Alvin Delagon

"""
@name: qt-textedit.py
@summary: A sample text editor using PyQt4
@author: Alvin Delagon
"""

import sys
from PyQt4 import QtGui, QtCore

def PutToCenter(widget):
    """
    I'm a helper function that move a widget to the
    center of the screen

    @param: QtGui.QWidget
    @return: None
    """
    screen = QtGui.QDesktopWidget().availableGeometry()
    size = widget.geometry()
    widget.move((screen.width() - size.width()) / 2, (screen.height() - size.height()) / 2)

def Maximize(widget):
    """
    I'm a helper function that can set the widget's size
    to maximum screen size

    @param: QtGui.QWidget
    @return: None
    """
    widget.showMaximized()

class TextEditor(QtGui.QMainWindow):
    def __init__(self, parent=None):
        self.filename = "untitled.txt"
        self.modified = False
        self.saved = False
        QtGui.QMainWindow.__init__(self)
        self.setWindowTitle ("Text Editor 1.0.0 - %s" % (self.filename))
        self.textedit = QtGui.QTextEdit()
        self.setCentralWidget(self.textedit)
        self.connect(self.textedit, QtCore.SIGNAL('textChanged()'), self.onTextChanged)
        self.buildMenuBar()
        self.buildAboutBox()
        Maximize(self)

    def buildMenuBar(self):
        """
        Build, Populate, and set Signals for the Menu bar

        @param: self
        @return: None
        """
        open = QtGui.QAction('&Open', self)
        new = QtGui.QAction('&New', self)
        save = QtGui.QAction('&Save', self)
        saveas = QtGui.QAction('Save As', self)
        exit = QtGui.QAction('E&xit', self)
        credits = QtGui.QAction('Credits', self)
        self.menu = self.menuBar()
        file = self.menu.addMenu('&File')
        file.addAction(open)
        file.addAction(new)
        file.addAction(save)
        file.addAction(saveas)
    file.addAction(exit)
        about = self.menu.addMenu('&About')
        about.addAction(credits)
        self.connect(open, QtCore.SIGNAL('triggered()'), self.onOpen)
        self.connect(new, QtCore.SIGNAL('triggered()'), self.onNew)
        self.connect(save, QtCore.SIGNAL('triggered()'), self.onSave)
        self.connect(saveas, QtCore.SIGNAL('triggered()'), self.onSaveAs)
        self.connect(exit, QtCore.SIGNAL('triggered()'), self.onExit)
        self.connect(credits, QtCore.SIGNAL('triggered()'), self.onCredits)

    def buildAboutBox(self):
        """
        Build the AboutBox

        @param: self
        @return: None
        """
        self.credits_window = QtGui.QWidget()
        self.credits_window.setGeometry(100, 50, 250, 150)
        self.credits_window.setWindowTitle("About")
        PutToCenter(self.credits_window)

    def onTextChanged(self):
        """
        Trigger for the textchanged() signal. My job is to detect if the
        buffer has been modified

        @param: self
        @return: None
        """
        self.modified = True
        self.setWindowTitle("Text Editor 1.0.0 - %s [modified]" % (self.filename))

    def onOpen(self):
        """
        I'm the trigger for the Menu-Open signal. Reads
        the chosen file and loads it to textedit widget

        @param: self
        @return: None
        """
        v = self.checkUnsaved("Warning!")
        if v == "cancel":
            return
        self.filename = QtGui.QFileDialog.getOpenFileName(self, 'Open File')
        file = open(self.filename)
        self.textedit.setText(file.read())
        self.setWindowTitle("Text Editor 1.0.0 - %s" % (self.filename))
        self.saved = True
        self.modified = False

    def onNew(self):
        """
        I'm the trigger for the Menu-New signal. Clears
        the textedit widget

        @param: self
        @return: None
        """
        v = self.checkUnsaved("Warning!")
        if v == "cancel":
            return
        self.saved = False
        self.modified = False
        self.filename = "untitled.txt"
        self.textedit.setText("")
        self.setWindowTitle("Text Editor 1.0.0 - %s" % (self.filename))

    def onSave(self):
        """
        I'm the trigger for the Menu-Save signal. Saves
        the textedit contents to the chosen filename

        @param: self
        @return: None
        """
        if self.saved == False:
            self.filename = QtGui.QFileDialog.getSaveFileName(self, 'Save As')
        if len(self.filename) == 0:
            return
        file = open(self.filename, 'w')
        file.write(self.textedit.toPlainText())
        file.close()
        self.modified = False
        self.saved = True
        self.setWindowTitle("Text Editor 1.0.0 - %s" % (self.filename))

    def onSaveAs(self):
        """
        I'm the trigger for the Menu-SaveAs signal. Saves the
        buffer in a different file

        @param: self
        @returns: None
        """
        self.filename = QtGui.QFileDialog.getSaveFileName(self, 'Save As')
        file = open(self.filename, 'w')
        file.write(self.textedit.toPlainText())
        file.close()
        self.modified = False
        self.saved = True
        self.setWindowTitle("Text Editor 1.0.0 - %s" % (self.filename))

    def onExit(self):
        """
        I'm the trigger for the Menu-Exit signal. Triggers
        application close

        @param: self
        @returns: None
        """
        v = self.checkUnsaved("Really Quit?")
        if v == "cancel":
            return
        self.close()

    def onCredits(self):
        """
        I'm the triggers for the Menu-Credits signal. Shows
        the About Window
        """
        self.credits_window.show()

    def checkUnsaved(self, title):
        """
        Checks if the buffer has been modified and unsaved.

        @param: title (String)
        @return: String
        """
        v = ""
        if self.modified and not(len(self.textedit.toPlainText()) == 0):
            reply = QtGui.QMessageBox.question(self,
                                               title,
                                               "You have some unsaved work!",
                                               QtGui.QMessageBox.Cancel,
                                               QtGui.QMessageBox.Save,
                                               QtGui.QMessageBox.Discard)
            if reply == QtGui.QMessageBox.Cancel:
                return ("cancel")
            elif reply == QtGui.QMessageBox.Save:
                self.onSave()
                return ("save")
            else:
                return ("discard")
        return (v)


app = QtGui.QApplication(sys.argv)
qts = TextEditor()
qts.show()
sys.exit(app.exec_())