是否可以创建一个可调整大小的QMenu？

Question

我有一个弹出的QMenu，它在QListView中显示了很多图标：

QMenu*menu=createMenu();
QListView*list=createList();
QWidgetAction*action=new QWidgetAction(menu);
action->setDefaultWidget(list);
menu->addAction(action);
menu->show();

​

​

是否有使其可调整大小的方法?，即我希望能够拖动弹出式菜单的角并用鼠标调整弹出式菜单的大小。我无法在google或Qt文档中找到这一点。

Answer 1

就像这样：

...
QListView*list=createList();
Qt::WindowFlags winFlags = list->windowFlags();
winFlags = winFlags & ~Qt::MSWindowsFixedSizeDialogHint;
list->setWindowFlags(winFlags);
...

或者menu上同样的事情

Answer 2

您需要创建一个自定义弹出窗口小部件。我不知道如何正确地捕捉焦点事件，但通常的想法是：

MegaPopup.h

#ifndef MEGAPOPUP_H
#define MEGAPOPUP_H

#include <QWidget>
#include <QPointer>
#include <QListView>
#include <QStandardItemModel>
#include <QVBoxLayout>
#include <QAction>
#include <QVariant>
#include <QCursor>

class MegaPopup
    : public QWidget
{
    Q_OBJECT

private:
    enum Roles
    {
        ActionRole = Qt::UserRole,
    };

public:
    MegaPopup( QWidget *parent );
    ~MegaPopup();

    void addItem( QAction *action );

public slots:
    void showMenu();

private:
    QPointer< QListView > m_view;
    QPointer< QStandardItemModel > m_model;

private slots:
    void onClicked( const QModelIndex& index );
    void onDestroyed();
};

Q_DECLARE_METATYPE( QAction * )

#endif // MEGAPOPUP_H

MeraPopup.cpp

#include "MegaPopup.h"


MegaPopup::MegaPopup( QWidget *parent )
    : QWidget( parent, Qt::Window | Qt::CustomizeWindowHint )
{
    qRegisterMetaType< QAction * >();

    m_model = new QStandardItemModel( this );
    m_view = new QListView( this );
    QVBoxLayout *l = new QVBoxLayout();

    setLayout( l );
    l->addWidget( m_view );
    m_view->setModel( m_model );
    m_view->setViewMode( QListView::IconMode );

    connect( m_view, &QListView::clicked, this, &MegaPopup::onClicked );
}

MegaPopup::~MegaPopup()
{
}

void MegaPopup::addItem( QAction* action )
{
    Q_ASSERT( action );
    QStandardItem *item = new QStandardItem();

    // Magic
    item->setData( QVariant::fromValue< QAction * >( action ), ActionRole );
    item->setEnabled( action->isEnabled() );
    item->setFont( action->font() );
    item->setIcon( action->icon() );
    item->setText( action->text() );
    item->setToolTip( action->toolTip() );

    m_model->appendRow( item );

    connect( action, &QAction::destroyed, this, &MegaPopup::onDestroyed );
}

void MegaPopup::showMenu()
{
    move( QCursor::pos() );
    show();
}

void MegaPopup::onClicked( const QModelIndex& index )
{
    QStandardItem *item = m_model->itemFromIndex( index );
    QAction *action = item->data( ActionRole ).value< QAction * >();
    action->trigger();
    hide();
}

void MegaPopup::onDestroyed()
{
    QAction *toDel = qobject_cast< QAction * >( sender() );

    const int n = m_model->rowCount();
    for ( int i = 0; i < n; i++ )
    {
        QStandardItem *item = m_model->item( i );
        QAction *action = item->data( ActionRole ).value< QAction * >();
        if ( action == toDel )
        {
            delete item;
            break;
        }
    }
}