如何将值从一个对话框传递到另一个对话框

Question

The code below creates a dialog window with a QLabel and a single QPushButton . Clicking the button brings up a second dialog with a text field and Confirm button. User enters a text in to the text field and clicks 'Confirm' button. The second dialog closes returning the user entered text. When returned the first dialog uses it to replace label's 'Default text value'.

How to pass the user text value to the first dialog?

from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
from PyQt5.QtCore import *
app = QApplication([])


class Modal(QDialog):
    def __init__(self, parent):
        super(Modal, self).__init__(parent)
        self.setLayout(QVBoxLayout())
        self.lineedit = QLineEdit(self)
        self.layout().addWidget(self.lineedit)
        button = QPushButton(self)
        button.setText('Confirm')
        button.clicked.connect(self.close)
        self.layout().addWidget(button)
        self.setModal(True)
        self.show()


class Dialog(QDialog):
    def __init__(self, parent=None):
        super(Dialog, self).__init__(parent)
        self.setLayout(QVBoxLayout())
        button = QPushButton('Show modal dialog')
        button.clicked.connect(self.showModal)
        self.label = QLabel('Default text value')
        self.layout().addWidget(self.label)
        self.layout().addWidget(button)
        self.resize(200, 50)
        self.show()


    def showModal(self):
        dialog = Modal(self)


dialog = Dialog()
app.exec_()

Answer 1

You could send a signal from a dialog and catch it in the other.

Define a signal in the emitting dialog, using pyqtSignal :

class Modal(QDialog):

    confirmed = pyqtSignal(str)
    # ...

The signal has one argument of type str and will be emitted from the confirm slot, after reading from the line edit the text entered by the user:

def confirm(self):
    self.close()
    value = self.lineedit.text()
    print ('entered value: %s' % value)
    self.confirmed.emit(value) #emit the signal, passing the text as its only argument

To catch the signal, the other class need a slot:

class Dialog(QDialog):
# ...
def changeText(self, t):
    self.label.setText(t)

The slot function will receive the text in its t argument, and set the label text accordingly, but for this to happen the signal and the slot must be connected .

First, let's edit the Modal class constructor, and remove this last two lines:

    self.setModal(True)
    self.show()

Let's use them in the Dialog 's showModal , after connecting the changeText slot and the Modal confirmed signal:

def showModal(self):
    modal_dialog = Modal(self)
    modal_dialog.confirmed.connect(self.changeText) #connect signal and slot
    modal_dialog.setModal(True)
    modal_dialog.show()

Full reference: Support for Signals and Slots

Answer 2

from PyQt5.QtWidgets import *
from PyQt5.QtCore import *
import sys
from functools import partial

class Modal(QDialog):
    def __init__(self, parent):
        super(Modal, self).__init__(parent)
        self.setLayout(QVBoxLayout())
        self.lineedit = QLineEdit(self)
        self.layout().addWidget(self.lineedit)
        button = QPushButton(self)
        button.setText('Confirm')
        button.clicked.connect(partial(self.confirm,parent)) #using partial to make a slot alog with parameters
        self.layout().addWidget(button)
        self.setModal(True)
        self.exec_()  #  Use exec if you want to really want to create modal dialog

    def confirm(self,parent):
        self.accept() #instead of close use its accept feature
        value = self.lineedit.text()
        parent.label.setText(value)  # acessing DialogClass object that you passed  while calling show modal
        print('entered value: %s' % value)


class Dialog(QDialog):
    def __init__(self, parent=None):
        super(Dialog, self).__init__(parent)
        self.setLayout(QVBoxLayout())
        button = QPushButton('Show modal dialog')
        button.clicked.connect(self.showModal)
        self.label = QLabel('Default text value')
        self.layout().addWidget(self.label)
        self.layout().addWidget(button)
        self.resize(200, 50)
        self.show()

    def showModal(self):
        modal_dialog = Modal(self)

app = QApplication([])
dialog = Dialog()
sys.exit(app.exec_())

Use the property accept of a dialog in confirm and before accepting the modal dialog,get access to parent dialog and its attribute label and set its text.Also I have used partial to pass a Slot with arguments