pyqt5 操作txt文件的功能

PyQt5可以通过QFileDialog对话框来实现打开和保存txt文件的功能，具体步骤如下：

1. 导入需要的模块：

from PyQt5.QtWidgets import QApplication, QWidget, QFileDialog

2. 创建一个QWidget窗口：

app = QApplication(sys.argv)
window = QWidget()

3. 创建打开文件的函数，使用QFileDialog.getOpenFileName()方法：

def open_file():
    file_path, _ = QFileDialog.getOpenFileName(window, "Open Text File", "", "Text Files (*.txt)")
    if file_path:
        with open(file_path, 'r') as file:
            text = file.read()
            # 在文本编辑框中显示读取到的文本
            text_edit.setText(text)

4. 创建保存文件的函数，使用QFileDialog.getSaveFileName()方法：

def save_file():
    file_path, _ = QFileDialog.getSaveFileName(window, "Save Text File", "", "Text Files (*.txt)")
    if file_path:
        with open(file_path, 'w') as file:
            file.write(text_edit.toPlainText())

5. 创建一个文本编辑框：

text_edit = QTextEdit()

6. 创建打开和保存按钮，并添加对应的函数：

open_button = QPushButton("Open")
open_button.clicked.connect(open_file)

save_button = QPushButton("Save")
save_button.clicked.connect(save_file)

完整代码示例：

import sys
from PyQt5.QtWidgets import QApplication, QWidget, QFileDialog, QPushButton, QTextEdit


app = QApplication(sys.argv)
window = QWidget()

text_edit = QTextEdit()

def open_file():
    file_path, _ = QFileDialog.getOpenFileName(window, "Open Text File", "", "Text Files (*.txt)")
    if file_path:
        with open(file_path, 'r') as file:
            text = file.read()
            # 在文本编辑框中显示读取到的文本
            text_edit.setText(text)

def save_file():
    file_path, _ = QFileDialog.getSaveFileName(window, "Save Text File", "", "Text Files (*.txt)")
    if file_path:
        with open(file_path, 'w') as file:
            file.write(text_edit.toPlainText())

open_button = QPushButton("Open")
open_button.clicked.connect(open_file)

save_button = QPushButton("Save")
save_button.clicked.connect(save_file)

layout = QVBoxLayout()
layout.addWidget(text_edit)
layout.addWidget(open_button)
layout.addWidget(save_button)

window.setLayout(layout)
window.show()

sys.exit(app.exec_())

该示例创建了一个窗口，包含一个文本编辑框，和打开、保存按钮。用户可以打开txt文件并显示到文本编辑框中，也可以将编辑框中的内容保存为txt文件。