单击QTREEWIDGET时，请使用Qthread来防止冻结

Question

每当用户单击qtreewidget中的项目时，计算机就会开始执行一些重型任务。我唯一的目标是使用QThread来防止冻结。

---

考虑以下代码：

from PyQt5.QtWidgets import*
from PyQt5.QtCore import*
import time

class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        self.setWindowTitle('MainWindow')
        self.layout = QVBoxLayout()
        
        self.treewidget = MyTreeWidget()
        self.treewidget.itemClicked.connect(self.tree_click)
        self.layout.addWidget(self.treewidget)
        
        self.label = QLabel("Label", self)
        self.layout.addWidget(self.label)
        
        widget = QWidget()
        widget.setLayout(self.layout)
        self.setCentralWidget(widget)
        self.show()
        
    @pyqtSlot(QTreeWidgetItem)
    def tree_click(self, item):
        time.sleep(2)
        self.label.setText(item.text(0))
        
class MyTreeWidget(QTreeWidget):
    def __init__(self):
        super().__init__()
        item_1 = QTreeWidgetItem()
        item_1.setText(0, 'one item')
        item_2 = QTreeWidgetItem()
        item_2.setText(0,'another item')
        self.addTopLevelItem(item_1)
        item_1.addChild(item_2)
        self.setHeaderHidden(True)

if __name__ == '__main__':
    import sys
    app = QApplication(sys.argv)
    main = MainWindow()
    app.exec()

如何修改上述代码以防止冻结，以及最合适的方法是什么？

---

我尝试按照，第二个答案：

from PyQt5.QtWidgets import*
from PyQt5.QtCore import*
import time

class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        self.setWindowTitle('MainWindow')
        self.layout = QVBoxLayout()
        
        self.treewidget = MyTreeWidget()
        self.treewidget.itemClicked.connect(self.tree_click)
        self.layout.addWidget(self.treewidget)
        
        self.label = QLabel("Label", self)
        self.layout.addWidget(self.label)
        
        widget = QWidget()
        widget.setLayout(self.layout)
        self.setCentralWidget(widget)
        self.show()
        
    @pyqtSlot(QTreeWidgetItem)
    def tree_click(self, item):
        self.obj = Worker()
        self.thread = QThread()
        self.obj.finished.connect(self.change_text)
        self.obj.moveToThread(self.thread)
        self.obj.finished.connect(self.thread.quit)
        self.thread.started.connect(self.obj.work)
        self.thread.start()
    
    def change_text(self):
        self.label.setText(item.text(0))
        
class Worker(QObject):
    finished = pyqtSignal()
    @pyqtSlot()
    def work(self):
        time.sleep(2)
    finished = pyqtSignal()
        
class MyTreeWidget(QTreeWidget):
    def __init__(self):
        super().__init__()
        item_1 = QTreeWidgetItem()
        item_1.setText(0, 'one item')
        item_2 = QTreeWidgetItem()
        item_2.setText(0,'another item')
        self.addTopLevelItem(item_1)
        item_1.addChild(item_2)
        self.setHeaderHidden(True)

if __name__ == '__main__':
    import sys
    app = QApplication(sys.argv)
    main = MainWindow()
    app.exec()

看起来我在做正确的事情。

Answer 1

我进行了几次小调调整，以使您的工人课程正确运行。这将阻止其余的GUI冻结，但是取决于长期运行过程的标签文本将继续花费这么长时间才能更新。

同样，如果经常重复单独的线程中实现的任务，则可能需要考虑使用QthreadPool。

我还提供了一些内联评论，以解释一些更改。

from PyQt5.QtWidgets import*
from PyQt5.QtCore import*
import time

class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        self.setWindowTitle('MainWindow')
        self.layout = QVBoxLayout()

        self.treewidget = MyTreeWidget()
        self.treewidget.itemClicked.connect(self.tree_click)
        self.layout.addWidget(self.treewidget)

        self.label = QLabel("Label", self)
        self.layout.addWidget(self.label)

        widget = QWidget()
        widget.setLayout(self.layout)
        self.setCentralWidget(widget)
        self.show()
        self.threads = []  # make shift threads container

    @pyqtSlot(QTreeWidgetItem)
    def tree_click(self, item):
        self.obj = Worker()
        thread = QThread()  
        self.obj.text = item.text(0) # the obj needs a copy of the text to emit
        self.obj.textReady.connect(self.change_text)
        self.obj.moveToThread(thread)
        self.obj.finished.connect(thread.quit)  
        thread.finished.connect(thread.deleteLater) # delete the threads once finished
        thread.started.connect(self.obj.work)
        thread.start()
        self.threads.append(thread)

    def change_text(self, text):
        self.label.setText(text)

class Worker(QObject):
    finished = pyqtSignal()
    textReady = pyqtSignal([str])

    @pyqtSlot()
    def work(self):
        time.sleep(2)
        self.textReady.emit(self.text) # emit the text that needs to be changed 
        self.finished.emit() 
                             
class MyTreeWidget(QTreeWidget):
    def __init__(self):
        super().__init__()
        item_1 = QTreeWidgetItem()
        item_1.setText(0, 'one item')
        item_2 = QTreeWidgetItem()
        item_2.setText(0,'another item')
        self.addTopLevelItem(item_1)
        item_1.addChild(item_2)
        self.setHeaderHidden(True)

if __name__ == '__main__':
    import sys
    app = QApplication(sys.argv)
    main = MainWindow()
    app.exec()