QTableView：没有 QHeaderView 的交互式列调整大小

Question

我有一个 QTableView 隐藏水平 header

table->horizontalHeader()->hide();

如您所见，中间列中的文本因列宽而被剪裁。

要查看文本，用户需要调整列的大小，但没有 header，我无法执行此操作。

我希望能够做的是将鼠标悬停在列的边缘并显示正常的调整大小图标，然后允许用户将列拖动得更宽。

这可能吗？

Answer 1

使用事件过滤器和以下两个类...

/*
 * Subclass of QTableView that provides notification when the mouse cursor
 *  enters/leaves a column boundary.
 */
class headerless_table_view: public QTableView {
  using super = QTableView;
public:
  explicit headerless_table_view (QWidget *parent = nullptr)
    : super(parent)
    , m_boundary_width(10)
    , m_column_index(-1)
    {
      viewport()->setMouseTracking(true);
      viewport()->installEventFilter(this);
    }

  /*
   * @return The index of the column whose right hand boundary the cursor lies
   *         on or -1 if not on a boundary.
   */
  int column_index () const
    {
      return(m_column_index);
    }
protected:
  virtual bool eventFilter (QObject *obj, QEvent *event) override
    {
      if (event->type() == QEvent::MouseMove) {
        if (auto *e = dynamic_cast<QMouseEvent *>(event)) {
          auto col_left = columnAt(e->pos().x() - m_boundary_width / 2);
          auto col_right = columnAt(e->pos().x() + m_boundary_width / 2);
          bool was_on_boundary = m_column_index != -1;
          if (col_left != col_right) {
            if (m_column_index == -1) {
              if (col_left != -1) {
                m_column_index = col_left;
              }
            }
          } else {
            m_column_index = -1;
          }
          bool is_on_boundary = m_column_index != -1;
          if (is_on_boundary != was_on_boundary) {
            entered_column_boundary(is_on_boundary);
          }
        }
      }
      return(super::eventFilter(obj, event));
    }

  /*
   * Called whenever the cursor enters or leaves a column boundary.  if
   * `entered' is true then the index of the column can be obtained using
   * `column_index()'.
   */
  virtual void entered_column_boundary (bool entered)
    {
    }
private:
  int  m_boundary_width;
  int  m_column_index;
};

/*
 * Subclass of headerless_table_view that allows resizing of columns.
 */
class resizable_headerless_table_view: public headerless_table_view {
  using super = headerless_table_view;
public:
  explicit resizable_headerless_table_view (QWidget *parent = nullptr)
    : super(parent)
    , m_dragging(false)
    {
      viewport()->installEventFilter(this);
    }
protected:
  virtual bool eventFilter (QObject *obj, QEvent *event) override
    {
      if (auto *e = dynamic_cast<QMouseEvent *>(event)) {
        if (event->type() == QEvent::MouseButtonPress) {
          if (column_index() != -1) {
            m_mouse_pos = e->pos();
            m_dragging = true;
            return(true);
          }
        } else if (event->type() == QEvent::MouseButtonRelease) {
          m_dragging = false;
        } else if (event->type() == QEvent::MouseMove) {
          if (m_dragging) {
            int delta = e->pos().x() - m_mouse_pos.x();
            setColumnWidth(column_index(), columnWidth(column_index()) + delta);
            m_mouse_pos = e->pos();
            return(true);
          }
        }
      }
      return(super::eventFilter(obj, event));
    }

  /*
   * Override entered_column_boundary to update the cursor sprite when
   * entering/leaving a column boundary.
   */
  virtual void entered_column_boundary (bool entered) override
    {
      if (entered) {
        m_cursor = viewport()->cursor();
        viewport()->setCursor(QCursor(Qt::SplitHCursor));
      } else {
        viewport()->setCursor(m_cursor);
      }
    }
private:
  bool    m_dragging;
  QPoint  m_mouse_pos;
  QCursor m_cursor;
};

我最终将它分成两个类，因为它看起来更干净。

无论如何，在我发现的一些旧示例代码中，只需将 QTableView 替换为 resizable_headerless_table_view 似乎就能达到预期的效果——当鼠标位于列边界和相关的边界可以拖动。

不确定它与您所追求的有多接近，但是...

QTableView：没有 QHeaderView 的交互式列调整大小

QTableView: interactive column resize without QHeaderView

qt

qtableview

qheaderview