PyQt4: central widget and parent modules - python

My question is similar to this one, except in one thing: what if classes widget1 and widget2 are big and I want to put them in two separate files. Problem gets in method Check(). So, is there a way to call self.parent().setCentralWidget(w2) even though widget2 isn't in the same file as widget1 (but they are both imported in main file containing MainWindow).
Code taken from How to set the central widget of existing MainWidnow in Python PyQt4?
class widget1(QtGui.QFrame):
def __init__(self,parent = None):
......
......
def Check(self):
if (condition):
w2=widget2(self)
self.parent().setCentralWidget(w2)
class widget2(QtGui.QFrame):
def __int__(self,parent = None):
.....
.....
class MainWindow(QtGui.QMainWindow):
def __init__(self,parent = None):
QtGui.QMainWindow.__init__(self,parent)
....
mywidgetone = widget1()
self.setCentralWidget(mywidgetone)
if __name__ == '__main__':
app = QtGui.QApplicaiton(sys.argv)
main = MainWindow()
main.show()
app.exec_()

Related

How to show My Labels and activate respective Shortcut in Pyqt5?

Here is my code, How to show My Labels and activate respective QShortcut?. Want to show my labels(both instances) and assign respective shortcut keys to labels and activate it.
import sys
from PyQt5.QtWidgets import *
from PyQt5.QtGui import *
class Create_workingDict(QWidget):
def __init__(self,lblname,lblscut):
super(). __init__()
self.lblname = lblname
self.lblscut = lblscut
lbl_1 = QLabel()
lbl_1.setText(self.lblname)
lbl_2 = QLabel()
lbl_2.setText(self.lblscut)
vbox = QVBoxLayout()
vbox.addWidget(lbl_1)
vbox.addWidget(lbl_2)
self.setLayout(vbox)
self.msgSc = QShortcut(QKeySequence(f'{self.lblscut}'), self)
self.msgSc.activated.connect(lambda: QMessageBox.information(self,'Message', 'Ctrl + M initiated'))
class Mainclass(QWidget):
def __init__(self):
super().__init__()
self.setWindowTitle("Sample Window")
x = Create_workingDict("Accounts","Alt+A")
y = Create_workingDict("Inventory", "Ctrl+B")
def main():
app = QApplication(sys.argv)
ex = Mainclass()
ex.show()
sys.exit(app.exec_())
if __name__ == '__main__':
main()
Shortcuts work based on the context (and visibility) of the parent widget: as long as the parent is visible and the context is compatible, they will be triggered, otherwise they will not even be considered.
Be aware that the visibility is of the parent widgets (note the plural) is mandatory, no matter of the context: Qt has no API for a "global" shortcut, not only external to the application, but also within it: there is no shortcut that can automatically work anywhere in the app if (any of) its parent(s) is hidden. The context only ensures that the shortcut can only be activated if the active widget is part of the application (ApplicationShortcut), if the current active window is an ancestor of the shortcut parent (WindowShortcut), if any of the grand[...]parent widgets has focus (WidgetWithChildrenShortcut) or the current parent has it (WidgetShortcut).
Long story short: if the shortcut's parent is not visible (at any level), it will not be triggered.
Not only. In your code, both x and y are potentially garbage collected (they are not due to the fact that the lambda scope avoids destruction, but that's just "sheer dumb luck"), so that code would be actually prone to fail anyway if the activated signal would have been connected to an instance method.
If you want them to be available to the visible window, you must add their parent widgets to that window, even if they're not shown. Otherwise, just add the shortcuts to that window.
For instance:
class Mainclass(QWidget):
def __init__(self):
super().__init__()
self.setWindowTitle("Sample Window")
x = Create_workingDict("Accounts","Alt+A")
y = Create_workingDict("Inventory", "Ctrl+B")
layout = QVBoxLayout(self)
layout.addWidget(x)
layout.addWidget(y)
The only and automatic way to access a global application shortcut from any window of the application is to create a QKeySequence that is checked within an event filter installed on the application.
This is a possible, but crude implementation, so, take it as it is and consider its consequences:
class ShortCutFilter(QObject):
triggered = pyqtSignal(QKeySequence)
def __init__(self, shortcuts=None):
super().__init__()
self.shortcuts = {}
def addShortcut(self, shortcut, slot=None):
if isinstance(shortcut, str):
shortcut = QKeySequence(shortcut)
slots = self.shortcuts.get(shortcut)
if not slots:
self.shortcuts[shortcut] = slots = []
if slot is not None:
slots.append(slot)
return shortcut
def eventFilter(self, obj, event):
if event.type() == event.KeyPress:
keyCode = event.key()
mods = event.modifiers()
if mods & Qt.ShiftModifier:
keyCode += Qt.SHIFT
if mods & Qt.MetaModifier:
keyCode += Qt.META
if mods & Qt.ControlModifier:
keyCode += Qt.CTRL
if mods & Qt.ALT:
keyCode += Qt.ALT
for sc, slots in self.shortcuts.items():
if sc == QKeySequence(keyCode):
self.triggered.emit(sc)
for slot in slots:
try:
slot()
except Exception as e:
print(type(e), e)
return True
return super().eventFilter(obj, event)
def main():
app = QApplication(sys.argv)
shortcutFilter = ShortCutFilter()
app.installEventFilter(shortcutFilter)
shortcutFilter.addShortcut('alt+b', lambda:
QMessageBox.information(None, 'Hello', 'How are you'))
shortcutFilter.triggered.connect(lambda sc:
print('triggered', sc.toString())
ex = Mainclass()
ex.show()
sys.exit(app.exec_())
if __name__ == '__main__':
main()
This, obviously, means that any key press event will pass through the known python bottleneck. A better solution would be to create global QActions and addAction() to any possible top level window that could accept it.
While this approach might seem more complex, it has its benefits; for instance, you have more control on the context of the shortcut: in the case above, you could trigger Alt+B from any window, including the one shown after previously triggering it, which is clearly not a good thing.
Add the layout in main widget.
Then pass the layout to the function where you are creating labels and add them to layout.
Below is the modified code.
Find the details as comments in below code.
Your main window class
class Mainclass(QWidget):
def __init__(self):
super().__init__()
self.setWindowTitle("Sample Window")
#CREATE THE LAYOUT HERE IN MAIN WINDOW
vbox = QVBoxLayout()
x = Create_workingDict("Accounts","Alt+A",vbox) #PASS THE LAYOUT OBJECT (vbox) AS AN ARGUMENT
y = Create_workingDict("Inventory", "Ctrl+B",vbox) #PASS THE LAYOUT OBJECT (vbox) AS AN ARGUMENT
#SET THE LAYOUT TO MAIN WINDOW
self.setLayout(vbox)
Your function where labels created.
Observe that the functions vbox = QVBoxLayout() and self.setLayout(vbox) are moved out of this function to main window.
class Create_workingDict(QWidget):
def __init__(self,lblname,lblscut,vbox): #RECEIVE LAYOUT (vbox) ARGUMENT
super(). __init__()
self.lblname = lblname
self.lblscut = lblscut
lbl_1 = QLabel()
lbl_1.setText(self.lblname)
lbl_2 = QLabel()
lbl_2.setText(self.lblscut)
vbox.addWidget(lbl_1)
vbox.addWidget(lbl_2)
self.msgSc = QShortcut(QKeySequence(f'{self.lblscut}'), self)
self.msgSc.activated.connect(lambda: QMessageBox.information(self,'Message', 'Ctrl + M initiated'))

How to open and close my SubWindow In QMdiArea in PyQt5?

In QMidArea how to open a SubWindow? My Programs as follows. My intention to open/attach my second program in SubWindow. But Nothing Will happen. visible Only blank Window. How to resolve it?
How to attach my file in QMdi Sub-window ? and after my work, how to close the sub-window properly?
Main Programme
import sys,os
from PyQt5.QtWidgets import *
from sample_countrypage import Countrypage
class MainPage(QMainWindow):
def __init__(self):
super().__init__()
self.mdi = QMdiArea()
self.setWindowTitle(" Sample Programme")
self.setGeometry(100,100,1600,600)
self.Ui()
self.show()
def Ui(self):
self.btn1=QPushButton("Country")
self.btn1.setFixedSize(100, 30)
self.btn1.clicked.connect(self.countrypage)
self.left_layout = QVBoxLayout()
self.main_layout = QHBoxLayout()
self.left_layout.setContentsMargins(3,5,5,3)
self.left_layout.addWidget(self.btn1)
self.left_layout.addStretch()
self.main_layout.setSpacing(5)
self.main_layout.setContentsMargins(0,0,0,0)
self.main_layout.addLayout(self.left_layout)
self.main_layout.addStretch()
self.setLayout(self.main_layout)
widget = QWidget()
widget.setLayout(self.main_layout)
self.setCentralWidget(widget)
def countrypage(self):
print("country page")
self.countrywindow = Countrypage()
subwindow = QMdiSubWindow()
subwindow.setWidget(self.countrywindow)
self.mdi.addSubWindow(subwindow)
# subwindow.setFixedSize(500,500)
subwindow.show()
if __name__ == "__main__":
app = QApplication(sys.argv)
mainwindow = MainPage()
app.setStyle("fusion")
mainwindow.show()
sys.exit(app.exec_())
Second Program
import sys,os
from PyQt5.QtWidgets import *
class Countrypage(QWidget):
def __init__(self):
super().__init__()
self.setWindowTitle("Country Page")
self.btn1 = QPushButton("Accept")
self.btn1.clicked.connect(self.result)
self.btn2 = QPushButton("Re Enter")
self.form_layout = QFormLayout()
self.form_layout.addRow("Country",QLineEdit())
self.form_layout.addRow("continent",QLineEdit())
self.layout_btn = QHBoxLayout()
self.layout_btn.addStretch()
self.layout_btn.addWidget(self.btn1)
self.layout_btn.addWidget(self.btn2)
self.layout_country = QVBoxLayout()
self.layout_country.addLayout(self.form_layout)
self.layout_country.addLayout(self.layout_btn)
self.layout_country.addStretch()
self.setLayout(self.layout_country)
def result(self):
print("bye")
exec .close()
if __name__=="__main__":
app = QApplication(sys.argv)
countrywin = Countrypage()
countrywin.show()
sys.exit(app.exec_())
First of all, there are two main issues with your code:
You never added the mdi area to the main layout (and you also tried to set the layout for the QMainWindow, which is forbidden);
exec is a python builtin, and has no close attribute; if you want to close the widget, you have to call self.close();
Then, the setWidget() method of QMdiSubWindow reparents the widget:
QMdiSubWindow takes temporary ownership of widget;
This means that if you want to close the sub window that contains the widget from that widget, you have to check the parent and eventually close it, as soon as you verify that it's an instance of QMdiSubWindow.
class Countrypage(QWidget):
# ...
def result(self):
print("bye")
# ensure that the parent is actually a subwindow
if isinstance(self.parent(), QMdiSubWindow):
self.parent().close()
else:
self.close()
Alternatively, you can use a custom signal and connect that when creating the subwindow.
class Countrypage(QWidget):
closeRequested = pyqtSignal()
# ...
def result(self):
print("bye")
self.closeRequested.emit()
class MainPage(QMainWindow):
# ...
def countrypage(self):
print("country page")
self.countrywindow = Countrypage()
subwindow = QMdiSubWindow()
subwindow.setWidget(self.countrywindow)
self.mdi.addSubWindow(subwindow)
subwindow.show()
self.countrywindow.closerequested.connect(subwindow.close)
If you want to close the active subwindow from the mdi area (or outside of it) and no matter what that sub window is, just call self.mdi.closeActiveSubWindow().
Note that if you're going to create multiple Countrypage instances, there's no point in creating an instance attribute (self.countrywindow) as it will always be overwritten as soon as another instance will be created. Adding the widget to the subwindow and that subwindow to the mdi area will automatically create a persistent reference (due to the parenting); if you need a python reference to existing pages, then create a list as an instance member in the __init__ (eg. self.pages = []) and add the new instances to that list.

How do I make a context menu for each item in a QListWidget?

I'm working on a QGIS plugin, where the UI is made with PyQt. I have a QListWidget and a function that fills it. I'd like to add a context menu for each item with only one option: to open another window.
I'm having trouble searching for info, since most of it works only on PyQt4 and I'm using version 5. The QListWidget that I want to add a context menu on is ds_list_widget. Here's some of the relevant code.
FORM_CLASS, _ = uic.loadUiType(os.path.join(
os.path.dirname(__file__), 'dialog_base.ui'))
class Dialog(QDialog, FORM_CLASS):
def __init__(self, parent=None):
...
self.p_list_widget = self.findChild(QListWidget, 'projects_listWidget')
self.p_list_widget.itemClicked.connect(self.project_clicked)
self.ds_list_widget = self.findChild(QListWidget, 'datasets_listWidget')
self.ds_list_widget.itemClicked.connect(self.dataset_clicked)
...
def project_clicked(self, item):
self.fill_datasets_list(str(item.data(Qt.UserRole)))
self.settings.setValue('projectIdValue', str(item.data(Qt.UserRole)))
def fill_datasets_list(self, project_id):
self.ds_list_widget.clear()
dataset_list = self.anotherClass.fetch_dataset_list(project_id)
for dataset in dataset_list:
#Query stuff from remote
...
item = QListWidgetItem(ds_name, self.ds_list_widget)
item.setIcon(self.newIcon(ds_img))
item.setData(Qt.UserRole, ds_id)
self.ds_list_widget.addItem(item)
self.ds_list_widget.setIconSize(self.iconSize)
Since your list-widget is created by Qt Designer, it is probably easiest to install an event-filter on it and trap the context-menu event. With that in place, the rest is quite straightforward - here is a simple demo:
import sys
from PyQt5 import QtCore, QtWidgets
class Dialog(QtWidgets.QDialog):
def __init__(self, parent=None):
super(Dialog, self).__init__()
self.listWidget = QtWidgets.QListWidget()
self.listWidget.addItems('One Two Three'.split())
self.listWidget.installEventFilter(self)
layout = QtWidgets.QVBoxLayout(self)
layout.addWidget(self.listWidget)
def eventFilter(self, source, event):
if (event.type() == QtCore.QEvent.ContextMenu and
source is self.listWidget):
menu = QtWidgets.QMenu()
menu.addAction('Open Window')
if menu.exec_(event.globalPos()):
item = source.itemAt(event.pos())
print(item.text())
return True
return super(Dialog, self).eventFilter(source, event)
if __name__ == '__main__':
app = QtWidgets.QApplication(sys.argv)
window = Dialog()
window.setGeometry(600, 100, 300, 200)
window.show()
sys.exit(app.exec_())
PS:
You should also note that code like this:
self.p_list_widget = self.findChild(QListWidget, 'projects_listWidget')
is completely unnecessary. All the widgets from Qt Designer are automatically added as attributes to the form class using the object-name. So your code can be simplified to this:
self.projects_listWidget.itemClicked.connect(self.project_clicked)
self.datasets_listWidget.itemClicked.connect(self.dataset_clicked)
there is no need to use findChild.
In addition to the answer above, you can also set multiple QAction() submenu items to do multiple things. As you would a normal menu.
One way is to edit your eventFilter so that menu.exec() becomes a variable:
def eventFilter(self, source, event):
if (event.type() == QtCore.QEvent.ContextMenu and source is self.listWidget):
menu = QtWidgets.QMenu()
open_window_1 = QAction("Open Window 1")
open_window_2 = QAction("Open Window 2")
menu.addAction(open_window_1)
menu.addAction(open_window_2)
menu_click = menu.exec(event.globalPos())
try:
item = source.itemAt(event.pos())
except Exception as e:
print(f"No item selected {e}")
if menu_click == open_window_1 :
print("Opening Window 1...")
# Your code here
if menu_click == open_window_2 :
print("Opening Window 2...")
# Your code here
# and so on... You can now add as many items as you want
return True
return super(Dialog, self).eventFilter(source, event)

PyQt4, how to get current widget created?

I have a class to create a PyQt4 widget and another class to parse xml to get inputs. I want to create an UI dyanamically add buttons to the widget, reading from the xml(s) passed, which is not happening:
import sys
import xml.etree.ElementTree as ET
from PyQt4 import QtGui
ui = None
class userInterface(QtGui.QWidget):
def __init__(self):
super(userInterface, self).__init__()
def getFilesWindow(self):
self.filesSelected = []
fDialog = QtGui.QFileDialog.getOpenFileNames(self, 'Open file', '/Learning/Python/substance_XML_reading/', "SBS (*.sbs)")
for path in fDialog:
if path:self.filesSelected.append(path)
return self.filesSelected
class ParseXML():
def getXMLTags(self,fileList):
self.tags = []
if fileList:
print fileList
for eachFile in fileList:
fileToParse = ET.parse(eachFile)
root = fileToParse.getroot()
for child in root:
self.tags.append(child.tag)
return self.tags
def getSetUI(flist):
global ui
if flist:
tagsForBtns = ParseXML().getXMLTags(flist)
print tagsForBtns
for eachitem in tagsForBtns:
btn = QtGui.QPushButton(ui,eachitem)
def main():
app = QtGui.QApplication(sys.argv)
ui = userInterface()
fileListForUIGen = ui.getFilesWindow() # will return a list of files
getSetUI(fileListForUIGen) # Parses each file, gets tags, creates buttons and has to add to the current window..NOT WORKING
ui.show()
sys.exit(app.exec_())
if __name__ == '__main__':
main()
In order to add buttons to a widget, you need to place them inside a QLayout
class Widget(QtGui.QWidget):
def __init__(self):
super(Widget, self).__init__()
self.ui_lay = QtGui.QVBoxLayout()
self.setLayout(self.ui_lay)
def addButton(self, text):
btn = QtGui.QPushButton(text, self)
self.ui_lay.addWidget(btn)
...
for eachitem in tagsForBtns:
ui.addButton(eachitem)
Also, make sure to use global ui in your main() function if you're going to be doing it this way.
Personally, I don't see the reasons for splitting up all the function calls. I would just put them all in the UserInterface class.

How to make a function in one class implement another class?

I am creating a GUI with a code like this:
class MyClass2(QtGui.QMainWindow):
def __init__(self, win_parent = None):
def on_blahblah_clicked(x):
if __name__ == "__main__":
# Someone is launching this directly
# Create the QApplication
app = QtGui.QApplication(sys.argv)
#The Main window
main_window = HyperlinkWindow()
main_window.show()
# Enter the main loop
app.exec_()
And I have a code for an add-in button like this:
class MyClass(object):
"""Impementation of Some_addin.button (Button)"""
def __init__(self):
#Code here
def onClick(self):
# Code
pass
I want to create an add-in button that when clicked it brings out the GUI created above. So I want to be able to call the class of the GUI code, MyClass2 in function onClick. Just like I do with a in y in the code below:
class x:
a = 1 + 1
class y:
print x.a

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