Calling functions between PyQt5 classes in Python - python

I'm trying to call a function in the main class with the PyQt5 button "dropEvent" event in Python. Although the "print("setText")" command in the function works, the next "self.lbl_1.setText("setText")" command does not work.
Code:
from PyQt5.QtWidgets import *
from PyQt5.QtGui import *
from PyQt5.QtCore import *
class Button(QPushButton):
def __init__(self, title, parent):
super(Button, self).__init__(title, parent)
self.setAcceptDrops(True)
def dragEnterEvent(self, event):
if event.mimeData().hasFormat('text/plain'):
event.accept()
else:
event.ignore()
def dropEvent(self, event):
self.setText(event.mimeData().text())
MainWindow().lbl_setText()
class MainWindow(QMainWindow):
def __init__(self):
super().__init__()
self.setGeometry(100, 100, 200, 150)
self.setWindowTitle("Example")
self.setup()
def setup(self):
self.btn_quit = Button('Quit', self)
self.btn_quit.clicked.connect(QApplication.instance().quit)
self.btn_quit.resize(self.btn_quit.sizeHint())
self.btn_quit.move(90, 100)
self.btn_quit.setAcceptDrops(True)
self.le_drag = QLineEdit('', self)
self.le_drag.setDragEnabled(True)
self.le_drag.move(50, 50)
self.lbl_1= QLabel('Hi', self)
self.lbl_1.move(50, 10)
def closeEvent(self, event: QCloseEvent):
reply = QMessageBox.question(self, 'Message', "r u sure!",
QMessageBox.Yes | QMessageBox.No, QMessageBox.No)
if reply == QMessageBox.Yes:
event.accept()
else:
event.ignore()
def lbl_setText(self):
print("setText")
self.lbl_1.setText("setText")
def main():
app = QApplication([])
app.setStyle("Fusion")
mainWin = MainWindow()
mainWin.show()
app.exec()
if __name__ == '__main__':
main()

The interaction does not occur between classes but between objects, in your case you are creating a new MainWindow object that is not visible so you have that problem. A simple way to communicate objects in Qt is through signals and slots:
class Button(QPushButton):
dropped = pyqtSignal(str)
# ....
def dropEvent(self, event):
self.setText(event.mimeData().text())
self.dropped.emit(self.text())
class MainWindow(QMainWindow):
# ...
def setup(self):
self.btn_quit = Button('Quit', self)
self.btn_quit.clicked.connect(QApplication.quit)
self.btn_quit.resize(self.btn_quit.sizeHint())
self.btn_quit.move(90, 100)
self.btn_quit.setAcceptDrops(True)
self.le_drag = QLineEdit('', self)
self.le_drag.setDragEnabled(True)
self.le_drag.move(50, 50)
self.lbl_1= QLabel('Hi', self)
self.lbl_1.move(50, 10)
self.btn_quit.dropped.connect(self.lbl_1.setText) # <---
# ...

Related

How can i capture a mouse clicks onto the main Window in a child class

I would like to capture mouse clicks onto the MainWindow in a child class of the application.
I've tried the following but without success:
import sys
from PyQt5 import QtWidgets, QtGui, QtCore
from abc import ABCMeta, abstractmethod
class BaseView(object):
def __init__(self,parent, page=None):
self.parent = parent
self.page = page
#abstractmethod
def preprare_view(self):
pass
#abstractmethod
def clean_up_view(self):
pass
class FooView(BaseView):
def __init__(self, parent, page):
super(FooView, self).__init__(parent, page)
self.parent = parent
def mousePressEvent(self, QMouseEvent):
print(parent.QMouseEvent.pos())
def mouseReleaseEvent(self, QMouseEvent):
cursor = QtGui.QCursor()
print(parent.cursor.pos())
class Example(QtWidgets.QMainWindow):
def __init__(self):
super(Example, self).__init__()
self.initUI()
def initUI(self):
self.foo = "fooview"
self.Foo = FooView(self,self.foo)
qbtn = QtWidgets.QPushButton('Quit', self)
qbtn.resize(qbtn.sizeHint())
qbtn.move(50, 50)
self.setGeometry(0, 0, 1024, 768)
self.setWindowTitle('Quit button')
self.setWindowFlags(self.windowFlags() | QtCore.Qt.FramelessWindowHint)
self.show()
def main():
app = QtWidgets.QApplication(sys.argv)
ex = Example()
sys.exit(app.exec_())
if __name__ == '__main__':
main()
I'm wondering how I can capture the mouse clicks in the FooView child class - is that even possible?
There is terminology that the OP uses that is confusing, for example FooView is a child class of BaseView but that has nothing to do with Qt so it is irrelevant for this case so I will omit that class and show the example of how another class can obtain information about the click event of a widget.
The logic is to create a class that inherits from QObject and apply an event filter to the other widget, then override the eventFilter method where the events of the widget are obtained.
import sys
from PyQt5 import QtWidgets, QtGui, QtCore
class MouseObserver(QtCore.QObject):
def __init__(self, widget):
super(MouseObserver, self).__init__(widget)
self._widget = widget
self.widget.installEventFilter(self)
#property
def widget(self):
return self._widget
def eventFilter(self, obj, event):
if obj is self.widget:
if event.type() == QtCore.QEvent.MouseButtonPress:
print(event.pos(), QtGui.QCursor.pos())
elif event.type() == QtCore.QEvent.MouseButtonRelease:
print(event.pos(), QtGui.QCursor.pos())
return super(MouseObserver, self).eventFilter(obj, event)
class Example(QtWidgets.QMainWindow):
def __init__(self):
super(Example, self).__init__()
self.initUI()
def initUI(self):
self.observer = MouseObserver(self)
qbtn = QtWidgets.QPushButton("Quit", self)
qbtn.resize(qbtn.sizeHint())
qbtn.move(50, 50)
self.setGeometry(0, 0, 1024, 768)
self.setWindowTitle("Quit button")
self.setWindowFlags(self.windowFlags() | QtCore.Qt.FramelessWindowHint)
self.show()
def main():
app = QtWidgets.QApplication(sys.argv)
ex = Example()
sys.exit(app.exec_())
if __name__ == "__main__":
main()

How to enable button after QListWidget is no longer empty

I would like my button to be disabled until there are items actually in my QListWidget. I have tried if and while statements in my AppDemo class but I feel like it needs to change in the ListBoxWidget class, however the listBoxWidget is already a sub class of the AppDemo.
Example Code:
import sys, os
from PyQt5.QtWidgets import QApplication, QMainWindow, QListWidget, QListWidgetItem, QPushButton
from PyQt5.QtCore import Qt, QUrl
class ListBoxWidget(QListWidget):
def __init__(self, parent=None):
super().__init__(parent)
self.setAcceptDrops(True)
self.resize(600, 600)
def dragEnterEvent(self, event):
if event.mimeData().hasUrls:
event.accept()
else:
event.ignore()
def dragMoveEvent(self, event):
if event.mimeData().hasUrls():
event.setDropAction(Qt.CopyAction)
event.accept()
else:
event.ignore()
def dropEvent(self, event):
if event.mimeData().hasUrls():
event.setDropAction(Qt.CopyAction)
event.accept()
links = []
for url in event.mimeData().urls():
if url.isLocalFile():
links.append(str(url.toLocalFile()))
else:
links.append(str(url.toString()))
self.addItems(links)
else:
event.ignore()
class AppDemo(QMainWindow):
def __init__(self):
super().__init__()
self.resize(1200, 600)
self.listbox_view = ListBoxWidget(self)
self.btn = QPushButton('Get Value', self)
self.btn.setEnabled(False)
self.btn.setGeometry(850, 400, 200, 50)
self.btn.clicked.connect(lambda: print(self.getSelectedItem()))
def getSelectedItem(self):
item = QListWidgetItem(self.listbox_view.currentItem())
return item.text()
if __name__ == '__main__':
app = QApplication(sys.argv)
demo = AppDemo()
demo.show()
sys.exit(app.exec_())
You have to use the signals that are emitted when the number of rows of the model associated with the view changes, those signals must invoke a method that updates the state of the button based on the number of items in the QListWidget:
class AppDemo(QMainWindow):
def __init__(self):
super().__init__()
self.resize(1200, 600)
self.listbox_view = ListBoxWidget(self)
self.listbox_view.model().modelReset.connect(self.handle_rows_changed)
self.listbox_view.model().rowsInserted.connect(self.handle_rows_changed)
self.listbox_view.model().rowsRemoved.connect(self.handle_rows_changed)
self.listbox_view.model().layoutChanged.connect(self.handle_rows_changed)
self.btn = QPushButton("Get Value", self)
self.btn.setEnabled(False)
self.btn.setGeometry(850, 400, 200, 50)
self.btn.clicked.connect(lambda: print(self.getSelectedItem()))
def getSelectedItem(self):
item = self.listbox_view.currentItem()
return item.text() if item is not None else ""
def handle_rows_changed(self):
self.btn.setEnabled(bool(self.listbox_view.count()))

Pyqt5 - Back to hidden MainWindows

I'm making a program to specify a specific area using pyqt5.
If I click on the capture button, I will hide the MainWindow and display a screen to specify the area. I want to clear the screen and return to the mainwindow by pressing the esc key. But MainWindow does not show again. How should I work it?
form_class = uic.loadUiType("prototype.ui")[0]
class MainWindow(QtWidgets.QMainWindow, form_class) :
def __init__(self):
super().__init__()
self.setupUi(self)
self.Capture_Button.clicked.connect(self.Capture_Btn_clicked)
self.CaptureWindow = CaptureWidget()
self.CaptureWindow.hide()
def Capture_Btn_clicked(self) :
self.hide()
self.CaptureWindow.close()
self.CaptureWindow.__init__()
self.CaptureWindow.show()
QtWidgets.QApplication.setOverrideCursor(QtGui.QCursor(QtCore.Qt.CrossCursor))
def enterEvent(self, QEvent):
QtWidgets.QApplication.setOverrideCursor(QtGui.QCursor(QtCore.Qt.ArrowCursor))
self.setWindowOpacity(1)
This is the class that specifies the area (some of the code is omitted).
class CaptureWidget(QtWidgets.QDialog):
def __init__(self):
super().__init__()
root = tk.Tk()
self.setupUi(self)
def setupUi(self) :
self.screen_width = root.winfo_screenwidth()
self.screen_height = root.winfo_screenheight()
self.setGeometry(0, 0, self.screen_width, self.screen_height)
self.setWindowTitle(' ')
self.begin = QtCore.QPoint()
self.end = QtCore.QPoint()
self.setWindowOpacity(0.3)
QtWidgets.QApplication.setOverrideCursor(QtGui.QCursor(QtCore.Qt.CrossCursor))
self.setWindowFlags(QtCore.Qt.FramelessWindowHint|QtCore.Qt.WindowStaysOnTopHint)
print('Capture the screen...')
self.is_set_region = False
self.is_mouse_click = False
self.show()
def keyPressEvent(self, event):
key = event.key()
if key == Qt.Key_Escape:
print('esc')
self.close()
elif key == Qt.Key_F1:
self.close()
self.__init__()
First of all, instead of overwriting the keyPressEvent method, it is easier to use QShortcut. On the other hand for this case it is better to create a signal that indicates when the escape key is pressed connecting it to the show method.
from PyQt5 import QtCore, QtGui, QtWidgets, uic
class CaptureWidget(QtWidgets.QDialog):
escape_pressed = QtCore.pyqtSignal()
def __init__(self):
super().__init__()
self.setupUi()
def setupUi(self):
self.setWindowOpacity(0.3)
QtWidgets.QApplication.setOverrideCursor(QtGui.QCursor(QtCore.Qt.CrossCursor))
self.setWindowFlags(QtCore.Qt.FramelessWindowHint | QtCore.Qt.WindowStaysOnTopHint)
shorcut_scaped = QtWidgets.QShortcut(QtCore.Qt.Key_Escape, self)
shorcut_scaped.activated.connect(self.escape_pressed)
shorcut_scaped.activated.connect(self.close)
shorcut = QtWidgets.QShortcut(QtCore.Qt.Key_F1, self)
shorcut.activated.connect(self.close)
form_class, _ = uic.loadUiType("prototype.ui")
class MainWindow(QtWidgets.QMainWindow, form_class):
def __init__(self):
super().__init__()
self.setupUi(self)
self.Capture_Button.clicked.connect(self.Capture_Btn_clicked)
self.CaptureWindow = CaptureWidget()
self.CaptureWindow.escape_pressed.connect(self.show)
#QtCore.pyqtSlot()
def Capture_Btn_clicked(self):
self.hide()
self.CaptureWindow.showFullScreen()
QtWidgets.QApplication.setOverrideCursor(QtGui.QCursor(QtCore.Qt.CrossCursor))
def enterEvent(self, QEvent):
QtWidgets.QApplication.setOverrideCursor(QtGui.QCursor(QtCore.Qt.ArrowCursor))
self.setWindowOpacity(1)
if __name__ == '__main__':
import sys
app = QtWidgets.QApplication(sys.argv)
w = MainWindow()
w.show()
sys.exit(app.exec_())

What is the best way of deleting a qpushbutton

Hello I need to know a way of deleting a QPushButton from my interface, i have not found a way that i
s usefull for my program.
for example:
class Button(QtGui.QPushButton):
def __init__(self, title, parent):
super(Button, self).__init__(title, parent)
self.setAcceptDrops(True)
def dragEnterEvent(self, e):
if e.mimeData().hasFormat('text/plain'):
e.accept()
else:
e.ignore()
def dropEvent(self, e):
self.setText(e.mimeData().text())
class Example(QtGui.QWidget):
def __init__(self):
super(Example, self).__init__()
self.initUI()
def initUI(self):
edit = QtGui.QLineEdit('', self)
edit.setDragEnabled(True)
edit.move(30, 65)
button = Button("Button", self)
button.move(190, 65)
self.setWindowTitle('Simple drag & drop')
self.setGeometry(300, 300, 300, 150)
def main():
app = QtGui.QApplication(sys.argv)
ex = Example()
ex.show()
app.exec_()
if __name__ == '__main__':
main()
there i created a button that can be dragged and dropped in my main window
now i want a way to delete this button from the mainwindow while im in the program.
thanks

pyQt Hover event with Svg image

I've been working on this for some time now and I can't figure out what I'm doing wrong. I hope someone here can help.
I'm trying to get hover events to work when I mouse over an Svg item that's in a QGraphicsScene. Here's the code that I've been playing with.
#!/usr/bin/python
import sys
from PyQt4.QtGui import *
from PyQt4.QtCore import *
from PyQt4.QtSvg import *
class Main(QWidget):
def __init__(self):
super(Main, self).__init__()
hbox = QHBoxLayout()
self.setLayout(hbox)
self.view = MyView(self)
self.scene = QGraphicsScene()
self.view.setScene(self.scene)
hbox.addWidget(self.view)
class MyView(QGraphicsView):
def __init__(self, parent):
super(MyView, self).__init__(parent)
self.parent = parent
def mousePressEvent(self, event):
super(MyView, self).mousePressEvent(event)
test = MySvg()
self.parent.scene.addItem(test.image)
class MySvg(QGraphicsSvgItem):
def __init__(self):
super(MySvg, self).__init__()
self.image = QGraphicsSvgItem('ubuntu.svg')
self.image.setFlags(QGraphicsItem.ItemIsSelectable|
QGraphicsItem.ItemIsMovable)
self.setAcceptsHoverEvents(True)
def hoverEnterEvent(self, event):
print 'Enter'
def hoverLeaveEvent(self, event):
print 'Leave'
def hoverMoveEvent(self, event):
print 'Moving'
def runMain():
app = QApplication(sys.argv)
ex = Main()
ex.show()
sys.exit(app.exec_())
if __name__ == '__main__':
runMain()
Hope someone can help.
You are monitoring hover events for MySvg but you are adding another QGraphicsSvgItem to the view that is just an instance (MySvg.image) in MySvg. Your MySvg is not even in the view. Try like this:
#!/usr/bin/python
import sys
from PyQt4.QtGui import *
from PyQt4.QtCore import *
from PyQt4.QtSvg import *
class Main(QWidget):
def __init__(self):
super(Main, self).__init__()
hbox = QHBoxLayout()
self.setLayout(hbox)
self.view = MyView(self)
self.scene = QGraphicsScene()
self.view.setScene(self.scene)
hbox.addWidget(self.view)
class MyView(QGraphicsView):
def __init__(self, parent):
super(MyView, self).__init__(parent)
self.parent = parent
def mousePressEvent(self, event):
super(MyView, self).mousePressEvent(event)
test = MySvg()
self.parent.scene.addItem(test)
class MySvg(QGraphicsSvgItem):
def __init__(self):
super(MySvg, self).__init__('ubuntu.svg')
self.setFlags(QGraphicsItem.ItemIsSelectable|
QGraphicsItem.ItemIsMovable)
self.setAcceptsHoverEvents(True)
def hoverEnterEvent(self, event):
print 'Enter'
def hoverLeaveEvent(self, event):
print 'Leave'
def hoverMoveEvent(self, event):
print 'Moving'
def runMain():
app = QApplication(sys.argv)
ex = Main()
ex.show()
sys.exit(app.exec_())
if __name__ == '__main__':
runMain()

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