python - QSortFilterProxyModel 返回人工行

Question

我正在使用 QSortFilterProxyModel 来过滤来自 QAbstractListModel 的结果。但是，我想返回原始模型中不存在的第一个条目，也就是说，它在某种程度上是人为的。

这是我目前所拥有的:

class ActivedAccountModel(QSortFilterProxyModel):                                                                                                                                  
    def __init__(self, model, parent=None):
        super(ActiveAccountModel, self).__init__(parent)
        self.setSourceModel(model)
        self.setDynamicSortFilter(True)

    def data(self, index, role=Qt.DisplayRole):
        account_info = super(ActiveAccountModel, self).data(index, Qt.UserRole).toPyObject()
        if role == Qt.DisplayRole:
            return account_info.name
        elif role == Qt.UserRole:
            return account_info
        return None

    def filterAcceptsRow(self, source_row, source_parent):
        source_model = self.sourceModel()
        source_index = source_model.index(source_row, 0, source_parent)
        account_info = source_model.data(source_index, Qt.UserRole)
        return isinstance(account_info.account, Account) and account_info.account.enabled

这将返回以下形式的列表:

Account 1
Account 2
...

我想在返回的列表 f 元素的开头返回一个额外的元素:

Extra Element
Account 1
Account 2
...

我试图重新实现 rowCount 以返回真正的 rowCount()+1，但不知何故我需要移动所有项目以返回索引 0 处的这个人工元素，并且我有点迷路了。

有什么线索吗？到目前为止我找不到任何相关的代码示例...谢谢!

Answer 1

因为我在这个实现上遇到了一些困难，而且我在整个网络中找不到任何其他示例代码，所以我发布了这个示例实现。

我希望这对其他人也有帮助...

/**
 ** Written by Sven Anders (ANDURAS AG). Public domain code.
 **/

#include <QDebug>
#include <QBrush>
#include <QFont>
#include <QSortFilterProxyModel>

/** Definition **/

class ProxyModelNoneEntry : public QSortFilterProxyModel
{
   Q_OBJECT
 public:
  ProxyModelNoneEntry(QString _entry_text = tr("(None)"), QObject *parent=0);
  int rowCount(const QModelIndex &parent = QModelIndex()) const;
  /* lessThan() is not necessary for this model to work, but can be
     implemented in a derived class if a custom sorting method is required. */
  // bool lessThan(const QModelIndex &left, const QModelIndex &right) const;
  QModelIndex mapFromSource(const QModelIndex &sourceIndex) const;
  QModelIndex mapToSource(const QModelIndex &proxyIndex) const;
  QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const;
  Qt::ItemFlags flags(const QModelIndex &index) const;
  QModelIndex index(int row, int column, const QModelIndex &parent = QModelIndex()) const;
  QModelIndex parent(const QModelIndex &child) const;

 private:
  QString entry_text;
};

/** Implementation **/

ProxyModelNoneEntry::ProxyModelNoneEntry(QString _entry_text, QObject *parent) : QSortFilterProxyModel(parent)
{
  entry_text = _entry_text;
}

int ProxyModelNoneEntry::rowCount(const QModelIndex &parent) const
{
  Q_UNUSED(parent)
  return QSortFilterProxyModel::rowCount()+1;
}

QModelIndex ProxyModelNoneEntry::mapFromSource(const QModelIndex &sourceIndex) const
{
  if (!sourceIndex.isValid()) return QModelIndex();
  else if (sourceIndex.parent().isValid()) return QModelIndex();
  return createIndex(sourceIndex.row()+1, sourceIndex.column());
}

QModelIndex ProxyModelNoneEntry::mapToSource(const QModelIndex &proxyIndex) const
{
  if (!proxyIndex.isValid()) return QModelIndex();
  else if (proxyIndex.row() == 0) return QModelIndex();
  return sourceModel()->index(proxyIndex.row()-1, proxyIndex.column());
}

QVariant ProxyModelNoneEntry::data(const QModelIndex &index, int role) const
{
  if (!index.isValid()) return QVariant();

  if (index.row() == 0)
  {
    if (role == Qt::DisplayRole)
      return entry_text;
    else if (role == Qt::DecorationRole)
      return QVariant();
    else if (role == Qt::FontRole)
    { QFont font; font.setItalic(true); return font; }
    else
      return QVariant();
  }
  return QSortFilterProxyModel::data(createIndex(index.row(),index.column()), role);
}

Qt::ItemFlags ProxyModelNoneEntry::flags(const QModelIndex &index) const
{
  if (!index.isValid()) return Qt::NoItemFlags;
  if (index.row() == 0) return Qt::ItemIsSelectable | Qt::ItemIsEnabled;
  return QSortFilterProxyModel::flags(createIndex(index.row(),index.column()));
}

QModelIndex ProxyModelNoneEntry::index(int row, int column, const QModelIndex &parent) const
{
  if (row > rowCount()) return QModelIndex();
  return createIndex(row, column);
}

QModelIndex ProxyModelNoneEntry::parent(const QModelIndex &child) const
{
  Q_UNUSED(child)
  return QModelIndex();
}

问候 斯文