/*!
\contentspage{index.html}{Qt Creator}
\page index.html
\nextpage qtcreator-quick-tour.html
\title Qt Creator Manual
\section1 Version 0.9 - Technical Preview
The goal of Qt Creator is to provide a cross-platform, complete Integrated
Development Environment (IDE) to develop Qt projects. It is available for
the Linux, Mac OS X and Windows platforms.
\note Qt Creator is currently released as a Technical Preview. It is
possible to edit source code, compile, run and debug applications; other
features are still under development. Please send bug reports and
suggestions to qt-creator@trolltech.com. To subscribe, send a
message with the word \e subscribe to qt-creator-request@trolltech.com.
For more information on Qt mailing lists, visit http://lists.trolltech.com
\table
\row
\o \inlineimage qtcreator.png
\o Qt Creator includes a wide range of useful features. Among them are:
\list 1
\o \bold{Smart Code Editor}: The code editor provides syntax
highlighting as well as code completion.
\o \bold{Qt4 Project Generating Wizard}: This wizard allows the user
to generate a project for a console application, a GUI application,
or a C++ library.
\o \bold{Qt Help Integration}: Qt's entire documentation can be
accessed easily by clicking on the \gui{Help} button.
\o \bold{Qt Designer Integration}: User interface forms can be designed
within Qt Creator. Simply double-click on a \c{.ui} file within the
\gui{Project Explorer} to launch the integration.
\o \bold{Locator}: A powerful navigation tool that lets the user locate
files and classes using minimal keystrokes.
\o \bold{Support for qmake's .pro file format}: The project's \c{.pro}
file is used as a project description file.
\o \bold{Debugging Interface to GDB}: Applications can be debugged
within Qt Creator using a graphical frontend to the GNU symbolic
debugger.
\endlist
\endtable
To learn more about the Qt Creator, click on one of the links below:
\list
\o \l{A Quick Tour Around Qt Creator}
\o \l{Creating a Project in Qt Creator}
\o \l{Build Settings}
\o \l{Writing a Simple Program with Qt Creator}
\o \l{Navigating Quickly Around Your Code with Locator}
\o \l{Debugging with Qt Creator}
\o \l{Tips and Tricks}
\o \l{Glossary}
\o \l{Known Issues of Version 0.9 (Technical Preview)}
\endlist
*/
/*!
\contentspage index.html
\page creator-quick-tour.html
\nextpage creator-build-settings.html
\title A Quick Tour Around Qt Creator
The labeled screenshot below shows some of the components of Qt Creator, in
\gui Edit mode.
\image qtcreator-breakdown.png
\section1 The Mode Selectors
When working in Qt Creator, you can be in one of six modes: \bold Welcome,
\bold Edit, \bold Debug, \bold Projects, \bold Help, and \bold Output.
Mode selectors allow you to quickly switch between tasks: Editing, browsing
the Qt Creator manual, setting up the build environment, etc. You can
activate a mode by either clicking on its mode selector, or using the
\l{keyboard-shortcuts}{corresponding shortcut}. Certain actions also
trigger a mode change, e.g., \gui{Debug}/\gui{Start Debugging} will switch
to the \gui Debug mode.
\list
\o \gui{Welcome Mode} - Displays a welcome screen allowing you to quickly
load recent sessions or individual projects. This is the mode you will see
if Qt Creator is run without command line switches.
\o \gui{Edit Mode} - Lets you edit both project and source files. A sidebar
on the left provides different views to navigate between files.
\o \gui{Debug Mode} - Provides various ways to inspect the state of the
program while debugging. See \l{qtcreator-debugging}{Debugging With Qt
Creator} for a hands-on description of how to use this mode.
\o \gui{Projects Mode} - Lets you configure how projects can be built and
executed. Under the list of projects, there are tabs to configure the
build, run, and editor settings.
\o \gui{Help Mode} - Shows any documentation registered by Qt Assistant,
such as the Qt library and Qt Creator documentation.
\o \gui{Output Mode} - Lets you examine various data in detail, for example
build issues as well as compile and application output. This information
is also available in the output panes.
\endlist
\section1 The Output Panes
The task pane in Qt Creator can display one of four different panes:
\gui{Build Issues}, \gui{Search Results}, \gui{Application Output}, and
\gui{Compile}. These panes are available in all modes.
\section2 Build Issues
The {Build Issues} pane provides a list of issues, e.g., error messages or
warnings that need to be fixed. It filters out irrelevant output from the
compiler and collects them in an organized way.
\image qtcreator-build-issues.png
\section2 Search Results
The \gui{Search Results} pane displays the results for global searches such
as searching within a current document, files on disk, or all projects. In
the screenshot below, we searched for all occurrences of \c{textfinder}
within the \c{"/TextFinder"} folder.
\image qtcreator-search-pane.png
\section2 Application Output
The \gui{Application Output} pane displays the status of the program when
it is executed and debug output, e.g., output from qDebug().
\image qtcreator-application-output.png
\section2 Compile
The \gui{Compile} pane provides all the output from the compiler. In other
words, it is a more verbose version of information displayed in the
\gui{Build Issues}
\image qtcreator-compile-pane.png
\section1 Qt Help Integration
Qt Creator comes fully integrated with all of Qt's documentation and
examples via the Qt Help plugin. To view the documentation, you can switch
to the \gui{Help} mode. To obtain context sensitive help, move your text
cursor to a Qt class or function and press \key{F1}. The documentation
will be displayed within a panel on the right, as shown in the screenshot
below.
External Documentation provided by the user can be used to augment or
replace the documentation shipped with Qt Creator and Qt.
\image qtcreator-context-sensitive-help.png
\section1 Qt Designer Integration
Qt Creator is fully integrated with Qt Designer to help you design user
interface forms just like you would with the standalone version. The Qt
Designer integration also includes project management and code completion.
For more information on Qt Designer, you can refer to
\l{The Designer Manual}.
\image qtcreator-formedit.png
\section1 Keyboard Navigation
Qt Creator caters not only to developers who are used to using the mouse,
but also to developers who are more comfortable with the keyboard. A wide
range of \l{keyboard-shortcuts}{keyboard} and
\l{Navigating Quickly Around Your Code with Locator}{navigation} shortcuts
are available to help speed up the process of developing your application.
*/
/*!
\contentspage index.html
\previouspage creator-quick-tour.html
\page creator-build-settings.html
\nextpage creator-creating-project.html
\title Build Settings
\table
\row
\i \note Qt Creator currently supports \c qmake only. \c Makefile
and \c CMake support is currently unavailable.
\endtable
To modify the build settings of your project, switch to the \gui{Projects}
mode using the mouse or with \key{Ctrl+4}.
\image qtcreator-buildsettings.png
Action items to create, clone, or delete build configurations can be found
on the right of the dialog. You can have as many build configurations as
needed. By default Qt Creator creates a \bold{debug} and \bold{release}
build configuration. Both these configurations use the
\l{glossary-default-qt}{Default Qt Version}.
In the tree on the left, a list of build configurations and their settings
are displayed. The screenshot below shows the \bold{debug} and
\bold{release} configurations and their corresponding settings:
\bold{Build Environment} and \bold{Build Steps}.
\image qtcreator-buildsettingstab.png
When you select a build configuration in the tree, a configuration page for
general build settings will be displayed. Here you can specify which
\l{glossary-project-qt}{Qt version} to use to build your project, whether
to \l{glossary-shadow-build}{shadow build} the project, and if a special
debugging helper is linked into the project or not.
The debugging helper enables the gdb integration to show the contents of
Qt data types. Enabling this option means that an additional file will be
compiled and linked to your project.
\image qtcreator-buildenvironment.png
In the \bold{Build Environment} page you can specify the environment used
for building. By default the environment in which Qt Creator was started
is used and modified to include the Qt version. Depending on the selected
Qt version, Qt Creator will automatically add the necessary environment
variables.
\image qtcreator-buildsteps.png
The build system of Qt Creator is built on top of \c qmake and \c make. The
settings for \c qmake and \c make can be changed in the
\bold{Build Settings} page. Qt Creator will run the make command using the
correct Qt version.
\note The default qmake arguments \c{-after SOURCES*=gdbmacros.cpp
-after QT*=network} are due to the debugging helper described above. If the
debugging helper seems to break your build or your application, you can
turn it off. You will still be able to debug applications, but the contents
of Qt data types will not be displayed properly.
\section1 Qt Version Management
Qt Creator allows you to use multiple versions of Qt installed on your hard
disk and switch between them easily.
Qt Creator automatically detects if \c qmake is in the environment variable
\c PATH. This \l{glossary-system-qt}{version of Qt} is referred to as
\bold{System Qt}. If you intend to use only one version of Qt - it is
already in your path and correctly set up for command line usage - you do
not need to manually configure your Qt version.
Otherwise, you can add your Qt version in
\gui{Tools -> Options... -> Qt Versions}. If you are on the Windows
platform and use MinGW to compile Qt, you need to tell Qt Creator where
MinGW is installed. This is done by setting the \gui{MinGW Directory}
under \gui{Tools -> Options... -> Qt4 -> Qt Versions -> MinGw Directory}.
If your Qt version is compiled with Microsoft Visual C++'s compiler, Qt
Creator will automatically set the correct environment variables for
compilation.
\note By default projects are compiled with the
\l{glossary-default-qt}{default Qt version}. You can override this in the
\gui{Build Configuration}.
*/
/*!
\contentspage index.html
\previouspage creator-quick-tour.html
\page creator-creating-project.html
\nextpage creator-writing-program.html
\title Creating a Project in Qt Creator
\table
\row
\i \inlineimage qtcreator-new-project.png
\i \bold{Creating a New Project}
To create a new project, select \gui{New Project} from the \gui{File} menu.
You can create one of the following three projects:
\list
\o Qt4 Console Application
\o Qt4 Gui Application
\o C++ Library
\endlist
In this example, we select a \e{Qt4 Gui Application} and click \gui{OK}.
\row
\i \inlineimage qtcreator-intro-and-location.png
\i \bold{Setting The Project Name and Location}
Next, we set the project's name and its path. Click on the \gui{...}
button to browse and select your path.
Ideally, the path should not contain spaces or special characters.
\row
\i \inlineimage qtcreator-select-modules.png
\i \bold{Selecting The Necessary Qt Modules}
Click on the check boxes of each Qt Module you would like to include in
your project.
Since we started a Qt4 Gui Application, the Core and Gui modules are
set, but you are free to add more.
\row
\i \inlineimage qtcreator-class-info.png
\i \bold{Specifying Class Information}
Lastly, specify the name of the class you would like to create. The
\e{Header file}, \e{Source file} and \e{Form file} fields will update
automatically according to your choice of class name.
You also have to select the base class for your class, either a
QWidget, QDialog or QMainWindow, from the drop down box. Click
\gui{Done} and your project will be generated.
\endtable
*/
/*!
\contentspage index.html
\previouspage creator-creating-project.html
\page creator-writing-program.html
\nextpage creator-navigation.html
\title Writing a Simple Program with Qt Creator
\table
\row
\o \note This tutorial assumes that the user has experience writing
basic Qt applications, designing user interfaces with Qt Designer
and and using the Qt Resource System.
\endtable
In this example, we will describe the steps involve in using Qt Creator
to create a small Qt program, Text Finder. Inspired by the QtUiTools'
\l{http://doc.trolltech.com/uitools-textfinder.html}{Text Finder}
example, we will write a similar but simplified version of it, as shown
below.
\image qtcreator-textfinder-screenshot.png
\section1 Setting Up Your Environment
Once you have installed Qt Creator, it will automatically detect if Qt's
location is in your \c PATH variable. If Qt's location is not in your
\c PATH, you can set it in one of the following ways, depending on your
platform:
\list
\o On Windows and Linux: in the \gui{Tools} menu, under \gui{Options}.
\o On Mac OS X: in \gui{Preferences}, under \gui{Qt4}.
\endlist
\note If Qt was compiled with Visual Studio, all environment variables set
in Visual Studio will be added to Qt Creator as well.
\section1 Setting Up The Project
We begin with a Qt4 Gui Application project generated by Qt Creator. The
\l{Creating a Project in Qt Creator} document describes this process in
detail. Remember to select QWidget as the Text Finder's base class.
Once your project is generated, you will have the following files:
\list
\o \c{textfinder.h}
\o \c{textfinder.cpp}
\o \c{main.cpp}
\o \c{textfinder.ui}
\o \c{textfinder.pro}
\endlist
The \c{.h} and \c{.cpp} files come with the necessary boiler plate code;
the \c{.pro} file is also complete.
\section1 Filling In The Missing Pieces
We will begin by designing the user interface and then move on to filling
in the missing code. Finally, we will add the find functionality.
\section2 Designing the User Interface
To begin designing the user interface, double-click on the
\c{textfinder.ui} file in your \gui{Project Explorer}. This will launch the
integrated Qt Designer.
\image qtcreator-textfinder-ui.png
Design the form above using a QLabel, QLineEdit, QPushButton and a
QTextEdit. We recommend that you use a QGridLayout to lay out the QLabel,
QLineEdit and QPushButton. The QTextEdit can then be added to a
QVBoxLayout, along with the QGridLayout. If you are new to designing forms
with \QD, you can take a look at the
\l{http://doc.trolltech.com/designer-manual.html}{Designer Manual}.
\section2 The Header File
The \c{textfinder.h} file already has the necessary includes, a
constructor, a destructor, and the \c{Ui} object. We need to add a private
slot, \c{on_findButton_clicked()}, to carry out our find operation. We
also need a private function, \c{loadTextFile()}, to read and display the
contents of our input text file in the QTextEdit. This is done with the
following code:
\code
private slots:
void on_findButton_clicked();
private:
Ui::Form ui;
void loadTextFile();
\endcode
\note The \c{Ui::Form} object is already provided.
\section2 The Source File
Now that our header file is complete we move on to our source file,
\c{textfinder.cpp}. We begin by filling in the functionality to load a
text file. The code snippet below describes this:
\code
void TextFinder::loadTextFile()
{
QFile inputFile(":/input.txt");
inputFile.open(QIODevice::ReadOnly);
QTextStream in(&inputFile);
QString line = in.readAll();
inputFile.close();
ui.textEdit->setPlainText(line);
QTextCursor cursor = ui.textEdit->textCursor();
}
\endcode
Basically, we load a text file using QFile, read it with QTextStream, and
then display it on \c{textEdit} with \l{QTextEdit::}{setPlainText()}.
For the \c{on_findButton_clicked()} slot, we extract the search string and
use the \l{QTextEdit::}{find()} function to look for the search string
within the text file. The code snippet below further describes it:
\code
void TextFinder::on_findButton_clicked()
{
QString searchString = ui.lineEdit->text();
ui.textEdit->find(searchString, QTextDocument::FindWholeWords);
}
\endcode
Once we have both these functions complete, we call \c{loadTextFile()} in
our constructor.
\code
TextFinder::TextFinder(QWidget *parent, Qt::WFlags flags)
: QWidget(parent, flags)
{
ui.setupUi(this);
loadTextFile();
}
\endcode
The \c{on_findButton_clicked()} slot will be called automatically due to
this line of code:
\code
QMetaObject::connectSlotsByName(Form);
\endcode
in the uic generated \c{ui_textfinder.h} file.
\section2 The Resource File
We require a resource file (\c{.qrc}) within which we will embed the input
text file. This can be any \c{.txt} file with a paragraph of text. To add
a resource file, right click on \gui{Resource Files} in the
\gui{Project Explorer} and select \gui{Add New File...}. You will see the
wizard dialog displayed below.
\image qtcreator-add-resource-wizard.png
Enter "textfinder" in the \gui{Name} field and use the given \gui{Path}.
Then, click \gui{Done}.
Your resource file will now be displayed with the Resource Editor. Click
on the \gui{Add} drop down box and select \gui{Add Prefix}. The prefix we
require is just a slash (\c{/}). Click \gui{Add} again but this time,
select \gui{Add File}. Locate the text file you are going to use, we use
\c{input.txt}.
\image qtcreator-add-resource.png
The screenshot above shows what you can expect to see once you have added
the resource file successfully.
\section1 Compiling and Running Your Program
Now that you have all the necessary files, you can compile your program by
clicking on the
\inlineimage qtcreator-run.png
button.
*/
/*!
\contentspage index.html
\previouspage creator-writing-program.html
\page creator-navigation.html
\nextpage creator-debugging.html
\title Navigating Quickly Around Your Code with Locator
With Qt Creator, navigating to different locations in your project or on
your disk, e.g., files, classes, methods, etc., is trivial using
\gui Locator -- a smart line edit at the bottom left of Qt Creator's
window.
\image qtcreator-locator.png
Suppose you would like to open your project's \c{main.cpp} file, click on
\gui Locator or use \key{Ctrl+K}, type in the file name and then press
\key Return. The file will be opened in the editor. You can also type
part of a file name and use wildcard characters \c{*} and \c{?} to match
\e{any} number of \e{any} characters. A list of all files matching your
criteria will be displayed.
\gui Locator not only allows you to navigate files on disk but also other
"locations", which are organized with \bold{Filters}.
As mentioned above, files are not the only type of locations you can
jump to. The different types of locations are organized in what we
call \c{filters}. There are filters for jumping to
\list
\o files mentioned in your \c{.pro} files, such as source and header,
resource and \c{.ui} files,
\o a specific line in your current text document,
\o class and method definitions in your project or anywhere referenced
from your project,
\o help topics, including the Qt API reference documentation,
\o files anywhere on your hard disk (by browsing through the file system),
\o any open document,
\o files from a subdirectory structure you define.
\endlist
Some of these filters are not used by default if you just start typing in the
input field, but require you to type a "prefix" in front, that is
assigned to that filter. The prefix is usually a single character,
followed by a space. As an example, to jump to the definition of the class
\c{QDataStream} type \key{Ctrl+K}, \key{:}, \key{Space}, and the class name.
You find a full list of filters and their prefixes below.
\image qtcreator-navigate-popup.png
You can add filters that provide quick navigation to files in a
subdirectory structure that you define. This way you have quick access to
files that are not directly mentioned in your project, but still relate to it.
Click on the little magnifier glass in the input field and choose
\gui{Configure...} from the menu that appears. This opens the preferences
dialog for navigation filters. Click the \gui{Add} button to create a new
filter. Give it a name, choose directories, set (a comma separated list of)
file patterns, and give it a prefix string. After closing the preferences
dialog the directories you specified are searched for files that match the
file patterns, and the information is cached. From now on you can jump to
these files by just typing part of the file name into the navigation input
field. You can force an update of the cached information about the files via
the \gui{Refresh} menu item in the magnifier menu.
\image qtcreator-navigate-customfilter.png
The following table lists the filters currently available:
\table
\header
\o Function
\o Key Combination
\row
\o Go to a Line in the Current Document
\o Ctrl + K, l, Space, and the line number
\row
\o Go to a Function Definitions
\o Ctrl + K, :, Space, and the function name
\row
\o Go to a Help Topic
\o Ctrl + K, ?, Space, and the topic
\row
\o Go to an Already Opened Document
\o Ctrl + K, o, Space, and the document name.
\row
\o Go to a File in the File System (browsing the file system)
\o Ctrl + K, f, Space, and the file name.
\row
\o Go to a File in any Loaded Project
\o Ctrl + K, a, Space, and the function name.
\row
\o Go to a File in the Current Project
\o Ctrl + K, p, Space, and the function name.
\endtable
*/
/*!
\contentspage index.html
\previouspage creator-navigation.html
\page creator-debugging.html
\nextpage creator-tips.html
\title Debugging with Qt Creator
\table
\row
\i \note Qt Creator's debugger integration currently does not
support debugging applications created with the Microsoft Visual
Studio Compiler.
\endtable
Qt Creator does not have its own debugger. Instead, it provides a graphical
frontend to the GNU Symbolic Debugger (gdb). This frontend allows you to
step through a program line-by-line or instruction-by-instruction,
interrupt running programs, set breakpoints, examine the contents of the
call stack, local and global variables, etc.
Within Qt Creator, the raw information provided by gdb is displayed in a
clear and concise manner, simplifying the process of debugging.
In addition to generic IDE functionality: stack view, views for locals and
watchers, registers, etc, Qt Creator comes with additional features to make
debugging Qt-based applications easy. The debugger frontend knows about the
internal layout of several Qt classes such as QString, the QTL containers,
and most importantly QObject (and classes derived from it). Therefore, it
is able to present Qt's data clearly.
\section1 Interacting with the Debugger
In \gui Debug mode, several dock widgets are used to interact with the
program you are debugging. The frequently used dock widgets are visible by
default; the rarely used ones are hidden. To change the default settings,
select \gui Debug and then select \gui View.
####SCREENSHOT
Here, you can lock or unlock the location of your views as well as display
or hide them. Among the views you can display are \gui Breakpoints,
\gui Disassembler, \gui Modules, \gui Registers, \gui Gdb, \gui Stack, and
\gui Thread. The position of your dock widgets will be saved for future
sessions.
\section2 Breakpoints
Breakpoints are shown in the \gui{Breakpoints} view which is enabled by
by default. This view is also accessible when the debugger and the program
being debugged is not running.
A breakpoint represents a position or sets of positions in the code that,
when executed, stops the program being debugged and passing the control to
the user. The user is then free to examine the state of the interrupted
program, or continue execution line-by-line or continuously.
Typically, breakpoints are associated with a source code file and line, or
the start of a function -- both allowed in Qt Creator.
Also, the interruption of a program by a breakpoint can be restricted with
certain conditions.
You can set a breakpoint:
\list
\o At a particular line you want the program to stop -- click on the
left margin or press \key F9 (\key F8 for Mac OS X).
\o At a function that you want the program to stop -- enter the
function's name in \gui{Set Breakpoint at Function...} under the
\gui Debug menu.
\endlist
You can remove a breakpoint:
\list
\o By clicking on the breakpoint marker in the text editor.
\o By selecting the breakpoint in the breakpoint view and pressing
\key{Delete}.
\o By selecting \gui{Delete Breakpoint} from the breakpoint's context
menu in the \gui Breakpoints view.
\endlist
Breakpoints can be set and deleted before the program has actually started
running or while it is running under the debugger's control. Also,
breakpoints are saved together with a session.
\section2 Running
To start a program under the debugger's control, select the \gui{Debug}
menu and \gui{Start Debugging}, or simply press \key{F5}. Qt Creator then
checks whether the compiled program is up-to-date, rebuilding it if
necessary. The debugger then takes over and starts the program.
\note Starting a program in the debugger will take considerable amount of
time, typically in the range of several seconds to minutes if complex
features (like QtWebKit) are used.
Once the program starts running, it behaves as usual; performance-wise as
well. The user can interrupt a running program by selecting
\gui {Interrupt} from the \gui{Debug} menu. The program is automatically
interrupted as soon as a breakpoint is hit.
\omit (and, if set, its associated conditions are met). \endomit
Once the program stops, Qt Creator:
\list
\o Retrieves data representing the call stack at the program's current
position.
\o Retrieves the contents of local variables.
\o Examines \gui Watchers.
\o Updates the \gui Registers, \gui Modules, and \gui Disassembler
views.
\endlist
You can use the debugger views to examine the data in more detail.
To finish debugging, Press \key{Shift+F5}. A line of code can be executed
as a whole with \key F10; to execute a function or a sub-function, use
\key F11. Alternatively, you can continue running the program with \key F5.
It is possible to continue executing your program until the current
function completes or jump to an arbitrary position in the current
function.
\section2 Stack
When the program being debugged is stopped, Qt Creator displays the nested
function calls leading to the current position as a \e call stack trace.
This stack trace is built up from \e{call stack frames}, each representing a
particular function. For each function, Qt Creator will try to retrieve the
file name and line number of the corresponding source files. This data is
shown in the \gui Stack view.
Since the call stack leading to the current position may originate or go
through code for which no debug information is available, not all stack
frames will have corresponding source locations. These frames will be
greyed out in the \gui Stack view.
###SCREENSHOT
If you click on a frame with a known source location, the text editor will
jump to the corresponding location and update the \gui{Locals and Watchers}
view, making it seem like the program stopped before entering the function.
\section2 Threads
If a multi-threaded program is stopped, the \gui Thread view or the
combobox named \gui Thread in the debugger's status bar can be used to
switch from one thread to another. The \gui Stack view will adjust itself
accordingly.
\section2 Locals and Watchers
Whenever a program stops under the control of the debugger, it retrieves
information about the topmost stack frame and displays it in the
\gui{Locals and Watchers} view. This typically includes information about
parameters of the function in that frame as well as the local variables.
Compound variables of struct or class type will be displayed as
"expandable" in the view. C lick on the "+" to expand the entry and show
all members. Together with the display of value and type, the user can
examine and traverse the low-level layout of an object's data.
\table
\row
\i \bold{Note:}
\i Gdb, and therefore Qt Creator's debugger works for optimized
builds on Linux and Mac OS X. However, optimization may lead
to re-ordering of instructions or sometimes even complete
removal of some local variables. In this case, the
\gui{Locals and Watchers} view may show unexpected data.
\i The debug information provided by gcc does not include enough
information about the time when a variable is initialized.
Qt Creator therefore can not tell whether the contents of a
local variable contains "real data", or "initial noise". If a
QObject appears uninitialized, its value will be reported as
"out of scope". However, not all uninitialized objects can be
recognized as such.
\endtable
The \gui{Locals and Watchers} view also provides access to the most
powerful feature of the debugger: comprehensive display of data belonging
to Qt's basic objects. To enable this feature, select \gui{Use Custom
Display for Qt Objects} from the \gui Debug menu.The
\gui{Locals and Watchers} view will be re-organized to provide a high-level
view of the objects. For example, in case of QObject, instead of displaying
a pointer to some private data structure, you will see a list of children,
signals and slots.
Similarly, instead of displaying many pointers and integers, Qt Creator's
debugger will display the contents of a QHash or QMap in an orderly manner.
Also, the debugger will display access data for QFileInfo and provide
access to the "real" contents of QVariant.
The \gui{Locals and Watchers} view can be used to change the contents of
variables of simple data types such as \c int or \c float when the program
is stopped. To do so, click on the \gui Value column, modify the value
with the inplace editor, and hit \key Enter (or \key Return).
\section2 Modules
By default, the \gui Modules view is hidden as it is only useful with the
experimental delayed loaing of debug information feature. You can turn
this feature on by selecting \gui{Fast Debugger Start}
With this feature, debug information from the Qt library itself is not
loaded when the application starts up, thereby reducing the startup times
for some applications. You can then use the \gui Modules view to manually
load this information, if required.
\note In this scenario, some breakpoints may not be set by the debugger.
\section2 Disassembler View and Registers View
By default, both the \gui Disassembler and \gui Registers view are hidden.
The \gui Disassembler view displays disassembled code for the current
function; the \gui Registers view displays the current state of the CPU's
registers. Both views are useful for low-level commands such as
\gui{Step Single Instruction} and \gui{Step Over Single Instruction}.
\section1 A Walkthrough for the Debugger Frontend
In our \l{Writing a Simple Program with Qt Creator}{TextFinder} example, we
read a text file into a QString and then display it with a QTextEdit.
Suppose, you would like to look at this QString, \c{line}, and see what
data it actually stores. Follow the steps described below to place a
breakpoint and view the QString object's data.
\table
\row
\i \inlineimage qtcreator-setting-breakpoint1.png
\i \bold{Setting a Breakpoint}
First, we set a breakpoint on the line where we invoke
\l{QTextEdit::}{setPlainText()} by clicking between the line number and the
window border. Then, select \gui{Start Debugging} from the \gui{Debug} menu
or press \key{F5}.
\endtable
Breakpoints are visible in the \gui{Breakpoints} view, shown below, in
\gui{Debug} mode. If you wish to remove a breakpoint, simply right-click on
it and select \gui{Delete breakpoint} from the context menu.
\image qtcreator-setting-breakpoint2.png
To view the contents of \c{line}, take a look at the \gui{Locals and
Watchers} view.
\image qtcreator-watcher.png
Suppose we modify our \c{on_findButton_clicked()} function to move back to
the start of the document and continue searching once the cursor hits the
end of the document. Adding this functionality can be done with the code
snippet below:
\code
void TextFinder::on_findButton_clicked()
{
QString searchString = ui.lineEdit->text();
QTextDocument *document = ui.textEdit->document();
QTextCursor cursor = ui.textEdit->textCursor();
cursor = document->find(searchString, cursor,
QTextDocument::FindWholeWords);
ui.textEdit->setTextCursor(cursor);
bool found = cursor.isNull();
if (!found && previouslyFound == true) {
int ret = QMessageBox::question(this, tr("End of Document"),
tr("I have reached the end of the document. Would you like "
"me to start searching from the beginning of the document?"),
QMessageBox::Yes | QMessageBox::No, QMessageBox::Yes);
if (ret == QMessageBox::Yes) {
cursor = document->find(searchString,
QTextDocument::FindWholeWords);
ui.textEdit->setTextCursor(cursor);
} else
return;
}
previouslyFound = found;
}
\endcode
However, if you compile and run this code, the application will not work
correctly due to a logic error. To locate this logic error, you can step
through the code using the following buttons:
\image qtcreator-debugging-buttons.png
*/
/*!
\contentspage index.html
\previouspage creator-debugging.html
\page creator-tips.html
\nextpage creator-glossary.html
\title Tips and Tricks
\bold{Quickly Switching between Modes}
You can quickly switch between modes by pressing \key{Ctrl+1},
\key{Ctrl+2}, and so on.
\bold{Keyboard Shortcuts}
Qt Creator provides a lot of useful keyboard shortcuts. A complete list can
be found \l{Keyboard Shortcuts}{here}.
\bold{Running Qt Creator from the Command Line}
You can start Qt Creator from a command prompt with the name of an existing
session or \c{.pro} file by giving the name as argument on the command
line.
\bold{Show and Hide the Sidebar}
You can show and hide the the sidebar in \gui Edit and \gui Debug mode by
clicking on the corresponding icon, or by pressing \key{Alt+0}.
\bold{Display Signals and Slots}
If you have an instance of a class that is derived from QObject, and you
you would like to find all other objects connected to one of your object's
slots using Qt's signals and slots mechanism -- you can enable
\gui{Use Custom Display for Qt Objects} feature under the \gui Debug menu.
In the \gui{Locals and Watchers} view, expand the object's entry and open
the slot in the \e slots subitem. The objects connected to this slot are
exposed as children of the slot. This method works with signals too.
\bold{Display Low Level Data}
If the special debugging of Qt objects fails due to data
corruption within the debugged objects, you can switch the
special debugging off in the \gui{Debug} menu. This will make
the low-level structures visible again.
*/
/*!
\contentspage index.html
\previouspage creator-tips.html
\page creator-glossary.html
\nextpage creator-known-issues.html
\title Glossary
\table
\header
\o Term
\o Meaning
\row
\o System Qt \target glossary-system-qt
\o The version of Qt installed on your system. This is the Qt
version for the \c qmake command found in your \c PATH.
\row
\o Default Qt \target glossary-default-qt
\o The version of Qt configured in \gui{Tools -> Options -> Qt 4
-> Default Qt Version}. This is the Qt version used by your
new projects. It defaults to System Qt.
\row
\o Project Qt \target glossary-project-qt
\o The version of Qt configured in \gui{Build&Run -> Build
Settings -> Build Configurations}. This is the Qt version that
is actually used by a particular project. It defaults to
Default Qt.
\row
\o Shadow Build \target glossary-shadow-build
\o Shadow building means building a project in a separate
directory, the \e{build directory}. The build directory is
different from the source directory. One of the benefits of
shadow building is that it keeps your source directory clean.
Shadow building is the best practice if you need many build
configurations for a single set of source.
\endtable
*/
/*!
\contentspage index.html
\previouspage creator-glossary.html
\page creator-keyboard-shortcuts.html
\title Keyboard Shortcuts
Qt Creator provides various keyboard shortcuts to aid in the development
process. These shortcuts are listed in the table below:
\table
\header
\o Function
\o Key Combination
\row
\o Activate Build & Run Mode
\o Ctrl + 4
\row
\o Activate Debug Mode
\o Ctrl + 3
\row
\o Activate Edit Mode
\o Ctrl + 2
\row
\o Activate Help Mode
\o Ctrl + 5
\row
\o Activate Output Mode
\o Ctrl + 6
\row
\o Activate Welcome Mode
\o Ctrl + 1
\row
\o Find
\o Ctrl + F
\row
\o Find Next
\o F3
\row
\o Go back to Code Editor (\gui Edit mode: The first press gives
the editor focus, without closing secondary windows; the second
press closes all secondary windows. \gui Debug mode or \gui Help
mode: Switch to \gui Edit mode.)
\o Esc
\row
\o Go to a Line
\o Ctrl + L
\row
\o Start Debugging
\o F5
\row
\o Stop Debugging
\o Shift + F5
\row
\o Toggle Application Output
\o Alt + 3
\row
\o Toggle Code Declaration and Definition
\o F2
\row
\o Toggle Header File and Source File
\o F4
\row
\o Toggle Side Bar
\o Alt + 0
\row
\o Toggle Task List
\o Alt + 1
\row
\o Toggle Search Results
\o Alt + 2
\row
\o Toggle Compile Output
\o Alt + 4
\row
\o Select Welcome Mode
\o Ctrl + 1
\row
\o Select Edit Mode
\o Ctrl + 2
\row
\o Select Debug Mode
\o Ctrl + 3
\row
\o Select Build & Run Mode
\o Ctrl + 4
\row
\o Select Help Mode
\o Ctrl + 5
\row
\o Select Output Mode
\o Ctrl + 6
\endtable
*/
/*!
\contentspage index.html
\previouspage creator-keyboard-shortcuts.html
\page creator-known-issues.html
\title Known Issues of Version 0.9 (Technical Preview)
There are some known issues with the Technical Preview.
The development team is aware of those, there is no need to report them as bug.
\list
\o The central editor sometimes loses it "changed" status marker.
\o There is a kernel bug essentially making debugging unreliable
on 2.6.24 kernels for i386 (which is, unfortunately, the default
on Ubuntu 8.04).
See \l{https://bugs.launchpad.net/ubuntu/+source/gdb/+bug/230315/}
for details.
The only solution for this problem is to boot another kernel.
\o gdb sometimes takes very long to load debugging symbol,
especially from big libraries like \c libQtWebKit. Starting debugging
can take up to several minutes without visible progress.
\o Paths or file names containing spaces or special characters like colons,
dollar signs, hash marks etc. may create difficulties.
Some of the tools Qt Creator uses in the background to do the "real
work" have restrictions on the characters that are allowed in file
and directory names. To be on the safe side, it is strongly
recommended to create projects and project items only with names
consisting of plain characters, numbers, underscores, and hyphens.
\o \c .pro files are reformatted if files are added/removed.
Whitespace is not preserved.
\o No IDE support for adding files to include (\c .pri) files.
\o No IDE support for adding/removing sub-projects.
Project hierarchies (SUBDIRS template) have to be created by hand.
\o The file system sidebar does not update automatically.
As a workaround you can switch to another directory and then back.
\o The resource system of the embedded version of Qt Designer
does not interact with the project management.
\o Loading KDE4 designer plugins breaks the style, due to a bug in KDE.
\endlist
*/