The following is the implementation of a simple text editor extended from the previous examples in its building version. This code contains some new features such as, QFontDialog, QFileDialog, and so on; which are discussed in Chapter 5, Dialogs and Widgets. Otherwise, the following code is self explanatory:
# Import required modules
import sys
from PySide.QtGui import *
class MainWindow(QMainWindow):
""" Our Main Window class
"""
def __init__(self, fileName=None):
""" Constructor Function
"""
QMainWindow.__init__(self)
self.setWindowTitle("A Simple Text Editor")
self.setWindowIcon(QIcon('appicon.png'))
self.setGeometry(100, 100, 800, 600)
self.textEdit = QTextEdit()
self.setCentralWidget(self.textEdit)
self.fileName = None
self.filters = "Text files (*.txt)"
def SetupComponents(self):
""" Function to setup status bar, central widget, menu bar, tool bar
"""
self.myStatusBar = QStatusBar()
self.setStatusBar(self.myStatusBar)
self.myStatusBar.showMessage('Ready', 10000)
self.CreateActions()
self.CreateMenus()
self.CreateToolBar()
self.fileMenu.addAction(self.newAction)
self.fileMenu.addAction(self.openAction)
self.fileMenu.addAction(self.saveAction)
self.fileMenu.addSeparator()
self.fileMenu.addAction(self.exitAction)
self.editMenu.addAction(self.cutAction)
self.editMenu.addAction(self.copyAction)
self.editMenu.addAction(self.pasteAction)
self.editMenu.addSeparator()
self.editMenu.addAction(self.undoAction)
self.editMenu.addAction(self.redoAction)
self.editMenu.addSeparator()
self.editMenu.addAction(self.selectAllAction)
self.formatMenu.addAction(self.fontAction)
self.helpMenu.addAction(self.aboutAction)
self.helpMenu.addSeparator()
self.helpMenu.addAction(self.aboutQtAction)
self.mainToolBar.addAction(self.newAction)
self.mainToolBar.addAction(self.openAction)
self.mainToolBar.addAction(self.saveAction)
self.mainToolBar.addSeparator()
self.mainToolBar.addAction(self.cutAction)
self.mainToolBar.addAction(self.copyAction)
self.mainToolBar.addAction(self.pasteAction)
self.mainToolBar.addSeparator()
self.mainToolBar.addAction(self.undoAction)
self.mainToolBar.addAction(self.redoAction)
# Slots called when the menu actions are triggered
def newFile(self):
self.textEdit.setText('')
self.fileName = None
def openFile(self):
self.fileName, self.filterName = QFileDialog.getOpenFileName(self)
self.textEdit.setText(open(self.fileName).read())
def saveFile(self):
if self.fileName == None or self.fileName == '':
self.fileName, self.filterName = QFileDialog.getSaveFileName(self,
filter=self.filters)
if(self.fileName != ''):
file = open(self.fileName, 'w')
file.write(self.textEdit.toPlainText())
self.statusBar().showMessage("File saved", 2000)
def exitFile(self):
self.close()
def fontChange(self):
(font, ok) = QFontDialog.getFont(QFont("Helvetica [Cronyx]", 10), self)
if ok:
self.textEdit.setCurrentFont(font)
def aboutHelp(self):
QMessageBox.about(self, "About Simple Text Editor",
"A Simple Text Editor where you can edit and save files")
def CreateActions(self):
""" Function to create actions for menus
"""
self.newAction = QAction( QIcon('new.png'), '&New',
self, shortcut=QKeySequence.New,
statusTip="Create a New File",
triggered=self.newFile)
self.openAction = QAction( QIcon('open.png'), 'O&pen',
self, shortcut=QKeySequence.Open,
statusTip="Open an existing file",
triggered=self.openFile)
self.saveAction = QAction( QIcon('save.png'), '&Save',
self, shortcut=QKeySequence.Save,
statusTip="Save the current file to disk",
triggered=self.saveFile)
self.exitAction = QAction( QIcon('exit.png'), 'E&xit',
self, shortcut="Ctrl+Q",
statusTip="Exit the Application",
triggered=self.exitFile)
self.cutAction = QAction( QIcon('cut.png'), 'C&ut',
self, shortcut=QKeySequence.Cut,
statusTip="Cut the current selection to clipboard",
triggered=self.textEdit.cut)
self.copyAction = QAction( QIcon('copy.png'), 'C&opy',
self, shortcut=QKeySequence.Copy,
statusTip="Copy the current selection to clipboard",
triggered=self.textEdit.copy)
self.pasteAction = QAction( QIcon('paste.png'), '&Paste',
self, shortcut=QKeySequence.Paste,
statusTip="Paste the clipboard's content in current location",
triggered=self.textEdit.paste)
self.selectAllAction = QAction( QIcon('selectAll.png'), 'Select All',
self, statusTip="Select All",
triggered=self.textEdit.selectAll)
self.redoAction = QAction( QIcon('redo.png'),'Redo', self,
shortcut=QKeySequence.Redo,
statusTip="Redo previous action",
triggered=self.textEdit.redo)
self.undoAction = QAction( QIcon('undo.png'),'Undo', self,
shortcut=QKeySequence.Undo,
statusTip="Undo previous action",
triggered=self.textEdit.undo)
self.fontAction = QAction( 'F&ont', self,
statusTip = "Modify font properties",
triggered = self.fontChange)
self.aboutAction = QAction( QIcon('about.png'), 'A&bout',
self, statusTip="Displays info about text editor",
triggered=self.aboutHelp)
self.aboutQtAction = QAction("About &Qt", self,
statusTip="Show the Qt library's About box",
triggered=qApp.aboutQt)
def CreateMenus(self):
self.fileMenu = self.menuBar().addMenu("&File")
self.editMenu = self.menuBar().addMenu("&Edit")
self.formatMenu = self.menuBar().addMenu("F&ormat")
self.helpMenu = self.menuBar().addMenu("&Help")
def CreateToolBar(self):
self.mainToolBar = self.addToolBar('Main')
if __name__ == '__main__':
# Exception Handling
try:
myApp = QApplication(sys.argv)
mainWindow = MainWindow()
mainWindow.SetupComponents()
mainWindow.show()
myApp.exec_()
sys.exit(0)
except NameError:
print("Name Error:", sys.exc_info()[1])
except SystemExit:
print("Closing Window...")
except Exception:
print(sys.exc_info()[1])The sample output of the preceding program is given in the following screenshot:
The preceding example is a very simple text editor performing some basic functions. We may build upon this example in the coming chapters as and when we discuss some new features.
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