from PyQt5.QtWidgets import QApplication, QPushButton, QMainWindow
from PyQt5.QtGui import QIcon
import sys
class Main(QMainWindow):
def __init__(self, parent=None) -> None:
super().__init__(parent=parent)
self.setWindowTitle("QPushButton")
left = 300
top = 200
width = 300
height = 250
self.setGeometry(left, top, width, height)
self.show()
def main():
App = QApplication(sys.argv)
Main()
sys.exit(App.exec())
if __name__=="__main__":
main()
I don't get it, it worked before now it closes within a second of opening. I'm thinking somehow my installation got corrupted. Do you have any ideas I tried
def main():
App = QApplication(sys.argv)
Main()
App.exec_()
Related
I have a QMainWindow which contains a QPlainTextEdit and a button with clicked even connected. When user finishes text input and press the button, I just want to execute user input for example "1+1". I should get "2", but it is "1+1". Very appreciated for your reply, thanks!
import sys
from PyQt5.QtWidgets import QMainWindow, QPushButton, \
QApplication, QVBoxLayout, QPlainTextEdit, QWidget
class MainWindow(QMainWindow):
def __init__(self):
super().__init__()
self.setFixedSize(600, 600)
l_layout = QVBoxLayout()
self.edit = QPlainTextEdit()
self.edit.setFixedSize(400, 300)
self.edit1 = QPlainTextEdit()
self.edit1.setFixedSize(100, 100)
self.btn = QPushButton('Test')
self.btn.clicked.connect(self.press)
l_layout.addWidget(self.edit)
l_layout.addWidget(self.edit1)
l_layout.addWidget(self.btn)
dummy_widget = QWidget()
dummy_widget.setLayout(l_layout)
self.setCentralWidget(dummy_widget)
def press(self):
text = self.edit.toPlainText()
try:
code = """print(text)"""
exec(code)
except Exception as e:
print('not ok!')
app = QApplication(sys.argv)
window = MainWindow()
window.show()
app.exec_()
You should evaluate the input text and then print it, like so:
def press(self):
text = self.edit.toPlainText()
try:
print(eval(text))
except Exception as e:
print('not ok!')
Pay attention, because eval() use can lead to security issues (people executing python code on your app). Make sure your input is sanitized.
I want to open a picture when I click the menu, but I don't know how
I want to be able to output the specified image file when clicking the submenu.
import sys
from PyQt5.QtWidgets import QMainWindow, QMenu, QApplication, QLabel
from PyQt5.QtGui import QPixmap, QIcon,QAction,*
class Example(QMainWindow):
def __init__(self):
super().__init__()
self.initUI()
def initUI(self):
menubar= self.menubar()
self.filemenu = menubar.addmenu('a')
x= QMenu('b',self)
y= QMenu('c',self)
self.filemenu.addmenu(y)
self.x1 =QAction('d',self)
x.addMenu(self.x1)
self.x1.triggered.connect(self.fileopen)
def fileopen(self):
qpixmapvar=QPixmap()
qpixmapvar.load("C:\\desktop\\A.png")
self.label.setPixmap(qPixmapvar)
self.label.resize(qPixmapvar.width(), qPixmapvar.height())
if__name__ =='__main__':
app= Qapplication(sys.argv)
ex = Example()
sys.exit(app.exec())
The following code crashes on clicking the button or after a few clicks when the signal is emitted from thread and caught in the main gui.
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtGui import QPixmap, QImage
from PyQt5.QtCore import pyqtSignal, pyqtSlot, Qt, QThread
import numpy as np
import time
from PyQt5.QtWidgets import QApplication, QDialog, QPushButton, QVBoxLayout
def convert_np_qimage(cv_img , width, height):
h, w, ch = cv_img.shape
bytes_per_line = ch * w
qim = QtGui.QImage(cv_img.data, w, h, bytes_per_line, QtGui.QImage.Format_RGB888)
print(qim.size())
return qim
class VideoThread(QThread):
change_qimage_signal = pyqtSignal(QImage)
def __init__(self):
super().__init__()
def run(self):
print("run")
width = 1280
height = 1280
cv_img = np.zeros([height,width,3],dtype=np.uint8)
cv_img.fill(255)
print("image shape: ", cv_img.shape)
qimg = convert_np_qimage(cv_img, width, height)
self.change_qimage_signal.emit(qimg)
print("emitted")
def stop(self):
self.wait()
import sys
class Dialog(QDialog):
def __init__(self):
super(Dialog, self).__init__()
Dialog.resize(self, 640, 480)
button=QPushButton("Click")
button.clicked.connect(self.startThread)
mainLayout = QVBoxLayout()
mainLayout.addWidget(button)
self.setLayout(mainLayout)
self.setWindowTitle("QImage Example")
def startThread(self):
self.thread = VideoThread()
self.thread.change_qimage_signal.connect(self.getPixmap)
self.thread.start()
def getPixmap(self, qimg):
print("got qimage")
qpixmap = QPixmap.fromImage(qimg)
if __name__ == '__main__':
app = QApplication(sys.argv)
dialog = Dialog()
sys.exit(dialog.exec_())
The program doesn't crash if height and width are set to small number say 3.
The program also doesn't crash if we convert qimage to qpixmap before emitting and change the signal
type to QPixmap.
The program was originally written to get images from webcam using opencv. The numpy array created
by opencv crashes too for big image sizes.
The OS used is Windows10, pyqt version is 5.12.3
Any idea what might be the reason for the crash?
In Linux with PyQt5 5.15 I do not reproduce the problem, but that error is common and occurs because passing "data" does not copy the information but rather the data is shared, so at some point cv_img and all associated objects are destroyed including to "data" so when transmitting it through the signal and setting it in the QLabel that "data" is read but it no longer has reserved memory. The solution in this case is to copy "data":
qim = QtGui.QImage(
cv_img.data.tobytes(), w, h, bytes_per_line, QtGui.QImage.Format_RGB888
)
or copy the QImage.
return qim.copy()
I'm trying to send signals between classes, which works fine from the HMI class to the WorkerThread class, but causes a program lockup, or infinite loop, when WorkerThread tries to connect to a signal from the HMI class.
import sys
import time
import PyQt5
from PyQt5 import QtCore, QtWidgets
from PyQt5.QtCore import QThread
from PyQt5.QtWidgets import QWidget, QApplication
from Home import Ui_HomeWin # PyQt5 Designer window
class WorkerThread(QThread):
hmiHandlesThis = PyQt5.QtCore.pyqtSignal(str)
def __init__(self, parent=None):
super(WorkerThread, self).__init__(parent)
self.counter = 0
# this attempted connection causes a lockup
self.HMI_Thread = HMI() # appears to be a recursive loop
self.HMI_Thread.updateGlobals.connect(self.update_global_widgets)
def run(self):
while True:
time.sleep(0.5)
print('Doing a bunch of other stuff: {}'.format(self.counter))
self.counter += 1
def build_a_command(self):
print('building a command...')
name = 'pbAutoMode'
# example command
command = name + '.setStyleSheet("QPushButton{ background-color: rgb(0, 0, 255); }")'
self.hmiHandlesThis.emit(command)
def update_global_widgets(self):
print('update some global widgets')
class HMI(QWidget):
updateGlobals = PyQt5.QtCore.pyqtSignal(name='updateGlobals')
def __init__(self, parent=None):
super(HMI, self).__init__(parent)
self.HomeWin = QtWidgets.QDialog()
self.HomeWin.setWindowFlags(QtCore.Qt.FramelessWindowHint)
ui = Ui_HomeWin()
ui.setupUi(self.HomeWin)
self.HomeWin.show()
# this connection works
self.workerThread = WorkerThread()
self.workerThread.hmiHandlesThis.connect(self.on_new_command)
self.workerThread.start()
def on_new_command(self, command):
print('New command is: {}'.format(command))
if __name__ == '__main__':
app = QApplication(sys.argv)
ex = HMI()
sys.exit(app.exec_())~~~
I've tried placing the signal definitions inside the init functions, with no difference.
With Dennis Jensen's help, i've been able to get this running properly. I'm posting the working snippet here as an example of 'proper' thread building and the passing of signals.
import sys
import time
import PyQt5
from PyQt5 import QtCore, QtWidgets
from PyQt5.QtCore import QObject, QThread
from PyQt5.QtWidgets import QWidget, QApplication
from Home import Ui_HomeWin # a PyQt5 Designer window
class WorkerThread(QObject):
hmiHandlesThis = PyQt5.QtCore.pyqtSignal(str, str)
def __init__(self, parent=None):
super(WorkerThread, self).__init__(parent)
self.counter = 0
def processRun(self):
while True:
time.sleep(0.5)
print('Doing a bunch of other stuff: {}'.format(self.counter))
self.counter += 1
def update_global_widgets(self):
print('update some global widgets')
def build_a_command(self):
print('building a command...')
name = 'pbAutoMode'
# example command
command = name + '.setStyleSheet("QPushButton{ background-color: rgb(0, 0, 255); }")'
self.hmiHandlesThis.emit(name, command)
class HMI(QWidget):
updateGlobals = PyQt5.QtCore.pyqtSignal(name='updateGlobals')
def __init__(self, parent=None):
super(HMI, self).__init__(parent)
self.HomeWin = QtWidgets.QDialog()
self.HomeWin.setWindowFlags(QtCore.Qt.FramelessWindowHint)
ui = Ui_HomeWin()
ui.setupUi(self.HomeWin)
self.HomeWin.show()
self.EstablishThread()
def EstablishThread(self):
# Create the Object from Class
self.Worker = WorkerThread()
# Assign the Database Signals to Slots
self.Worker.hmiHandlesThis.connect(self.on_new_command)
# Create the Thread
self.ThredHolder = QThread()
# Move the Listener to the Thread
self.Worker.moveToThread(self.ThredHolder)
# Assign the Listener Starting Function to the Thread Call
self.ThredHolder.started.connect(self.Worker.processRun)
# Start the Thread which launches Listener.Connect( )
self.ThredHolder.start()
def on_new_command(self):
print('Handling new command...')
if __name__ == '__main__':
app = QApplication(sys.argv)
ex = HMI()
sys.exit(app.exec_())
Thanks Dennis!
I am writing a program with pyqt5 where pressing a button first cycles through some pictures then cycles through some videos.
from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
from PyQt5.QtMultimedia import *
from PyQt5.QtMultimediaWidgets import *
import glob
import argparse
import sys
class MainWindow(QMainWindow):
def __init__(self,args):
super(MainWindow, self).__init__()
self.setWindowTitle('Navon test')
self.setWindowFlags(Qt.FramelessWindowHint)
# exit option for the menu bar File menu
self.exit = QAction('Exit', self)
self.exit.setShortcut('Ctrl+q')
# message for the status bar if mouse is over Exit
self.exit.setStatusTip('Exit program')
# newer connect style (PySide/PyQT 4.5 and higher)
self.exit.triggered.connect(app.quit)
self.setWindowIcon(QIcon('icon.ico'))
self.centralwidget = CentralWidget(args)
self.setCentralWidget(self.centralwidget)
def keyPressEvent(self, QKeyEvent):
if QKeyEvent.key() == Qt.Key_Escape:
QCoreApplication.instance().quit()
self.centralwidget.startvid()
class CentralWidget(QWidget):
def __init__(self,args):
super(CentralWidget, self).__init__()
self.layout = QVBoxLayout()
self.layout.setAlignment(Qt.AlignCenter)
self.setLayout(self.layout)
self.player = QMediaPlayer(None, QMediaPlayer.VideoSurface)
self.vw = QVideoWidget()
self.player.setVideoOutput(self.vw)
def startvid(self):
self.layout.addWidget(self.vw)
url= QUrl.fromLocalFile(glob.glob("videos/*")[0])
content= QMediaContent(url)
self.player.setMedia(content)
self.player.setVideoOutput(self.vw)
self.player.play()
if __name__== "__main__":
parser = argparse.ArgumentParser()
#~ parser.add_argument("-nb","--nobox",action="store_true", help="do not wait for the box connection")
args = parser.parse_args()
app = QApplication(sys.argv)
mainwindow = MainWindow(args)
#~ mainwindow.showFullScreen()
mainwindow.show()
sys.exit(app.exec_())
I tried to paste the minimal code. The thing is, I press the button nothing shows, although I used examples like this one PyQt5 - Can't play video using QVideoWidget to test if playing the video is ok, and these work. It's as if it is not adding the widget to the layout or something. Any idea what might be wrong?
I had to use QGraphicsView to achieve what I wanted, here is a fix:
from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
from PyQt5.QtMultimedia import *
from PyQt5.QtMultimediaWidgets import *
import glob
class MainWindow(QMainWindow):
def __init__(self):
super(MainWindow, self).__init__()
self.setWindowTitle('Navon test')
self.setWindowFlags(Qt.FramelessWindowHint)
# exit option for the menu bar File menu
self.exit = QAction('Exit', self)
self.exit.setShortcut('Ctrl+q')
# message for the status bar if mouse is over Exit
self.exit.setStatusTip('Exit program')
# newer connect style (PySide/PyQT 4.5 and higher)
self.exit.triggered.connect(app.quit)
self.setWindowIcon(QIcon('icon.ico'))
self.centralwidget = VideoPlayer()
self.setCentralWidget(self.centralwidget)
def keyPressEvent(self, QKeyEvent):
if QKeyEvent.key() == Qt.Key_Escape:
self.centralwidget.phaseQuit(2)
self.centralwidget.play()
class VideoPlayer(QWidget):
def __init__(self, parent=None):
super(VideoPlayer, self).__init__(parent)
self.mediaPlayer = QMediaPlayer(None, QMediaPlayer.VideoSurface)
self.videoItem = QGraphicsVideoItem()
self.videoItem.setSize(QSizeF(640, 480))
scene = QGraphicsScene(self)
graphicsView = QGraphicsView(scene)
scene.addItem(self.videoItem)
layout = QVBoxLayout()
layout.addWidget(graphicsView)
self.setLayout(layout)
self.mediaPlayer.setVideoOutput(self.videoItem)
self.counter = 0
def play(self):
if self.mediaPlayer.state() == QMediaPlayer.PlayingState:
pass
else:
self.mediaPlayer.setMedia(QMediaContent(QUrl.fromLocalFile(glob.glob("videos/*")[self.counter])))
self.mediaPlayer.play()
self.counter += 1
if __name__ == '__main__':
import sys
app = QApplication(sys.argv)
player = MainWindow()
player.show()
sys.exit(app.exec_())