【PyQt5 学习记录】004：简单QThread笔记

在文本编辑框中每隔几秒添加一行文本，代码如下：

#!/usr/bin/python3
# -*- coding:utf-8 -*-

import sys
from PyQt5.QtWidgets import (QApplication,
                             QWidget,
                             QLineEdit,
                             QPushButton,
                             QTextEdit,
                             QGridLayout)
from PyQt5.QtCore import (Qt,
                          QThread,
                          pyqtSignal,
                          pyqtSlot)


class Window(QWidget):
    def __init__(self, parent=None):
        super(Window, self).__init__(parent, Qt.Widget)

        self.resize(460, 460)
        self.setWindowTitle("Thread Test")

        self.lineEdit = QLineEdit(self)
        self.lineEdit.setPlaceholderText("connect to...")
        self.pushButton = QPushButton(">>", self)
        self.pushButton.setFixedWidth(30)
        self.stopButton = QPushButton("×", self)
        self.stopButton.setFixedWidth(30)
        self.textEdit = QTextEdit(self)
        self.textEdit.setPlaceholderText("result...")

        grid = QGridLayout()
        grid.addWidget(self.lineEdit, 0, 0, 1, 3)
        grid.addWidget(self.pushButton, 0, 3)
        grid.addWidget(self.stopButton, 0, 4)
        grid.addWidget(self.textEdit, 1, 0, 5, 5)
        self.setLayout(grid)

        self.show()


class Run(Window):
    sig = pyqtSignal(str)

    def __init__(self):
        super().__init__()

        self.my_thread = None
        self.pushButton.clicked.connect(self.button)
        self.stopButton.clicked.connect(self.stop_button)

    def button(self):
        self.textEdit.clear()
        line_text = self.lineEdit.text()
        # 创建线程
        self.my_thread = MyThread()
        # 将自定义信号sig连接到MyThread.on_source函数
        self.sig.connect(self.my_thread.on_source)
        # 向MyThread.on_source函数传递line_text
        self.sig.emit(line_text)
        # 直接调用MyThread.on_source()也可以，但还是建议使用信号传递，在灵活性和性能上更佳
        # self.my_thread.on_source(line_text)
        # 将自定义信号signal连接到information()槽函数
        self.my_thread.signal.connect(self.information)
        # 启动线程
        self.my_thread.start()
        self.pushButton.setEnabled(False)

    @pyqtSlot(str)
    def information(self, info):
        # 向textEdit添加lineEdit的文本
        self.textEdit.append(info)

    def stop_button(self):
        self.pushButton.setEnabled(True)
        # 将MyThread.running设为False以停止线程
        self.my_thread.running = False


class MyThread(QThread):
    # 自定义型号，执行run()函数时，从相关线程发射此信号
    signal = pyqtSignal(str)

    def __init__(self):
        super().__init__()
        self.source_txt = None
        self.running = True

    # 当发生QThread: Destroyed while thread is still running错误时，添加QThread.wait()
    # def __del__(self):
    #    self.wait()

    def on_source(self, line_text):
            self.source_txt = line_text

    @pyqtSlot()
    def run(self):
        while self.running:
            # 发出信号
            self.signal.emit(self.source_txt)
            # 线程休眠1秒
            self.sleep(1)


if __name__ == "__main__":
    app = QApplication(sys.argv)
    win = Run()
    sys.exit(app.exec_())

界面如图：

当线程开始运行时，每隔1秒传递一个self.source_txt。

点击pushButton时，使按钮不可用，并启动线程，在文本编辑框内不断插入lienEdit的内容。

点击stopButton时，停止线程。