget.setParent(self)
-            self.bottomLayout.insertWidget(index, widget, 0, Qt.AlignBottom)
+            self.bottomLayout.insertWidget(index, widget, 0, Qt.AlignBottom | Qt.AlignHCenter)
 
         widget.show()