PyQt5 自动更改 QlineEdit 文本

Question

我有一个主 window 和一个只读 QlineEdit，它显示今天的日期和一个打开日历小部件 window （来自项目中的另一个模块）的按钮来选择另一个日期，当我选择另一个日期时，Gui 中的 QlineEdit 文本的问题是虽然存储值的变量成功更改，但没有更改，我搜索了很多没有线索

• 在使用 QlineEdit 之前，我尝试了 Qlabel 但也无法达到结果

这是主要的 window：

import sys
from PyQt5.QtGui import QFont
from PyQt5.QtWidgets import QApplication, QMainWindow, QPushButton, QLineEdit
from PyQt5 import QtCore, QtGui, QtWidgets
from cal_window import prev_day, today_str, UiCalWindow


class MainWindow(QMainWindow):


    def __init__(self, *args, **kwargs):
        super(MainWindow, self).__init__(*args, **kwargs)

        self.setWindowTitle("My App")
        self.setGeometry(50, 50, 800, 600)

        self.label = QLineEdit(self)
        self.label.setFont(QFont("Arial", 20))

        self.label.setReadOnly(True)
        self.label.setText(today_str)

        self.setCentralWidget(self.label)

        self.btn = QPushButton('open calender', self)
        self.btn.move(50, 50)
        self.btn.clicked.connect(self.choose_date)


    def choose_date(self):
        self.window = QtWidgets.QMainWindow()
        self.ui = UiCalWindow()
        self.ui.setupUi(self.window)
        self.window.show()



app = QApplication(sys.argv)

window = MainWindow()
window.show()

app.exec_()

这是日历子窗口：

from PyQt5 import QtCore, QtGui, QtWidgets, Qt
from datetime import date




today = date.today()
today_str = today.strftime("%Y-%m-%d")
prev_day = "2000-01-01"


class UiCalWindow(object):

    def get_date(self, qDate):
        global prev_day
        self.day = '{0}-{1}-{2}'.format(qDate.year(), qDate.month(), qDate.day())
        prev_day = self.day
        print(prev_day)

    def setupUi(self, cal_window):
        cal_window.setObjectName("cal_window")
        cal_window.setWindowModality(QtCore.Qt.ApplicationModal)
        cal_window.resize(800, 600)
        font = QtGui.QFont()
        font.setPointSize(12)
        font.setBold(True)
        font.setWeight(75)
        cal_window.setFont(font)
        self.centralwidget = QtWidgets.QWidget(cal_window)
        self.centralwidget.setObjectName("centralwidget")
        self.gridLayout = QtWidgets.QGridLayout(self.centralwidget)
        self.gridLayout.setObjectName("gridLayout")
        self.calendarWidget = QtWidgets.QCalendarWidget(self.centralwidget)
        font = QtGui.QFont()
        font.setPointSize(16)
        font.setBold(True)
        font.setWeight(75)
        self.calendarWidget.setFont(font)
        self.calendarWidget.setLayoutDirection(QtCore.Qt.RightToLeft)
        self.calendarWidget.setFirstDayOfWeek(QtCore.Qt.Monday)
        self.calendarWidget.setGridVisible(True)
        self.calendarWidget.setVerticalHeaderFormat(QtWidgets.QCalendarWidget.NoVerticalHeader)
        self.calendarWidget.setObjectName("calendarWidget")
        self.gridLayout.addWidget(self.calendarWidget, 0, 0, 1, 1)
        self.calendarWidget.clicked.connect(self.get_date)
        self.ok_dt_btn = QtWidgets.QPushButton(self.centralwidget)
        self.ok_dt_btn.setMinimumSize(QtCore.QSize(0, 50))
        self.ok_dt_btn.setObjectName("ok_dt_btn")
        self.ok_dt_btn.clicked.connect(cal_window.close)
        self.gridLayout.addWidget(self.ok_dt_btn, 1, 0, 1, 1)
        cal_window.setCentralWidget(self.centralwidget)

        self.retranslateUi(cal_window)
        QtCore.QMetaObject.connectSlotsByName(cal_window)

    def retranslateUi(self, cal_window):
        _translate = QtCore.QCoreApplication.translate
        cal_window.setWindowTitle(_translate("cal_window", "MainWindow"))
        self.ok_dt_btn.setText(_translate("cal_window", "go"))


if __name__ == "__main__":
    import sys

    app = QtWidgets.QApplication(sys.argv)
    cal_window = QtWidgets.QMainWindow()
    ui = UiCalWindow()
    ui.setupUi(cal_window)
    cal_window.show()
    sys.exit(app.exec_())```

Answer 1

你有概念问题：

• 请勿修改 Qt Designer 生成的代码（建议恢复 cal_window.py。

• 不要使用全局变量，它们是不必要的，并且会产生比解决方案更多的问题。

• 变量“prev_day”被更新并不意味着QLabel显示的文本被更新，QLabel复制信息并且不监控字符串。

逻辑是使用信号来更新文本。

import sys
from PyQt5.QtCore import pyqtSignal, QDate
from PyQt5.QtGui import QFont
from PyQt5.QtWidgets import QApplication, QMainWindow, QPushButton, QLineEdit
from cal_window import UiCalWindow


class CalendarWindow(QMainWindow, UiCalWindow):
    def __init__(self, parent=None):
        super(CalendarWindow, self).__init__(parent)
        self.setupUi(self)


class MainWindow(QMainWindow):
    def __init__(self, *args, **kwargs):
        super(MainWindow, self).__init__(*args, **kwargs)

        self.setWindowTitle("My App")
        self.setGeometry(50, 50, 800, 600)

        self.label = QLineEdit(self)
        self.label.setFont(QFont("Arial", 20))
        self.label.setReadOnly(True)

        self.setCentralWidget(self.label)

        self.btn = QPushButton("open calender", self)
        self.btn.move(50, 50)

        self.cal = CalendarWindow()
        self.cal.calendarWidget.clicked.connect(self.handle_date_clicked)
        self.btn.clicked.connect(self.cal.show)

    def handle_date_clicked(self, date):
        self.label.setText(date.toString("yyyy-MM-dd"))


app = QApplication(sys.argv)

window = MainWindow()
window.show()

app.exec_()