QFileDialog:如何通过触摸屏输入选择多个文件

由于我未能将复选框添加到项目视图中，我实现了一个"破解"的解决方案。它在对话框中添加了一个额外的可检查按钮，充当"ctrl"键。选中该按钮时，可以选择多个文件。这个解决方案有点难看，因为它依赖于了解对话框的内部，但它能完成任务。

这是标题的代码。。。

// file touchfiledialog.h
/*
Event filter that is used to add a shift modifier to left mouse button events.
This is used as a helper class for the TouchFileDialog
*/
class EventFilterCtrlModifier : public QObject
{
    Q_OBJECT;
    bool addCtrlModifier;
public:
    EventFilterCtrlModifier( QObject* parent);
    void setAddCtrlModifier(bool b);
protected:
    virtual bool eventFilter( QObject* watched, QEvent* e);
};

/*
TouchDialog adds the possibility to select multiple files with touch input to the QFileDialog.
This is done by adding an extra button which can be used as control key replacement.
*/
class QTOOLS_API TouchFileDialog : public QFileDialog
{
    Q_OBJECT
    EventFilterCtrlModifier* listViewEventFilter;
    EventFilterCtrlModifier* treeViewEventFilter;
    bool initialized;
public:
    TouchFileDialog( QWidget* parent);

protected:
    virtual void showEvent( QShowEvent* e);
private slots:
    void activateCtrlModifier(bool b);
private:
    void initObjectsForMultipleFileSelection();
};

随着实施。。。

// file touchfiledialog.cpp
#include "touchfiledialog.h"

EventFilterCtrlModifier::EventFilterCtrlModifier(QObject* parent)
    : QObject(parent)
    , addCtrlModifier(false)
{
}
void EventFilterCtrlModifier::setAddCtrlModifier(bool b)
{
    addCtrlModifier = b;
}
bool EventFilterCtrlModifier::eventFilter(QObject* watched, QEvent* e)
{
    QEvent::Type type = e->type();
    if( type == QEvent::MouseButtonPress || type == QEvent::MouseButtonRelease)
    {
        if( addCtrlModifier)
        {
            QMouseEvent* mouseEvent = static_cast<QMouseEvent*>(e);
            // Create and post a new event with ctrl modifier if the event does not already have one.
            if( !mouseEvent->modifiers().testFlag(Qt::ControlModifier)) 
            {
                QMouseEvent* newEventWithModifier = new QMouseEvent( 
                    type, 
                    mouseEvent->pos(),
                    mouseEvent->globalPos(), 
                    mouseEvent->button(),
                    mouseEvent->buttons(),
                    mouseEvent->modifiers() | Qt::ControlModifier
                    );
                QCoreApplication::postEvent(watched, newEventWithModifier);
                return true;    // absorb the original event
            }
        }
    }
    return false;
}

//#######################################################################################
TouchFileDialog::TouchFileDialog(QWidget* parent)
    : QFileDialog(parent)
    , listViewEventFilter(NULL)
    , treeViewEventFilter(NULL)
    , initialized(false)
{
}
void TouchFileDialog::showEvent(QShowEvent* e)
{
    // install objects that are needed for multiple file selection if needed
    if( !initialized)
    {
        if( fileMode() == QFileDialog::ExistingFiles)
        {
            initObjectsForMultipleFileSelection();
        }
        initialized = true;
    }
    QFileDialog::showEvent(e);
}
void TouchFileDialog::initObjectsForMultipleFileSelection()
{
    // install event filter to item views that are used to add ctrl modifiers to mouse events
    listViewEventFilter = new EventFilterCtrlModifier(this);
    QListView* listView = findChild<QListView*>();
    listView->viewport()->installEventFilter(listViewEventFilter);
    treeViewEventFilter = new EventFilterCtrlModifier(this);
    QTreeView* treeView = findChild<QTreeView*>();
    treeView->viewport()->installEventFilter(treeViewEventFilter);
    QGridLayout* dialogLayout = static_cast<QGridLayout*>(layout()); // Ugly because it makes assumptions about the internals of the QFileDialog
    QPushButton* pushButtonSelectMultiple = new QPushButton(this);
    pushButtonSelectMultiple->setText(tr("Select multiple"));
    pushButtonSelectMultiple->setCheckable(true);
    connect( pushButtonSelectMultiple, SIGNAL(toggled(bool)), this, SLOT(activateCtrlModifier(bool)));
    dialogLayout->addWidget(pushButtonSelectMultiple, 2, 0);
}
void ZFFileDialog::activateCtrlModifier(bool b)
{
    listViewEventFilter->setAddCtrlModifier(b);
    treeViewEventFilter->setAddCtrlModifier(b);
}

TouchFileDialog为项目视图安装一个事件过滤器，当选中对话框中的相应按钮时，该过滤器将为视图的鼠标事件添加一个ControlModifier。

请随意发布其他解决方案，因为这在某种程度上是即兴创作的。