PyQt小部件重新加载或刷新

Question

My problem is that when I choose a name on widget "Form1" this name is written to file. When I click on OK button on widget "Form1" I can't see the same name on widget "Form2" which I chose previously.

The problem is that the widget "Form2" is not up to date. I tried to insert self.update at the beginning on the widget "Form2" but it doesn't work. How can I refresh widget "Form2" or reload the content of the file?

I have a simple code:

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

import sys

from functools import partial
from PyQt4.QtGui import *
from PyQt4.QtCore import *
from PyQt4 import QtGui, QtCore
from math import sqrt
from time import gmtime, strftime

class Form1(QWidget):
    showForm2Signal = pyqtSignal()

    def __init__(self, parent=None):
        super(Form1, self).__init__(parent)

        self.label = QtGui.QLabel(self)
        self.label.setGeometry(0, 40, 480, 400)
        self.label.move(0,40)

        #Select name
        self.styleTerminalSettings = QtGui.QLabel("Please select your name:", self)
        self.styleTerminalSettings.move(20,40)
        self.styleTerminalSettings.resize(250,30)
        self.styleTerminalSettings.setStyleSheet("color: black;  background-color: transparent; font-size: 12pt; font-weight: bold;")

        self.comboBox = QtGui.QComboBox(self)
        self.comboBox.addItem("NAME 1")
        self.comboBox.addItem("NAME 2")
        self.comboBox.addItem("NAME 3")
        self.comboBox.addItem("NAME 4")
        self.comboBox.move(20,80)
        self.comboBox.resize(440,50)
        self.comboBox.currentIndexChanged.connect(self.selectionchange)

        #OK button
        self.ok_button = QtGui.QPushButton("OK", self)
        self.ok_button.resize(self.ok_button.minimumSizeHint())
        self.ok_button.move(0,340)
        self.ok_button.resize(480,60)
        self.ok_button.setStyleSheet("color: #25373D; background-color: #71BA51;  font-size: 16pt; font-weight: bold;")

        layout = QVBoxLayout(self)

        self.ok_button.clicked.connect(self.showForm2Signal.emit)

    def selectionchange(self,i): 
        pos_user_name = self.comboBox.currentText()
        self.users_write(pos_user_name)

    #Name write to file 
    def users_write(self, pos_user_name):
        filename = "user_name_session"

        target = open(filename, 'w')
        target.truncate()
        target.write(pos_user_name)
        target.close()    

class Form2(QWidget):
    def __init__(self, parent=None):
        super(Form2, self).__init__(parent)

        global pos_user_name 

        self.label = QtGui.QLabel(self)
        self.label.setGeometry(0, 40, 480, 400)
        self.label.move(0,40)

        #Name read from file
        filename = "user_name_session"
        target = open(filename, "r+")
        name = target.read(10);

        self.styleCashRegister = QtGui.QLabel("Name:", self)
        self.styleCashRegister.move(20,40)
        self.styleCashRegister.resize(170,30)
        self.styleCashRegister.setStyleSheet("color: black; background-color: transparent;  font-size: 16pt; font-weight: bold;")

        self.cashregisterid = QtGui.QLineEdit(self)
        self.cashregisterid.setText(str(name))
        self.cashregisterid.move(100, 40)
        self.cashregisterid.resize(260,30)
        self.cashregisterid.setStyleSheet("color: #25373D;  font-size: 16pt; font-weight: bold;")

class MainWidget(QWidget):
    def __init__(self, parent=None):
        super(MainWidget, self).__init__(parent)
        self.stack = QStackedWidget()
        layout = QVBoxLayout(self)
        layout.addWidget(self.stack)
        layout.setContentsMargins(0, 0, 0, 0)

        self.setGeometry(0, 0, 480, 400)
        self.setWindowTitle("PYQT WIDGET TEST")
        self.setStyleSheet("background-color: #E8E8E8")

        self.form1 = Form1(self)
        self.form2 = Form2(self)

        self.stack.addWidget(self.form1)
        self.stack.addWidget(self.form2)

        self.form1.showForm2Signal.connect(partial(self.stack.setCurrentWidget,self.form2))

        self.stack.setCurrentWidget(self.form1) 

if __name__ == '__main__':
    app = QApplication(sys.argv)
    w = MainWidget()
    w.show()
    app.exec_()
    sys.exit()

Answer 1

There are a couple ways you could do this. The first thing you need is a "refresh" function on form2 that will update the text on form2.

def refresh(self):
    filename = "user_name_session"
    target = open(filename, "r+")
    name = target.read(10);
    self.cashregisterid.setText(str(name))

The second thing you need is a way to call that refresh function whenever the file is rewritten.

You could just use the existing signal that form1 already emits to show form2. In your MainWidget, connect that signal to the refresh function

self.form1.showForm2Signal.connect(self.form2.refresh)