Qt C++ 在表格之间拖动 QHeaderView。

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英文:

Qt C++ Drag QHeaderView between tables

问题

我想复制QTableWidget的选定列到另一个表格。

所以我尝试通过添加以下代码使选定列可拖动：

  1. void makeDraggable(QTableWidget *table)
  2. {
  3.     table->setDragEnabled(true);
  4.     table->setAcceptDrops(true);
  5.     table->setSelectionBehavior(QAbstractItemView::SelectColumns);
  6. }

我得到的结果：

Qt C++ 在表格之间拖动 QHeaderView。

但我想要通过仅点击标题来拖动整列（水平和垂直标题），并将其数据复制到另一个表格，包括标题文本。

英文:

I want to copy the selected column of a QTableWidget to another one.

So I tried to make selected columns draggable by adding this code:

  1. void makeDraggable(QTableWidget *table)
  2. {
  3.     table->setDragEnabled(true);
  4.     table->setAcceptDrops(true);
  5.     table->setSelectionBehavior(QAbstractItemView::SelectColumns);
  6. }

Result I got:

Qt C++ 在表格之间拖动 QHeaderView。

But I want to drag a whole column (horizontal and vertical headers) by clicking on headers only, not on cells, and copy its data to another table including the header text.

答案1

得分: 0

在一个应用程序内，可以通过重新实现自定义的 QHeaderView 和 QTableWidget 来在不同表格之间进行拖动。在我的示例中，我生成了包含表格和列的索引的文本以进行拖动事件。自定义头部：

  1. #include <QHeaderView>
  3. class ITableManager;
  5. class DraggableHeaderView : public QHeaderView
  6. {
  7.     Q_OBJECT
  8. public:
  9.     explicit DraggableHeaderView(Qt::Orientation orientation, QWidget *parent = 0);
  11.     int tag() const;
  12.     void setTag(const int tag);
  13.     void setTableManager(ITableManager* manager);
  15. protected:
  16.     void mouseMoveEvent(QMouseEvent *e);
  18.     void dragEnterEvent(QDragEnterEvent *event);
  19.     void dragMoveEvent(QDragMoveEvent *event);
  20.     void dropEvent(QDropEvent *event);
  22. signals:
  24. public slots:
  26. private:
  27.     int m_tag;  // 表格的内部索引
  28.     ITableManager *m_tableManager;  // 管理器将表格索引转换为指针
  29. };

自定义头部 cpp：

  1. #include <QMouseEvent>
  2. #include <QDrag>
  3. #include <QMimeData>
  4. #include <QDebug>
  5. #include <QTableWidget>
  7. #include <ITableManager.h>
  9. DraggableHeaderView::DraggableHeaderView(Qt::Orientation orientation, QWidget *parent) :
  10.     QHeaderView(orientation, parent)
  11. {
  12.     m_tag = 0;
  13.     m_tableManager = 0;
  14.     setAcceptDrops(true);
  15. }
  17. void DraggableHeaderView::mouseMoveEvent(QMouseEvent *e)
  18. {
  19.     if (e->buttons() & Qt::LeftButton)
  20.     {
  21.         int index = logicalIndexAt(e->pos());
  22.         QDrag *drag = new QDrag(this);
  23.         QMimeData *mimeData = new QMimeData;
  24.         // 自定义拖动文本，包含索引
  25.         QString mimeTxt = "MoveHeader;Table:" + QString::number(m_tag) +
  26.                 ";Index:" + QString::number(index);
  27.         mimeData->setText(mimeTxt);
  28.         drag->setMimeData(mimeData);
  29.         Qt::DropAction dropAction = drag->exec();
  30.     }
  31. }
  33. int DraggableHeaderView::tag() const
  34. {
  35.     return m_tag;
  36. }
  38. void DraggableHeaderView::setTag(const int tag)
  39. {
  40.     m_tag = tag;
  41. }
  43. void DraggableHeaderView::dragEnterEvent(QDragEnterEvent *event)
  44. {
  45.     if (!m_tableManager)
  46.     {
  47.         event->ignore();
  48.         return;
  49.     }
  51.     QString dragText = event->mimeData()->text();
  52.     int index = dragText.indexOf("MoveHeader;");
  53.     if (index == 0)
  54.     {
  55.         event->accept();
  56.     }
  57.     else
  58.     {
  59.         event->ignore();
  60.     }
  61. }
  63. void DraggableHeaderView::dropEvent(QDropEvent *event)
  64. {
  65.     if (!m_tableManager)
  66.     {
  67.         event->ignore();
  68.         return;
  69.     }
  71.     QStringList dragText = event->mimeData()->text().split(';');
  72.     if (dragText.count() < 3 || dragText.at(0) != "MoveHeader")
  73.     {
  74.         event->ignore();
  75.         return;
  76.     }
  78.     int tableIndex = dragText.at(1).mid(6).toInt(); // 6 - "Table:" 的长度
  79.     QTableWidget* tableSrc = m_tableManager->getTableFromIndex(tableIndex);
  80.     if (!tableSrc)
  81.     {
  82.         event->ignore();
  83.         return;
  84.     }
  86.     // 目标表格作为头部视图的父级
  87.     QTableWidget *tableDst = qobject_cast<QTableWidget*> (this->parentWidget());
  88.     if (!tableDst)
  89.     {
  90.         event->ignore();
  91.         return;
  92.     }
  94.     // 移动列：根据您的需要进行修改
  95.     // 现在只移动项目文本
  96.     int columnIndex = logicalIndexAt(event->pos());
  97.     int srcColumnIndex = dragText.at(2).mid(6).toInt(); // 6 - "Index:" 的长度
  98.     tableDst->insertColumn(columnIndex);
  99.     for (int iRow = 0; iRow < tableDst->rowCount() && iRow < tableSrc->rowCount(); ++iRow)
  100.     {
  101.         if (tableSrc->item(iRow, srcColumnIndex))
  102.         {
  103.             tableDst->setItem(iRow, columnIndex,
  104.                               new QTableWidgetItem(tableSrc->item(iRow, srcColumnIndex)->text()));
  105.         }
  106.         else
  107.         {
  108.             tableDst->setItem(iRow, columnIndex, new QTableWidgetItem());
  109.         }
  110.     }
  111.     tableSrc->removeColumn(srcColumnIndex);
  112. }
  114. void DraggableHeaderView::setTableManager(ITableManager *manager)
  115. {
  116.     m_tableManager = manager;
  117. }

现在创建带有 DraggableHeaderView 的自定义 QTableWidget：

  1. class CustomTableWidget : public QTableWidget
  2. {
  3.     Q_OBJECT
  4. public:
  5.     explicit CustomTableWidget(QWidget *parent = 0);
  7.     void setTag(const int tag);
  8.     void setTableManager(ITableManager* manager);
  9. };
  11. CustomTableWidget::CustomTableWidget(QWidget *parent) :
  12.     QTableWidget(parent)
  13. {
  14.     DraggableHeaderView *headerView = new DraggableHeaderView(Qt::Horizontal, this);
  16.     setHorizontalHeader(headerView);
  18.     setAcceptDrops(true);
  19. }
  21. void CustomTableWidget::setTag(const int tag)
  22. {
  23.     DraggableHeaderView *header = qobject_cast<DraggableHeaderView*> (horizontalHeader());
  24.     if (header)
  25.     {
  26.         header->setTag(tag);
  27.     }
  28. }
  30. void CustomTableWidget::setTableManager(ITableManager *manager)
  31. {
  32.     DraggableHeaderView *header = qobject_cast<DraggableHeaderView*> (horizontalHeader());
  33.     if (header)
  34.     {
  35.         header->setTableManager(manager);
  36.     }
  37. }

为了将表格索引转换为指针，我使用了 ITableManager：

  1. class ITableManager
  2. {
  3. public:
  4.     virtual QTableWidget* getTableFromIndex(const int index) = 0;
  5. };

并在 QMainWindow 中实现它：

  1. class MainWindow : public QMainWindow, ITableManager
  2. {
  3.     Q_OBJECT
  5. public:
  6.     explicit MainWindow(QWidget *parent = 0);
  7.     ~MainWindow();
  9.     QTableWidget* getTableFromIndex(const int index);
  10. }
  12. QTableWidget *MainWindow::getTableFromIndex(const int index)
  13. {
  14.     switch (index)
  15.     {
  16.     case 1:
  17.         return ui->tableWidget;
  18.     case 2:
  19.         return ui->tableWidget_2;
  20.     default:
  21.         return nullptr;
  22.     }
  23. }

不要忘记在表格（在主窗口构造函数中）中设置标签（索引）和表格管理器：

  1. ui->tableWidget->setTag(1);
  2. ui->tableWidget_2->setTag(2);
  3. ui->tableWidget->setTableManager(this);
  4. ui->tableWidget_2->setTableManager(this);

编辑： 如果您想更改拖动的自定义图像，只需设置 QDrag::setPixmap：

  1. void
  3. <details>
  4. <summary>英文:</summary>
  6. Dragging between different tables inside one application can be done with reimplementing custom `QHeaderView` and `QTableWidget`. In my example I generate text with indecies of table and column for drag event. **Custom header:**
  8.     #include &lt;QHeaderView&gt;
  9.     
  10.     class ITableManager;
  11.     
  12.     class DraggableHeaderView : public QHeaderView
  13.     {
  14.         Q_OBJECT
  15.     public:
  16.         explicit DraggableHeaderView(Qt::Orientation orientation, QWidget *parent = 0);
  17.     
  18.         int tag() const;
  19.         void setTag(const int tag);
  20.         void setTableManager(ITableManager* manager);
  21.     
  22.     protected:
  23.         void mouseMoveEvent(QMouseEvent *e);
  24.     
  25.         void dragEnterEvent(QDragEnterEvent *event);
  26.         void dragMoveEvent(QDragMoveEvent *event);
  27.         void dropEvent(QDropEvent *event);
  28.     
  29.     signals:
  30.     
  31.     public slots:
  32.     
  33.     private:
  34.         int m_tag;  //internal index of table
  35.         ITableManager *m_tableManager;  //manager will convert table index into pointer
  36.     };
  38. **Custom header cpp**
  40.     #include &lt;QMouseEvent&gt;
  41.     #include &lt;QDrag&gt;
  42.     #include &lt;QMimeData&gt;
  43.     #include &lt;QDebug&gt;
  44.     #include &lt;QTableWidget&gt;
  45.     
  46.     #include &lt;ITableManager.h&gt;
  47.     
  48.     DraggableHeaderView::DraggableHeaderView(Qt::Orientation orientation, QWidget *parent) :
  49.         QHeaderView(orientation, parent)
  50.     {
  51.         m_tag = 0;
  52.         m_tableManager = 0;
  53.         setAcceptDrops(true);
  54.     }
  55.     
  56.     void DraggableHeaderView::mouseMoveEvent(QMouseEvent *e)
  57.     {
  58.         if (e-&gt;buttons() &amp; Qt::LeftButton)
  59.         {
  60.             int index = logicalIndexAt(e-&gt;pos());
  61.             QDrag *drag = new QDrag(this);
  62.             QMimeData *mimeData = new QMimeData;
  63.             //custom drag text with indecies inside
  64.             QString mimeTxt = &quot;MoveHeader;Table:&quot; + QString::number(m_tag) +
  65.                     &quot;;Index:&quot; + QString::number(index);
  66.             mimeData-&gt;setText(mimeTxt);
  67.             drag-&gt;setMimeData(mimeData);
  68.             Qt::DropAction dropAction = drag-&gt;exec();
  69.         }
  70.     }
  71.     
  72.     int DraggableHeaderView::tag() const
  73.     {
  74.         return m_tag;
  75.     }
  76.     
  77.     void DraggableHeaderView::setTag(const int tag)
  78.     {
  79.         m_tag = tag;
  80.     }
  81.     
  82.     void DraggableHeaderView::dragEnterEvent(QDragEnterEvent *event)
  83.     {
  84.         if (!m_tableManager)
  85.         {
  86.             event-&gt;ignore();
  87.             return;
  88.         }
  89.     
  90.         QString dragText = event-&gt;mimeData()-&gt;text();
  91.         int index = dragText.indexOf(&quot;MoveHeader;&quot;);
  92.         if (index == 0)
  93.         {
  94.             event-&gt;accept();
  95.         }
  96.         else
  97.         {
  98.             event-&gt;ignore();
  99.         }
  100.     }
  101.     
  102.     void DraggableHeaderView::dropEvent(QDropEvent *event)
  103.     {
  104.         if (!m_tableManager)
  105.         {
  106.             event-&gt;ignore();
  107.             return;
  108.         }
  109.     
  110.         QStringList dragText = event-&gt;mimeData()-&gt;text().split(&#39;;&#39;);
  111.         if (dragText.count() &lt; 3 || dragText.at(0) != &quot;MoveHeader&quot;)
  112.         {
  113.             event-&gt;ignore();
  114.             return;
  115.         }
  116.     
  117.         int tableIndex = dragText.at(1).mid(6).toInt();//6 - length &#39;Table:&#39;
  118.         QTableWidget* tableSrc = m_tableManager-&gt;getTableFromIndex(tableIndex);
  119.         if (!tableSrc)
  120.         {
  121.             event-&gt;ignore();
  122.             return;
  123.         }
  125.         //dst table as parent for header view
  126.         QTableWidget *tableDst = qobject_cast&lt;QTableWidget*&gt; (this-&gt;parentWidget());
  127.         if (!tableDst)
  128.         {
  129.             event-&gt;ignore();
  130.             return;
  131.         }
  132.     
  133.         //move column: modify for your needs
  134.         //now moves only items text
  135.         int columnIndex = logicalIndexAt(event-&gt;pos());
  136.         int srcColumnIndex = dragText.at(2).mid(6).toInt(); //6 - length of &#39;Index:&#39;
  137.         tableDst-&gt;insertColumn(columnIndex);
  138.         for (int iRow = 0; iRow &lt; tableDst-&gt;rowCount() &amp;&amp; iRow &lt; tableSrc-&gt;rowCount(); ++iRow)
  139.         {
  140.             if (tableSrc-&gt;item(iRow, srcColumnIndex))
  141.             {
  142.                 tableDst-&gt;setItem(iRow, columnIndex,
  143.                                   new QTableWidgetItem(tableSrc-&gt;item(iRow, srcColumnIndex)-&gt;text()));
  144.             }
  145.             else
  146.             {
  147.                 tableDst-&gt;setItem(iRow, columnIndex, new QTableWidgetItem());
  148.             }
  149.         }
  150.         tableSrc-&gt;removeColumn(srcColumnIndex);
  151.     }
  152.     
  153.     void DraggableHeaderView::setTableManager(ITableManager *manager)
  154.     {
  155.         m_tableManager = manager;
  156.     }
  158. Now create custom `QTableWidget` with `DraggableHeaderView` inside
  160.     class CustomTableWidget : public QTableWidget
  161.     {
  162.         Q_OBJECT
  163.     public:
  164.         explicit CustomTableWidget(QWidget *parent = 0);
  165.     
  166.         void setTag(const int tag);
  167.         void setTableManager(ITableManager* manager);
  168.     };
  170.     CustomTableWidget::CustomTableWidget(QWidget *parent) :
  171.         QTableWidget(parent)
  172.     {
  173.         DraggableHeaderView *headerView = new DraggableHeaderView(Qt::Horizontal, this);
  174.     
  175.         setHorizontalHeader(headerView);
  176.     
  177.         setAcceptDrops(true);
  178.     }
  179.     
  180.     void CustomTableWidget::setTag(const int tag)
  181.     {
  182.         DraggableHeaderView *header = qobject_cast&lt;DraggableHeaderView*&gt; (horizontalHeader());
  183.         if (header)
  184.         {
  185.             header-&gt;setTag(tag);
  186.         }
  187.     }
  188.     
  189.     void CustomTableWidget::setTableManager(ITableManager *manager)
  190.     {
  191.         DraggableHeaderView *header = qobject_cast&lt;DraggableHeaderView*&gt; (horizontalHeader());
  192.         if (header)
  193.         {
  194.             header-&gt;setTableManager(manager);
  195.         }
  196.     }
  198. For converting table index to pointer I use `ITableManager`
  200.     class ITableManager
  201.     {
  202.     public:
  203.         virtual QTableWidget* getTableFromIndex(const int index) = 0;
  204.     };
  206. And implement it in `QMainWindow`
  208.     class MainWindow : public QMainWindow, ITableManager
  209.     {
  210.         Q_OBJECT
  211.     
  212.     public:
  213.         explicit MainWindow(QWidget *parent = 0);
  214.         ~MainWindow();
  215.     
  216.         QTableWidget* getTableFromIndex(const int index);
  217.     }
  219.     QTableWidget * MainWindow::getTableFromIndex(const int index)
  220.     {
  221.         switch (index)
  222.         {
  223.         case 1:
  224.             return ui-&gt;tableWidget;
  225.         case 2:
  226.             return ui-&gt;tableWidget_2;
  227.         default:
  228.             return nullptr;
  229.         }
  230.     }
  232. Dont forget setup tags (indecies) and table manager for tables (in main window constructor)
  234.     ui-&gt;tableWidget-&gt;setTag(1);
  235.     ui-&gt;tableWidget_2-&gt;setTag(2);
  236.     ui-&gt;tableWidget-&gt;setTableManager(this);
  237.     ui-&gt;tableWidget_2-&gt;setTableManager(this);
  239. **EDIT:** If you want change custom pixmap for dragging just set `QDrag::setPixmap`
  241.     void DraggableHeaderView::mouseMoveEvent(QMouseEvent *e)
  242.     {
  243.         if (e-&gt;buttons() &amp; Qt::LeftButton)
  244.         {
  245.             int index = logicalIndexAt(e-&gt;pos());
  246.             QDrag *drag = new QDrag(this);
  247.             QMimeData *mimeData = new QMimeData;
  248.             QString mimeTxt = &quot;MoveHeader;Table:&quot; + QString::number(m_tag) +
  249.                     &quot;;Index:&quot; + QString::number(index);
  250.             mimeData-&gt;setText(mimeTxt);
  251.             drag-&gt;setMimeData(mimeData);
  252.             drag-&gt;setPixmap(pixmapForDrag(index));
  253.             Qt::DropAction dropAction = drag-&gt;exec();
  254.         }
  255.     }
  257. And method for taking pixmap of column can be like this
  259.     QPixmap DraggableHeaderView::pixmapForDrag(const int columnIndex) const
  260.     {
  261.         QTableWidget *table = qobject_cast&lt;QTableWidget*&gt; (this-&gt;parentWidget());
  262.         if (!table)
  263.         {
  264.             return QPixmap();
  265.         }
  266.     
  267.         //image for first 5 row
  268.         int height = table-&gt;horizontalHeader()-&gt;height();
  269.         for (int iRow = 0; iRow &lt; 5 &amp;&amp; iRow &lt; table-&gt;rowCount(); ++iRow)
  270.         {
  271.             height += table-&gt;rowHeight(iRow);
  272.         }
  273.     
  274.         //clip maximum size
  275.         if (height &gt; 200)
  276.         {
  277.             height = 200;
  278.         }
  279.     
  280.         QRect rect(table-&gt;columnViewportPosition(columnIndex) + table-&gt;verticalHeader()-&gt;width(),
  281.                      table-&gt;rowViewportPosition(0),
  282.                      table-&gt;columnWidth(columnIndex),
  283.                      height);
  284.         QPixmap pixmap(rect.size());
  285.         table-&gt;render(&amp;pixmap, QPoint(), QRegion(rect));
  286.         return pixmap;
  287.     }
  289. </details>

huangapple
  • 本文由 发表于 2020年1月6日 23:18:05
  • 转载请务必保留本文链接：https://go.coder-hub.com/59614591.html
  • c++
  • draggable
  • qt
  • qtableview
  • qtablewidget
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