diff options
Diffstat (limited to 'doc/src/tutorials/addressbook.qdoc')
| -rw-r--r-- | doc/src/tutorials/addressbook.qdoc | 48 |
1 files changed, 25 insertions, 23 deletions
diff --git a/doc/src/tutorials/addressbook.qdoc b/doc/src/tutorials/addressbook.qdoc index 23dabb3..95394eb 100644 --- a/doc/src/tutorials/addressbook.qdoc +++ b/doc/src/tutorials/addressbook.qdoc @@ -818,21 +818,23 @@ \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. - - 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. + 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. + + 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. + \section1 Defining the AddressBook Class @@ -874,7 +876,7 @@ \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. @@ -904,18 +906,18 @@ \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 |