1

我在正确转置从 db 收到的表时遇到问题。我按照此处找到的路径，最终将 QAbstractProxyModel 子类化，就像此处描述的那样。不幸的是，它不能完全工作，这就是问题所在：

我有的：

X | A  | B
----------
1 | A1 | B1
2 | A2 | B2

我想要的是：

X | 1  | 2
----------
A | A1 | A2
B | B1 | B2

我得到什么：

X | 1  | 1
----------
A | A1 | A2
A | B1 | B2

如您所见，数据已正确转置，但标题变坏了……我真的需要它们:(

我尝试手动设置标头数据，但也失败了：

origModel = new QSqlQueryModel; // set query and so on
transposedModel = new TransposeProxyModel;
transposedModel->setSourceModel(origModel );
for (int i = 0; i < origModel->columnCount(); i++) {
    qDebug() << "origModel->Qt::Horizontal(" << i << ")" << origModel->headerData(i, Qt::Horizontal, Qt::DisplayRole);
    //transposedModel->setHeaderData(i, Qt::Vertical, origModel->headerData(i, Qt::Horizontal, Qt::DisplayRole), Qt::DisplayRole); //#try1
    transposedModel->setHeaderData(i, Qt::Vertical, QVariant( "abc" ), Qt::DisplayRole); // #try2
}

无论我尝试 #1 还是 #2 - 调用 setHeaderData 的结果为假...

有任何想法吗？

固定为@Vinícius Gobbo A. de Oliveira 指出

4

2 回答 2

4

好吧，如果您使用链接的示例代码，您应该覆盖 TransposeProxyModel 类的 headerData 方法的默认定义，就像这样：

QVariant headerData(int section, Qt::Orientation orientation, int role = Qt::DisplayRole) const {
    return sourceModel()->headerData(section, (orientation == Qt::Horizontal ? Qt::Vertical : Qt::Horizontal), role);
}

忘记 setHeaderData 和 setData 方法：你想要一个依赖于原始模型的代理模型！

好吧，不知道到底出了什么问题，您使用的是哪个 Qt 版本？试试这段代码，它在这里完美运行：

#include <QtCore>
#include <QtWidgets>

class TransposeProxyModel: public QAbstractProxyModel {
public:
    TransposeProxyModel(QObject *p = 0):
        QAbstractProxyModel(p)
    {
    }
    QModelIndex mapFromSource ( const QModelIndex & sourceIndex ) const{
        return index(sourceIndex.column(), sourceIndex.row());
    }
    QModelIndex mapToSource ( const QModelIndex & proxyIndex ) const{
        return sourceModel()->index(proxyIndex.column(), proxyIndex.row());
    }
    QModelIndex index(int r, int c, const QModelIndex &ind=QModelIndex()) const{
        return createIndex(r,c);
    }
    QModelIndex parent(const QModelIndex&) const {
        return QModelIndex();
    }
    int rowCount(const QModelIndex &) const{
        return sourceModel()->columnCount();
    }
    int columnCount(const QModelIndex &) const{
        return sourceModel()->rowCount();
    }
    QVariant data(const QModelIndex &ind, int role) const {
        return sourceModel()->data(mapToSource(ind), role);
    }
    QVariant headerData(int section, Qt::Orientation orientation,
        int role = Qt::DisplayRole) const {
        return sourceModel()->headerData(section,
            (orientation == Qt::Horizontal ? Qt::Vertical : Qt::Horizontal),
            role);
    }
};

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    QStandardItemModel model(3,3);
    model.setData(model.index(0,0), "1");
    model.setData(model.index(0,1), "2");
    model.setData(model.index(0,2), "3");
    model.setData(model.index(1,0), "4");
    model.setData(model.index(1,1), "5");
    model.setData(model.index(1,2), "6");
    model.setData(model.index(2,0), "7");
    model.setData(model.index(2,1), "8");
    model.setData(model.index(2,2), "9");
    model.setHeaderData(0, Qt::Horizontal, "a");
    model.setHeaderData(1, Qt::Horizontal, "b");
    model.setHeaderData(2, Qt::Horizontal, "c");
    TransposeProxyModel trans;
    trans.setSourceModel(&model);
    QSplitter split;
    QTableView *t1 = new QTableView(&split);
    t1->setModel(&model);
    QTableView *t2 = new QTableView(&split);
    t2->setModel(&trans);
    split.show();
    return a.exec();
}

大部分代码来自您提供的链接，我只是编写了 headerData 方法。

于 2014-09-26T10:23:19.667 回答
0

有趣的是 -文档指出这是一个虚拟方法：

virtual QVariant headerData(int section, Qt::Orientationorientation, int role) const

(...)

QVariant QAbstractProxyModel::headerData(int section, Qt::Orientationorientation, int role) const [虚拟]

从 QAbstractItemModel::headerData() 重新实现。

但在实际标题virtual中缺少关键字：

C:\Qt\Qt5.2.1\5.2.1\msvc2010\include\QtCore\qabstractproxymodel.h

(...)
QVariant data(const QModelIndex &proxyIndex, int role = Qt::DisplayRole) const; //line76
QVariant headerData(int section, Qt::Orientation orientation, int role) const; //line77

我检查了正常的 Qt 目录，它也不见了：

C:\Qt\Qt5.2.1\5.2.1\Src\qtbase\src\corelib\itemmodels\qabstractproxymodel.h

(...)
QVariant data(const QModelIndex &proxyIndex, int role = Qt::DisplayRole) const;
QVariant headerData(int section, Qt::Orientation orientation, int role) const;

我做了一个测试：

sim = new QStandardItemModel (3,3);

for (int i = 0; i < 3; i++) {
    for (int j = 0; j < 3; j++ ) {
        sim->setData(sim->index(i,j), QString("%1%2").arg(QChar(j+65), QString().setNum(i+1)));
        if (i==0)
            sim->setHeaderData(j, Qt::Horizontal, QChar(j+65));
    }
    sim->setHeaderData(i, Qt::Vertical, i+1);
}

transposedModel = new TransposeProxyModel;
transposedModel->setSourceModel(sim);

QAbstractItemModel * aim = transposedModel;
QAbstractProxyModel *apm = transposedModel;

for (int i = 0; i < apm->rowCount(); i++) {
    qDebug() << "aim->Qt::Vertical(" << i << ")" << aim->headerData(i, Qt::Vertical, Qt::DisplayRole);
    qDebug() << "apm->Qt::Vertical(" << i << ")" << apm->headerData(i, Qt::Vertical, Qt::DisplayRole);
    qDebug() << "transposedModel->Qt::Vertical(" << i << ")" << transposedModel->headerData(i, Qt::Vertical, Qt::DisplayRole);
}

调试是：

aim->Qt::Vertical( 0 ) QVariant(int, 1) 
apm->Qt::Vertical( 0 ) QVariant(int, 1) 
[ TransposeProxyModel::headerData ] //qDebug in TransposeProxyModel::headerData
transposedModel->Qt::Vertical( 0 ) QVariant(QChar, 'A') 
aim->Qt::Vertical( 1 ) QVariant(int, 1) 
apm->Qt::Vertical( 1 ) QVariant(int, 1) 
[ TransposeProxyModel::headerData ] //qDebug in TransposeProxyModel::headerData
transposedModel->Qt::Vertical( 1 ) QVariant(QChar, 'B') 
aim->Qt::Vertical( 2 ) QVariant(int, 1) 
apm->Qt::Vertical( 2 ) QVariant(int, 1) 
[ TransposeProxyModel::headerData ] //qDebug in TransposeProxyModel::headerData
transposedModel->Qt::Vertical( 2 ) QVariant(QChar, 'C')

所以我想这就是问题所在 - 该方法不是抽象的，这就是它不调用我的重写方法的原因。Qt 错误？还是故意的？我也看了一眼

C:\Qt\Qt5.2.1\5.2.1\Src\qtbase\src\corelib\itemmodels\qabstractproxymodel.cpp

/*!
    \reimp
 */
QVariant QAbstractProxyModel::headerData(int section, Qt::Orientation orientation, int role) const
{
    Q_D(const QAbstractProxyModel);
    int sourceSection;
    if (orientation == Qt::Horizontal) {
        const QModelIndex proxyIndex = index(0, section);
        sourceSection = mapToSource(proxyIndex).column();
    } else {
        const QModelIndex proxyIndex = index(section, 0);
        sourceSection = mapToSource(proxyIndex).row();
    }
    return d->model->headerData(sourceSection, orientation, role);
}

我想它应该得到正确的标题 - 它调用 mapToSource，它是纯虚拟的，这应该获得正确的索引？

于 2014-09-26T14:29:52.670 回答