book

Programming with Qt, 2nd Edition

by Matthias Kalle Dalheimer

January 2002

Beginner to intermediate

522 pages

14h 36m

English

O'Reilly Media, Inc.

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A Productive WeekendWhat You Should KnowOrganization of This BookConventions Used in This BookComments and QuestionsAcknowledgments
Why GUI Toolkits?Why Portability?Why Qt?Implementing Cross-Platform GUI LibrariesAPI LayeringAPI EmulationGUI EmulationAcquiring QtQt EditionsHow Free Is Qt?Compiling and Installing QtInstalling Qt or Qt/Embedded on Unix or MacOS X systemsCompiling and Installing Qt on WindowsC++ as Used by QtGetting Help
Hello, world!ExercisesUsing the Qt Reference DocumentationExercisesAdding an Exit ButtonExercisesIntroduction to Signals and SlotsThe Problem of Callback FunctionsA New ApproachSignals and Slots in QtAnother Example of Signals and SlotsRunning mocExercisesEvent Handling and Simple Drawings with QPainterExercises
Adding MenusExercisesAdding a Scrolled ViewExercisesAdding a Context MenuExerciseFile I/OExercises
General Widget ParametersWidget StylesButtonsPush ButtonsRadio Buttons and CheckboxesSelection WidgetsList BoxesCombo BoxesWidgets for Bounded-Range InputSlidersDialsSpin BoxesWidgets for Entering Date and TimeScrollbarsMenu-Related WidgetsArrangersFramesGroup BoxesSplittersWidget StacksSize GripsTab-Related WidgetsText-Entry FieldsLabelsSimple LabelsQLCDNumberWidgets for the OfficeThe Main WindowToolbarsStatus BarsMultiple Document Interface (MDI)Docking WindowsTooltips and “What’s This” WindowsProgress BarsScrolled ViewsList ViewsIcon ViewsWidgets for Tabular MaterialWidgets for Displaying Rich Text
Predefined Dialog BoxesFile Selection Dialog BoxesColor Dialog BoxesFont Dialog BoxesMessage BoxesInput Dialog BoxesProgress Dialog BoxesError Message Dialog BoxesBuilding Blocks for Your Own Dialog BoxesTab Dialog BoxesWizards
Layout Manager BasicsLaying Out Widgets in Rows and ColumnsNested Layout ManagersGrid LayoutImplicit Geometry Management

Available Container ClassesChoosing a Container ClassWorking with Reference-Based Container ClassesBasic UsageCaching DataIteratorsStacks and QueuesWorking with Value-Based Container Classes
AnimationsPrintingManaging ColorsColor AllocationColor ModelsColor Groups and PalettesBasic QPainter: Drawing FiguresSelecting Brushes, Colors, and PensDrawing Operations in QPainterAdvanced QPainterTwo-Dimensional TransformationsView TransformationsClippingDouble-Buffering and Other Nifty TechniquesIndependently Movable Objects with QCanvasAdding Different Items to the CanvasWorking with StylesLoading and Saving Custom Image FormatsSetting a Cursor
Internationalization and Localization of On-Screen TextInternationalizing a Qt ApplicationLocalizing Your ApplicationValidating User InputWorking with Regular ExpressionsReading and Writing XML FilesProcessing XML with SAXProcessing XML with DOMRich Text
Reading a Text FileTraversing a DirectoryFile InformationReading and Writing Configuration Data
Using the ClipboardDrag-and-Drop
Working with Date and Time ValuesLoading Code Libraries DynamicallySpawning Child ProcessesPlaying Sounds
Implementing a Coordinate SelectorImplementing a Browse Box
Event FiltersSending Synthetic Events
Signals and Slots RevisitedConnecting Several Buttons to One SlotActions
Installation of the SQL ModuleConnecting to a DatabaseSimple Data RetrievalData Retrieval with CursorsData DisplayData ManipulationAnything Else?MetadataTransactionsMore Features
Configuring Qt for MultithreadingUsing Qt’s Multithreading ClassesMultithreading PitfallsAlternatives to Multithreading
Why Portability Is DesirableHow to Write Portable ProgramsDanger Ahead: When Even Qt Is Not PortableBuilding Projects Portably with qmake
Low-Level Socket AccessHigher-Level Network Access
OpenGL Programming with QtWriting Netscape Plug-insIntegrating Xt WidgetsInterfacing Qt with Perl
Importing an Existing MakefileCreating Your Own Project from ScratchUsing qmake to Create a Project FileUsing the MS Visual Studio Integration
Why Do You Need A GUI Designer?Creating a Simple Application with the Help of Qt DesignerBecoming Familiar with Qt DesignerA first look at the property editorA first look at the form editorMore Widgets for Our FormGenerating C++ source code from the Qt Designer filePutting It All TogetherAdding Functionality to a Dialog Box by SubclassingContinuing Work on an Already Existing Dialog BoxAdding Functionality to the Push ButtonsInitializing the State of Widgets in the FormConnecting Widgets to One AnotherUsing Layout ManagementPutting a Form Together with LayoutsPopular Mechanics: Working with SpacersUseful TechniquesWorking with Signals and SlotsThe connection toolThe slots toolChanging the Tab OrderAll About Layout ManagementIntegrating Qt Designer Files into Your ProjectUsing qmake for Generating and Building Qt Designer FilesUsing Project ManagementCreating Main WindowsAccessing Databases from Qt DesignerAccessing the Help SystemDynamically Creating Forms at RuntimeCustom Widgets
Answers to Exercises in Chapter 2Answers to Exercises in the Section “Hello, world!”Answers to Exercises in the Section “Using the Qt Reference Documentation”Answers to Exercises in the Section “Adding an Exit Button”Answers to Exercises in the Section “Introduction to Signals and Slots”Answers to Exercises in the Section “Event Handling and Simple Drawings with QPainter”Answers to Exercises in Chapter 3Answers to Exercises in the Section “Adding Menus”Answers to Exercises in the Section “Adding a Scrolled View”Answers to Exercises in the Section “Adding a Context Menu”Answers to Exercises in the Section “File I/O”

Content preview from Programming with Qt, 2nd Edition

Chapter 13. Interfacing with the Operating System

In this chapter, we will cover some tasks that are inherently unportable, but for which Qt provides portable abstractions that shield your application programs from the operating system APIs. More precisely, we will cover working with date and time values, dynamically loading code libraries, starting other processes and possibly capturing these processes’ output, and finally playing simple sounds.

Working with Date and Time Values

Date and time values are inherently hard to make portable. Therefore, it’s a good idea to use the classes provided by Qt when you work with this kind of data.

Three Qt classes are in this area: QDate, QTime, and QDateTime. Their purposes are obvious: QDate encapsulates a date value, QTime encapsulates a time value, and QDateTime encapsulates both. You can pass either the scalar values that make up a date (day, month, and year) or a time value (hour, minute, and optional second and millisecond), or set these values later.

For computations with date and time values, use the methods QTime::addSecs(), QTime::addMSecs(), QDate:addDays(), QDateTime::addSecs(), and QDateTime::addDays(). There are also many comparison operators, and you can stream date and time values to and from QDataStream streams.

Getting the current time and date is a popular feature. All three classes provide static methods for this: QDate::currentDate(), QTime::currentTime(), and QDateTime::currentDateTime().

QTime can also be used as ...