I want these TreeWidget Arrows to align with the top of the TreeWidgetItem.
I've got a QtWidgets.QTreeWidget(), and have created a custom QtWidgets.QTreeWidgetItem().
I then set a custom Item widget self.tree_widget.setItemWidget(self.tree_widget_item, 0, self.main_widget)
As a result the decorator / arrow positions itself evenly in the center of the geometry, however I want it to be aligned at the top.
I've been looking into setting the alignment for this, but am not 100% sure where to set it, or if I need to set it through a style sheet. If I'm unable to move this I can create a custom widget to replace the decorator, and hide the default ones, but I'd prefer to use what's here if possible.
Any ideas? Thanks!
You could reimplement QTreeView.drawBranches and set a smaller height to the QRect used to draw each branch. Simply using the width is a good value if the arrows are symmetrical.
import sys
from PySide2.QtWidgets import *
class Tree(QTreeWidget):
def drawBranches(self, painter, rect, index):
rect.setHeight(rect.width())
super().drawBranches(painter, rect, index)
if __name__ == '__main__':
app = QApplication(sys.argv)
tree = Tree()
for i in range(5):
item = QTreeWidgetItem([f'Item {i}\n\n'])
item.addChild(QTreeWidgetItem([f'Child {i}']))
tree.addTopLevelItem(item)
tree.show()
sys.exit(app.exec_())
Before | After:
Related
A Qt packing layout, such as QVBoxLayout, can pack widgets inside it, such as buttons. In this case, they will be packed vertically as shown in image below:
When we pack too many widgets inside such a layout, and since scrolling is not added by default, the buttons will eventually get squeezed onto each other up to a point that they will overlap, as shown below:
My questions are:
How to tell Qt to not show/pack widgets beyond the available viewing space in the non-scrolling layout?
How to handle the case when the window is resized? I.e. Qt should add/remove widgets accordingly. E.g. if there is extra space available, then perhaps Qt should add some extra widgets that it couldn't add previously.
To be specific: "too many packed widgets" is when the widgets start invading spaces of other widgets, including their inter-widget spacings or margins.
Appendix
Images above are generated by this code below as run in a tile in i3, which is a modified version of this.
from PyQt5 import QtCore, QtWidgets
app = QtWidgets.QApplication([])
widget = QtWidgets.QWidget()
layout = QtWidgets.QVBoxLayout(widget)
for i in range(40):
layout.addWidget(QtWidgets.QPushButton(str(i + 1)))
widget.show()
app.exec_()
When too many widgets are packed:
If the window is tiled, you see them overcrowded as in in the image.
If the window is floating, the window will keep growing until it is no longer fully visible in the monitor.
None of these outcomes are acceptable in my case. My goal is to have Qt only pack as much as will be visible, and add/remove/hide/show dynamically as the window gets resized.
Try this code. It does not rely on QVBoxLayout but it basically does the same as this layout. It hides the child widgets which are outside of the area. There are no partially visible widgets.
from PyQt5 import QtWidgets
class Container(QtWidgets.QWidget):
_spacing = 5
def __init__(self, parent=None):
super().__init__(parent)
y = self._spacing
for i in range(40):
button = QtWidgets.QPushButton("Button" + str(i + 1), self)
button.move(self._spacing, y)
y += button.sizeHint().height() + self._spacing
def resizeEvent(self, event):
super().resizeEvent(event)
for child in self.children():
if isinstance(child, QtWidgets.QWidget):
child.resize(self.width() - 2 * self._spacing, child.height())
child.setVisible(child.geometry().bottom() < self.height())
app = QtWidgets.QApplication([])
w = Container()
w.resize(500, 500)
w.show()
app.exec_()
Note that is in fact does not add nor remove widgets dynamically, this would be much more code and it would probably be very depending on your specific use case. Moreover it feels as a premature optimization. Unless you really need it, do not do it.
UPDATE:
I experimented with the code above and proposed some improvements. I especially wanted to make it responsive to changes in child widgets. The problem is that if the child widget changes it size, the parent container must be re-layouted. The code above does not react in any way. To make it responsive, we need to react to LayoutRequest event. Note that in the code below, I have created three types of buttons - one add a line to itself, other increases font size, and yet another decreases font size.
from PyQt5 import QtCore, QtWidgets
def changeFontSize(increment):
font = QtWidgets.QApplication.font()
font.setPointSize(font.pointSize() + increment)
QtWidgets.QApplication.setFont(font)
class Container(QtWidgets.QWidget):
_spacing = 5
_children = [] # maintains the order of creation unlike children()
def __init__(self, parent=None):
super().__init__(parent)
for i in range(100):
child = QtWidgets.QPushButton(self)
child.installEventFilter(self)
# these are just to test various changes in child widget itself to force relayout
r = i % 3
if r == 0:
text = "New line"
onClicked = lambda state, w=child: w.setText(w.text() + "\nclicked")
elif r == 1:
text = "Bigger font"
onClicked = lambda: changeFontSize(1)
elif r == 2:
text = "Smaller font"
onClicked = lambda: changeFontSize(-1)
child.setText(text)
child.clicked.connect(onClicked)
self._children.append(child)
def resizeEvent(self, event):
super().resizeEvent(event)
self._relayout()
def event(self, event):
if event.type() == QtCore.QEvent.LayoutRequest:
self._relayout()
return super().event(event)
def _relayout(self):
y = self._spacing
for child in self._children:
h = child.sizeHint().height()
child.move(self._spacing, y)
child.resize(self.width() - 2 * self._spacing, h)
y += h + self._spacing
child.setVisible(y < self.height())
app = QtWidgets.QApplication([])
w = Container()
w.resize(500, 500)
w.show()
app.exec_()
This code is satisfactory, however it is not perfect. I have observed that when the container is being re-layouted and some of the child widgets will change its visibility state, re-layouting is called again. This is not needed but I have not discovered how to prevent it.
Maybe there is some better way...
I'm doing something cool with a custom QWebView, basically I paint a rectangle over the element which is under the mouse pointer, see:
However, if I scroll down and move the pointer again, it draws the rect on the wrong area. In the next screenshot the mouse is over the which contains the search results, the top of the rectangle and the top of the QWebView have a big gap:
What I did to insert this bug was simply calculating the position of the rect taking into account the horizontal and vertical scroll positions, I did this wrong calculation because the rect wasn't correctly positioned in regard to the content if I scrolled it. In both cases I have a rect painted in the wrong position if any scroll occurs.
So far, this is the code I have at the moment:
#!/usr/bin/env python2
# coding: utf-8
# VENI, SANCTE SPIRITUS
from PySide.QtWebKit import QWebView
from PySide import QtCore, QtGui
class CustomQWebView(QWebView):
def __init__(self, *args, **kwargs):
""" Init the custom class
"""
super(CustomQWebView, self).__init__(*args, **kwargs)
self.currentframe = None
self.lastelement = None
self.lastelementboundingrect = None
self.loadFinished.connect(self.setframeafterloadfinished)
# default test pen
self.defaultpen = QtGui.QPen(QtCore.Qt.blue)
self.defaultpen.setWidth(3)
#QtCore.Slot(QtGui.QMouseEvent)
def mouseMoveEvent(self, event):
super(CustomQWebView, self).mouseMoveEvent(event)
if self.currentframe:
hittestresult = self.currentframe.hitTestContent(event.pos())
element = hittestresult.element()
if self.lastelement != element:
self.lastelement = element
self.lastelementboundingrect = hittestresult.boundingRect()
self.update()
#QtCore.Slot(QtGui.QPaintEvent)
def paintEvent(self, event):
# draw the content first
super(CustomQWebView, self).paintEvent(event)
# then the rectangle
if self.lastelementboundingrect:
painter = QtGui.QPainter(self)
painter.setPen(self.defaultpen)
# This rectangles takes into account any offset of the scroll bar
# so the rectangle can be drawn correctly
rect = QtCore.QRect()
rect.setRect(self.lastelementboundingrect.x() +
self.currentframe.scrollPosition().x(),
self.lastelementboundingrect.y() +
self.currentframe.scrollPosition().y(),
self.lastelementboundingrect.width(),
self.lastelementboundingrect.height())
# painter.drawRect(QtCore.QRectF(self.lastelementcurrectrect))
painter.fillRect(
QtCore.QRectF(rect), QtGui.QColor(255, 165, 0, 128))
def setframeafterloadfinished(self):
self.currentframe = self.page().mainFrame()
How can I correctly solve this positioning problem?
P.S.: Yes, the pointer don't appears in the screenshots because scrot cannot capture it, I did not realize before uploading the screenshots. Sorry.
I think you need to subtract the x/y components of page()->mainFrame()->scrollPosition() from your rect's x/y components.
This property holds the position the frame is currently scrolled to.
I am trying to create a main window (fixed size) that contains a QTableView, with QSpacerItems above and below, in order to centralise the table (vertically).
(Sorry, can't post an image, apparently).
I have a QVBoxLayout, into which I have a vertical spacer, the QTableView, and another vertical spacer. I've played with all combinations of QSizePolicy for all three widgets, but I cannot get the table to be displayed without scrollbars. (I cannot use Qt.ScrollBarAlwaysOff because they will be needed if the number of items exceeds the main window's size). So the vertical scrollbars on the QTableView are displayed, even though the vertical spacers are absorbing plenty of space between the view and the main window.
I want the vertical spacers to take up the minimum space required above and below the table widget in order to centralise the rows, and the table widget to display as many rows as possible, without scrollbars.
You can subclass QTableView, use QSizePolicy::Fixed in the vertical direction and override sizeHint() to return your preferred vertical height.
Here's a working example (You didn't specify language, so I am going to assume it is Python :-) :
import sys
from PySide import QtCore, QtGui
class MyTableView(QtGui.QTableView):
def __init__(self, parent=None):
super().__init__(parent)
#assume expanding in horizontal direction and fixed in vertica direction
self.setSizePolicy(QtGui.QSizePolicy.Expanding, QtGui.QSizePolicy.Fixed)
def sizeHint(self):
return QtCore.QSize(400, 500) #I allow you to edit that!
class MyApplication(QtGui.QWidget):
def __init__(self, parent=None):
super().__init__(parent)
layout = QtGui.QVBoxLayout()
table_view = MyTableView()
layout.addWidget(table_view)
self.model = QtGui.QStringListModel() #use a string list model for simplicity
table_view.setModel(self.model)
self.strings = ['1', '2', '3']
self.model.setStringList(self.strings) #initialize the model
self.counter = 4
button = QtGui.QPushButton('Add Cell') #this button updates the model and adds cells
button.clicked.connect(self.addCell)
layout.addWidget(button)
self.setLayout(layout)
def addCell(self):
self.strings.append(str(self.counter))
self.counter += 1
self.model.setStringList(self.strings)
app = QtGui.QApplication(sys.argv)
main = MyApplication()
main.show()
sys.exit(app.exec_())
In Qt, When I add widgets to my layout, they are vertically centered by default. Is there a way to "List" the widgets from top to bottom instead of centering them vertically?
If you have a QVBoxLayout and want your fixed size widgets to be stacked at the top, you can simply append a vertical stretch at the end:
layout.addStretch()
If you have multiple stretchers or other stretch items, you can specify an integer stretch factor argument that defines their size ratio.
See also addStretch and addSpacerItem.
Add two layout.addStretch() before and after adding the widgets to center them vertically:
layout.addStretch()
layout.addWidget(self.message)
layout.addWidget(self.userid_field)
layout.addWidget(self.password_field)
layout.addWidget(self.loginButton)
layout.addStretch()
Not sure whether this answers your original question, but it is the answer to the one that I had when googling and being led to this page - so it might be useful for others too.
use void QLayout::setAlignment ( Qt::Alignment alignment ) method to set alignment according to your choice.
I find this a little more complicated than just using layout.setAlignment(). It kept not working for me until just now, when I figured out that if you have expanding widgets that you set a maximum height for, then that widget will not be aligned the way you want.
Here is example code that does not top align the QTextBrowser() widget even though I call layout.setAlignment(Qt.AlignTop). Sorry that it is in Python, but it is pretty easy to translate to C++ (I have gone the other way many times).
from PyQt4.QtCore import *
from PyQt4.QtGui import *
class MyWidget(QWidget):
"""
Create a widget that aligns its contents to the top.
"""
def __init__(self, parent=None):
QWidget.__init__(self, parent)
layout = QVBoxLayout()
label = QLabel('label:')
layout.addWidget(label)
info = QTextBrowser(self)
info.setMinimumHeight(100)
info.setMaximumHeight(200)
layout.addWidget(info)
# Uncomment the next line to get this to align top.
# layout.setAlignment(info, Qt.AlignTop)
# Create a progress bar layout.
button = QPushButton('Button 1')
layout.addWidget(button)
# This will align all the widgets to the top except
# for the QTextBrowser() since it has a maximum size set.
layout.setAlignment(Qt.AlignTop)
self.setLayout(layout)
if __name__ == '__main__':
import sys
app = QApplication(sys.argv)
widget = MyWidget()
widget.show()
widget.resize(QSize(900, 400))
app.exec_()
The following explicitly calls layout.setAlignment(info, Qt.AlignTop) to get the expanding text widget to work.
from PyQt4.QtCore import *
from PyQt4.QtGui import *
class MyWidget(QWidget):
"""
Create a widget that aligns its contents to the top.
"""
def __init__(self, parent=None):
QWidget.__init__(self, parent)
layout = QVBoxLayout()
label = QLabel('label:')
layout.addWidget(label)
info = QTextBrowser(self)
info.setMinimumHeight(100)
info.setMaximumHeight(200)
layout.addWidget(info)
# Uncomment the next line to get this to align top.
layout.setAlignment(info, Qt.AlignTop)
# Create a progress bar layout.
button = QPushButton('Button 1')
layout.addWidget(button)
# This will align all the widgets to the top except
# for the QTextBrowser() since it has a maximum size set.
layout.setAlignment(Qt.AlignTop)
self.setLayout(layout)
if __name__ == '__main__':
import sys
app = QApplication(sys.argv)
widget = MyWidget()
widget.show()
widget.resize(QSize(900, 400))
app.exec_()
After comparison between the two solutions, it seems that :
myLayout.setAlignment(Qt::AlignTop)
works for several widget alignement but :
myLayout.setAlignment(myWidget, Qt::AlignTop)
works only for the first widget you add to the layout.
After all, the solution depends also to the QSizePolicy of yours widgets.
If you are using QT creator, you just add a "Vertical Spacers" at the bottom of your widget.
In pyQt (and PySide) we have Qt.AlignCenter (align on main direction), Qt.AlignHCenter (align on horizontal direction), Qt.AlignVCenter (align on vertical direction), use one of it when you need it.
Is it possible to adjust QListWidget height and width to it's content?
sizeHint() always returns 256, 192 no matter what its content is.
QListWidgetItem's sizeHint() returns -1, -1, so I can not get content width.
Problem the same as here - http://www.qtcentre.org/threads/31787-QListWidget-width , but there is no solution.
import sys
from PyQt4.QtGui import *
class MainWindow(QWidget):
def __init__(self, parent=None):
QWidget.__init__(self, parent)
list = QListWidget()
list.addItem('111111111111111')
vbox = QVBoxLayout(self)
vbox.addWidget(list)
app = QApplication(sys.argv)
myapp = MainWindow()
myapp.show()
sys.exit(app.exec_())
sizeHint() always returns 256, 192 no
matter what its content is.
Thats because this is the size of the QListWidget, the viewport, not the items. sizeHintForColumn() will give you the max size over all items, so you can resize the widget like this:
list.setMinimumWidth(list.sizeHintForColumn(0))
If you don't want to force minimum width, then subclass and provide this as the size hint instead. E.g.:
class ListWidget(QListWidget):
def sizeHint(self):
s = QSize()
s.setHeight(super(ListWidget,self).sizeHint().height())
s.setWidth(self.sizeHintForColumn(0))
return s
Using takois answer I played around with the sizeHintForColumn or sizeHintForRow and found that you have to add slightly larger numbers, because there might be some style dependent margins still. ekhumoros comment then put me on the right track.
In short the full size of the list widget is:
list.sizeHintForColumn(0) + 2 * list.frameWidth()
list.sizeHintForRow(0) * list.count() + 2 * list.frameWidth())
According to the comment by Violet it may not work in Qt 5.
Also be aware that setting the size to the content, you don't need scrollbars, so I turn them off.
My full example for a QListWidget ajusted to its content size:
from PySide import QtGui, QtCore
app = QtGui.QApplication([])
window = QtGui.QWidget()
layout = QtGui.QVBoxLayout(window)
list = QtGui.QListWidget()
list.addItems(['Winnie Puh', 'Monday', 'Tuesday', 'Minnesota', 'Dracula Calista Flockhart Meningitis', 'Once', '123345', 'Fin'])
list.setHorizontalScrollBarPolicy(QtCore.Qt.ScrollBarAlwaysOff)
list.setVerticalScrollBarPolicy(QtCore.Qt.ScrollBarAlwaysOff)
list.setFixedSize(list.sizeHintForColumn(0) + 2 * list.frameWidth(), list.sizeHintForRow(0) * list.count() + 2 * list.frameWidth())
layout.addWidget(list)
window.show()
app.exec_()
In order to effectively use sizeHint, you have to override it, at least in c++. In my experience, the default implementations for widgets can be pretty useless when you want a specific behavior. Attempts to force what you want with spacers or layouts end in disaster. If you can derive from QListWidget and override sizeHint, you can iterate through your items and find the longest string, then do some kind of magic to determine how wide it should be.
That's what I'd do, anyway.
First you should get your largest string in the list, that is easy to obtain.
After you get that string, do the following:
QFontMetrics * fm = new QFontMetrics(widget->font());
QRect rect;
rect = fm->boundingRect(string);
rect.width() has the width in pixels of the largest string
rect.height() has it's height.
Set the QListWidget width to that rect's width (plus the margins)
and it's height to that rect's height times the number of items
I didn't test the code, but hope it puts you on the right track
QListWidget *valList;
valList = new QListWidget(this);
valList->setSizePolicy (QSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored));
valList->setMinimumSize (QSize(1111, 111));
You need to get the QHeaderView of your QListWidget and adjust its resize mode.
Read this documentation for more information
http://doc.qt.nokia.com/latest/qheaderview.html#ResizeMode-enum