【PyQt5 學習記錄】004：簡單QThread筆記

在文本編輯框中每隔幾秒添加一行文本，代碼如下：

#!/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()
        # 創建線程
        self.my_thread = MyThread()
        # 將自定義信號sig連接到MyThread.on_source函數
        self.sig.connect(self.my_thread.on_source)
        # 向MyThread.on_source函數傳遞line_text
        self.sig.emit(line_text)
        # 直接調用MyThread.on_source()也可以，但還是建議使用信號傳遞，在靈活性和性能上更佳
        # self.my_thread.on_source(line_text)
        # 將自定義信號signal連接到information()槽函數
        self.my_thread.signal.connect(self.information)
        # 啟動線程
        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)
        # 將MyThread.running設為False以停止線程
        self.my_thread.running = False


class MyThread(QThread):
    # 自定義型號，執行run()函數時，從相關線程發射此信號
    signal = pyqtSignal(str)

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

    # 當發生QThread: Destroyed while thread is still running錯誤時，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:
            # 發出信號
            self.signal.emit(self.source_txt)
            # 線程休眠1秒
            self.sleep(1)


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

 

界面如圖：

當線程開始運行時，每隔1秒傳遞一個self.source_txt。

點擊pushButton時，使按鈕不可用，並啟動線程，在文本編輯框內不斷插入lienEdit的內容。

點擊stopButton時，停止線程。