The book of qt 4 the art of building qt applications - phần 5 pptx

... recycled paper Qt 4 Qt 4 THE ART OF BUILDING Qt APPLICATIONS DANIEL MOLKENTIN THE BOOK of THE BOOK of Qt 4 THE BOOK of THE BOOK of Qt 4 ®MOLKENTIN1 Basics,Tools, and First CodeSeveral Qt classeshaveQObject ... 391 .4. 2QString andOther Classesnot Derived from QObject 40 1 .4. 3The Qt InheritanceHierarchy 41 1.5QtataGlance 42 1 .5. 1The Qt Libraries 42 1 .5. 2Toolsand Utilities 47 1 .5. 3Examples andDemos 58 1.6Howto ... 2 45 8.10WithoutYourOwnDataSource: TheStandardModel. 249 8.11 Element-basedViewsWithout Model Access 251 8.11.1Items 251 8.11. 2The List View 251 8.11. 3The Tree View 252 8.11. 4The Table View 253 8.11.5Cloning Items. 2 54 9The QtSqlModule...

... nowByteConverterDialogdecEdittextChanged()setText()hexEdittextChanged()setText()binEdittextChanged()setText()decChanged()hexChanged()binChanged()We can connect thesignals andslots of theline-edit widgets from theByteCon-verterDialog to thesignals andslots of theByteConverter class, for example, the hexChanged()signalofthe decEdit object ... enter them in theIndextaboftheAssistant. From thestart page you can also accessalistofall classesand alistgroupedaccordingtotopics.20ForQt4.1,see http://doc.trolltech.com /4. 1/. 59 2 TheToolsNeeded ... implements both thegraphical interfaceand theprocessing logicfor theap-plication: If theuserchanges thevalue in oneofthe line-edit widgets ,the Byte-ConverterDialog classcalls thecorresponding...

... areasofthe window,orpositionthem floatingover themainwindow.Iftheyaredocked, thelatter haveasplitter(see Chapter 5. 3onpage 150 ), withwhich theusercan fine-tune thesizeratio of thedockwindowto themainwindow,ifnecessary.Dockwindowsalsohaveahandle ... usingthe Designer,which allowsthe basicgraphicalframeworkofmostapplications to be puttogether “bymouseclick” in Qt versions 4. 1and later .The basisofthisisthe QMainWindowQt class. 4. 1The Anatomy of ... Delphi who startonQt/C++developmentfindthesignal/slot conceptunusual, andtheymiss theeventhandler .Qt4 allowsthemto sticktothe semanticstheyareusedto, permitting slot declarationsofthe formvoid...

... ClickSplitterHandle::mouseDoubleClickEvent()wefirstdetermine thealignment of thesplitter.Weobtainthe positionofthe splitter,using theQSplitter::indexOf()method. This is also thepositionofthe widgetlyingtothe rightof(or directlybeneath) thesplitter.Forreasons ... lastUncollapsedSizeremembers thelastsize of thewidgetinanuncollapsed state. If th is is 0for anyreason ,the implementationuses thevalue of therespectivesizeHint(). Thecurrent positionofour splitter 155 6 DialogsHowthedisplayed ... as the rstargu-ment,thenthe dialog willnot be modal .The nexttwoargumentsare thedialogheading andthe startdirectory.TheQDirclass provides static methods for retrievingthe paths to themostim-portant...

... weconstruct thedescription of theaddressbook entryusingthe <table>tag. Each rowof thetable consists of twocells,one of which contains thenameofthe address book field (the key)andtheother ,the matching ... QModelIndex&parent)const{Q_UNUSED(parent);returnaddressBook.at(0).count();}Viewsthatuse ouraddressbook modelcan discover thelabelingofthe rowsandcolumns via theheaderData()method. To do so,theymustspecifythenumericpositionofthe section of ... “Interview”Q_UNUSED(parent);returnaddressBook.count() -2 ;}To determine thenumber of columns,welook at thedataset from th efirstlineoftheCSV file. TheQStringList::cou nt() method is used to determine thenumber of stringsinthe string...

... nowconnect theclicked()signalofthe Screenshot!buttontothe slot thatprepares thescreenshot,and thesignalofthe Printbuttontothe slot that enablestheconfiguration of theprintingparameters. Then wecallgrabDesktop(), ... procedure(QPainter::CompositionMode_SourceIn), thecolor of thenewpixel can be derived from thesource, reducedbythealpha value of thedestination .The reduct ionofthe alphachannelheremeans ahighertrans-parency, 15 as can be seen ... determine the diameter via pieRect(). So that the gradient later “creases” the edge of the pie chart circle, thus creating the impression of spatial depth, we place the focus to the edge of the upper...

... QStringobjects,making useofthe toLocal8Bit()method internally.11.4Startingand ControllingProcessesNowandagainyou maywanttomake useofthe services of command-linebasedprograms, particularlyon Unix-based operating ... andusethese to read datainthe orderinwhich theywerereadinbyoperator<<().Then wefill therespectivepropertyof thepasseddataset instance usingthe corre-sponding setmethod. Finallywepassonthe ... {produceMessage();msleep((rand()%3000)+1);} ;}} ;In thecritical sectionwecheck whether thereisstill room in thequeue.Ifthisisnotthe case, thewaitcondition comesintoforce .Since themutexmustnot beblockedduringthe waiting period,...

... In ourcasethese arecuteedit_de.qm, cuteedit_fr.q m,andcuteedit_it.qm. 14. 1.3Using Translations in theProgramLoading thecorrect translationwhenthe program starts is thetaskofthe QTrans-latorclass.Itwillsearchfor ... the rsttimeinthe UserRole, in this casethe com-plete contents of <description>. We willuse this later to displaythecontents of thecurrent entryin aQTextBrowser.In the nalpartofthe RssHandlerimplementation, ... down-load an RSSfeed,parse it,and displayit.Figure13.1showshowtheapplicationisconstructed :The lineeditwaits for theaddressofthe fe ed ,the contents of whicharedisplayed byaQTextViewon theleft-hand...