src/uisupport/treeviewtouch.cpp

   1 /***************************************************************************
   2  *   Copyright (C) 2005-2019 by the Quassel Project                        *
   3  *   devel@quassel-irc.org                                                 *
   4  *                                                                         *
   5  *   This program is free software; you can redistribute it and/or modify  *
   6  *   it under the terms of the GNU General Public License as published by  *
   7  *   the Free Software Foundation; either version 2 of the License, or     *
   8  *   (at your option) version 3.                                           *
   9  *                                                                         *
  10  *   This program is distributed in the hope that it will be useful,       *
  11  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  13  *   GNU General Public License for more details.                          *
  14  *                                                                         *
  15  *   You should have received a copy of the GNU General Public License     *
  16  *   along with this program; if not, write to the                         *
  17  *   Free Software Foundation, Inc.,                                       *
  18  *   51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.         *
  19  ***************************************************************************/
  20
  21 #include "treeviewtouch.h"
  22
  23 #include <QEvent>
  24 #include <QScrollBar>
  25 #include <QTouchEvent>
  26
  27 TreeViewTouch::TreeViewTouch(QWidget* parent)
  28     : QTreeView(parent)
  29 {
  30     setAttribute(Qt::WA_AcceptTouchEvents);
  31 }
  32
  33 bool TreeViewTouch::event(QEvent* event)
  34 {
  35     if (event->type() == QEvent::TouchBegin && ((QTouchEvent*)event)->device()->type() == QTouchDevice::TouchScreen) {
  36         // Register that we may be scrolling, set the scroll mode to scroll-per-pixel
  37         // and accept the event (return true) so that we will receive TouchUpdate and TouchEnd/TouchCancel
  38         _touchScrollInProgress = true;
  39         setVerticalScrollMode(QAbstractItemView::ScrollPerPixel);
  40         return true;
  41     }
  42
  43     if (event->type() == QEvent::TouchUpdate && _touchScrollInProgress) {
  44         QTouchEvent::TouchPoint p = ((QTouchEvent*)event)->touchPoints().at(0);
  45         if (!_firstTouchUpdateHappened) {
  46             // After the first movement of a Touch-Point, calculate the distance in both axis
  47             // and if the point moved more horizontally abort scroll.
  48             double dx = qAbs(p.lastPos().x() - p.pos().x());
  49             double dy = qAbs(p.lastPos().y() - p.pos().y());
  50             if (dx > dy) {
  51                 _touchScrollInProgress = false;
  52             }
  53             _firstTouchUpdateHappened = true;
  54         }
  55         // Apply touch movement to scrollbar
  56         verticalScrollBar()->setValue(verticalScrollBar()->value() - (p.pos().y() - p.lastPos().y()));
  57         return true;
  58     }
  59
  60     if (event->type() == QEvent::TouchEnd || event->type() == QEvent::TouchCancel) {
  61         // End scroll and reset variables
  62         _touchScrollInProgress = false;
  63         _firstTouchUpdateHappened = false;
  64         return true;
  65     }
  66
  67     return QTreeView::event(event);
  68 }
  69
  70 void TreeViewTouch::mousePressEvent(QMouseEvent* event)
  71 {
  72     if (!_touchScrollInProgress)
  73         QTreeView::mousePressEvent(event);
  74 }
  75
  76 void TreeViewTouch::mouseMoveEvent(QMouseEvent* event)
  77 {
  78     if (!_touchScrollInProgress)
  79         QTreeView::mouseMoveEvent(event);
  80 }