In this PyQt5 article i want to show you creating of QProgressbar With QThread Practical Example, also we are going to use QThread class for this article. A progress bar is used to give the user an indication of the progress of an operation and to reassure them that the application is still running.
What is PyQt5 QProgressbar ?
QProgressBar widget consists of horizontal or vertical bar that fills up gradually to indicate the progress of a task. it is often used in applications that involve time consuming operations, such as file uploads or downloads, software installations or any other process that may take a while to complete.
QProgressBar widget can be customized to display different colors, fonts, and sizes. It also provides various properties and methods that allow developers to control its behavior, such as the minimum and maximum values, the current value, and the orientation of the bar.
Overall, the QProgressBar widget is a useful tool for providing visual feedback to users on the progress of a task and can help make applications more user-friendly and intuitive.
Also you can read more Python GUI articles in the below links
- Kivy GUI Development Tutorials
- TKinter GUI Development Tutorials
- Pyside2 GUI Development
- wxPython GUI Development Tutorials
- PyQt5 GUI Development Tutorials
These are the imports that we need for example
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from PyQt5 import QtGui from PyQt5.QtWidgets import QApplication, QDialog, QProgressBar, QPushButton, QVBoxLayout import sys from PyQt5.QtCore import Qt, QThread, pyqtSignal import time |
This is our thread class and this class extends from QThread, a QThread object manages one thread of control within the program. QThreads begin executing in run(). By default, run() starts the event loop by calling exec() and runs a Qt event loop inside the thread.
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class MyThread(QThread): # Create a counter thread change_value = pyqtSignal(int) def run(self): cnt = 0 while cnt < 100: cnt+=1 time.sleep(0.3) self.change_value.emit(cnt) |
After we create our Window class that extends from QDialog and in that class we add the requirements of our window like title, geometry and icon with QProgresBar and also a QPushButton. also we have used some style and design for our progressbar.
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class Window(QDialog): def __init__(self): super().__init__() self.title = "PyQt5 ProgressBar" self.top = 200 self.left = 500 self.width = 300 self.height = 100 self.setWindowIcon(QtGui.QIcon("icon.png")) self.setWindowTitle(self.title) self.setGeometry(self.left, self.top, self.width, self.height) vbox = QVBoxLayout() self.progressbar = QProgressBar() #self.progressbar.setOrientation(Qt.Vertical) self.progressbar.setMaximum(100) self.progressbar.setStyleSheet("QProgressBar {border: 2px solid grey;border-radius:8px;padding:1px}" "QProgressBar::chunk {background:yellow}") #qlineargradient(x1: 0, y1: 0.5, x2: 1, y2: 0.5, stop: 0 red, stop: 1 white); #self.progressbar.setStyleSheet("QProgressBar::chunk {background: qlineargradient(x1: 0, y1: 0.5, x2: 1, y2: 0.5, stop: 0 red, stop: 1 white); }") #self.progressbar.setTextVisible(False) vbox.addWidget(self.progressbar) self.button = QPushButton("Start Progressbar") self.button.clicked.connect(self.startProgressBar) self.button.setStyleSheet('background-color:yellow') vbox.addWidget(self.button) self.setLayout(vbox) self.show() |
These are the methods that we are going to use for starting and setting the value of the QProgressBar.
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def startProgressBar(self): self.thread = MyThread() self.thread.change_value.connect(self.setProgressVal) self.thread.start() def setProgressVal(self, val): self.progressbar.setValue(val) |
Also every PyQt5 application must create an application object.
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App = QApplication(sys.argv) |
Finally, we enter the mainloop of the application. The event handling starts from this point.
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window = Window() sys.exit(App.exec_()) |
Complete source code for QProgressbar with QThread
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from PyQt5 import QtGui from PyQt5.QtWidgets import QApplication, QDialog, QProgressBar, QPushButton, QVBoxLayout import sys from PyQt5.QtCore import Qt, QThread, pyqtSignal import time class MyThread(QThread): # Create a counter thread change_value = pyqtSignal(int) def run(self): cnt = 0 while cnt < 100: cnt+=1 time.sleep(0.3) self.change_value.emit(cnt) class Window(QDialog): def __init__(self): super().__init__() self.title = "PyQt5 ProgressBar" self.top = 200 self.left = 500 self.width = 300 self.height = 100 self.setWindowIcon(QtGui.QIcon("icon.png")) self.setWindowTitle(self.title) self.setGeometry(self.left, self.top, self.width, self.height) vbox = QVBoxLayout() self.progressbar = QProgressBar() #self.progressbar.setOrientation(Qt.Vertical) self.progressbar.setMaximum(100) self.progressbar.setStyleSheet("QProgressBar {border: 2px solid grey;border-radius:8px;padding:1px}" "QProgressBar::chunk {background:yellow}") #qlineargradient(x1: 0, y1: 0.5, x2: 1, y2: 0.5, stop: 0 red, stop: 1 white); #self.progressbar.setStyleSheet("QProgressBar:: # chunk {background: # qlineargradient(x1: 0, y1: 0.5, x2: 1, y2: 0.5, stop: 0 red, stop: 1 white); }") #self.progressbar.setTextVisible(False) vbox.addWidget(self.progressbar) self.button = QPushButton("Start Progressbar") self.button.clicked.connect(self.startProgressBar) self.button.setStyleSheet('background-color:yellow') vbox.addWidget(self.button) self.setLayout(vbox) self.show() def startProgressBar(self): self.thread = MyThread() self.thread.change_value.connect(self.setProgressVal) self.thread.start() def setProgressVal(self, val): self.progressbar.setValue(val) App = QApplication(sys.argv) window = Window() sys.exit(App.exec_()) |
This will be the result of the code for the PyQt5 QProgressBar.
Also you can watch the complete video for PyQt5 QProgressbar With QThread Practical Example.
the best! Good forum.
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your welcome
This approach has significant drawbacks. For example, imagine you wanted to perform two such loops in parallel calling one of them would effectively halt the other until the first one is finished (so you can’t distribute computing power among different tasks). It also makes the application react with delays to events. Furthermore the code is difficult to read and analyze, therefore this solution is only suited for short and simple problems that are to be processed in a single thread, such as splash screens and the monitoring of short operations.
The clearest tutorial I have found on this topic!