Develop Reference

Pyqt QSplitter not visualizing correctly

I'm trying to incorporate a QSplitter. The code works perfectly from a functionality standpoint, but the QSplitter itself doesn't appear correctly under the default PyQt style... possibly because it is itself embedded within a vertical splitter. This is confusing for the user.
If you uncomment out the line (and thus change the default PyQt style), the QSplitter visualizes correctly only when hovered over... however, I also don't want this other style.
Can anyone provide any guidance on this matter?
import sys
from PyQt4.QtGui import *
from PyQt4.QtCore import *
class Example(QWidget):
def __init__(self):
super(Example, self).__init__()
self.initUI()
def initUI(self):
hbox = QHBoxLayout(self)
L_layout = QGridLayout()
R_layout = QGridLayout()
L_widgets = QWidget()
L_widgets.setLayout(L_layout)
R_widgets = QWidget()
R_widgets.setLayout(R_layout)
topleft = QFrame()
topleft.setFrameShape(QFrame.StyledPanel)
btn1 = QPushButton('btn1')
bottom = QFrame()
bottom.setFrameShape(QFrame.StyledPanel)
textedit = QTextEdit()
L_layout.addWidget(topleft, 0, 0, 1, 1)
L_layout.addWidget(btn1, 1, 0, 1, 1)
R_layout.addWidget(textedit)
splitter1 = QSplitter(Qt.Horizontal,frameShape=QFrame.StyledPanel,frameShadow=QFrame.Plain)
splitter1.addWidget(L_widgets)
splitter1.addWidget(R_widgets)
splitter1.setStretchFactor(1,1)
splitter2 = QSplitter(Qt.Vertical)
splitter2.addWidget(splitter1)
splitter2.addWidget(bottom)
hbox.addWidget(splitter2)
self.setLayout(hbox)
#QApplication.setStyle(QStyleFactory.create('Cleanlooks'))
self.setGeometry(300, 300, 300, 200)
self.setWindowTitle('QSplitter demo')
self.show()
def main():
app = QApplication(sys.argv)
ex = Example()
sys.exit(app.exec_())
if __name__ == '__main__':
main()
EDIT: This is apparently a known macOS bug. When viewed on Linux, the bar of splitter1 has the same look as splitter2. I'll leave this topic open in case anyone else knows of a suitable workaround for mac.

Because the QPushButton has default minimum size, when you want to move splitter to left,
the button has reached its minimum size. So you can not move left anymore, otherwise the left will will collapse.
So if you want the left showing as you want, you can set the minimum size off button widget.
import sys
from PyQt4.QtGui import *
from PyQt4.QtCore import *
class Example(QWidget):
def __init__(self):
super(Example, self).__init__()
self.initUI()
def initUI(self):
hbox = QHBoxLayout(self)
L_layout = QGridLayout()
R_layout = QGridLayout()
L_widgets = QWidget()
L_widgets.setLayout(L_layout)
R_widgets = QWidget()
R_widgets.setLayout(R_layout)
topleft = QFrame()
topleft.setFrameShape(QFrame.StyledPanel)
btn1 = QPushButton('btn1')
btn1.setMinimumWidth(1) # For example : set the minimum width to 1, then you can move left until the btn1 width is 1
bottom = QFrame()
bottom.setFrameShape(QFrame.StyledPanel)
textedit = QTextEdit()
L_layout.addWidget(topleft, 0, 0, 1, 1)
L_layout.addWidget(btn1, 1, 0, 1, 1)
R_layout.addWidget(textedit)
splitter1 = QSplitter(Qt.Horizontal,frameShape=QFrame.StyledPanel,frameShadow=QFrame.Plain)
splitter1.addWidget(L_widgets)
splitter1.addWidget(R_widgets)
splitter1.setStretchFactor(1,1)
splitter2 = QSplitter(Qt.Vertical)
splitter2.addWidget(splitter1)
splitter2.addWidget(bottom)
hbox.addWidget(splitter2)
self.setLayout(hbox)
#QApplication.setStyle(QStyleFactory.create('Cleanlooks'))
self.setGeometry(300, 300, 300, 200)
self.setWindowTitle('QSplitter demo')
self.show()
def main():
app = QApplication(sys.argv)
ex = Example()
sys.exit(app.exec_())
if __name__ == '__main__':
main()

Have QScrollArea react on wheelEvent, also in space taken up by children?

Consider this example:
#!/usr/bin/env python
import sys,os
from PyQt5 import QtCore, QtWidgets, QtGui
from PyQt5.QtCore import Qt
class MainWindow(QtWidgets.QMainWindow):
class ScrollAreaWheel(QtWidgets.QScrollArea): # SO:9475772
def __init__(self, parent=None):
super(MainWindow.ScrollAreaWheel, self).__init__(parent)
self.parent = parent
def wheelEvent(self, event):
print("wheelEvent", event.angleDelta().y())
def __init__(self):
#~ self.do_init = QtCore.QEvent.registerEventType()
QtWidgets.QMainWindow.__init__(self)
self.setMinimumWidth(1000)
self.setMinimumHeight(400)
self.frame1 = QtWidgets.QFrame(self)
self.frame1.setFrameShape(QtWidgets.QFrame.StyledPanel)
self.frame1layout = QtWidgets.QGridLayout(self.frame1)
self.frame1layout.setSpacing(0);
self.frame1layout.setContentsMargins(0,0,0,0);
self.frame1widget = QtWidgets.QWidget()
self.frame1widget.setLayout(QtWidgets.QGridLayout())
self.frame1layout.addWidget(self.frame1widget)
self.frame1scroll = MainWindow.ScrollAreaWheel(self) #QtWidgets.QScrollArea()
self.frame1scroll.setHorizontalScrollBarPolicy(Qt.ScrollBarAlwaysOn)
self.frame1scroll.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOn)
self.frame1widget.layout().addWidget(self.frame1scroll, 0, 0) #, Qt.AlignCenter)
#self.frame1scrolllayout = QtWidgets.QHBoxLayout(self.frame1scroll)
self.frame1scrolllayout = QtWidgets.QGridLayout(self.frame1scroll)
self.frame1scroll.setWidget(self.frame1scrolllayout.widget())
self.frame1scroll.setWidgetResizable(True)
self.frame1scroll.setAlignment(Qt.AlignCenter)
self.frame1label = QtWidgets.QLabel()
self.frame1scrolllayout.addWidget(self.frame1label, 0, 0, Qt.AlignCenter) ##
pixmap = QtGui.QPixmap(200, 100)
pixmap.fill(Qt.red)
self.frame1label.setPixmap(pixmap)
self.frame2 = QtWidgets.QFrame(self)
self.frame2.setFrameShape(QtWidgets.QFrame.StyledPanel)
self.frame2layout = QtWidgets.QHBoxLayout(self.frame2)
self.frame2layout.setSpacing(0);
self.frame2layout.setContentsMargins(0,0,0,0);
self.frame2scroll = QtWidgets.QScrollArea(self)
self.frame2scroll.setWidgetResizable(True)
self.frame2widget = QtWidgets.QWidget()
self.frame2widget.setLayout(QtWidgets.QGridLayout())
self.frame2scroll.setWidget(self.frame2widget)
self.frame2layout.addWidget(self.frame2scroll)
self.mainwid = QtWidgets.QWidget()
self.mainwid.setLayout(QtWidgets.QGridLayout())
self.setCentralWidget(self.mainwid)
self.splitter1 = QtWidgets.QSplitter(Qt.Horizontal)
self.splitter1.addWidget(self.frame1)
self.splitter1.addWidget(self.frame2)
self.splitter1.setSizes([600, 600]); # equal splitter at start
self.mainwid.layout().addWidget(self.splitter1)
self.mainwid.layout().update()
if __name__ == "__main__":
app = QtWidgets.QApplication([])
main = MainWindow()
main.show()
sys.exit(app.exec_())
It generates this (Ubuntu 18.04):
I want to use mousewheel only on the left QScrollArea, for which I've made a separate class. However, its wheelEvent fires only when I'm outside the red box, not when I hover over it. How can I make ScrollAreaWheel.wheelEvent fire even when mouse is over the child label (the red box)?

You are the QLabel placing on top of the QScrollArea instead of placing it inside, visually it is the same but at the level of events it is not.
from PyQt5 import QtCore, QtGui, QtWidgets
class ScrollAreaWheel(QtWidgets.QScrollArea):
def wheelEvent(self, event):
print("wheelEvent", event.angleDelta().y())
class MainWindow(QtWidgets.QMainWindow):
def __init__(self, parent=None):
super(MainWindow, self).__init__(parent)
self.setMinimumSize(1000, 400)
frame1 = QtWidgets.QFrame(frameShape=QtWidgets.QFrame.StyledPanel)
scrollarea1 = ScrollAreaWheel(widgetResizable=True)
scrollarea1.setHorizontalScrollBarPolicy(QtCore.Qt.ScrollBarAlwaysOn)
scrollarea1.setVerticalScrollBarPolicy(QtCore.Qt.ScrollBarAlwaysOn)
widget1 = QtWidgets.QWidget()
scrollarea1.setWidget(widget1)
label_lay = QtWidgets.QGridLayout(widget1)
lay1 = QtWidgets.QVBoxLayout(frame1)
lay1.addWidget(scrollarea1)
pixmap = QtGui.QPixmap(200, 100)
pixmap.fill(QtCore.Qt.red)
label = QtWidgets.QLabel(pixmap=pixmap)
label_lay.addWidget(label, 0, 0, QtCore.Qt.AlignCenter)
#==============================
frame2 = QtWidgets.QFrame(frameShape=QtWidgets.QFrame.StyledPanel)
scrollarea2 = QtWidgets.QScrollArea(widgetResizable=True)
scrollarea2.setHorizontalScrollBarPolicy(QtCore.Qt.ScrollBarAlwaysOn)
scrollarea2.setVerticalScrollBarPolicy(QtCore.Qt.ScrollBarAlwaysOn)
widget2 = QtWidgets.QWidget()
scrollarea2.setWidget(widget2)
splitter = QtWidgets.QSplitter(QtCore.Qt.Horizontal)
splitter.addWidget(frame1)
splitter.addWidget(frame2)
splitter.setSizes([600, 600])
self.setCentralWidget(splitter)
if __name__ == '__main__':
import sys
app = QtWidgets.QApplication(sys.argv)
w = MainWindow()
w.resize(640, 480)
w.show()
sys.exit(app.exec_())

PyQt5 QScrollArea widget with dynamically created GroupBoxes

I'm trying to make a toolbox widget that will do various different things. But I'm having trouble with the layout management regarding the QScrollArea. Following the stripped version of the code I have:
from PyQt5 import QtWidgets
import sys
class MyScrollWidget(QtWidgets.QWidget):
def __init__(self):
super(MyScrollWidget, self).__init__()
scrollArea = QtWidgets.QScrollArea(self)
top_widget = QtWidgets.QWidget()
top_layout = QtWidgets.QVBoxLayout()
for i in range(10):
group_box = QtWidgets.QGroupBox()
group_box.setTitle('GroupBox For Item {0}'.format(i))
layout = QtWidgets.QHBoxLayout(group_box)
label = QtWidgets.QLabel()
label.setText('Label For Item {0}'.format(i))
layout.addWidget(label)
push_button = QtWidgets.QPushButton(group_box)
push_button.setText('Run Button')
push_button.setFixedSize(100, 32)
layout.addWidget(push_button)
group_box.setLayout(layout)
top_layout.addWidget(group_box)
top_widget.setLayout(top_layout)
scrollArea.setWidget(top_widget)
self.resize(200, 500)
if __name__ == '__main__':
app = QtWidgets.QApplication(sys.argv)
widget = MyScrollWidget()
widget.show()
sys.exit(app.exec_())
But this only gives me a small fixed subsection of the widget that scrolled. But what I really wants is the whole widget to be scrollable if the widget/window is smaller than the total size of all the group boxes. I.e I'd like the widget to be used as if it was all fixed width, but if the user resized the widget smaller than that, it would scroll appropriately. I've tried various different methods with no good results so now I'm deferring to those who have more experience with layout management than I. Thank you for your time.

You have to set the scrollArea to MyScrollWidget using a layout.
from PyQt5 import QtWidgets
import sys
class MyScrollWidget(QtWidgets.QWidget):
def __init__(self):
super(MyScrollWidget, self).__init__()
lay = QtWidgets.QVBoxLayout(self)
scrollArea = QtWidgets.QScrollArea()
lay.addWidget(scrollArea)
top_widget = QtWidgets.QWidget()
top_layout = QtWidgets.QVBoxLayout()
for i in range(10):
group_box = QtWidgets.QGroupBox()
group_box.setTitle('GroupBox For Item {0}'.format(i))
layout = QtWidgets.QHBoxLayout(group_box)
label = QtWidgets.QLabel()
label.setText('Label For Item {0}'.format(i))
layout.addWidget(label)
push_button = QtWidgets.QPushButton(group_box)
push_button.setText('Run Button')
push_button.setFixedSize(100, 32)
layout.addWidget(push_button)
top_layout.addWidget(group_box)
top_widget.setLayout(top_layout)
scrollArea.setWidget(top_widget)
self.resize(200, 500)
if __name__ == '__main__':
app = QtWidgets.QApplication(sys.argv)
widget = MyScrollWidget()
widget.show()
sys.exit(app.exec_())

How to make a widget attached to QTabWidget's gap and move accordingly with QSplitter in pyqt5

I want to make the button always next to the second tab's label, even when I use splitter to move the edge between two tabs. How to achieve that? I believe it's because I use the absolute position, but how make an widget attached in the gap in QTabWidget?
from PyQt5.QtWidgets import (QWidget, QHBoxLayout, QFrame,
QSplitter, QStyleFactory, QApplication,QTabWidget,QPushButton)
from PyQt5.QtCore import Qt
import sys
class Example(QWidget):
def __init__(self):
super().__init__()
self.initUI()
def initUI(self):
hbox = QHBoxLayout(self)
tab1 = QTabWidget(self)
tab2 = QTabWidget(self)
a=QWidget()
a.setGeometry(0,0, 40, 40)
tab2.addTab(a,"2")
splitter1 = QSplitter(Qt.Vertical)
splitter1.addWidget(tab1)
splitter1.addWidget(tab2)
splitter1.setSizes([100,100])
hbox.addWidget(splitter1)
self.setLayout(hbox)
z=QPushButton(self)
z.setGeometry(100,100,70,20)
z.setText("button")
self.setGeometry(300, 300, 300, 200)
self.show()
if __name__ == '__main__':
app = QApplication(sys.argv)
ex = Example()
sys.exit(app.exec_())
This is what I want to achieve all the time.
This is what happened when I adjust the edge between two tabs.

When you add a parent to a widget, the widget has a coordinate system relative to the parent, so you must change the parent. In addition to adjusting the position of the button to one relative to the parent:
[...]
z=QPushButton(tab2)
z.setGeometry(100,0,70,20)
z.setText("button")
[...]
Another series improvement that even if the size of the QtabWidget changes, the button remains centered:
class TabWidgetWithButton(QTabWidget):
def __init__(self, *args, **kwargs):
QTabWidget.__init__(self, *args, **kwargs)
self.button = QPushButton("button", self)
def resizeEvent(self, event):
self.button.move((self.width()-self.button.width())/2, 0)
QTabWidget.resizeEvent(self, event)
class Example(QWidget):
def __init__(self):
super().__init__()
self.initUI()
def initUI(self):
hbox = QHBoxLayout(self)
tab1 = QTabWidget(self)
tab2 = TabWidgetWithButton(self)
a=QWidget(self)
tab2.addTab(a,"2")
splitter1 = QSplitter(Qt.Vertical)
splitter1.addWidget(tab1)
splitter1.addWidget(tab2)
splitter1.setSizes([100,100])
hbox.addWidget(splitter1)
self.setLayout(hbox)
self.setGeometry(300, 300, 300, 200)
self.show()
if __name__ == '__main__':
app = QApplication(sys.argv)
ex = Example()
sys.exit(app.exec_())

PyQt: How to create a scrollable window

I think it should be much easier to create a scrollable window in PyQt.
I have a list of labels that goes out of the window and I would like to scroll down to view them. At the moment the code does not give me an error, but the window just doesn't appear:
class Example(QWidget):
def __init__(self):
super().__init__()
layout = QVBoxLayout()
lbl_arr = makeLabelArr()
for i in range(1,8):
qb = lbl_arr[i]
# qb.setFixedWidth(300)
layout.addWidget(qb)
layout.setAlignment(Qt.AlignTop)
scroll = QScrollArea()
scroll.setWidget(self)
scroll.setWidgetResizable(True)
scroll.setFixedHeight(400)
layout.addWidget(scroll)
self.setLayout(layout)
self.setGeometry(0, 0, 600, 220)
self.setWindowTitle('SnP watchlist')
self.show()
if __name__ == '__main__':
app = QApplication(sys.argv)
#print(QDesktopWidget().availableGeometry())
ex = Example()
sys.exit(app.exec_())

Make the window itself a QScrollArea, like this:
class Window(QScrollArea):
def __init__(self):
super(Window, self).__init__()
widget = QWidget()
layout = QVBoxLayout(widget)
layout.setAlignment(Qt.AlignTop)
for index in range(100):
layout.addWidget(QLabel('Label %02d' % index))
self.setWidget(widget)
self.setWidgetResizable(True)

There is an example here: https://www.learnpyqt.com/tutorials/qscrollarea/
from PyQt5.QtWidgets import (QWidget, QSlider, QLineEdit, QLabel, QPushButton, QScrollArea,QApplication,
QHBoxLayout, QVBoxLayout, QMainWindow)
from PyQt5.QtCore import Qt, QSize
from PyQt5 import QtWidgets, uic
import sys
class MainWindow(QMainWindow):
def __init__(self):
super().__init__()
self.initUI()
def initUI(self):
self.scroll = QScrollArea() # Scroll Area which contains the widgets, set as the centralWidget
self.widget = QWidget() # Widget that contains the collection of Vertical Box
self.vbox = QVBoxLayout() # The Vertical Box that contains the Horizontal Boxes of labels and buttons
for i in range(1,50):
object = QLabel("TextLabel: "+str(i))
self.vbox.addWidget(object)
self.widget.setLayout(self.vbox)
#Scroll Area Properties
self.scroll.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOn)
self.scroll.setHorizontalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
self.scroll.setWidgetResizable(True)
self.scroll.setWidget(self.widget)
self.setCentralWidget(self.scroll)
self.setGeometry(600, 100, 1000, 900)
self.setWindowTitle('Scroll Area Demonstration')
self.show()
return
def main():
app = QtWidgets.QApplication(sys.argv)
main = MainWindow()
sys.exit(app.exec_())
if __name__ == '__main__':
main()

You should set layout after adding the scroll bar widget.
class Example(QWidget):
def __init__(self):
super().__init__()
layout = QVBoxLayout()
lbl_arr = makeArrayOfLabelsHTML()
for i in range(1,8):
qb = lbl_arr[i]
layout.addWidget(qb)
layout.setAlignment(Qt.AlignTop)
scroll = QScrollArea()
scroll.setWidget(self)
scroll.setWidgetResizable(True)
scroll.setFixedHeight(400)
layout.addWidget(scroll)
# set layout after adding scroll bar
self.setLayout(layout)
self.setGeometry(0, 0, 600, 220)
self.setWindowTitle('SnP watchlist')
self.show()
if __name__ == '__main__':
app = QApplication(sys.argv)
#print(QDesktopWidget().availableGeometry())
ex = Example()
sys.exit(app.exec_())