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Diffstat (limited to 'doc/src/tutorials/addressbook.qdoc')
| -rw-r--r-- | doc/src/tutorials/addressbook.qdoc | 87 |
1 files changed, 46 insertions, 41 deletions
diff --git a/doc/src/tutorials/addressbook.qdoc b/doc/src/tutorials/addressbook.qdoc index 3133f33..22583ff 100644 --- a/doc/src/tutorials/addressbook.qdoc +++ b/doc/src/tutorials/addressbook.qdoc @@ -43,11 +43,10 @@ \page tutorials-addressbook.html \startpage {index.html}{Qt Reference Documentation} + \contentspage Tutorials \nextpage {tutorials/addressbook/part1}{Chapter 1} \title Address Book Tutorial - \ingroup howto - \ingroup tutorials \brief An introduction to GUI programming, showing how to put together a simple yet fully-functioning application. @@ -222,8 +221,8 @@ Notice that \c addressLabel is positioned using Qt::AlignTop as an additional argument. This is to make sure it is not vertically centered in - cell (1,0). For a basic overview on Qt Layouts, refer to the \l{Layout Classes} - document. + cell (1,0). For a basic overview on Qt Layouts, refer to the + \l{Layout Management} documentation. In order to install the layout object onto the widget, we have to invoke the widget's \l{QWidget::setLayout()}{setLayout()} function: @@ -242,12 +241,15 @@ \snippet tutorials/addressbook/part1/main.cpp main function - We construct a new \c AddressBook widget on the heap using the \c new - keyword and invoke its \l{QWidget::show()}{show()} function to display it. + We construct a new \c AddressBook widget on the stack and invoke + its \l{QWidget::show()}{show()} function to display it. However, the widget will not be shown until the application's event loop is started. We start the event loop by calling the application's \l{QApplication::}{exec()} function; the result returned by this function - is used as the return value from the \c main() function. + is used as the return value from the \c main() function. At this point, + it becomes apparent why we instanciated \c AddressBook on the stack: It + will now go out of scope. Therefore, \c AddressBook and all its child widgets + will be deleted, thus preventing memory leaks. */ /*! @@ -694,10 +696,11 @@ \snippet tutorials/addressbook/part5/finddialog.h FindDialog header - We define a public function, \c getFindText() for use by classes that - instantiate \c FindDialog, which allows them to obtain the text - entered by the user. A public slot, \c findClicked(), is defined to - handle the search string when the user clicks the \gui Find button. + We define a public function, \c getFindText(), to be used by classes that + instantiate \c FindDialog. This function allows these classes to obtain the + search string entered by the user. A public slot, \c findClicked(), is also + defined to handle the search string when the user clicks the \gui Find + button. Lastly, we define the private variables, \c findButton, \c lineEdit and \c findText, corresponding to the \gui Find button, the line edit @@ -712,15 +715,15 @@ \snippet tutorials/addressbook/part5/finddialog.cpp constructor - We set the layout and window title, as well as connect the signals - to their respective slots. Notice that \c{findButton}'s - \l{QPushButton::clicked()}{clicked()} signal is connected to to - \c findClicked() and \l{QDialog::accept()}{accept()}. The - \l{QDialog::accept()}{accept()} slot provided by QDialog hides - the dialog and sets the result code to \l{QDialog::}{Accepted}. - We use this function to help \c{AddressBook}'s \c findContact() function - know when the \c FindDialog object has been closed. This will be - further explained when discussing the \c findContact() function. + We set the layout and window title, as well as connect the signals to their + respective slots. Notice that \c{findButton}'s \l{QPushButton::clicked()} + {clicked()} signal is connected to to \c findClicked() and + \l{QDialog::accept()}{accept()}. The \l{QDialog::accept()}{accept()} slot + provided by QDialog hides the dialog and sets the result code to + \l{QDialog::}{Accepted}. We use this function to help \c{AddressBook}'s + \c findContact() function know when the \c FindDialog object has been + closed. We will explain this logic in further detail when discussing the + \c findContact() function. \image addressbook-tutorial-part5-signals-and-slots.png @@ -814,21 +817,23 @@ \image addressbook-tutorial-part6-screenshot.png - Although browsing and searching for contacts are useful features, our address - book is not really fully ready for use until we can saving existing contacts - and load them again at a later time. - Qt provides a number of classes for \l{Input/Output and Networking}{input and output}, - but we have chosen to use two which are simple to use in combination: QFile and - QDataStream. + Although browsing and searching for contacts are useful features, our + address book is not ready for use until we can save existing contacts and + load them again at a later time. - A QFile object represents a file on disk that can be read from and written to. - QFile is a subclass of the more general QIODevice class which represents many - different kinds of devices. + Qt provides a number of classes for \l{Input/Output and Networking} + {input and output}, but we have chosen to use two which are simple to use + in combination: QFile and QDataStream. + + A QFile object represents a file on disk that can be read from and written + to. QFile is a subclass of the more general QIODevice class which + represents many different kinds of devices. + + A QDataStream object is used to serialize binary data so that it can be + stored in a QIODevice and retrieved again later. Reading from a QIODevice + and writing to it is as simple as opening the stream - with the respective + device as a parameter - and reading from or writing to it. - A QDataStream object is used to serialize binary data so that it can be stored - in a QIODevice and retrieved again later. Reading from a QIODevice and writing - to it is as simple as opening the stream - with the respective device as a - parameter - and reading from or writing to it. \section1 Defining the AddressBook Class @@ -870,7 +875,7 @@ \image addressbook-tutorial-part6-save.png - If \c fileName is not empty, we create a QFile object, \c file with + If \c fileName is not empty, we create a QFile object, \c file, with \c fileName. QFile works with QDataStream as QFile is a QIODevice. Next, we attempt to open the file in \l{QIODevice::}{WriteOnly} mode. @@ -900,18 +905,18 @@ \image addressbook-tutorial-part6-load.png If \c fileName is not empty, again, we use a QFile object, \c file, and - attempt to open it in \l{QIODevice::}{ReadOnly} mode. In a similar way - to our implementation of \c saveToFile(), if this attempt is unsuccessful, - we display a QMessageBox to inform the user. + attempt to open it in \l{QIODevice::}{ReadOnly} mode. Similar to our + implementation of \c saveToFile(), if this attempt is unsuccessful, we + display a QMessageBox to inform the user. \snippet tutorials/addressbook/part6/addressbook.cpp loadFromFile() function part2 Otherwise, we instantiate a QDataStream object, \c in, set its version as above and read the serialized data into the \c contacts data structure. - Note that we empty \c contacts before reading data into it to simplify the - file reading process. A more advanced method would be to read the contacts - into temporary QMap object, and copy only the contacts that do not already - exist in \c contacts. + The \c contacts object is emptied before data is read into it to simplify + the file reading process. A more advanced method would be to read the + contacts into a temporary QMap object, and copy over non-duplicate contacts + into \c contacts. \snippet tutorials/addressbook/part6/addressbook.cpp loadFromFile() function part3 |