[FIXED] Scrolling a QTreeWidget with gestures

Issue

I am writing a program in Python 3.5 and PyQt5. I have a QTreeWidget that has a list of items in it. I want to hide the scrollbar and make touch scrolling for it in the vertical direction. This is my code:

    self.category_tree = QTreeWidget(self.framemain)
    self.category_tree.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
    self.category_tree.setHorizontalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
    self.category_tree.setGeometry(QRect(630, 90, 161, 381))
    self.category_tree.setLayoutDirection(Qt.RightToLeft)
    self.category_tree.setLocale(QLocale(QLocale.Persian, QLocale.Iran))
    self.category_tree.setEditTriggers(QAbstractItemView.NoEditTriggers)
    self.category_tree.setUniformRowHeights(False)
    self.category_tree.setColumnCount(1)
    self.category_tree.setObjectName("category_tree")
    self.category_tree.headerItem().setText(0, "1")
    self.category_tree.setFrameShape(QFrame.NoFrame)
    self.category_tree.header().setVisible(False)
    self.category_tree.header().setSortIndicatorShown(False)
    self.category_tree.setFocusPolicy(Qt.NoFocus)
    self.category_tree.verticalScrollBar().setSingleStep(25)

def checkscroll(self,startx,endx):
    if (startx - endx) >= 25:
    #swipe from right to left
        self.category_tree.verticalScrollBar().setSliderPosition(self.category_tree.verticalScrollBar().sliderPosition()+(25))
    elif (startx - endx) <= -25:
            self.category_tree.verticalScrollBar().setSliderPosition(self.category_tree.verticalScrollBar().sliderPosition()-abs(25))

The problem is that when I swipe on the QTreeWidget to make it scroll it goes to the end or start of the view and doesn't scroll normally.

Solution

It looks like you need to use the QScroller class for this. It seems that something like this should work:

QScroller.grabGesture(self.category_tree.viewport(), QScroller.TouchGesture)

However, I cannot test this myself, so you may need to experiment a bit to get the behaviour you want.

UPDATE:

You may also need to change the vertical scroll mode:

self.category_tree.setVerticalScrollMode(QAbstractItemView.ScrollPerPixel)

Answered By - ekhumoro