qdatawidgetmapper.cpp

奇趣公司比较新的qt/emd版本

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#include "qdatawidgetmapper.h"

#ifndef QT_NO_DATAWIDGETMAPPER

#include "qabstractitemmodel.h"
#include "qitemdelegate.h"
#include "qmetaobject.h"
#include "qwidget.h"
#include "private/qobject_p.h"
#include "private/qabstractitemmodel_p.h"

class QDataWidgetMapperPrivate: public QObjectPrivate
{
public:
    Q_DECLARE_PUBLIC(QDataWidgetMapper)

    QDataWidgetMapperPrivate()
        : model(QAbstractItemModelPrivate::staticEmptyModel()), delegate(0),
          orientation(Qt::Horizontal), submitPolicy(QDataWidgetMapper::AutoSubmit)
    {
    }

    QAbstractItemModel *model;
    QAbstractItemDelegate *delegate;
    Qt::Orientation orientation;
    QDataWidgetMapper::SubmitPolicy submitPolicy;
    QPersistentModelIndex rootIndex;
    QPersistentModelIndex currentTopLeft;

    inline int itemCount()
    {
        return orientation == Qt::Horizontal
            ? model->rowCount(rootIndex)
            : model->columnCount(rootIndex);
    }

    inline int currentIdx() const
    {
        return orientation == Qt::Horizontal ? currentTopLeft.row() : currentTopLeft.column();
    }

    inline QModelIndex indexAt(int itemPos)
    {
        return orientation == Qt::Horizontal
            ? model->index(currentIdx(), itemPos, rootIndex)
            : model->index(itemPos, currentIdx(), rootIndex);
    }

    inline void flipEventFilters(QAbstractItemDelegate *oldDelegate,
                                 QAbstractItemDelegate *newDelegate)
    {
        for (int i = 0; i < widgetMap.count(); ++i) {
            QWidget *w = widgetMap.at(i).widget;
            if (!w)
                continue;
            w->removeEventFilter(oldDelegate);
            w->installEventFilter(newDelegate);
        }
    }

    void populate();

    // private slots
    void _q_dataChanged(const QModelIndex &topLeft, const QModelIndex &bottomRight);
    void _q_commitData(QWidget *);
    void _q_closeEditor(QWidget *, QAbstractItemDelegate::EndEditHint);
    void _q_modelDestroyed();

    struct WidgetMapper
    {
        inline WidgetMapper(QWidget *w = 0, int c = 0)
            : widget(w), section(c) {}
        inline WidgetMapper(QWidget *w, int c, const QByteArray &p)
            : widget(w), section(c), property(p) {}

        QPointer<QWidget> widget;
        int section;
        QPersistentModelIndex currentIndex;
        QByteArray property;
    };
  
    void populate(WidgetMapper &m);
    int findWidget(QWidget *w) const;

    bool commit(const WidgetMapper &m);

    QList<WidgetMapper> widgetMap;
};

int QDataWidgetMapperPrivate::findWidget(QWidget *w) const
{
    for (int i = 0; i < widgetMap.count(); ++i) {
        if (widgetMap.at(i).widget == w)
            return i;
    }
    return -1;
}

bool QDataWidgetMapperPrivate::commit(const WidgetMapper &m)
{
    if (m.widget.isNull())
        return true; // just ignore

    if (!m.currentIndex.isValid())
        return false;

    if (m.property.isEmpty())
        delegate->setModelData(m.widget, model, m.currentIndex);
    else {
        // Create copy to avoid passing the widget mappers data
        QModelIndex idx = m.currentIndex;
        model->setData(idx, m.widget->property(m.property), Qt::EditRole);
    }

    return true;
}

void QDataWidgetMapperPrivate::populate(WidgetMapper &m)
{
    if (m.widget.isNull())
        return;

    m.currentIndex = indexAt(m.section);
    if (m.property.isEmpty())
        delegate->setEditorData(m.widget, m.currentIndex);
    else
        m.widget->setProperty(m.property, m.currentIndex.data(Qt::EditRole));
}

void QDataWidgetMapperPrivate::populate()
{
    for (int i = 0; i < widgetMap.count(); ++i)
        populate(widgetMap[i]);
}

static bool qContainsIndex(const QModelIndex &idx, const QModelIndex &topLeft,
                           const QModelIndex &bottomRight)
{
    return idx.row() >= topLeft.row() && idx.row() <= bottomRight.row()
           && idx.column() >= topLeft.column() && idx.column() <= bottomRight.column();
}

void QDataWidgetMapperPrivate::_q_dataChanged(const QModelIndex &topLeft, const QModelIndex &bottomRight)
{
    if (topLeft.parent() != rootIndex)
        return; // not in our hierarchy

    for (int i = 0; i < widgetMap.count(); ++i) {
        WidgetMapper &m = widgetMap[i];
        if (qContainsIndex(m.currentIndex, topLeft, bottomRight))
            populate(m);
    }
}

void QDataWidgetMapperPrivate::_q_commitData(QWidget *w)
{
    if (submitPolicy == QDataWidgetMapper::ManualSubmit)
        return;

    int idx = findWidget(w);
    if (idx == -1)
        return; // not our widget

    commit(widgetMap.at(idx));
}

class QFocusHelper: public QWidget
{
public:
    bool focusNextPrevChild(bool next)
    {
        return QWidget::focusNextPrevChild(next);
    }

    static inline void focusNextPrevChild(QWidget *w, bool next)
    {
        static_cast<QFocusHelper *>(w)->focusNextPrevChild(next);
    }
};

void QDataWidgetMapperPrivate::_q_closeEditor(QWidget *w, QAbstractItemDelegate::EndEditHint hint)
{
    int idx = findWidget(w);
    if (idx == -1)
        return; // not our widget

    switch (hint) {
    case QAbstractItemDelegate::RevertModelCache: {
        populate(widgetMap[idx]);
        break; }
    case QAbstractItemDelegate::EditNextItem:
        QFocusHelper::focusNextPrevChild(w, true);
        break;
    case QAbstractItemDelegate::EditPreviousItem:
        QFocusHelper::focusNextPrevChild(w, false);
        break;
    case QAbstractItemDelegate::SubmitModelCache:
    case QAbstractItemDelegate::NoHint:
        // nothing
        break;
    }
}

void QDataWidgetMapperPrivate::_q_modelDestroyed()
{
    Q_Q(QDataWidgetMapper);

    model = 0;
    q->setModel(QAbstractItemModelPrivate::staticEmptyModel());
}

/*!
    \class QDataWidgetMapper
    \brief The QDataWidgetMapper class provides mapping between a section
    of a data model to widgets.
    \since 4.2
    \ingroup model-view

    QDataWidgetMapper can be used to create data-aware widgets by mapping
    them to sections of an item model. A section is a column of a model
    if the orientation is horizontal (the default), otherwise a row.

    Every time the current index changes, each widget is updated with data
    from the model via the property specified when its mapping was made.
    If the user edits the contents of a widget, the changes are read using
    the same property and written back to the model.
    By default, each widget's \l{Q_PROPERTY()}{user property} is used to
    transfer data between the model and the widget. Since Qt 4.3, an
    additional addMapping() function enables a named property to be used
    instead of the default user property.

    It is possible to set an item delegate to support custom widgets. By default,
    a QItemDelegate is used to synchronize the model with the widgets.

    Let us assume that we have an item model named \c{model} with the following contents:

    \table
    \row \o 1 \o Trolltech ASA    \o Oslo
    \row \o 2 \o Trolltech Pty   \o Brisbane
    \row \o 3 \o Trolltech Inc   \o Palo Alto
    \row \o 4 \o Trolltech China \o Beijing
    \row \o 5 \o Trolltech GmbH  \o Berlin
    \endtable

    The following code will map the columns of the model to widgets called \c mySpinBox,
    \c myLineEdit and \c{myCountryChooser}:

    \code
    QDataWidgetMapper *mapper = new QDataWidgetMapper;
    mapper->setModel(model);
    mapper->addMapping(mySpinBox, 0);
    mapper->addMapping(myLineEdit, 1);
    mapper->addMapping(myCountryChooser, 2);
    mapper->toFirst();
    \endcode

    After the call to toFirst(), \c mySpinBox displays the value \c{1}, \c myLineEdit
    displays \c {Trolltech ASA} and \c myCountryChooser displays \c{Oslo}. The
    navigational functions toFirst(), toNext(), toPrevious(), toLast() and setCurrentIndex()
    can be used to navigate in the model and update the widgets with contents from
    the model.

    The setRootIndex() function enables a particular item in a model to be
    specified as the root index - children of this item will be mapped to
    the relevant widgets in the user interface.

    QDataWidgetMapper supports two submit policies, \c AutoSubmit and \c{ManualSubmit}.
    \c AutoSubmit will update the model as soon as the current widget loses focus,
    \c ManualSubmit will not update the model unless submit() is called. \c ManualSubmit
    is useful when displaying a dialog that lets the user cancel all modifications.
    Also, other views that display the model won't update until the user finishes
    all their modifications and submits.

    Note that QDataWidgetMapper keeps track of external modifications. If the contents
    of the model are updated in another module of the application, the widgets are
    updated as well.

    \sa QAbstractItemModel, QAbstractItemDelegate
 */

/*! \enum QDataWidgetMapper::SubmitPolicy

    This enum describes the possible submit policies a QDataWidgetMapper
    supports.

    \value AutoSubmit    Whenever a widget loses focus, the widget's current
                         value is set to the item model.
    \value ManualSubmit  The model is not updated until submit() is called.
 */

/*!
    \fn void QDataWidgetMapper::currentIndexChanged(int index)

    This signal is emitted after the current index has changed and
    all widgets were populated with new data. \a index is the new
    current index.

    \sa currentIndex(), setCurrentIndex()
 */

/*!
    Constructs a new QDataWidgetMapper with parent object \a parent.
    By default, the orientation is horizontal and the submit policy
    is \c{AutoSubmit}.

    \sa setOrientation(), setSubmitPolicy()
 */
QDataWidgetMapper::QDataWidgetMapper(QObject *parent)
    : QObject(*new QDataWidgetMapperPrivate, parent)
{
    setItemDelegate(new QItemDelegate(this));
}

/*!
    Destroys the object.
 */
QDataWidgetMapper::~QDataWidgetMapper()
{
}

/*!
     Sets the current model to \a model. If another model was set,
     all mappings to that old model are cleared.

     \sa model()
 */
void QDataWidgetMapper::setModel(QAbstractItemModel *model)
{
    Q_D(QDataWidgetMapper);

    if (d->model == model)
        return;

    if (d->model) {
        disconnect(d->model, SIGNAL(dataChanged(QModelIndex,QModelIndex)), this,
                   SLOT(_q_dataChanged(QModelIndex,QModelIndex)));
        disconnect(d->model, SIGNAL(destroyed()), this,
                   SLOT(_q_modelDestroyed()));
    }
    clearMapping();
    d->rootIndex = QModelIndex();
    d->currentTopLeft = QModelIndex();

    d->model = model;

    connect(model, SIGNAL(dataChanged(QModelIndex,QModelIndex)),
            SLOT(_q_dataChanged(QModelIndex,QModelIndex)));
    connect(model, SIGNAL(destroyed()), SLOT(_q_modelDestroyed()));
}

/*!
    Returns the current model.

    \sa setModel()
 */
QAbstractItemModel *QDataWidgetMapper::model() const
{
    Q_D(const QDataWidgetMapper);
    return d->model == QAbstractItemModelPrivate::staticEmptyModel()
            ? static_cast<QAbstractItemModel *>(0)
            : d->model;
}

/*!
    Sets the item delegate to \a delegate. The delegate will be used to write
    data from the model into the widget and from the widget to the model,
    using QAbstractItemDelegate::setEditorData() and QAbstractItemDelegate::setModelData().

    The delegate also decides when to apply data and when to change the editor,
    using QAbstractItemDelegate::commitData() and QAbstractItemDelegate::closeEditor().

    \warning You should not share the same instance of a delegate between widget mappers
    or views. Doing so can cause incorrect or unintuitive editing behavior since each
    view connected to a given delegate may receive the \l{QAbstractItemDelegate::}{closeEditor()}
    signal, and attempt to access, modify or close an editor that has already been closed.
 */
void QDataWidgetMapper::setItemDelegate(QAbstractItemDelegate *delegate)
{
    Q_D(QDataWidgetMapper);
    QAbstractItemDelegate *oldDelegate = d->delegate;
    if (oldDelegate) {
        disconnect(oldDelegate, SIGNAL(commitData(QWidget*)), this, SLOT(_q_commitData(QWidget*)));
        disconnect(oldDelegate, SIGNAL(closeEditor(QWidget*,QAbstractItemDelegate::EndEditHint)),
                   this, SLOT(_q_closeEditor(QWidget*,QAbstractItemDelegate::EndEditHint)));
    }

    d->delegate = delegate;

    if (delegate) {
        connect(delegate, SIGNAL(commitData(QWidget*)), SLOT(_q_commitData(QWidget*)));
        connect(delegate, SIGNAL(closeEditor(QWidget*,QAbstractItemDelegate::EndEditHint)),
                SLOT(_q_closeEditor(QWidget*,QAbstractItemDelegate::EndEditHint)));
    }