QgsFileWidget mandatory field in QWizard issue

Question

I'm trying to create a mandatory QgsFileWidget in a QWizard form for a plugin but the result is a Next button that doesn't get active when I choose the path to save the project. Here is the snippet of the code:

import os

from PyQt5.QtWidgets import QWizard, QWizardPage
from qgis.PyQt import uic

FORM_CLASS, _ = uic.loadUiType(os.path.join(
    os.path.dirname(__file__), 'plugin_wizard_base.ui'))

class PluginDialog(QWizard, QWizardPage, FORM_CLASS):
    def __init__(self, parent=None):
        """Constructor."""
        super(PluginDialog, self).__init__(parent)
        self.setupUi(self)
        try:
            self.wizardPage.registerField('projPath*', self.projPath, self.projPath.filePath(), 'fileChanged')
        except TypeError:
            self.wizardPage.registerField('projPath*', self.projPath, self.projPath.filePath(), self.projPath.fileChanged)

This code works with a QLineEdit perfectly, the only difference is the method to retrieve the path string and the signal (.text() instead .filePath() and .textChanged instead .fileChanged).

I've tried searching in the documentation but I didn't find an example specifically for QgsFileWidget. I feel that is a minor detail I've been missing. Any suggestions?

I'm using PyQt5 with Qt Designer to generate the GUI for the plugin.

Update:

I replaced the code as follows:

        ...
        self.setupUi(self)
        self.wizardPage.registerField('projPath*', self.projPath, 'filePath', self.projPath.fileChanged)
        self.projPath.fileChanged.connect(self.file_changed)

    def file_changed(self):
        self.setField("projPath", self.projPath.filePath())

    def isComplete(self):  # Re-implementation of isComplete
        return bool(self.projPath.filePath())

But the result was that the next button get unlocked only if I type the path directly in the text field. It doesn't work if I choose a path in the explorer dialog. Even so, after unlock the button, if I clean the field, the button remain active.

Answer 1

Try to pass the third parameter as string which refers property name, filePath here.

self.wizardPage.registerField('projPath*', self.projPath, 'filePath', self.projPath.fileChanged)

Here is a working example in QGIS Python Editor:

from qgis.PyQt.QtCore import *
from qgis.PyQt.QtGui import *


class Wizard(QWizard):
    def __init__(self, parent=None):
        super(Wizard, self).__init__(parent)
        self.addPage(Page1(self))
        self.addPage(Page2(self))
        self.setWindowTitle("Test")


class Page1(QWizardPage):
    def __init__(self, parent=None):
        super(Page1, self).__init__(parent)

        self.projPath = QgsFileWidget(self)
        self.registerField('projPath*', self.projPath, 'filePath', self.projPath.fileChanged)
        self.projPath.fileChanged.connect(self.file_changed)
        
        layout = QVBoxLayout()
        layout.addWidget(self.projPath)
        self.setLayout(layout)
        
    def file_changed(self):
        self.setField("projPath", self.projPath.filePath())
    
    def isComplete(self): # Re-implementation of isComplete
        return bool(self.projPath.filePath())


class Page2(QWizardPage):
    def __init__(self, parent=None):
        super(Page2, self).__init__(parent)
        self.label = QLabel()
        layout = QVBoxLayout()
        layout.addWidget(self.label)
        self.setLayout(layout)
    
    def initializePage(self):
        path = self.field("projPath")
        self.label.setText(f"Path: '{path}'")
        

wizard = Wizard()
wizard.show()