examples/widgets/mainwindows/application¶
(You can also check this code in the repository)
<!DOCTYPE RCC><RCC version="1.0">
<qresource>
<file>images/copy.png</file>
<file>images/cut.png</file>
<file>images/new.png</file>
<file>images/open.png</file>
<file>images/paste.png</file>
<file>images/save.png</file>
</qresource>
</RCC>
# Copyright (C) 2013 Riverbank Computing Limited.
# Copyright (C) 2022 The Qt Company Ltd.
# SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
from __future__ import annotations
from argparse import ArgumentParser, RawTextHelpFormatter
import sys
from PySide6.QtCore import (QByteArray, QFile, QFileInfo, QSaveFile, QSettings,
QTextStream, Qt, Slot)
from PySide6.QtGui import QAction, QIcon, QKeySequence
from PySide6.QtWidgets import (QApplication, QFileDialog, QMainWindow,
QMessageBox, QTextEdit)
import application_rc # noqa: F401
class MainWindow(QMainWindow):
def __init__(self):
super().__init__()
self._cur_file = ''
self._text_edit = QTextEdit()
self.setCentralWidget(self._text_edit)
self.create_actions()
self.create_menus()
self.create_tool_bars()
self.create_status_bar()
self.read_settings()
self._text_edit.document().contentsChanged.connect(self.document_was_modified)
self.set_current_file('')
self.setUnifiedTitleAndToolBarOnMac(True)
def closeEvent(self, event):
if self.maybe_save():
self.write_settings()
event.accept()
else:
event.ignore()
@Slot()
def new_file(self):
if self.maybe_save():
self._text_edit.clear()
self.set_current_file('')
@Slot()
def open(self):
if self.maybe_save():
fileName, filtr = QFileDialog.getOpenFileName(self)
if fileName:
self.load_file(fileName)
@Slot()
def save(self):
if self._cur_file:
return self.save_file(self._cur_file)
return self.save_as()
@Slot()
def save_as(self):
fileName, filtr = QFileDialog.getSaveFileName(self)
if fileName:
return self.save_file(fileName)
return False
@Slot()
def about(self):
QMessageBox.about(self, "About Application",
"The <b>Application</b> example demonstrates how to write "
"modern GUI applications using Qt, with a menu bar, "
"toolbars, and a status bar.")
@Slot()
def document_was_modified(self):
self.setWindowModified(self._text_edit.document().isModified())
def create_actions(self):
icon = QIcon.fromTheme(QIcon.ThemeIcon.DocumentNew, QIcon(':/images/new.png'))
self._new_act = QAction(icon, "&New", self, shortcut=QKeySequence.New,
statusTip="Create a new file", triggered=self.new_file)
icon = QIcon.fromTheme(QIcon.ThemeIcon.DocumentOpen, QIcon(':/images/open.png'))
self._open_act = QAction(icon, "&Open...", self,
shortcut=QKeySequence.Open, statusTip="Open an existing file",
triggered=self.open)
icon = QIcon.fromTheme(QIcon.ThemeIcon.DocumentSave, QIcon(':/images/save.png'))
self._save_act = QAction(icon, "&Save", self,
shortcut=QKeySequence.Save,
statusTip="Save the document to disk", triggered=self.save)
self._save_as_act = QAction("Save &As...", self,
shortcut=QKeySequence.SaveAs,
statusTip="Save the document under a new name",
triggered=self.save_as)
icon = QIcon.fromTheme(QIcon.ThemeIcon.ApplicationExit)
self._exit_act = QAction(icon, "E&xit", self, shortcut="Ctrl+Q",
statusTip="Exit the application", triggered=self.close)
icon = QIcon.fromTheme(QIcon.ThemeIcon.EditCut, QIcon(':/images/cut.png'))
self._cut_act = QAction(icon, "Cu&t", self, shortcut=QKeySequence.Cut,
statusTip="Cut the current selection's contents to the clipboard",
triggered=self._text_edit.cut)
icon = QIcon.fromTheme(QIcon.ThemeIcon.EditCopy, QIcon(':/images/copy.png'))
self._copy_act = QAction(icon, "&Copy",
self, shortcut=QKeySequence.Copy,
statusTip="Copy the current selection's contents to the clipboard",
triggered=self._text_edit.copy)
icon = QIcon.fromTheme(QIcon.ThemeIcon.EditPaste, QIcon(':/images/paste.png'))
self._paste_act = QAction(icon, "&Paste",
self, shortcut=QKeySequence.Paste,
statusTip="Paste the clipboard's contents into the current "
"selection",
triggered=self._text_edit.paste)
icon = QIcon.fromTheme(QIcon.ThemeIcon.HelpAbout)
self._about_act = QAction(icon, "&About", self,
statusTip="Show the application's About box",
triggered=self.about)
self._about_qt_act = QAction("About &Qt", self,
statusTip="Show the Qt library's About box",
triggered=qApp.aboutQt) # noqa: F821
self._cut_act.setEnabled(False)
self._copy_act.setEnabled(False)
self._text_edit.copyAvailable.connect(self._cut_act.setEnabled)
self._text_edit.copyAvailable.connect(self._copy_act.setEnabled)
def create_menus(self):
self._file_menu = self.menuBar().addMenu("&File")
self._file_menu.addAction(self._new_act)
self._file_menu.addAction(self._open_act)
self._file_menu.addAction(self._save_act)
self._file_menu.addAction(self._save_as_act)
self._file_menu.addSeparator()
self._file_menu.addAction(self._exit_act)
self._edit_menu = self.menuBar().addMenu("&Edit")
self._edit_menu.addAction(self._cut_act)
self._edit_menu.addAction(self._copy_act)
self._edit_menu.addAction(self._paste_act)
self.menuBar().addSeparator()
self._help_menu = self.menuBar().addMenu("&Help")
self._help_menu.addAction(self._about_act)
self._help_menu.addAction(self._about_qt_act)
def create_tool_bars(self):
self._file_tool_bar = self.addToolBar("File")
self._file_tool_bar.addAction(self._new_act)
self._file_tool_bar.addAction(self._open_act)
self._file_tool_bar.addAction(self._save_act)
self._edit_tool_bar = self.addToolBar("Edit")
self._edit_tool_bar.addAction(self._cut_act)
self._edit_tool_bar.addAction(self._copy_act)
self._edit_tool_bar.addAction(self._paste_act)
def create_status_bar(self):
self.statusBar().showMessage("Ready")
def read_settings(self):
settings = QSettings('QtProject', 'Application Example')
geometry = settings.value('geometry', QByteArray())
if geometry.size():
self.restoreGeometry(geometry)
def write_settings(self):
settings = QSettings('QtProject', 'Application Example')
settings.setValue('geometry', self.saveGeometry())
def maybe_save(self):
if self._text_edit.document().isModified():
ret = QMessageBox.warning(self, "Application",
"The document has been modified.\nDo you want to save "
"your changes?",
QMessageBox.Save | QMessageBox.Discard | QMessageBox.Cancel)
if ret == QMessageBox.Save:
return self.save()
elif ret == QMessageBox.Cancel:
return False
return True
def load_file(self, fileName):
file = QFile(fileName)
if not file.open(QFile.ReadOnly | QFile.Text):
reason = file.errorString()
QMessageBox.warning(self, "Application", f"Cannot read file {fileName}:\n{reason}.")
return
inf = QTextStream(file)
with QApplication.setOverrideCursor(Qt.WaitCursor):
self._text_edit.setPlainText(inf.readAll())
self.set_current_file(fileName)
self.statusBar().showMessage("File loaded", 2000)
def save_file(self, fileName):
error = None
with QApplication.setOverrideCursor(Qt.WaitCursor):
file = QSaveFile(fileName)
if file.open(QFile.WriteOnly | QFile.Text):
outf = QTextStream(file)
outf << self._text_edit.toPlainText()
if not file.commit():
reason = file.errorString()
error = f"Cannot write file {fileName}:\n{reason}."
else:
reason = file.errorString()
error = f"Cannot open file {fileName}:\n{reason}."
if error:
QMessageBox.warning(self, "Application", error)
return False
self.set_current_file(fileName)
self.statusBar().showMessage("File saved", 2000)
return True
def set_current_file(self, fileName):
self._cur_file = fileName
self._text_edit.document().setModified(False)
self.setWindowModified(False)
if self._cur_file:
shown_name = self.stripped_name(self._cur_file)
else:
shown_name = 'untitled.txt'
self.setWindowTitle(f"{shown_name}[*] - Application")
def stripped_name(self, fullFileName):
return QFileInfo(fullFileName).fileName()
if __name__ == '__main__':
argument_parser = ArgumentParser(description='Application Example',
formatter_class=RawTextHelpFormatter)
argument_parser.add_argument("file", help="File",
nargs='?', type=str)
options = argument_parser.parse_args()
app = QApplication(sys.argv)
main_win = MainWindow()
if options.file:
main_win.load_file(options.file)
main_win.show()
sys.exit(app.exec())