QMainWindow中自定义槽函数控制QDockWidget的显示问题

下面是定义的一个测试QMainWindow的类，在这个类里我们来测试一下QObject::connect(scrollBar, SIGNAL(valueChanged(int)),
label, SLOT(setNum(int)));
设计的测试思路是这样的，在QMainWindow的UI文件中画上菜单，同时在QMainWindow类文件定义QDockWiget，目的就是通过菜单的响应来测试connect函数，具体类定义如下：
//deviceinfoview.h
class DeviceInfoView : public QMainWindow
{

Q_OBJECT

public:

DeviceInfoView(QWidget *parent = 0);

~DeviceInfoView();

private:

void initDockWiget();

private:
Ui::DeviceInfoView *ui;

QDockWidget *dockWidget;

QDirModel *model;

QTreeView * treeView;

signals:
void setShowDockingSignals(bool shown);

private slots:
void setShowDockingSlot(bool shown);

};

类定义就不在详细解释，主要注意一下，我们自定义了信号void setShowDockingSignals(bool shown)和自定义了槽函数void setShowDockingSlot(bool shown)。

下面看源文件：

////deviceinfoview.cpp
DeviceInfoView::DeviceInfoView(QWidget *parent)

: QMainWindow(parent)

, ui(new Ui::DeviceInfoView)

, bShow(false)

{
ui->setupUi(this);

model = new QDirModel;

model->setReadOnly(false);

model->setSorting(QDir::DirsFirst|QDir::IgnoreCase|QDir::Name);

ui->deviceTreeView->setModel(model);

ui->deviceTreeView->header()->setStretchLastSection(true);

ui->deviceTreeView->header()->setSortIndicator(0,Qt::AscendingOrder);

ui->deviceTreeView->header()->setSortIndicatorShown(true);

ui->deviceTreeView->header()->setClickable(true);

QModelIndex index = model->index(QDir::rootPath());

ui->deviceTreeView->expand(index);

ui->deviceTreeView->scrollTo(index);

ui->deviceTreeView->resizeColumnToContents(0);

QHBoxLayout *btnLayout = new QHBoxLayout;

QVBoxLayout *mainLayout = new QVBoxLayout(this);

mainLayout->addWidget(ui->deviceTreeView);

mainLayout->addLayout(btnLayout);

this->setLayout(mainLayout);
///this->setCentralWidget(ui->deviceTreeView);

ui->actionDocking->setCheckable(true); //将设备器工具栏菜单设置为可复选

ui->actionDocking->setChecked(true); //默认为选中

ui->actionDocking->setVisible(true); //默认为显示设备器工具栏

initDockWiget();

connect(ui->pushButton,SIGNAL(clicked()),this,SLOT(setShowDocking()));

connect(ui->actionDocking, SIGNAL(triggered(bool)),dockWidget, SLOT(setShown(bool)));
}//end of construction DeviceInfoView

DeviceInfoView::~DeviceInfoView()

{
delete ui;
}//end of distruciton DeviceInfoView

void DeviceInfoView::initDockWiget(){

QWidget *dv = new QLabel("Docking");

dockWidget = new QDockWidget("Test",this);

dockWidget->setAllowedAreas(Qt::RightDockWidgetArea);

dockWidget->setFeatures(QDockWidget::AllDockWidgetFeatures);

dockWidget->setFloating(false);

dockWidget->setWidget(dv);

dockWidget->setVisible(true);

addDockWidget(Qt::RightDockWidgetArea,dockWidget);

}//end of method initDockWiget

void DeviceInfoView::setShowDockingSlot(bool shown){

dockWidget->setShown(shown);

}//end of slots setShowDockingSlot

以上是完整的源文件，我测试的时候，点击菜单按钮，能够正常的隐藏和显示dockWidget，但是当我将connect(ui->actionDocking, SIGNAL(triggered(bool)),dockWidget, SLOT(setShown(bool)));这一句的SLOT换成我自定义的槽函数setShowDockingSlot(bool shown)的时候，dockWidget就无法正常隐藏和显示了，点击菜单毫无反应。

请问各位达人，在自定义的槽函数中同样是通过QDockWidget对象dockWidget来调用了setShown(bool)，为何无法正常控制dockWidget的隐藏和显示呢？

QT Creator 在ubuntu下编写的源代码已上传我的资源 http://download.csdn.net/source/2101907。
期待与各位热心达人交流！

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