deselectabletreeview.h

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// SPDX-FileCopyrightText: 2016 Anne Jan Brouwer
// SPDX-License-Identifier: GPL-3.0-or-later
#ifndef SRC_DESELECTABLETREEVIEW_H_
#define SRC_DESELECTABLETREEVIEW_H_
 
#include <QCoreApplication>
#include <QMouseEvent>
#include <QTime>
#include <QTreeView>
 
class DeselectableTreeView : public QTreeView {
  Q_OBJECT
 
public:
  DeselectableTreeView(QWidget *parent) : QTreeView(parent) {}
  virtual ~DeselectableTreeView() {}
 
signals:
  void emptyClicked();
 
private:
  bool doubleClickHappened = false;
  bool clickSelected = false;
 
  virtual void mousePressEvent(QMouseEvent *event) {
    clickSelected = selectionModel()->isSelected(indexAt(event->pos()));
    QTreeView::mousePressEvent(event);
  }
 
  void mouseReleaseEvent(QMouseEvent *event) {
    doubleClickHappened = false;
    // The timer is to distinguish between single and double click
    QTime dieTime = QTime::currentTime().addMSecs(200);
    while (QTime::currentTime() < dieTime)
      QCoreApplication::processEvents(QEventLoop::AllEvents, 100);
    // could this be done nicer?
    if (!doubleClickHappened && clickSelected) {
      QModelIndex item = indexAt(event->pos());
      bool selected = selectionModel()->isSelected(indexAt(event->pos()));
      if ((item.row() == -1 && item.column() == -1) || selected) {
        clearSelection();
        const QModelIndex index;
        selectionModel()->setCurrentIndex(index, QItemSelectionModel::Select);
        emit emptyClicked();
      } else {
        QTreeView::mouseReleaseEvent(event);
      }
    } else {
      QTreeView::mouseReleaseEvent(event);
    }
    clickSelected = false;
  }
 
  void mouseDoubleClickEvent(QMouseEvent *event) {
    doubleClickHappened = true;
    QTreeView::mouseDoubleClickEvent(event);
  }
};
 
#endif // SRC_DESELECTABLETREEVIEW_H_