qt3 to qt4

Qt4 custom slot and Signal The code shown in this article is successfully debugged in Windows XP + mingw3.4.2 + eclipse3.4 + cdt5.0 The QT System provides a comprehensive Signal Processing Mechanism for us, and its internal signal and slot are already very comprehensive. Therefore, in most cases, we do not need to design signals and slots by ourselves, however, sometimes we may need to design some unique signals and slots to meet the needs of the prog

Qt4 application mounting to arm Board (using NFS sharing) Set NFS sharing On a PC Virtual Machine /Etc/exports Add/root/Yizhi 192.168.0. * (RW) Set the IP address ifconfig 192.168.0.230 to the same segment as the target IP address. Service NFS restart Copy the application to/root/share/QtopiaCore-4.3.0-arm/bin Copy/usr/src/usr/local/ARM/3.4.1/ARM-Linux/lib to/root/share/QtopiaCore-4.3.0-arm/lib On the target board Ping 192.168.0.230 to check whether t

name must not contain Chinese characters. Otherwise, the name cannot be Chinese ). Create a new file under eclipse_plugins.Language folder. Finally, extract the Language Pack file to the language folder. Next, create a new age.linkfile under the linksfolder (the suffix cannot be changed, or it can be named language.txt ).In this example, enter Path =/opt/Eclipse/eclipse_plugins/language (this is the location where I store the Language Pack ). Directory structure screenshot:

+ = Fakeliblibwidget_name = $ $qtLibraryTarget (widget) TEMPLATE-= Fakelibinclude (.. /COMMON.PRI)!widget-buildlib{ LIBS + =-l$ $PROJECT _libdir-l$ $LIBWIDGET _name}else{ SOURCES + = Widget.cpp HEADERS + = widget.h} Full version of the Libwidget/libwidget.pro file (the contents of this document will not be changed later) TEMPLATE = Libconfig + = Widget-buildlibinclude (libwidget.pri) TARGET = $ $LIBWIDGET _namedestdir = $ $PROJECT _libdirwin32{ Dlldestdir = $ $PROJECT

running to check whether the program depends on the folder. Try again and finally find the folder D:/QT/qt46/QT/plugins/sqldrivers1 (like the guess, it is caused by the plug-in Library of qt4.6) As long as I change the name of this folder, my program will report an error. If I do not change the name, the program will run normally. Then I guess if I copy this folder to another machine based on this address, the program release error will be solved! Based on this idea, I copied the rel

represent the individual selections , each of which is oftenreferred to as "flag", and the bitwise operator can be used | "or" |= to combine these tags, you can use the bitwise operator totest whether a tag is selected. Type aliasesType conversionsStatic_cast converts a pointer to a pointer to b , class b must be a class A sub-classDynamic_castrun-time type information (RTTI,runtime type information) validation Const_castadd / Remove a const qualifier on a pointer or referenceReinterpret_castc

; build failed.1>1> used Time 00:00:03.23========== All rebuilds: 0 successful, 1 failed, 0 ========== skipped2, the cause of the above error is due to missing a moc_xxx.cpp file in the Generatedfiles/debug file, as shown in:3. What is the missing file name? So first to find the Q_object macro in that header file, such as in the macro in the LoginDlg.h file, then the generated file Moc_logindlg.cpp, to generate this file requires a Moc.exe file in the QT library, as shown in:4. Enter into this d

to large to tidy up a bit:The smallest is that the qtablewigetitem is the representation of the cells of the two-dimensional table qtablewidget, but what is entered shows nothing, no functionAnd then the Cell is the extension of the Qtablewigetitem added to the special input format processing and expression calculation functionAnd then the spreadsheet extended from the two-dimensional table qtablewidget uses the cell, adding copy, paste, find, sort, save, read function.Finally, the function of

QT4 Reading notes 5 Chapter II Creating a dialog box This chapter will teach you how to create a dialog box with Qt. The dialog box presents the user with some options (options and Choices), which run the user to set these options. This is called a dialog box (dialog boxes,or simply "dialogs"), which provides a way for users and applications to talk to each other. Many GUI applications include a main window (a main Windows) and a menu, a toolbar, and

Label:QT4 installation Please refer to: Installing QT 4 under CentOS 6.5For MySQL installation Please refer to the following: CentOS 6.5 installation configuration MySQL1. Prevention in case, first install the Mysql-devel (must be installed!) ）。 If you do not install, there will be no problem with-lmysqlclient after compiling.2. Start compiling:CD $QTDIR/src/plugins/sqldrivers/mysql//Enter QT that store MySQL driver source directory "Qmake "Includepath+=/usr/include/mysql" "Libs+=-l/usr/lib/mysq

Label:Code in the operation of the database will appear garbled, the solutionOne, Qtextcodec::setcodecfortr (Qtextcodec::codecforname ("GBK")); Insert Data statement If the Chinese must first qobject::tr (), that is, to encode,such as Query.exec ("INSERT into student (schnum, name, Sex, Nation) VALUES (2614103, ' tianmen, ' male ', ' Han ')"); Change to Query.exec (Qobject::tr ("INSERT into student (schnum, name, Sex, Nation) VALUES (2614103, ' tianmen, ' male ', ' Han ')");The results will be d

1. First download the instance source code, address: http://download.csdn.net/source/2333153 2. After downloading the SDK, you can see the openal-SDK. You need to install it. Suppose you have installed it in E:/openal/SDK/ 3. decompress the ALUT

A signal is a specific identifier; a slot is a function, unlike a normal function, a slot function can be either associated with a signal or called directly as a normal function. When an event occurs, by sending a signal, you can activate the slot

License plate recognition equipment returned to the license plate results for GB2312,QT to be able to parse the display, it is necessary to transcode, qstring storage Unicode, the implementation of code simple as follows Char plate_num[256] = {0};

1. Install Kdevelop in Ubuntu in two ways: 1. terminal: KDevelop can be easily obtained using apt-get. The details are as follows: (take KDE as an example) 1 ). apt-getbuild-depgcc2 ). apt-getinstallkdevelop33 ). if you cannot obtain information

When the computer installed RedHat, it tried to include development tools as much as possible, but there were still a lot of RPM containing "-devel", which were not included in the installation image file. This is a very troublesome task. You need

Since the QT version of the recent project has been upgraded from qt4.8 to qt5.5, although the change from 4 to 5 is small, there are a number of questions that need to be recorded to help more people.1. Because QT5 has moved most of the desktop

RED: horizontal layoutPink: grid layoutBlue: vertical layout # Include # Include # Include # Include # Include # Include Int main (INT argc, char * argv []){Qapplication app (argc, argv );Qpushbutton * button1 = new qpushbutton ("button1

Original Web site: http://www.linuxidc.com/Linux/2011-06/36922.htm   Char * encoding = "ABCD "; Const char * CH2; Substring = (char *) CH2; convert Char to qstring Char CH = 'a '; Qstring STR; STR = qstring (CH ); convert qstring to char * Qstring

1: VoidQtimer: singleshot (INT msec, qobject * receiver, const char * member) [Static] Example:# Include # Include Int main (INT argc, char * argv []){Qapplication app (argc, argv );Qtimer: singleshot (600000, & App, slot (quit ()));...Return