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Cross-platform C++ development using Qt

Cross-platform C++ development using Qt 12
Crossplatform C++ ® development using Qt Fall 2005 QT Presentation By Gabe RudyQT Presentation Overview ® • About Trolltech /QT • Qt Features and Benefits • Examples and Code • Demos and more Code • QuestionsAbout Trolltech/QT QT Presentation By Gabe RudyQT Presentation Trolltech • Founded in 1994 • Offices: Eirik ChambeEng Haavard Nord – Oslo, Norway (HQ) – Santa Clara, California – Brisbane, Australia • Ownership: – Majority by employees – 24 VC ® • Main products: Qt and QtopiaQT Presentation Products • Qt: a complete C++ application development framework • Qtopia: a comprehensive application platform and user interface for Linuxbased consumer electronics • QSA: Qt Script for Applications • Teambuilder: distributed compilation solution ® Linux /UnixQT Presentation Other Products First • Any Linux based PDQ will be running QTopia, which is based on QTembedded. • If you know QT, you could easily write for this platform.QT Presentation Qt in a nutshell • Qt is a complete C++ application development framework, including – A comprehensive C++ class library – RAD GUI development tool (Qt Designer) – Internationalization tool (Qt Linguist) – Help browser (Qt Assistant) – Source code and comprehensive documentationQT Presentation Qt is comprehensive • Qt supplies 8090 of commonly needed functionality for rich client developers – 400+ fully documented classes – Core libs: GUI, Utility, Events, File, Print, Network, Plugins, Threads, Date and Time, Image processing, Styles, Standard dialogs ® – Modules: Canvas, Iconview, Network, OpenGL , SQL, Table, Workspace, XML – Tools: Designer, Assistant, Linguist – Extensions: ActiveQt, Motif migration, MFC migration • Qt Solutions for platformspecific customer requests • Easy to add/extend/customize QT Presentation Qt is crossplatform • The Qt API and tools are consistent across all supported platforms – Qt runs on mobile phones to Cray supercomputers • Consequence for users and customers – Freedom of choice in terms of development and deployment platform – Protection against changing platform fashionsQT Presentation A few platforms it runs on: ® • Windows 95 through Server 2003 ® • Mac OS X • Linux and embedded Linux • AIX, BSD/OS, FreeBSD, HPUX, IRIX, NetBSD, OpenBSD, Solaris, Tru64 UNIX • And moreQT Presentation Qt is native • Qt builds on the native graphics layer • Qt applications run at compiled speedQT Presentation Native look on WindowsQT Presentation Native look on LinuxQT Presentation Native look on Mac OS XQT Presentation Qt is open source, but…QT Presentation QT is also Commercial • QT requires a commercial license if you plan to sell your product written in QT. • Per developer licensing • License cost based on edition and number of platforms • Windows does not have GPL version of QT • NO runtime fees/roalties etc.QT Presentation Qt is rock solid • Qt is used as the basis of the Linux KDE (K Desktop Environment) – Millions of lines of code, strong reliability requirements, industry strength stability • Widely used by Linux community – thousands of developers – millions of endusers • Used commercially in a wide variety of demanding applications – Medical devices – Air traffic guidanceQT Presentation Qt customers • Adobe, Agilent, ARM, Boeing, Bosch, Cadence, Canon, CEA Technologies, ChevronTexaco, DaimlerChrysler, Deutsche Telekom, Earth Decision Sciences, ESA, Fraunhofer, HP, IBM, Intel, ipenta JD Edwards, Lockheed Martin, LogicaCMG, Mentor Graphics, NASA, NEC, NTT, PGS, Pioneer, Rohde Schwarz, Scania, Schlumberger, Sharp, Shell, Siemens, Sony, STNAtlas, Stryker Leibinger, Synopsys, Thales... • Qt is used for a wide variety of applications: massmarket and custom software, internal apps, research, modeling, visualization, etc..QT Presentation Sample application: Abobe Photoshop AlbumQt Features and Benefits QT Presentation By Gabe RudyQT Presentation Qt Features • Unique features in Qt – Crossplatform, consistent, compiled API – Signals and slots • Class library overview • Qt tools overview • Documentation • Thirdparty integration QT Presentation Crossplatform, consistent API Application Application Application Qt/X11 lib Qt/Windows lib Qt/Mac lib Unix or Linux MS Windows MacOS • Use the standard native tools to build Qt apps (IDE, debugger etc.) • Qt provides a platformindependent encapsulation of the local window system and operating system • The Qt API is identical on every platform, applications are compiled to native executables • Result: Write once, compile everywhereQT Presentation Signals Slots • Unique interobject communication mechanism, provides – Typesafe callback between objects – Facilitates loose coupling / encapsulation • Sender and receiver does not ”know about” each other – 1tomany, manyto1 communication between objects • Fully ObjectorientedQT Presentation Class Library Overview • Full set of GUI classes – Widget set and GUI toolkit • Operating system encapsulation classes – OO, C++ class interface to C system calls • SQL database access classes – Data storing and retrieval • Utility classes – Commonly useful classes • Integration Migration classes – Using Qt with other libraries and legacy codeQT Presentation OS encapsulation classes • File directory handling • Date time • Registry / preferences • Networking – URL, socket, TCP, DNS, FTP, HTTP • Process handling – exec, terminate, kill, stdin/stdout/stderr I/O • Threading – start, terminate, semaphore, mutex, wait • Dynamic library loading QT Presentation SQL Database classes Application SQL Qt library Database DBvendor’s OS driver library • Store, retrieve, query, traverse modify DB data • Databaseindependent API – Oracle, Sybase/MS SQL Server, MySQL, PostgreSQL, DB/2, Interbase, ODBC • DBaware widgets – Editable forms and tableviewsQT Presentation Utility classes • String and regular expressions – Unicode • Text and binary I/O – codecs • Collections – Optional alternatives to STL collections • XML I/O – Parser with SAX2 interface – DOM level 2 implementationQT Presentation Integration Migration classes • OpenGL – 3D graphics rendering in a Qt widget • ActiveX – Host ActiveX controls in a Qt app – Use Qt to create ActiveX controls • Motif – coexist with legacy Motif code; stepwise migration • Netscape Plugins – Create Netscape/Mozilla/Opera LiveConnect plugins with QtQT Presentation Development Tools Overview • Qt Designer – Visual GUI builder • Qt Linguist – Language translators’ tool • Qt Assistant – Help browser • qmake – Makefile generator, eases crossplatform buildsQT Presentation Qt Designer MyDialog.xml MyDialogBase.cpp MyDialog.cpp • WYSIWYG, drag drop GUI builder • Supports the Qt autolayout system • Designs stored in open, documented XML format • Does not interfere with user’s source codeQT Presentation Documentation • Reference Manual – HTML – generated from the source code – Fully crossreferenced – Browsable from Qt Assistant – or normal web browser: • Tutorials • Examples • Qt programming booksExamples and Code The fun stuff. QT Presentation By Gabe RudyQT Presentation Hello World(ish) include qapplication.h include qlabel.h int main(int argc, char argv) QApplication myapp(argc, argv); QLabel mylabel = new QLabel("Hello MSU“,0); mylabelresize(80,30); myapp.setMainWidget(mylabel); mylabelshow(); return myapp.exec(); QT Presentation Signals and Slots (indepth)QT Presentation Signals and Slots – exampleQT Presentation Defining Signals and Slots • New C++ Syntax for defining Signals/Slots class myClass : public QObject QOBJECT //required macro, no semicolon … signals: void somethingHappened(); … public slots: void slotDoSomething(); … private slots: void slotDoSomethingInternal(); … ;QT Presentation Gory Details • Signals: emit events – declare as signals, otherwise normal member functions – You don't implement them. Rather, you send them with the keyword emit – E.g. emit sliderChanged(5) • Slots: receive and handle events – Normal member functions declared as slots • Connect: must connect signals to slots – QObject::connect( mymenu, SIGNAL(activated(int)), myobject, SLOT(slotDoMenuFunction(int)) ); • moc: meta object compiler (preprocessor) converts these new keywords to real C++QT Presentation Hello World Proper int main(int argc, char argv) QApplication myApp(argc, argv); QWidget myWidget = new QWidget(); myWidgetsetGeometry(400, 300, 120, 90); QLabel myLabel = new QLabel("Hello MSU",myWidget); myLabelsetGeometry(10, 10, 80, 30); QPushButton myQuitButton = new QPushButton("Quit", myWidget); myQuitButtonsetGeometry(10, 50, 100, 30); QObject::connect(myQuitButton, SIGNAL(clicked()), myApp, SLOT(quit()); myapp.setMainWidget( myWidget ); myWidgetshow(); return myApp.exec(); QT Presentation Hello with QT Designer • Create a widget/dialog/wizard etc in Designer • Use the code generated at compile time in the program. include "helloui.h" //Generated at compile time int main(int argc, char argv) QApplication myApp(argc, argv); HelloUI hello = new HelloUI(0); myApp.setMainWidget( hello ); helloshow(); return myApp.exec(); QT Presentation Look at Designer .ui and Demo • Designer generates clean xml code • Demo shows off QT well.QT Presentation Thank you Additional information resources: • • • Gabe Questions
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