String policy 28 in Java Attach Code 128 in Java String policy 28

String policy 28 using jar topaint code 128 in web,windows application GS1 Bar Codes Center Main Window Responsibilities object to write data usi ng setValue() and to read data using value(), in both cases converting between QVariant and the relevant type. In the following section we will look at the high-level le handling and data presentation that are performed by the application s main window subclass. In the second section, we will look at the application s data module, including the implementation of individual data items, and of the data item container in which the application s data is held.

Then, in the subsequent sections, we will look at saving and loading data in various formats. In the section on binary les, we will look at how to use PyQt s QDataStream class and also the standard Python library s cPickle module to load and save our collection of movie records. In the section on text les, we will see how to load and save our movie records in plain text using PyQt s QTextStream and the Python standard library s codecs module.

And in the last section we will write the code to save the records as XML by hand, and see how to use both DOM and SAX parsers to read back the XML data.. Main Window Responsibilities The main window is usual ly given responsibility for offering the user the highlevel le-handling actions, and for presenting the application s data. In this section, we will focus particularly on the le actions, since they differ from what we did in 6 s Image Changer application and they are more representative of what happens in larger applications. We will also look at how the data is presented to the user.

In the My Movies application, the data is held in a container (a MovieContainer), and all the work of saving and loading (and exporting and importing) is passed on to the container by the main window. We will look at the container in the next section, and at the container s saving and loading code in the sections that follow that. The source code is in the chap08 directory, and it includes a Qt Designer-designed user interface for adding and editing movie records.

Figure 8.2 shows the application s Python modules. We have chosen to make a distinction between saving and exporting, and between loading and importing.

When we load a le, the lename we used becomes the application s current lename for when we save. If we save a le, we use the application s current lename, so subsequent saves will be to the same le. We can change the current lename by using the save as action.

When we import a le, we clear the current lename; this means that the data must be given a new lename if the user wants to save it. If the user exports the data, they are asked for a new lename, and the current lename is not affected. Now we are ready to look at the main window s le-handling functionality.

We will begin by looking at the start of the main window s initializer, to see. 8. Data Handling and Custom File Formats mymovies.pyw MainWindow main() AddEditMovieDlg User interface module Movie Movie Container intFromQStr() encodedNewlines() decodedNewlines(). Icons Figure 8.2 The My Movie application s modules, classes, and functions the creation of the data-holding movie container and the data-presenting QTableWidget. class MainWindow(QMainWi jsp USS Code 128 ndow): def __init__(self, parent=None): super(MainWindow, self).__init__(parent) self.movies = moviedata.

MovieContainer() self.table = QTableWidget() self.setCentralWidget(self.

table). After calling super(), w e create a new empty movies container. (We will look at the Movie and MovieContainer classes shortly.) Then we create a QTableWidget.

This widget is used to present and optionally to edit tabular data. The table is set up and populated in updateTable(). We have omitted the rest of the initializer, since we already know from 6 how to set up the status bar, create the le, edit, and help actions, populate the menus and toolbars, and restore the application s state from the previous session s settings.

For completeness, we will now take a brief detour to review updateTable() to see how the table widget is set up and populated. (You could skip ahead to the fileNew() method on page 232 if you prefer to focus purely on the le handling.) The approach we are using is very simple and direct.

PyQt also offers a more sophisticated approach to populating and editing item-based widgets such as lists, tables, and trees, using PyQt s model/view architecture we will learn about this in 14.. def updateTable(self, cu code 128a for Java rrent=None): self.table.clear() self.

table.setRowCount(len(self.movies)) self.

table.setColumnCount(5) self.table.

setHorizontalHeaderLabels(["Title", "Year", "Mins", "Acquired", "Notes"]).
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