当程序运行时，如何改变它的内容？

Question

我正在用PyQt5编写一个计算器，用户界面已经完成，但是当我修改QLineEdit的内容时有一个问题。详细的更改方法是当用户按下按钮时调用QLineEdit.setText()方法。你知道吗

但当我按下按钮时，程序结束并显示如下消息：“进程结束，退出代码为1”。没有任何错误或警告信息。以下是完整的程序：

# -*- coding:utf-8 -*-
import sys
from PyQt5.QtWidgets import (QWidget, QGridLayout,
        QPushButton, QLineEdit, QVBoxLayout, QApplication, QMessageBox)


class Calculator(QWidget):
    def __init__(self):
        super().__init__()
        self.initUI()

    def initUI(self):
        # grid = QGridLayout()
        qvbox = QVBoxLayout()
        gridBar = QGridLayout()
        gridWidget = QWidget()

        numberEdit = QLineEdit()
        numberEdit.setReadOnly(True)

        names = ["Cls", "Bck", "", "Close",
                 "7", "8", "9", "/",
                 "4", "5", "6", "*",
                 "1", "2", "3", "-",
                 "0", ".", "=", "+"]

        position = [(i, j) for i in range(5) for j in range(4)]

        for position, name in zip(position, names):
            if name == "":
                continue
            button = QPushButton(name)
            gridBar.addWidget(button, *position)
            button.clicked.connect(self.buttonClicked)
        qvbox.addWidget(numberEdit)
        gridWidget.setLayout(gridBar)
        qvbox.addWidget(gridWidget)

        self.setLayout(qvbox)

        self.move(300, 150)
        self.setWindowTitle("Calculator")
        self.show()

    def buttonClicked(self):
        sender = self.sender()
        self.dealData(sender.text())

    def dealData(self, data):
        self.numberEdit.setText(data) # Here, the program exited!!!
        print(data) # The output in consle was right.

if __name__ == "__main__":
    app = QApplication(sys.argv)
    ex = Calculator()
    sys.exit(app.exec_())

我哪里出错了？你知道吗

Answer 1

必须为numberEdit设置一个属性，以便以后可以访问它：

class Calculator(QWidget):
    ...    
    def initUI(self):
        ...
        self.numberEdit = QLineEdit()
        self.numberEdit.setReadOnly(True)

此外，还需要附加新文本，因此dealData应该如下所示：

    def dealData(self, data):
        self.numberEdit.end(False)
        self.numberEdit.insert(data)
        print(data) # The output in consle was right.