Welcome from Budapest

Transcription

1 Welcome from Budapest 1

2 Welcome from ELTE University Rozália Szabó Nacsa Eötvös Loránd University, Budapest Faculty of Informatics 2

3 C++ GUI Programming with Qt 3 3

4 Qt Overview Qt Qtis is a complete C++ C++ application development framework. It Itincludes a class classlibrary and andtools toolsfor forcross-platform development and and internationalization. Qt Qtapplications run runnatively, compiled from fromthe thesame samesource code, on onall all supported platforms: --Qt/Windows (Microsoft Windows XP, XP, 2000, NT NT 4, 4, Me/98/95) --Qt/X11 (Linux, Solaris, HP-UX, IRIX, AIX, AIX, and andother otherunix variants) --Qt/Mac (Mac (MacOS X) X) --Qt/Embedded (embedded Linux) 4

5 Why Qt? expanded markets short learning curves, ease of ofuse platform independence for fordevelopers native look and feel no runtime environment high performance (no virtual machine or oremulation layers) robustness (+simple memory management) easy integration with 3rd party libraries and products (C++ libs) migration from MFC, Motif extra widgets and components available good C++ performance available source code nice documentation high-quality technical support.... 5

6 Running Qt Assistant 6

7 The Qt s Welcome window 7

8 Class Hierarchy 8

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11 Hello Qt application QObject QWidget QFrame QLabel #include #include <qapplication.h> #include #include <qlabel.h> int int main(int main(int argc,char argc,char *argv[]) *argv[]) {{ QApplication app(argc,argv); hello.cpp QLabel QLabel *label *label = new new QLabel("Hello Qt!",0); Qt!",0); QApplication }} app.setmainwidget(label); label->show(); return return app.exec(); 11

12 Hello Qt: includes #include #include <qapplication.h> <qapplication.h> #include #include <qlabel.h> <qlabel.h> hello.cpp int int main(int main(intargc,char argc,char *argv[]) *argv[]) {{ QApplication QApplicationapp(argc,argv); app(argc,argv); QLabel QLabel *label *label = new newqlabel("hello Qt!",0); Qt!",0); }} app.setmainwidget(label); label->show(); label->show(); return returnapp.exec(); Give Givethe thedefinitions of ofused usedclasses 12

13 Hello Qt: application #include #include <qapplication.h> <qapplication.h> #include #include <qlabel.h> <qlabel.h> int int main(int main(intargc,char argc,char *argv[]) *argv[]) {{ QApplication QApplicationapp(argc,argv); app(argc,argv); hello.cpp Qt Qtsupports command-line arguments on onits itsown. QLabel QLabel *label *label = new newqlabel("hello Qt!",0); Qt!",0); }} app.setmainwidget(label); label->show(); label->show(); return returnapp.exec(); Gives the thedefinitions of ofused usedclasses Create a QApplication object. 13

14 Hello Qt: label #include #include <qapplication.h> <qapplication.h> #include #include <qlabel.h> <qlabel.h> int int main(int main(intargc,char argc,char *argv[]) *argv[]) {{ QApplication QApplicationapp(argc,argv); app(argc,argv); hello.cpp Second parameter (0) (0) means no no parent. QLabel QLabel *label *label = new newqlabel("hello Qt!",0); Qt!",0); }} app.setmainwidget(label); label->show(); label->show(); return returnapp.exec(); Gives the thedefinitions of ofused usedclasses Creates a QApplication object Create a QLabel object with withno no parent. 14

15 Hello Qt:main widget #include #include <qapplication.h> <qapplication.h> #include #include <qlabel.h> <qlabel.h> int int main(int main(intargc,char argc,char *argv[]) *argv[]) {{ QApplication QApplicationapp(argc,argv); app(argc,argv); hello.cpp If Iflabel labelis is said saidtotobe be a main widget it itvanishes from fromthe the memory AND from fromthe thescreen as aswell wellwhen it itis is closed. QLabel QLabel *label *label = new newqlabel("hello Qt!",0); Qt!",0); }} app.setmainwidget(label); label->show(); label->show(); return returnapp.exec(); Gives the thedefinitions of ofused usedclasses Creates a QApplication object Creates a QLabel object with withno no parent Set Setthe thelabel labelas asthe theapplication s main mainwidget. 15

16 Hello Qt: show #include #include <qapplication.h> <qapplication.h> #include #include <qlabel.h> <qlabel.h> int int main(int main(intargc,char argc,char *argv[]) *argv[]) {{ QApplication QApplicationapp(argc,argv); app(argc,argv); hello.cpp Widgets are arecreated hidden by by default. (no (no flickering) QLabel QLabel *label *label = new newqlabel("hello Qt!",0); Qt!",0); }} app.setmainwidget(label); label->show(); label->show(); return returnapp.exec(); Gives the thedefinitions of ofused usedclasses Creates a QApplication object Creates a QLabel object with withno no parent Sets Setsthe thelabel labelas asthe theapplication s main mainwidget Make the thelabel labelvisible 16

17 Hello Qt: exec #include #include <qapplication.h> <qapplication.h> #include #include <qlabel.h> <qlabel.h> int int main(int main(intargc,char argc,char *argv[]) *argv[]) {{ QApplication QApplicationapp(argc,argv); app(argc,argv); hello.cpp Application turns turnsinto intoa stand by by state statewaiting for formessages. QLabel QLabel *label *label = new newqlabel("hello Qt!",0); Qt!",0); }} app.setmainwidget(label); label->show(); label->show(); return returnapp.exec(); Give Givethe thedefinitions of ofused usedclasses Create a QApplication object Create a QLabel object with withno no parent Set Setthe thelabel labelas asthe theapplication s main mainwidget Make the thelabel labelvisible Pass Passapplication s control on onqt. ( event loop ) 17

18 HTML - style formatting #include <qapplication.h> #include <qlabel.h> hello.cpp int int main(int argc,char *argv[]) *argv[]) { QApplication app(argc,argv); QLabel QLabel *label *label = new newqlabel("<h1><i>hello</i>" "<font "<font color=red> Qt!</font></h2>",0); } app.setmainwidget(label); label->show(); return returnapp.exec(); 18

19 Compiling & Running Directory s Contents hello.cpp hello.exe hello.obj hello.pro Makefile qmake project qmake hello.pro nmake hello hello 19

20 20

21 QPushButton The Quit application QApplication #include #include <qapplication.h> #include #include <qpushbutton.h> quit.cpp int int main(int main(int argc, argc, char char *argv[]) *argv[]) {{ QApplication QApplication app(argc,argv); app(argc,argv); QPushButton QPushButton *button *button = new new QPushButton("Quit",0); QObject::connect(button,SIGNAL(clicked()),&app,SLOT(quit())); }} app.setmainwidget(button); button->show(); button->show(); return return app.exec(); app.exec(); 21

22 Responding to User Actions #include #include <qapplication.h> <qapplication.h> #include #include <qpushbutton.h> <qpushbutton.h> quit.cpp int int main(int main(intargc, argc, char char *argv[]) *argv[]) {{ QApplication QApplicationapp(argc,argv); app(argc,argv); QPushButton QPushButton *button *button = new newqpushbutton("quit",0); QObject::connect(button,SIGNAL(clicked()),&app,SLOT(quit())); }} app.setmainwidget(button); button->show(); button->show(); return returnapp.exec(); Give Givethe thedefinitions of ofused usedclasses Create a QApplication object Create a QPushButton object with withno no parent Make connection to torespond Set Setthe thebutton as asthe theapplication s main mainwidget Make the thebutton visible Pass Passapplication s control on onqt. 22

23 macros QObject::connect(button,SIGNAL(clicked()),&app,SLOT(quit())); member function of ofthe theqobject class class 23

24 Making Connections button clicked() quit() application QObject::connect(button,SIGNAL(clicked()),&app,SLOT(quit())); 24

25 Compiling & Running Directory s Contents quit.cpp quit.exe quit.obj quit.pro Makefile qmake project qmake o o Makefile quit.pro nmake quit quit 25

26 Numbers application form.h form.h form.cpp form.cpp main.cpp main.cpp Form FormClass repesenting the the main mainwindow 26

27 Form s Design Caption QVBox QHBox QSpinBox QSlider QEditLine 27

28 QSpinBox Classes QSlider QHBox QLineEdit QVBox Form QApplication 28

29 Modularization form.h form.cpp main.cpp 29

30 Form Class - Declaration #ifndef #ifndef FORM_H FORM_H #define #define FORM_H FORM_H #include #include <qwidget.h> <qwidget.h> #include #include <qvbox.h> <qvbox.h> form.h class class QHBox; QHBox; class class QSpinBox; QSpinBox; class class QSlider; QSlider; class class QLineEdit; QLineEdit; class class Form: Form: public public QVBox QVBox { { Forward declaration Form inherits from QVBox public: public: Form(QWidget Form(QWidget *parent=0, *parent=0, const const char char *name=0); *name=0); constructor private: private: }; }; #endif #endif QVBox QVBox *vbox; *vbox; QHBox QHBox *hbox; *hbox; QSpinBox QSpinBox *spinbox; *spinbox; QSlider QSlider *slider; *slider; QLineEdit QLineEdit *lineedit; *lineedit; Pointers 30

31 #include #include <qvbox.h> <qvbox.h> #include #include <qhbox.h> <qhbox.h> #include #include <qspinbox.h> <qspinbox.h> #include #include <qslider.h> <qslider.h> #include #include <qlineedit.h> <qlineedit.h> #include #include "form.h "form.h Form Class - Implementation form.cpp Form::Form(QWidget Form::Form(QWidget *parent, *parent, const const char char *name) *name) : : QVBox(parent,name) QVBox(parent,name) { { setmargin(6); setmargin(6); setspacing(6); setspacing(6); hbox hbox = = new new QHBox(this); QHBox(this); lineedit lineedit = = new new QLineEdit(this); QLineEdit(this); hbox->setmargin(6); hbox->setmargin(6); hbox->setspacing(6); hbox->setspacing(6); spinbox spinbox = = new new QSpinBox(hbox); QSpinBox(hbox); slider slider = = new new QSlider(Qt::Horizontal,hbox); QSlider(Qt::Horizontal,hbox); slider->setrange(0,10); slider->setrange(0,10); spinbox->setrange(0,10); spinbox->setrange(0,10); Caption QVBox QHBox QSpinBox QSlider QLineEdit } } spinbox->setvalue(5); spinbox->setvalue(5); connect(slider,signal(valuechanged(int)),spinbox,slot(setvalue(int))); connect(slider,signal(valuechanged(int)),spinbox,slot(setvalue(int))); connect(spinbox,signal(valuechanged(int)),slider,slot(setvalue(int))); connect(spinbox,signal(valuechanged(int)),slider,slot(setvalue(int))); 31

32 Numbers application s main program #include #include <qapplication.h> <qapplication.h> #include #include"form.h" int int main(int main(intargc, argc, char char *argv[]) *argv[]) {{ QApplication QApplicationapp(argc,argv); app(argc,argv); Form Form *form *form = new newform; app.setmainwidget(form); form->show(); form->show(); return returnapp.exec(); }} main.cpp Caption QVBox QHBox QSpinBox QSlider QLineEdit 32

33 Creating Custom Slots - Declaration.... class class Form: Form: public public QVBox form.h QVBox {{ Q_OBJECT Q_OBJECT macro consists of offunction declarations for formoc. public: public: Form(QWidget *parent=0, const const char char *name=0); private: private: QHBox QHBox *hbox; *hbox; QSpinBox *spinbox; QSlider QSlider *slider; *slider; QLineEdit *lineedit; *lineedit; QString QString words[11]; void void initwords(); public public slots: slots: void void sayasword(int i); i); }; };.... Words of ofnumbers are are stored in inan anarray. array. moc: meta object compiler This Thisis is not nota standard C++ C++ element. It Itwill willbe be transferred into into standard C++ C++ code codeby bymoc. 33

34 Custom Slot Implementation Form::Form(QWidget *parent, *parent, const const char char *name) *name):qvbox(parent,name) {{ setmargin(6); setspacing(6); form.cpp.... connect(slider,signal(valuechanged(int)),spinbox,slot(setvalue(int))); connect(spinbox,signal(valuechanged(int)),slider,slot(setvalue(int))); connect(slider,signal(valuechanged(int)),this,slot(sayasword(int))); }} initwords(); spinbox->setvalue(5); custom slot slot The The initial value valuemust be be set set AFTER establishing connections. 34

35 Custom Slot Implementation void void Form::sayAsWord(int i) i) {{ lineedit->settext(words[i]); }} form.cpp void void Form::initWords() {{ words[0] words[0] = "null"; "null"; words[1] words[1] = "one"; "one";.... words[10] = "ten"; "ten"; }} 35

36 Compiling & Running qmake project qmake numbers.pro nmake numbers.pro ########################## Automatically Automatically generated generated by by ########################## TEMPLATE TEMPLATE = app app INCLUDEPATH INCLUDEPATH += +=.. ## Input Input HEADERS HEADERS += += form.h form.h SOURCES SOURCES += += form.cpp form.cppmain.cpp main.cpp 36

37 Memory Management & Parent-Children Relationship Form QHBox(hbox) list of children The The only onlyobjects we wehave havetoto delete are arethe theobjects we wecreate with withnew newand andthat thathave haveno no parents. QSpinBox(spinBox) QSilder(slider) Main Mainwidget is is automatically deleted after afterclose. QLineEdit(lineEdit) We Wehave haveused usednew newbut butwe wedo do not nothave havetoto delete them themeither. 37

38 38

39 Layout Manager Object to manage the size and position of the widget. Layout manager classes are arenot notwidgets, but butthey theycan have haveparent and andchidren. 39

40 #ifndef #ifndefform_h #define #defineform_h #include #include <qwidget.h> <qwidget.h> form.h class classqspinbox; class classqslider; class classqlineedit; class classform: public publicqwidget {{ public: public: Form(QWidget Form(QWidget *parent=0, *parent=0, const constchar char *name=0); *name=0); private: private: QSpinBox QSpinBox *spinbox; *spinbox; QSlider QSlider *slider; *slider; QLineEdit QLineEdit *lineedit; *lineedit; }; }; #endif #endif 40

41 Form::Form(QWidget *parent, *parent, const constchar char *name) *name): : QWidget(parent,name) {{ spinbox spinbox = new newqspinbox(this); #include slider slider = new newqslider(qt::horizontal,this); #include <qlayout.h> <qlayout.h> #include slider->setrange(0,10); #include <qspinbox.h> <qspinbox.h> #include spinbox->setrange(0,10); #include <qslider.h> <qslider.h> #include lineedit lineedit = new newqlineedit(this); <qlineedit.h> <qlineedit.h> #include #include"form.h" QHBoxLayout QHBoxLayout *toplayout *toplayout = new newqhboxlayout; //Layout //Layoutwith withno no parent parent toplayout->addwidget(spinbox); toplayout->addwidget(slider); QVBoxLayout QVBoxLayout *mainlayout *mainlayout = new newqvboxlayout(this); //Layout //Layoutwith with "this" "this" parent parent mainlayout->addlayout(toplayout); mainlayout->addwidget(lineedit); mainlayout->setmargin(11); mainlayout->setspacing(6); connect(slider,signal(valuechanged(int)),spinbox,slot(setvalue(int))); connect(spinbox,signal(valuechanged(int)),slider,slot(setvalue(int))); } spinbox->setvalue(5); //Set //Setvalue valueafter connections!! connections!! } form.cpp 41

42 Caption Caption QVBox mainlayout mainlayout QHBox QSpinBox QSlider QSpinBox QSlider toplayout toplayout QLineEdit QLineEdit 42

43 Parent - children relationship mainlayout mainlayout Form Caption QSpinBox (spinbox) QSlider (slider) QSpinBox QLineEdit QSlider QLineEdit (lineedit) QVBoxLayout(mainLayout) toplayout toplayout QHBoxLayout(topLayout) Main Mainwidget and andits itschildrens are areautomatically deleted after after close. 43

44 Form QSpinBox (spinbox) QSlider (slider) QLineEdit (lineedit) QVBoxLayout(mainLayout) First FirsttopLayout is is created with with no no parent, but butwe wedo donot nothave to tomanage its itsdeletion, because it itwill willbe be added to tothe the mainlayout and andtherefore mainlayout became its itsparent. QHBoxLayout(topLayout) to todelete deleteor ornot nottoto delete? delete? QHBoxLayout QHBoxLayout *toplayout *toplayout = new newqhboxlayout; //Layout //Layoutwith withno no parent parent toplayout->addwidget(spinbox); toplayout->addwidget(slider); QVBoxLayout QVBoxLayout *mainlayout *mainlayout = new newqvboxlayout(this); //Layout //Layoutwith with "this" "this" parent parent mainlayout->addlayout(toplayout); //mainlayout //mainlayoutwill willbe be the theparent parentfor fortoplayout mainlayout->addwidget(lineedit); // this // this (Form) remains remainsthe theparent parentfor forlineedit 44

45 45

46 The.ui file and the generated C++ code Qt designer form.ui form.ui UIC form.h form.h Reads and writes Reading Generates #includes Tool Generated source file Revision controlled source file form.cpp form.cpp main.cpp main.cpp 46

47 The subclassing approach Qt designer formbase.ui formbase.ui Inheritance UIC formbase.h formbase.h form.h form.h Reads and writes Reading Generates #includes Tool Generated source file Revision controlled source file formbase.cpp formbase.cpp form.cpp form.cpp File Fileformbase.h és és a formbase.cpp are are generated after aftermodification of ofthe theform. Application specific functions will willbe be added in inthe thesubclass. main.cpp main.cpp 47

48 The ui.h extension approach Qt designer Application specific functions can can be be given given in in form.ui.h file. file. form.ui form.ui UIC form.ui.h form.ui.h form.h form.h Reads and writes Reading Generates #includes Tool Generated source file Revision controlled source file form.cpp form.cpp main.cpp main.cpp 48

49 Starting Qt Designer 49

50 The QtDesigner s screen ProjectOverview Toolbox ObjectExplorer Properties Editor/ Signal Handlers 50

51 File/New/C++ Project 51

52 File/New/Widget 52

53 53

54 Laying Out Elements 54

55 Conneting widgets: Edit/Connections <connections> <connection> form.ui <sender>slider</sender> <signal>valuechanged(int)</signal> <receiver>spinbox</receiver> <slot>setvalue(int)</slot> </connection> <connection> <sender>spinbox</sender> <signal>valuechanged(int)</signal> <receiver>slider</receiver> <slot>setvalue(int)</slot> </connection> </connections> 55

56 Declaring variable 56

57 Creating Custom Slots Edit/Slots....../New Function Edit/Connections 57

58 void void Form::sayAsWord( int int i) i) {{ lineedit->settext(words[i]); }} 58

59 Creating custom functions and the constructor Edit/Slots....../New Function void void Form::init() {{ spinbox->setmaxvalue(10); slider->setmaxvalue(10); initwords(); spinbox->setvalue(5); }} Creating Creatingthe theform Forminit() function functionwill willbe be performed automatically. void void Form::initWords() {{ words[0] words[0] = "null"; "null";.... words[10] = "ten"; "ten"; }} 59

60 Adding main function File/New....../C++ Main Main file file 60

61 The generated main.cpp program #include <qapplication.h> #include #include"form.h" int int main( main( int int argc, argc, char char ** ** argv argv )) {{ QApplication a( a( argc, argc, argv argv ); ); Form Form w; w; w.show(); a.connect( &a, &a, SIGNAL( SIGNAL( lastwindowclosed() ), ),&a, SLOT( SLOT( quit() quit() )));); return return a.exec(); a.exec(); }} 61

62 Compiling & Running 1. qmake project 2. qmake words.pro 3. make 62

63 Project file of Words application TEMPLATE = app INCLUDEPATH +=. # Input HEADERS += form.ui.h INTERFACES += form.ui SOURCES += main.cpp 1. qmake project 2. qmake -o Makefile words.pro 3. nmake 4. words 63

64 Extending the functionality of the program Task: Task: Let Letus usmake makeitit works works vice vice verse. verse. Typing 64

65 Defining a new slot 65

66 Implementing the new slot void void Form::slotTextChanged_( const const QString QString & s s )) {{ bool bool l=false; l=false; for for (int (int i=0; i=0; i< i< (int) (int) sizeof(words)/sizeof(words[0]) && &&!l;i++) {{ if(words[i]==s) {{ l=true; l=true; slider->setvalue(i); }} }} }} 66

67 Connecting the widgets 67

68 Compiling & Running 68

69 69