Qt Documentation

part3.py¶

from PySide6 import QtCore, QtWidgets


class SortedDict(dict):
    class Iterator(object):
        def __init__(self, sorted_dict):
            self._dict = sorted_dict
            self._keys = sorted(self._dict.keys())
            self._nr_items = len(self._keys)
            self._idx = 0

        def __iter__(self):
            return self

        def next(self):
            if self._idx >= self._nr_items:
                raise StopIteration

            key = self._keys[self._idx]
            value = self._dict[key]
            self._idx += 1

            return key, value

        __next__ = next

    def __iter__(self):
        return SortedDict.Iterator(self)

    iterkeys = __iter__


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

        self.contacts = SortedDict()
        self.oldName = ''
        self.oldAddress = ''

        nameLabel = QtWidgets.QLabel("Name:")
        self.nameLine = QtWidgets.QLineEdit()
        self.nameLine.setReadOnly(True)

        addressLabel = QtWidgets.QLabel("Address:")
        self.addressText = QtWidgets.QTextEdit()
        self.addressText.setReadOnly(True)

        self.addButton = QtWidgets.QPushButton("&Add")
        self.submitButton = QtWidgets.QPushButton("&Submit")
        self.submitButton.hide()
        self.cancelButton = QtWidgets.QPushButton("&Cancel")
        self.cancelButton.hide()
        self.nextButton = QtWidgets.QPushButton("&Next")
        self.nextButton.setEnabled(False)
        self.previousButton = QtWidgets.QPushButton("&Previous")
        self.previousButton.setEnabled(False)

        self.addButton.clicked.connect(self.addContact)
        self.submitButton.clicked.connect(self.submitContact)
        self.cancelButton.clicked.connect(self.cancel)
        self.nextButton.clicked.connect(self.next)
        self.previousButton.clicked.connect(self.previous)

        buttonLayout1 = QtWidgets.QVBoxLayout()
        buttonLayout1.addWidget(self.addButton, QtCore.Qt.AlignTop)
        buttonLayout1.addWidget(self.submitButton)
        buttonLayout1.addWidget(self.cancelButton)
        buttonLayout1.addStretch()

        buttonLayout2 = QtWidgets.QHBoxLayout()
        buttonLayout2.addWidget(self.previousButton)
        buttonLayout2.addWidget(self.nextButton)

        mainLayout = QtWidgets.QGridLayout()
        mainLayout.addWidget(nameLabel, 0, 0)
        mainLayout.addWidget(self.nameLine, 0, 1)
        mainLayout.addWidget(addressLabel, 1, 0, QtCore.Qt.AlignTop)
        mainLayout.addWidget(self.addressText, 1, 1)
        mainLayout.addLayout(buttonLayout1, 1, 2)
        mainLayout.addLayout(buttonLayout2, 3, 1)

        self.setLayout(mainLayout)
        self.setWindowTitle("Simple Address Book")

    def addContact(self):
        self.oldName = self.nameLine.text()
        self.oldAddress = self.addressText.toPlainText()

        self.nameLine.clear()
        self.addressText.clear()

        self.nameLine.setReadOnly(False)
        self.nameLine.setFocus(QtCore.Qt.OtherFocusReason)
        self.addressText.setReadOnly(False)

        self.addButton.setEnabled(False)
        self.nextButton.setEnabled(False)
        self.previousButton.setEnabled(False)
        self.submitButton.show()
        self.cancelButton.show()

    def submitContact(self):
        name = self.nameLine.text()
        address = self.addressText.toPlainText()

        if name == "" or address == "":
            QtWidgets.QMessageBox.information(self, "Empty Field",
                    "Please enter a name and address.")
            return

        if name not in self.contacts:
            self.contacts[name] = address
            QtWidgets.QMessageBox.information(self, "Add Successful",
                    "\"%s\" has been added to your address book." % name)
        else:
            QtWidgets.QMessageBox.information(self, "Add Unsuccessful",
                    "Sorry, \"%s\" is already in your address book." % name)
            return

        if not self.contacts:
            self.nameLine.clear()
            self.addressText.clear()

        self.nameLine.setReadOnly(True)
        self.addressText.setReadOnly(True)
        self.addButton.setEnabled(True)

        number = len(self.contacts)
        self.nextButton.setEnabled(number > 1)
        self.previousButton.setEnabled(number > 1)

        self.submitButton.hide()
        self.cancelButton.hide()

    def cancel(self):
        self.nameLine.setText(self.oldName)
        self.addressText.setText(self.oldAddress)

        if not self.contacts:
            self.nameLine.clear()
            self.addressText.clear()

        self.nameLine.setReadOnly(True)
        self.addressText.setReadOnly(True)
        self.addButton.setEnabled(True)

        number = len(self.contacts)
        self.nextButton.setEnabled(number > 1)
        self.previousButton.setEnabled(number > 1)

        self.submitButton.hide()
        self.cancelButton.hide()

    def next(self):
        name = self.nameLine.text()
        it = iter(self.contacts)

        try:
            while True:
                this_name, _ = it.next()

                if this_name == name:
                    next_name, next_address = it.next()
                    break
        except StopIteration:
            next_name, next_address = iter(self.contacts).next()

        self.nameLine.setText(next_name)
        self.addressText.setText(next_address)

    def previous(self):
        name = self.nameLine.text()

        prev_name = prev_address = None
        for this_name, this_address in self.contacts:
            if this_name == name:
                break

            prev_name = this_name
            prev_address = this_address
        else:
            self.nameLine.clear()
            self.addressText.clear()
            return

        if prev_name is None:
            for prev_name, prev_address in self.contacts:
                pass

        self.nameLine.setText(prev_name)
        self.addressText.setText(prev_address)


if __name__ == '__main__':
    import sys

    app = QtWidgets.QApplication(sys.argv)

    addressBook = AddressBook()
    addressBook.show()

    sys.exit(app.exec_())

part1.py¶

from PySide6 import QtCore, QtWidgets


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

        nameLabel = QtWidgets.QLabel("Name:")
        self.nameLine = QtWidgets.QLineEdit()

        addressLabel = QtWidgets.QLabel("Address:")
        self.addressText = QtWidgets.QTextEdit()

        mainLayout = QtWidgets.QGridLayout()
        mainLayout.addWidget(nameLabel, 0, 0)
        mainLayout.addWidget(self.nameLine, 0, 1)
        mainLayout.addWidget(addressLabel, 1, 0, QtCore.Qt.AlignTop)
        mainLayout.addWidget(self.addressText, 1, 1)

        self.setLayout(mainLayout)
        self.setWindowTitle("Simple Address Book")


if __name__ == '__main__':
    import sys

    app = QtWidgets.QApplication(sys.argv)

    addressBook = AddressBook()
    addressBook.show()

    sys.exit(app.exec_())

part5.py¶

from PySide6 import QtCore, QtWidgets


class SortedDict(dict):
    class Iterator(object):
        def __init__(self, sorted_dict):
            self._dict = sorted_dict
            self._keys = sorted(self._dict.keys())
            self._nr_items = len(self._keys)
            self._idx = 0

        def __iter__(self):
            return self

        def next(self):
            if self._idx >= self._nr_items:
                raise StopIteration

            key = self._keys[self._idx]
            value = self._dict[key]
            self._idx += 1

            return key, value

        __next__ = next

    def __iter__(self):
        return SortedDict.Iterator(self)

    iterkeys = __iter__


class AddressBook(QtWidgets.QWidget):
    NavigationMode, AddingMode, EditingMode = range(3)

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

        self.contacts = SortedDict()
        self.oldName = ''
        self.oldAddress = ''
        self.currentMode = self.NavigationMode

        nameLabel = QtWidgets.QLabel("Name:")
        self.nameLine = QtWidgets.QLineEdit()
        self.nameLine.setReadOnly(True)

        addressLabel = QtWidgets.QLabel("Address:")
        self.addressText = QtWidgets.QTextEdit()
        self.addressText.setReadOnly(True)

        self.addButton = QtWidgets.QPushButton("&Add")
        self.editButton = QtWidgets.QPushButton("&Edit")
        self.editButton.setEnabled(False)
        self.removeButton = QtWidgets.QPushButton("&Remove")
        self.removeButton.setEnabled(False)
        self.findButton = QtWidgets.QPushButton("&Find")
        self.findButton.setEnabled(False)
        self.submitButton = QtWidgets.QPushButton("&Submit")
        self.submitButton.hide()
        self.cancelButton = QtWidgets.QPushButton("&Cancel")
        self.cancelButton.hide()

        self.nextButton = QtWidgets.QPushButton("&Next")
        self.nextButton.setEnabled(False)
        self.previousButton = QtWidgets.QPushButton("&Previous")
        self.previousButton.setEnabled(False)

        self.dialog = FindDialog()

        self.addButton.clicked.connect(self.addContact)
        self.submitButton.clicked.connect(self.submitContact)
        self.editButton.clicked.connect(self.editContact)
        self.removeButton.clicked.connect(self.removeContact)
        self.findButton.clicked.connect(self.findContact)
        self.cancelButton.clicked.connect(self.cancel)
        self.nextButton.clicked.connect(self.next)
        self.previousButton.clicked.connect(self.previous)

        buttonLayout1 = QtWidgets.QVBoxLayout()
        buttonLayout1.addWidget(self.addButton)
        buttonLayout1.addWidget(self.editButton)
        buttonLayout1.addWidget(self.removeButton)
        buttonLayout1.addWidget(self.findButton)
        buttonLayout1.addWidget(self.submitButton)
        buttonLayout1.addWidget(self.cancelButton)
        buttonLayout1.addStretch()

        buttonLayout2 = QtWidgets.QHBoxLayout()
        buttonLayout2.addWidget(self.previousButton)
        buttonLayout2.addWidget(self.nextButton)

        mainLayout = QtWidgets.QGridLayout()
        mainLayout.addWidget(nameLabel, 0, 0)
        mainLayout.addWidget(self.nameLine, 0, 1)
        mainLayout.addWidget(addressLabel, 1, 0, QtCore.Qt.AlignTop)
        mainLayout.addWidget(self.addressText, 1, 1)
        mainLayout.addLayout(buttonLayout1, 1, 2)
        mainLayout.addLayout(buttonLayout2, 2, 1)

        self.setLayout(mainLayout)
        self.setWindowTitle("Simple Address Book")

    def addContact(self):
        self.oldName = self.nameLine.text()
        self.oldAddress = self.addressText.toPlainText()

        self.nameLine.clear()
        self.addressText.clear()

        self.updateInterface(self.AddingMode)

    def editContact(self):
        self.oldName = self.nameLine.text()
        self.oldAddress = self.addressText.toPlainText()

        self.updateInterface(self.EditingMode)

    def submitContact(self):
        name = self.nameLine.text()
        address = self.addressText.toPlainText()

        if name == "" or address == "":
            QtWidgets.QMessageBox.information(self, "Empty Field",
                    "Please enter a name and address.")
            return

        if self.currentMode == self.AddingMode:
            if name not in self.contacts:
                self.contacts[name] = address
                QtWidgets.QMessageBox.information(self, "Add Successful",
                        "\"%s\" has been added to your address book." % name)
            else:
                QtWidgets.QMessageBox.information(self, "Add Unsuccessful",
                        "Sorry, \"%s\" is already in your address book." % name)
                return

        elif self.currentMode == self.EditingMode:
            if self.oldName != name:
                if name not in self.contacts:
                    QtWidgets.QMessageBox.information(self, "Edit Successful",
                            "\"%s\" has been edited in your address book." % self.oldName)
                    del self.contacts[self.oldName]
                    self.contacts[name] = address
                else:
                    QtWidgets.QMessageBox.information(self, "Edit Unsuccessful",
                            "Sorry, \"%s\" is already in your address book." % name)
                    return
            elif self.oldAddress != address:
                QtWidgets.QMessageBox.information(self, "Edit Successful",
                        "\"%s\" has been edited in your address book." % name)
                self.contacts[name] = address

        self.updateInterface(self.NavigationMode)

    def cancel(self):
        self.nameLine.setText(self.oldName)
        self.addressText.setText(self.oldAddress)
        self.updateInterface(self.NavigationMode)

    def removeContact(self):
        name = self.nameLine.text()
        address = self.addressText.toPlainText()

        if name in self.contacts:
            button = QtWidgets.QMessageBox.question(self, "Confirm Remove",
                    "Are you sure you want to remove \"%s\"?" % name,
                    QtWidgets.QMessageBox.Yes | QtWidgets.QMessageBox.No)

            if button == QtWidgets.QMessageBox.Yes:
                self.previous()
                del self.contacts[name]

                QtWidgets.QMessageBox.information(self, "Remove Successful",
                        "\"%s\" has been removed from your address book." % name)

        self.updateInterface(self.NavigationMode)

    def next(self):
        name = self.nameLine.text()
        it = iter(self.contacts)

        try:
            while True:
                this_name, _ = it.next()

                if this_name == name:
                    next_name, next_address = it.next()
                    break
        except StopIteration:
            next_name, next_address = iter(self.contacts).next()

        self.nameLine.setText(next_name)
        self.addressText.setText(next_address)

    def previous(self):
        name = self.nameLine.text()

        prev_name = prev_address = None
        for this_name, this_address in self.contacts:
            if this_name == name:
                break

            prev_name = this_name
            prev_address = this_address
        else:
            self.nameLine.clear()
            self.addressText.clear()
            return

        if prev_name is None:
            for prev_name, prev_address in self.contacts:
                pass

        self.nameLine.setText(prev_name)
        self.addressText.setText(prev_address)

    def findContact(self):
        self.dialog.show()

        if self.dialog.exec_() == QtWidgets.QDialog.Accepted:
            contactName = self.dialog.getFindText()

            if contactName in self.contacts:
                self.nameLine.setText(contactName)
                self.addressText.setText(self.contacts[contactName])
            else:
                QtWidgets.QMessageBox.information(self, "Contact Not Found",
                        "Sorry, \"%s\" is not in your address book." % contactName)
                return

        self.updateInterface(self.NavigationMode)

    def updateInterface(self, mode):
        self.currentMode = mode

        if self.currentMode in (self.AddingMode, self.EditingMode):
            self.nameLine.setReadOnly(False)
            self.nameLine.setFocus(QtCore.Qt.OtherFocusReason)
            self.addressText.setReadOnly(False)

            self.addButton.setEnabled(False)
            self.editButton.setEnabled(False)
            self.removeButton.setEnabled(False)

            self.nextButton.setEnabled(False)
            self.previousButton.setEnabled(False)

            self.submitButton.show()
            self.cancelButton.show()

        elif self.currentMode == self.NavigationMode:
            if not self.contacts:
                self.nameLine.clear()
                self.addressText.clear()

            self.nameLine.setReadOnly(True)
            self.addressText.setReadOnly(True)
            self.addButton.setEnabled(True)

            number = len(self.contacts)
            self.editButton.setEnabled(number >= 1)
            self.removeButton.setEnabled(number >= 1)
            self.findButton.setEnabled(number > 2)
            self.nextButton.setEnabled(number > 1)
            self.previousButton.setEnabled(number >1 )

            self.submitButton.hide()
            self.cancelButton.hide()


class FindDialog(QtWidgets.QDialog):
    def __init__(self, parent=None):
        super(FindDialog, self).__init__(parent)

        findLabel = QtWidgets.QLabel("Enter the name of a contact:")
        self.lineEdit = QtWidgets.QLineEdit()

        self.findButton = QtWidgets.QPushButton("&Find")
        self.findText = ''

        layout = QtWidgets.QHBoxLayout()
        layout.addWidget(findLabel)
        layout.addWidget(self.lineEdit)
        layout.addWidget(self.findButton)

        self.setLayout(layout)
        self.setWindowTitle("Find a Contact")

        self.findButton.clicked.connect(self.findClicked)
        self.findButton.clicked.connect(self.accept)

    def findClicked(self):
        text = self.lineEdit.text()

        if not text:
            QtWidgets.QMessageBox.information(self, "Empty Field",
                    "Please enter a name.")
            return
        else:
            self.findText = text
            self.lineEdit.clear()
            self.hide()

    def getFindText(self):
        return self.findText


if __name__ == '__main__':
    import sys

    app = QtWidgets.QApplication(sys.argv)

    addressBook = AddressBook()
    addressBook.show()

    sys.exit(app.exec_())

part2.py¶

from PySide6 import QtCore, QtWidgets


class SortedDict(dict):
    class Iterator(object):
        def __init__(self, sorted_dict):
            self._dict = sorted_dict
            self._keys = sorted(self._dict.keys())
            self._nr_items = len(self._keys)
            self._idx = 0

        def __iter__(self):
            return self

        def next(self):
            if self._idx >= self._nr_items:
                raise StopIteration

            key = self._keys[self._idx]
            value = self._dict[key]
            self._idx += 1

            return key, value

        __next__ = next

    def __iter__(self):
        return SortedDict.Iterator(self)

    iterkeys = __iter__


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

        self.contacts = SortedDict()
        self.oldName = ''
        self.oldAddress = ''

        nameLabel = QtWidgets.QLabel("Name:")
        self.nameLine = QtWidgets.QLineEdit()
        self.nameLine.setReadOnly(True)

        addressLabel = QtWidgets.QLabel("Address:")
        self.addressText = QtWidgets.QTextEdit()
        self.addressText.setReadOnly(True)

        self.addButton = QtWidgets.QPushButton("&Add")
        self.submitButton = QtWidgets.QPushButton("&Submit")
        self.submitButton.hide()
        self.cancelButton = QtWidgets.QPushButton("&Cancel")
        self.cancelButton.hide()

        self.addButton.clicked.connect(self.addContact)
        self.submitButton.clicked.connect(self.submitContact)
        self.cancelButton.clicked.connect(self.cancel)

        buttonLayout1 = QtWidgets.QVBoxLayout()
        buttonLayout1.addWidget(self.addButton, QtCore.Qt.AlignTop)
        buttonLayout1.addWidget(self.submitButton)
        buttonLayout1.addWidget(self.cancelButton)
        buttonLayout1.addStretch()

        mainLayout = QtWidgets.QGridLayout()
        mainLayout.addWidget(nameLabel, 0, 0)
        mainLayout.addWidget(self.nameLine, 0, 1)
        mainLayout.addWidget(addressLabel, 1, 0, QtCore.Qt.AlignTop)
        mainLayout.addWidget(self.addressText, 1, 1)
        mainLayout.addLayout(buttonLayout1, 1, 2)

        self.setLayout(mainLayout)
        self.setWindowTitle("Simple Address Book")

    def addContact(self):
        self.oldName = self.nameLine.text()
        self.oldAddress = self.addressText.toPlainText()

        self.nameLine.clear()
        self.addressText.clear()

        self.nameLine.setReadOnly(False)
        self.nameLine.setFocus(QtCore.Qt.OtherFocusReason)
        self.addressText.setReadOnly(False)

        self.addButton.setEnabled(False)
        self.submitButton.show()
        self.cancelButton.show()

    def submitContact(self):
        name = self.nameLine.text()
        address = self.addressText.toPlainText()

        if name == "" or address == "":
            QtWidgets.QMessageBox.information(self, "Empty Field",
                    "Please enter a name and address.")
            return

        if name not in self.contacts:
            self.contacts[name] = address
            QtWidgets.QMessageBox.information(self, "Add Successful",
                    "\"%s\" has been added to your address book." % name)
        else:
            QtWidgets.QMessageBox.information(self, "Add Unsuccessful",
                    "Sorry, \"%s\" is already in your address book." % name)
            return

        if not self.contacts:
            self.nameLine.clear()
            self.addressText.clear()

        self.nameLine.setReadOnly(True)
        self.addressText.setReadOnly(True)
        self.addButton.setEnabled(True)
        self.submitButton.hide()
        self.cancelButton.hide()

    def cancel(self):
        self.nameLine.setText(self.oldName)
        self.nameLine.setReadOnly(True)

        self.addressText.setText(self.oldAddress)
        self.addressText.setReadOnly(True)

        self.addButton.setEnabled(True)
        self.submitButton.hide()
        self.cancelButton.hide()


if __name__ == '__main__':
    import sys

    app = QtWidgets.QApplication(sys.argv)

    addressBook = AddressBook()
    addressBook.show()

    sys.exit(app.exec_())

part7.py¶

import pickle

from PySide6 import QtCore, QtWidgets


class SortedDict(dict):
    class Iterator(object):
        def __init__(self, sorted_dict):
            self._dict = sorted_dict
            self._keys = sorted(self._dict.keys())
            self._nr_items = len(self._keys)
            self._idx = 0

        def __iter__(self):
            return self

        def next(self):
            if self._idx >= self._nr_items:
                raise StopIteration

            key = self._keys[self._idx]
            value = self._dict[key]
            self._idx += 1

            return key, value

        __next__ = next

    def __iter__(self):
        return SortedDict.Iterator(self)

    iterkeys = __iter__


class AddressBook(QtWidgets.QWidget):
    NavigationMode, AddingMode, EditingMode = range(3)

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

        self.contacts = SortedDict()
        self.oldName = ''
        self.oldAddress = ''
        self.currentMode = self.NavigationMode

        nameLabel = QtWidgets.QLabel("Name:")
        self.nameLine = QtWidgets.QLineEdit()
        self.nameLine.setReadOnly(True)

        addressLabel = QtWidgets.QLabel("Address:")
        self.addressText = QtWidgets.QTextEdit()
        self.addressText.setReadOnly(True)

        self.addButton = QtWidgets.QPushButton("&Add")
        self.editButton = QtWidgets.QPushButton("&Edit")
        self.editButton.setEnabled(False)
        self.removeButton = QtWidgets.QPushButton("&Remove")
        self.removeButton.setEnabled(False)
        self.findButton = QtWidgets.QPushButton("&Find")
        self.findButton.setEnabled(False)
        self.submitButton = QtWidgets.QPushButton("&Submit")
        self.submitButton.hide()
        self.cancelButton = QtWidgets.QPushButton("&Cancel")
        self.cancelButton.hide()

        self.nextButton = QtWidgets.QPushButton("&Next")
        self.nextButton.setEnabled(False)
        self.previousButton = QtWidgets.QPushButton("&Previous")
        self.previousButton.setEnabled(False)

        self.loadButton = QtWidgets.QPushButton("&Load...")
        self.loadButton.setToolTip("Load contacts from a file")
        self.saveButton = QtWidgets.QPushButton("Sa&ve...")
        self.saveButton.setToolTip("Save contacts to a file")
        self.saveButton.setEnabled(False)

        self.exportButton = QtWidgets.QPushButton("Ex&port")
        self.exportButton.setToolTip("Export as vCard")
        self.exportButton.setEnabled(False)

        self.dialog = FindDialog()

        self.addButton.clicked.connect(self.addContact)
        self.submitButton.clicked.connect(self.submitContact)
        self.editButton.clicked.connect(self.editContact)
        self.removeButton.clicked.connect(self.removeContact)
        self.findButton.clicked.connect(self.findContact)
        self.cancelButton.clicked.connect(self.cancel)
        self.nextButton.clicked.connect(self.next)
        self.previousButton.clicked.connect(self.previous)
        self.loadButton.clicked.connect(self.loadFromFile)
        self.saveButton.clicked.connect(self.saveToFile)
        self.exportButton.clicked.connect(self.exportAsVCard)

        buttonLayout1 = QtWidgets.QVBoxLayout()
        buttonLayout1.addWidget(self.addButton)
        buttonLayout1.addWidget(self.editButton)
        buttonLayout1.addWidget(self.removeButton)
        buttonLayout1.addWidget(self.findButton)
        buttonLayout1.addWidget(self.submitButton)
        buttonLayout1.addWidget(self.cancelButton)
        buttonLayout1.addWidget(self.loadButton)
        buttonLayout1.addWidget(self.saveButton)
        buttonLayout1.addWidget(self.exportButton)
        buttonLayout1.addStretch()

        buttonLayout2 = QtWidgets.QHBoxLayout()
        buttonLayout2.addWidget(self.previousButton)
        buttonLayout2.addWidget(self.nextButton)

        mainLayout = QtWidgets.QGridLayout()
        mainLayout.addWidget(nameLabel, 0, 0)
        mainLayout.addWidget(self.nameLine, 0, 1)
        mainLayout.addWidget(addressLabel, 1, 0, QtCore.Qt.AlignTop)
        mainLayout.addWidget(self.addressText, 1, 1)
        mainLayout.addLayout(buttonLayout1, 1, 2)
        mainLayout.addLayout(buttonLayout2, 2, 1)

        self.setLayout(mainLayout)
        self.setWindowTitle("Simple Address Book")

    def addContact(self):
        self.oldName = self.nameLine.text()
        self.oldAddress = self.addressText.toPlainText()

        self.nameLine.clear()
        self.addressText.clear()

        self.updateInterface(self.AddingMode)

    def editContact(self):
        self.oldName = self.nameLine.text()
        self.oldAddress = self.addressText.toPlainText()

        self.updateInterface(self.EditingMode)

    def submitContact(self):
        name = self.nameLine.text()
        address = self.addressText.toPlainText()

        if name == "" or address == "":
            QtWidgets.QMessageBox.information(self, "Empty Field",
                    "Please enter a name and address.")
            return

        if self.currentMode == self.AddingMode:
            if name not in self.contacts:
                self.contacts[name] = address
                QtWidgets.QMessageBox.information(self, "Add Successful",
                        "\"%s\" has been added to your address book." % name)
            else:
                QtWidgets.QMessageBox.information(self, "Add Unsuccessful",
                        "Sorry, \"%s\" is already in your address book." % name)
                return

        elif self.currentMode == self.EditingMode:
            if self.oldName != name:
                if name not in self.contacts:
                    QtWidgets.QMessageBox.information(self, "Edit Successful",
                            "\"%s\" has been edited in your address book." % self.oldName)
                    del self.contacts[self.oldName]
                    self.contacts[name] = address
                else:
                    QtWidgets.QMessageBox.information(self, "Edit Unsuccessful",
                            "Sorry, \"%s\" is already in your address book." % name)
                    return
            elif self.oldAddress != address:
                QtWidgets.QMessageBox.information(self, "Edit Successful",
                        "\"%s\" has been edited in your address book." % name)
                self.contacts[name] = address

        self.updateInterface(self.NavigationMode)

    def cancel(self):
        self.nameLine.setText(self.oldName)
        self.addressText.setText(self.oldAddress)
        self.updateInterface(self.NavigationMode)

    def removeContact(self):
        name = self.nameLine.text()
        address = self.addressText.toPlainText()

        if name in self.contacts:
            button = QtWidgets.QMessageBox.question(self, "Confirm Remove",
                    "Are you sure you want to remove \"%s\"?" % name,
                    QtWidgets.QMessageBox.Yes | QtWidgets.QMessageBox.No)

            if button == QtWidgets.QMessageBox.Yes:
                self.previous()
                del self.contacts[name]

                QtWidgets.QMessageBox.information(self, "Remove Successful",
                        "\"%s\" has been removed from your address book." % name)

        self.updateInterface(self.NavigationMode)

    def next(self):
        name = self.nameLine.text()
        it = iter(self.contacts)

        try:
            while True:
                this_name, _ = it.next()

                if this_name == name:
                    next_name, next_address = it.next()
                    break
        except StopIteration:
            next_name, next_address = iter(self.contacts).next()

        self.nameLine.setText(next_name)
        self.addressText.setText(next_address)

    def previous(self):
        name = self.nameLine.text()

        prev_name = prev_address = None
        for this_name, this_address in self.contacts:
            if this_name == name:
                break

            prev_name = this_name
            prev_address = this_address
        else:
            self.nameLine.clear()
            self.addressText.clear()
            return

        if prev_name is None:
            for prev_name, prev_address in self.contacts:
                pass

        self.nameLine.setText(prev_name)
        self.addressText.setText(prev_address)

    def findContact(self):
        self.dialog.show()

        if self.dialog.exec_() == QtWidgets.QDialog.Accepted:
            contactName = self.dialog.getFindText()

            if contactName in self.contacts:
                self.nameLine.setText(contactName)
                self.addressText.setText(self.contacts[contactName])
            else:
                QtWidgets.QMessageBox.information(self, "Contact Not Found",
                        "Sorry, \"%s\" is not in your address book." % contactName)
                return

        self.updateInterface(self.NavigationMode)

    def updateInterface(self, mode):
        self.currentMode = mode

        if self.currentMode in (self.AddingMode, self.EditingMode):
            self.nameLine.setReadOnly(False)
            self.nameLine.setFocus(QtCore.Qt.OtherFocusReason)
            self.addressText.setReadOnly(False)

            self.addButton.setEnabled(False)
            self.editButton.setEnabled(False)
            self.removeButton.setEnabled(False)

            self.nextButton.setEnabled(False)
            self.previousButton.setEnabled(False)

            self.submitButton.show()
            self.cancelButton.show()

            self.loadButton.setEnabled(False)
            self.saveButton.setEnabled(False)
            self.exportButton.setEnabled(False)

        elif self.currentMode == self.NavigationMode:
            if not self.contacts:
                self.nameLine.clear()
                self.addressText.clear()

            self.nameLine.setReadOnly(True)
            self.addressText.setReadOnly(True)
            self.addButton.setEnabled(True)

            number = len(self.contacts)
            self.editButton.setEnabled(number >= 1)
            self.removeButton.setEnabled(number >= 1)
            self.findButton.setEnabled(number > 2)
            self.nextButton.setEnabled(number > 1)
            self.previousButton.setEnabled(number >1 )

            self.submitButton.hide()
            self.cancelButton.hide()

            self.exportButton.setEnabled(number >= 1)

            self.loadButton.setEnabled(True)
            self.saveButton.setEnabled(number >= 1)

    def saveToFile(self):
        fileName,_ = QtWidgets.QFileDialog.getSaveFileName(self,
                "Save Address Book", '',
                "Address Book (*.abk);;All Files (*)")

        if not fileName:
            return

        try:
            out_file = open(str(fileName), 'wb')
        except IOError:
            QtWidgets.QMessageBox.information(self, "Unable to open file",
                    "There was an error opening \"%s\"" % fileName)
            return

        pickle.dump(self.contacts, out_file)
        out_file.close()

    def loadFromFile(self):
        fileName,_ = QtWidgets.QFileDialog.getOpenFileName(self,
                "Open Address Book", '',
                "Address Book (*.abk);;All Files (*)")

        if not fileName:
            return

        try:
            in_file = open(str(fileName), 'rb')
        except IOError:
            QtWidgets.QMessageBox.information(self, "Unable to open file",
                    "There was an error opening \"%s\"" % fileName)
            return

        self.contacts = pickle.load(in_file)
        in_file.close()

        if len(self.contacts) == 0:
            QtWidgets.QMessageBox.information(self, "No contacts in file",
                    "The file you are attempting to open contains no "
                    "contacts.")
        else:
            for name, address in self.contacts:
                self.nameLine.setText(name)
                self.addressText.setText(address)

        self.updateInterface(self.NavigationMode)

    def exportAsVCard(self):
        name = str(self.nameLine.text())
        address = self.addressText.toPlainText()

        nameList = name.split()

        if len(nameList) > 1:
            firstName = nameList[0]
            lastName = nameList[-1]
        else:
            firstName = name
            lastName = ''

        fileName = QtWidgets.QFileDialog.getSaveFileName(self, "Export Contact",
                '', "vCard Files (*.vcf);;All Files (*)")[0]

        if not fileName:
            return

        out_file = QtCore.QFile(fileName)

        if not out_file.open(QtCore.QIODevice.WriteOnly):
            QtWidgets.QMessageBox.information(self, "Unable to open file",
                    out_file.errorString())
            return

        out_s = QtCore.QTextStream(out_file)

        out_s << 'BEGIN:VCARD' << '\n'
        out_s << 'VERSION:2.1' << '\n'
        out_s << 'N:' << lastName << ';' << firstName << '\n'
        out_s << 'FN:' << ' '.join(nameList) << '\n'

        address.replace(';', '\\;')
        address.replace('\n', ';')
        address.replace(',', ' ')

        out_s << 'ADR;HOME:;' << address << '\n'
        out_s << 'END:VCARD' << '\n'

        QtWidgets.QMessageBox.information(self, "Export Successful",
                "\"%s\" has been exported as a vCard." % name)


class FindDialog(QtWidgets.QDialog):
    def __init__(self, parent=None):
        super(FindDialog, self).__init__(parent)

        findLabel = QtWidgets.QLabel("Enter the name of a contact:")
        self.lineEdit = QtWidgets.QLineEdit()

        self.findButton = QtWidgets.QPushButton("&Find")
        self.findText = ''

        layout = QtWidgets.QHBoxLayout()
        layout.addWidget(findLabel)
        layout.addWidget(self.lineEdit)
        layout.addWidget(self.findButton)

        self.setLayout(layout)
        self.setWindowTitle("Find a Contact")

        self.findButton.clicked.connect(self.findClicked)
        self.findButton.clicked.connect(self.accept)

    def findClicked(self):
        text = self.lineEdit.text()

        if not text:
            QtWidgets.QMessageBox.information(self, "Empty Field",
                    "Please enter a name.")
            return

        self.findText = text
        self.lineEdit.clear()
        self.hide()

    def getFindText(self):
        return self.findText


if __name__ == '__main__':
    import sys

    app = QtWidgets.QApplication(sys.argv)

    addressBook = AddressBook()
    addressBook.show()

    sys.exit(app.exec_())

part6.py¶

import pickle

from PySide6 import QtCore, QtWidgets


class SortedDict(dict):
    class Iterator(object):
        def __init__(self, sorted_dict):
            self._dict = sorted_dict
            self._keys = sorted(self._dict.keys())
            self._nr_items = len(self._keys)
            self._idx = 0

        def __iter__(self):
            return self

        def next(self):
            if self._idx >= self._nr_items:
                raise StopIteration

            key = self._keys[self._idx]
            value = self._dict[key]
            self._idx += 1

            return key, value

        __next__ = next

    def __iter__(self):
        return SortedDict.Iterator(self)

    iterkeys = __iter__


class AddressBook(QtWidgets.QWidget):
    NavigationMode, AddingMode, EditingMode = range(3)

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

        self.contacts = SortedDict()
        self.oldName = ''
        self.oldAddress = ''
        self.currentMode = self.NavigationMode

        nameLabel = QtWidgets.QLabel("Name:")
        self.nameLine = QtWidgets.QLineEdit()
        self.nameLine.setReadOnly(True)

        addressLabel = QtWidgets.QLabel("Address:")
        self.addressText = QtWidgets.QTextEdit()
        self.addressText.setReadOnly(True)

        self.addButton = QtWidgets.QPushButton("&Add")
        self.editButton = QtWidgets.QPushButton("&Edit")
        self.editButton.setEnabled(False)
        self.removeButton = QtWidgets.QPushButton("&Remove")
        self.removeButton.setEnabled(False)
        self.findButton = QtWidgets.QPushButton("&Find")
        self.findButton.setEnabled(False)
        self.submitButton = QtWidgets.QPushButton("&Submit")
        self.submitButton.hide()
        self.cancelButton = QtWidgets.QPushButton("&Cancel")
        self.cancelButton.hide()

        self.nextButton = QtWidgets.QPushButton("&Next")
        self.nextButton.setEnabled(False)
        self.previousButton = QtWidgets.QPushButton("&Previous")
        self.previousButton.setEnabled(False)

        self.loadButton = QtWidgets.QPushButton("&Load...")
        self.loadButton.setToolTip("Load contacts from a file")
        self.saveButton = QtWidgets.QPushButton("Sa&ve...")
        self.saveButton.setToolTip("Save contacts to a file")
        self.saveButton.setEnabled(False)

        self.dialog = FindDialog()

        self.addButton.clicked.connect(self.addContact)
        self.submitButton.clicked.connect(self.submitContact)
        self.editButton.clicked.connect(self.editContact)
        self.removeButton.clicked.connect(self.removeContact)
        self.findButton.clicked.connect(self.findContact)
        self.cancelButton.clicked.connect(self.cancel)
        self.nextButton.clicked.connect(self.next)
        self.previousButton.clicked.connect(self.previous)
        self.loadButton.clicked.connect(self.loadFromFile)
        self.saveButton.clicked.connect(self.saveToFile)

        buttonLayout1 = QtWidgets.QVBoxLayout()
        buttonLayout1.addWidget(self.addButton)
        buttonLayout1.addWidget(self.editButton)
        buttonLayout1.addWidget(self.removeButton)
        buttonLayout1.addWidget(self.findButton)
        buttonLayout1.addWidget(self.submitButton)
        buttonLayout1.addWidget(self.cancelButton)
        buttonLayout1.addWidget(self.loadButton)
        buttonLayout1.addWidget(self.saveButton)
        buttonLayout1.addStretch()

        buttonLayout2 = QtWidgets.QHBoxLayout()
        buttonLayout2.addWidget(self.previousButton)
        buttonLayout2.addWidget(self.nextButton)

        mainLayout = QtWidgets.QGridLayout()
        mainLayout.addWidget(nameLabel, 0, 0)
        mainLayout.addWidget(self.nameLine, 0, 1)
        mainLayout.addWidget(addressLabel, 1, 0, QtCore.Qt.AlignTop)
        mainLayout.addWidget(self.addressText, 1, 1)
        mainLayout.addLayout(buttonLayout1, 1, 2)
        mainLayout.addLayout(buttonLayout2, 2, 1)

        self.setLayout(mainLayout)
        self.setWindowTitle("Simple Address Book")

    def addContact(self):
        self.oldName = self.nameLine.text()
        self.oldAddress = self.addressText.toPlainText()

        self.nameLine.clear()
        self.addressText.clear()

        self.updateInterface(self.AddingMode)

    def editContact(self):
        self.oldName = self.nameLine.text()
        self.oldAddress = self.addressText.toPlainText()

        self.updateInterface(self.EditingMode)

    def submitContact(self):
        name = self.nameLine.text()
        address = self.addressText.toPlainText()

        if name == "" or address == "":
            QtWidgets.QMessageBox.information(self, "Empty Field",
                    "Please enter a name and address.")
            return

        if self.currentMode == self.AddingMode:
            if name not in self.contacts:
                self.contacts[name] = address
                QtWidgets.QMessageBox.information(self, "Add Successful",
                        "\"%s\" has been added to your address book." % name)
            else:
                QtWidgets.QMessageBox.information(self, "Add Unsuccessful",
                        "Sorry, \"%s\" is already in your address book." % name)
                return

        elif self.currentMode == self.EditingMode:
            if self.oldName != name:
                if name not in self.contacts:
                    QtWidgets.QMessageBox.information(self, "Edit Successful",
                            "\"%s\" has been edited in your address book." % self.oldName)
                    del self.contacts[self.oldName]
                    self.contacts[name] = address
                else:
                    QtWidgets.QMessageBox.information(self, "Edit Unsuccessful",
                            "Sorry, \"%s\" is already in your address book." % name)
                    return
            elif self.oldAddress != address:
                QtWidgets.QMessageBox.information(self, "Edit Successful",
                        "\"%s\" has been edited in your address book." % name)
                self.contacts[name] = address

        self.updateInterface(self.NavigationMode)

    def cancel(self):
        self.nameLine.setText(self.oldName)
        self.addressText.setText(self.oldAddress)
        self.updateInterface(self.NavigationMode)

    def removeContact(self):
        name = self.nameLine.text()
        address = self.addressText.toPlainText()

        if name in self.contacts:
            button = QtWidgets.QMessageBox.question(self, "Confirm Remove",
                    "Are you sure you want to remove \"%s\"?" % name,
                    QtWidgets.QMessageBox.Yes | QtWidgets.QMessageBox.No)

            if button == QtWidgets.QMessageBox.Yes:
                self.previous()
                del self.contacts[name]

                QtWidgets.QMessageBox.information(self, "Remove Successful",
                        "\"%s\" has been removed from your address book." % name)

        self.updateInterface(self.NavigationMode)

    def next(self):
        name = self.nameLine.text()
        it = iter(self.contacts)

        try:
            while True:
                this_name, _ = it.next()

                if this_name == name:
                    next_name, next_address = it.next()
                    break
        except StopIteration:
            next_name, next_address = iter(self.contacts).next()

        self.nameLine.setText(next_name)
        self.addressText.setText(next_address)

    def previous(self):
        name = self.nameLine.text()

        prev_name = prev_address = None
        for this_name, this_address in self.contacts:
            if this_name == name:
                break

            prev_name = this_name
            prev_address = this_address
        else:
            self.nameLine.clear()
            self.addressText.clear()
            return

        if prev_name is None:
            for prev_name, prev_address in self.contacts:
                pass

        self.nameLine.setText(prev_name)
        self.addressText.setText(prev_address)

    def findContact(self):
        self.dialog.show()

        if self.dialog.exec_() == QtWidgets.QDialog.Accepted:
            contactName = self.dialog.getFindText()

            if contactName in self.contacts:
                self.nameLine.setText(contactName)
                self.addressText.setText(self.contacts[contactName])
            else:
                QtWidgets.QMessageBox.information(self, "Contact Not Found",
                        "Sorry, \"%s\" is not in your address book." % contactName)
                return

        self.updateInterface(self.NavigationMode)

    def updateInterface(self, mode):
        self.currentMode = mode

        if self.currentMode in (self.AddingMode, self.EditingMode):
            self.nameLine.setReadOnly(False)
            self.nameLine.setFocus(QtCore.Qt.OtherFocusReason)
            self.addressText.setReadOnly(False)

            self.addButton.setEnabled(False)
            self.editButton.setEnabled(False)
            self.removeButton.setEnabled(False)

            self.nextButton.setEnabled(False)
            self.previousButton.setEnabled(False)

            self.submitButton.show()
            self.cancelButton.show()

            self.loadButton.setEnabled(False)
            self.saveButton.setEnabled(False)

        elif self.currentMode == self.NavigationMode:
            if not self.contacts:
                self.nameLine.clear()
                self.addressText.clear()

            self.nameLine.setReadOnly(True)
            self.addressText.setReadOnly(True)
            self.addButton.setEnabled(True)

            number = len(self.contacts)
            self.editButton.setEnabled(number >= 1)
            self.removeButton.setEnabled(number >= 1)
            self.findButton.setEnabled(number > 2)
            self.nextButton.setEnabled(number > 1)
            self.previousButton.setEnabled(number >1 )

            self.submitButton.hide()
            self.cancelButton.hide()

            self.loadButton.setEnabled(True)
            self.saveButton.setEnabled(number >= 1)

    def saveToFile(self):
        fileName,_ = QtWidgets.QFileDialog.getSaveFileName(self,
                "Save Address Book", '',
                "Address Book (*.abk);;All Files (*)")

        if not fileName:
            return

        try:
            out_file = open(str(fileName), 'wb')
        except IOError:
            QtWidgets.QMessageBox.information(self, "Unable to open file",
                    "There was an error opening \"%s\"" % fileName)
            return

        pickle.dump(self.contacts, out_file)
        out_file.close()

    def loadFromFile(self):
        fileName,_ = QtWidgets.QFileDialog.getOpenFileName(self,
                "Open Address Book", '',
                "Address Book (*.abk);;All Files (*)")

        if not fileName:
            return

        try:
            in_file = open(str(fileName), 'rb')
        except IOError:
            QtWidgets.QMessageBox.information(self, "Unable to open file",
                    "There was an error opening \"%s\"" % fileName)
            return

        self.contacts = pickle.load(in_file)
        in_file.close()

        if len(self.contacts) == 0:
            QtWidgets.QMessageBox.information(self, "No contacts in file",
                    "The file you are attempting to open contains no "
                    "contacts.")
        else:
            for name, address in self.contacts:
                self.nameLine.setText(name)
                self.addressText.setText(address)

        self.updateInterface(self.NavigationMode)


class FindDialog(QtWidgets.QDialog):
    def __init__(self, parent=None):
        super(FindDialog, self).__init__(parent)

        findLabel = QtWidgets.QLabel("Enter the name of a contact:")
        self.lineEdit = QtWidgets.QLineEdit()

        self.findButton = QtWidgets.QPushButton("&Find")
        self.findText = ''

        layout = QtWidgets.QHBoxLayout()
        layout.addWidget(findLabel)
        layout.addWidget(self.lineEdit)
        layout.addWidget(self.findButton)

        self.setLayout(layout)
        self.setWindowTitle("Find a Contact")

        self.findButton.clicked.connect(self.findClicked)
        self.findButton.clicked.connect(self.accept)

    def findClicked(self):
        text = self.lineEdit.text()

        if not text:
            QtWidgets.QMessageBox.information(self, "Empty Field",
                    "Please enter a name.")
            return

        self.findText = text
        self.lineEdit.clear()
        self.hide()

    def getFindText(self):
        return self.findText


if __name__ == '__main__':
    import sys

    app = QtWidgets.QApplication(sys.argv)

    addressBook = AddressBook()
    addressBook.show()

    sys.exit(app.exec_())

part4.py¶

from PySide6 import QtCore, QtWidgets


class SortedDict(dict):
    class Iterator(object):
        def __init__(self, sorted_dict):
            self._dict = sorted_dict
            self._keys = sorted(self._dict.keys())
            self._nr_items = len(self._keys)
            self._idx = 0

        def __iter__(self):
            return self

        def next(self):
            if self._idx >= self._nr_items:
                raise StopIteration

            key = self._keys[self._idx]
            value = self._dict[key]
            self._idx += 1

            return key, value

        __next__ = next

    def __iter__(self):
        return SortedDict.Iterator(self)

    iterkeys = __iter__


class AddressBook(QtWidgets.QWidget):
    NavigationMode, AddingMode, EditingMode = range(3)

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

        self.contacts = SortedDict()
        self.oldName = ''
        self.oldAddress = ''
        self.currentMode = self.NavigationMode

        nameLabel = QtWidgets.QLabel("Name:")
        self.nameLine = QtWidgets.QLineEdit()
        self.nameLine.setReadOnly(True)

        addressLabel = QtWidgets.QLabel("Address:")
        self.addressText = QtWidgets.QTextEdit()
        self.addressText.setReadOnly(True)

        self.addButton = QtWidgets.QPushButton("&Add")
        self.editButton = QtWidgets.QPushButton("&Edit")
        self.editButton.setEnabled(False)
        self.removeButton = QtWidgets.QPushButton("&Remove")
        self.removeButton.setEnabled(False)
        self.submitButton = QtWidgets.QPushButton("&Submit")
        self.submitButton.hide()
        self.cancelButton = QtWidgets.QPushButton("&Cancel")
        self.cancelButton.hide()

        self.nextButton = QtWidgets.QPushButton("&Next")
        self.nextButton.setEnabled(False)
        self.previousButton = QtWidgets.QPushButton("&Previous")
        self.previousButton.setEnabled(False)

        self.addButton.clicked.connect(self.addContact)
        self.submitButton.clicked.connect(self.submitContact)
        self.editButton.clicked.connect(self.editContact)
        self.removeButton.clicked.connect(self.removeContact)
        self.cancelButton.clicked.connect(self.cancel)
        self.nextButton.clicked.connect(self.next)
        self.previousButton.clicked.connect(self.previous)

        buttonLayout1 = QtWidgets.QVBoxLayout()
        buttonLayout1.addWidget(self.addButton)
        buttonLayout1.addWidget(self.editButton)
        buttonLayout1.addWidget(self.removeButton)
        buttonLayout1.addWidget(self.submitButton)
        buttonLayout1.addWidget(self.cancelButton)
        buttonLayout1.addStretch()

        buttonLayout2 = QtWidgets.QHBoxLayout()
        buttonLayout2.addWidget(self.previousButton)
        buttonLayout2.addWidget(self.nextButton)

        mainLayout = QtWidgets.QGridLayout()
        mainLayout.addWidget(nameLabel, 0, 0)
        mainLayout.addWidget(self.nameLine, 0, 1)
        mainLayout.addWidget(addressLabel, 1, 0, QtCore.Qt.AlignTop)
        mainLayout.addWidget(self.addressText, 1, 1)
        mainLayout.addLayout(buttonLayout1, 1, 2)
        mainLayout.addLayout(buttonLayout2, 3, 1)

        self.setLayout(mainLayout)
        self.setWindowTitle("Simple Address Book")

    def addContact(self):
        self.oldName = self.nameLine.text()
        self.oldAddress = self.addressText.toPlainText()

        self.nameLine.clear()
        self.addressText.clear()

        self.updateInterface(self.AddingMode)

    def editContact(self):
        self.oldName = self.nameLine.text()
        self.oldAddress = self.addressText.toPlainText()

        self.updateInterface(self.EditingMode)

    def submitContact(self):
        name = self.nameLine.text()
        address = self.addressText.toPlainText()

        if name == "" or address == "":
            QtWidgets.QMessageBox.information(self, "Empty Field",
                    "Please enter a name and address.")
            return

        if self.currentMode == self.AddingMode:
            if name not in self.contacts:
                self.contacts[name] = address
                QtWidgets.QMessageBox.information(self, "Add Successful",
                        "\"%s\" has been added to your address book." % name)
            else:
                QtWidgets.QMessageBox.information(self, "Add Unsuccessful",
                        "Sorry, \"%s\" is already in your address book." % name)
                return

        elif self.currentMode == self.EditingMode:
            if self.oldName != name:
                if name not in self.contacts:
                    QtWidgets.QMessageBox.information(self, "Edit Successful",
                            "\"%s\" has been edited in your address book." % self.oldName)
                    del self.contacts[self.oldName]
                    self.contacts[name] = address
                else:
                    QtWidgets.QMessageBox.information(self, "Edit Unsuccessful",
                            "Sorry, \"%s\" is already in your address book." % name)
                    return
            elif self.oldAddress != address:
                QtWidgets.QMessageBox.information(self, "Edit Successful",
                        "\"%s\" has been edited in your address book." % name)
                self.contacts[name] = address

        self.updateInterface(self.NavigationMode)

    def cancel(self):
        self.nameLine.setText(self.oldName)
        self.addressText.setText(self.oldAddress)
        self.updateInterface(self.NavigationMode)

    def removeContact(self):
        name = self.nameLine.text()
        address = self.addressText.toPlainText()

        if name in self.contacts:
            button = QtWidgets.QMessageBox.question(self, "Confirm Remove",
                    "Are you sure you want to remove \"%s\"?" % name,
                    QtWidgets.QMessageBox.Yes | QtWidgets.QMessageBox.No)

            if button == QtWidgets.QMessageBox.Yes:
                self.previous()
                del self.contacts[name]

                QtWidgets.QMessageBox.information(self, "Remove Successful",
                        "\"%s\" has been removed from your address book." % name)

        self.updateInterface(self.NavigationMode)

    def next(self):
        name = self.nameLine.text()
        it = iter(self.contacts)

        try:
            while True:
                this_name, _ = it.next()

                if this_name == name:
                    next_name, next_address = it.next()
                    break
        except StopIteration:
            next_name, next_address = iter(self.contacts).next()

        self.nameLine.setText(next_name)
        self.addressText.setText(next_address)

    def previous(self):
        name = self.nameLine.text()

        prev_name = prev_address = None
        for this_name, this_address in self.contacts:
            if this_name == name:
                break

            prev_name = this_name
            prev_address = this_address
        else:
            self.nameLine.clear()
            self.addressText.clear()
            return

        if prev_name is None:
            for prev_name, prev_address in self.contacts:
                pass

        self.nameLine.setText(prev_name)
        self.addressText.setText(prev_address)

    def updateInterface(self, mode):
        self.currentMode = mode

        if self.currentMode in (self.AddingMode, self.EditingMode):
            self.nameLine.setReadOnly(False)
            self.nameLine.setFocus(QtCore.Qt.OtherFocusReason)
            self.addressText.setReadOnly(False)

            self.addButton.setEnabled(False)
            self.editButton.setEnabled(False)
            self.removeButton.setEnabled(False)

            self.nextButton.setEnabled(False)
            self.previousButton.setEnabled(False)

            self.submitButton.show()
            self.cancelButton.show()

        elif self.currentMode == self.NavigationMode:
            if not self.contacts:
                self.nameLine.clear()
                self.addressText.clear()

            self.nameLine.setReadOnly(True)
            self.addressText.setReadOnly(True)
            self.addButton.setEnabled(True)

            number = len(self.contacts)
            self.editButton.setEnabled(number >= 1)
            self.removeButton.setEnabled(number >= 1)
            self.nextButton.setEnabled(number > 1)
            self.previousButton.setEnabled(number >1 )

            self.submitButton.hide()
            self.cancelButton.hide()


if __name__ == '__main__':
    import sys

    app = QtWidgets.QApplication(sys.argv)

    addressBook = AddressBook()
    addressBook.show()

    sys.exit(app.exec_())

© 2021 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners.