diff options
Diffstat (limited to 'doc/src/windows-and-dialogs/mainwindow.qdoc')
| -rw-r--r-- | doc/src/windows-and-dialogs/mainwindow.qdoc | 279 |
1 files changed, 279 insertions, 0 deletions
diff --git a/doc/src/windows-and-dialogs/mainwindow.qdoc b/doc/src/windows-and-dialogs/mainwindow.qdoc new file mode 100644 index 0000000..e0134a4 --- /dev/null +++ b/doc/src/windows-and-dialogs/mainwindow.qdoc @@ -0,0 +1,279 @@ +/**************************************************************************** +** +** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). +** Contact: Nokia Corporation (qt-info@nokia.com) +** +** This file is part of the documentation of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** No Commercial Usage +** This file contains pre-release code and may not be distributed. +** You may use this file in accordance with the terms and conditions +** contained in the either Technology Preview License Agreement or the +** Beta Release License Agreement. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 2.1 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 2.1 requirements +** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** In addition, as a special exception, Nokia gives you certain +** additional rights. These rights are described in the Nokia Qt LGPL +** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this +** package. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3.0 as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU General Public License version 3.0 requirements will be +** met: http://www.gnu.org/copyleft/gpl.html. +** +** If you are unsure which license is appropriate for your use, please +** contact the sales department at http://qt.nokia.com/contact. +** $QT_END_LICENSE$ +** +****************************************************************************/ + +/*! + \group mainwindow-classes + \title Main Window and Related Classes +*/ + +/*! + \page application-windows.html + \title Application Windows and Dialogs + \ingroup frameworks-technologies + + \nextpage The Application Main Window + + A \l{Widgets}{widget} that is not embedded in a parent widget is called a window. + Usually, windows have a frame and a title bar, although it is also possible to create + windows without such decoration using suitable window flags). In Qt, QMainWindow + and the various subclasses of QDialog are the most common window types. + + In applications, windows provide the screen space upon which the user + interface is built. Windows separate applications visually from each other + and usually provide a window decoration that allows the user to resize and + position the applications according to his preferences. Windows are typically + integrated into the desktop environment and to some degree managed by the + window management system that the desktop environment provides. For instance, + selected windows of an application are represented in the task bar. + + \section1 Primary and Secondary Windows + + Any QWidget that has no parent will become a window, and will on most platforms + be listed in the desktop's task bar. This is usually only wanted for one + window in the application, the \e{primary window}. + + In addition, a QWidget that has a parent can become a window by setting the + \l{Qt::WindowType}{Qt::WA_Window} flag. Depending on the window management system + such \e{secondary windows} are usually stacked on top of their respective parent + window, and not have a task bar entry of their own. + + The QMainWindow and the QDialog classes set the Qt::WA_Window flag in their + constructor, as they are designed to be used as windows and provide facilities + that are not wanted for child widgets. + + \section1 Main Windows and Dialogs + + \l{The Application Main Window} provides the framework for building the + application's main user interface, and are created by subclassing QMainWindow. + QMainWindow has its own layout to which you can add a \l{QMenuBar}{menu bar}, + \l{QToolBar}{tool bars}, \l{QDockWidget}{dockable widgets} and a + \l{QStatusBar}{status bar}. The center area can be occupied by any kind of + QWidget. + + \l{Dialog Windows} are used as secondary windows that present the user with + options and choices. Dialogs are created by subclassing QDialog and using + \l{Widgets and Layouts}{widgets and layouts} to implement the user interface. + In addition, Qt provides a number of ready-made standard dialogs that can be + used for standard tasks like file or font selection. + + Both main windows and dialogs can be created with \QD, Qt's visual design tool. + Using \QD is a lot faster than hand-coding, and makes it easy to test different + design ideas. Creating designs visually and reading the code generated by + \l{uic} is a great way to learn Qt! + + \keyword window geometry + \section1 Window Geometry + + QWidget provides several functions that deal with a widget's + geometry. Some of these functions operate on the pure client area + (i.e. the window excluding the window frame), others include the + window frame. The differentiation is done in a way that covers the + most common usage transparently. + + \list + \o \bold{Including the window frame:} + \l{QWidget::x()}{x()}, + \l{QWidget::y()}{y()}, + \l{QWidget::frameGeometry()}{frameGeometry()}, + \l{QWidget::pos()}{pos()}, and + \l{QWidget::move()}{move()}. + \o \bold{Excluding the window frame:} + \l{QWidget::geometry()}{geometry()}, + \l{QWidget::width()}{width()}, + \l{QWidget::height()}{height()}, + \l{QWidget::rect()}{rect()}, and + \l{QWidget::size()}{size()}. + \endlist + + Note that the distinction only matters for decorated top-level + widgets. For all child widgets, the frame geometry is equal to the + widget's client geometry. + + This diagram shows most of the functions in use: + \img geometry.png Geometry diagram + + \section2 X11 Peculiarities + + On X11, a window does not have a frame until the window manager + decorates it. This happens asynchronously at some point in time + after calling QWidget::show() and the first paint event the + window receives, or it does not happen at all. Bear in mind that + X11 is policy-free (others call it flexible). Thus you cannot + make any safe assumption about the decoration frame your window + will get. Basic rule: There's always one user who uses a window + manager that breaks your assumption, and who will complain to + you. + + Furthermore, a toolkit cannot simply place windows on the screen. All + Qt can do is to send certain hints to the window manager. The window + manager, a separate process, may either obey, ignore or misunderstand + them. Due to the partially unclear Inter-Client Communication + Conventions Manual (ICCCM), window placement is handled quite + differently in existing window managers. + + X11 provides no standard or easy way to get the frame geometry + once the window is decorated. Qt solves this problem with nifty + heuristics and clever code that works on a wide range of window + managers that exist today. Don't be surprised if you find one + where QWidget::frameGeometry() returns wrong results though. + + Nor does X11 provide a way to maximize a window. + QWidget::showMaximized() has to emulate the feature. Its result + depends on the result of QWidget::frameGeometry() and the + capability of the window manager to do proper window placement, + neither of which can be guaranteed. +*/ + +/*! + \page mainwindow.html + \title The Application Main Window + \brief Everything you need for a typical modern main application window, + including menus, toolbars, workspace, etc. + + \contentspage Application Windows and Dialogs + \nextpage Dialog Windows + + \tableofcontents + + \section1 Overview of the Main Window Classes + + These classes provide everything you need for a typical modern main + application window, like the main window itself, menu and tool bars, + a status bar, etc. + + \annotatedlist mainwindow-classes + + \section1 The Main Window Classes + + Qt 4 provides the following classes for managing main windows and + associated user interface components: + + \list + \o QMainWindow remains the central class around which applications + can be built. The interface to this class has been simplified, and + much of the functionality previously included in this class is now + present in the companion QDockWidget and QToolBar classes. + + \o QDockWidget provides a widget that can be used to create + detachable tool palettes or helper windows. Dock widgets keep track + of their own properties, and they can be moved, closed, and floated + as external windows. + + \o QToolBar provides a generic toolbar widget that can hold a + number of different action-related widgets, such as buttons, + drop-down menus, comboboxes, and spin boxes. The emphasis on a + unified action model in Qt 4 means that toolbars cooperate well + with menus and keyboard shortcuts. + \endlist + + \section1 Example Code + + Using QMainWindow is straightforward. Generally, we subclass + QMainWindow and set up menus, toolbars, and dock widgets inside + the QMainWindow constructor. + + To add a menu bar to the main window, we simply create the menus, and + add them to the main window's menu bar. Note that the + QMainWindow::menuBar() function will automatically create the menu bar + the first time it is called. You can also call + QMainWindow::setMenuBar() to use a custom menu bar in the main window. + + \snippet doc/src/snippets/code/doc_src_qt4-mainwindow.qdoc 0 + \dots + \snippet examples/mainwindows/menus/mainwindow.cpp 5 + \dots + + Once actions have been created, we can add them to the main window + components. To begin with, we add them to the pop-up menus: + + \snippet examples/mainwindows/menus/mainwindow.cpp 10 + \dots + \snippet examples/mainwindows/menus/mainwindow.cpp 11 + \dots + + The QToolBar and QMenu classes use Qt's action system to provide a + consistent API. In the above code, some existing actions were added to + the file menu with the QMenu::addAction() function. QToolBar also + provides this function, making it easy to reuse actions in different + parts of the main window. This avoids unnecessary duplication of work. + + We create a toolbar as a child of the main window, and add the desired + actions to it: + + \snippet examples/mainwindows/sdi/mainwindow.cpp 0 + \dots + \snippet doc/src/snippets/code/doc_src_qt4-mainwindow.qdoc 1 + + In this example, the toolbar is restricted to the top and bottom + toolbar areas of the main window, and is initially placed in the + top tool bar area. We can see that the actions specified by \c + newAct and \c openAct will be displayed both on the toolbar and in + the file menu. + + QDockWidget is used in a similar way to QToolBar. We create a + dock widget as a child of the main window, and add widgets as children + of the dock widget: + + \snippet doc/src/snippets/dockwidgets/mainwindow.cpp 0 + + In this example, the dock widget can only be placed in the left and + right dock areas, and it is initially placed in the left dock area. + + The QMainWindow API allows the programmer to customize which dock + widget areas occupy the four corners of the dock widget area. If + required, the default can be changed with the + QMainWindow::setCorner() function: + + \snippet doc/src/snippets/code/doc_src_qt4-mainwindow.qdoc 2 + + The following diagram shows the configuration produced by the above code. + Note that the left and right dock widgets will occupy the top and bottom + corners of the main window in this layout. + + \image mainwindow-docks-example.png + + Once all of the main window components have been set up, the central widget + is created and installed by using code similar to the following: + + \snippet doc/src/snippets/code/doc_src_qt4-mainwindow.qdoc 3 + + The central widget can be any subclass of QWidget. +*/ |