be15856f61
Change copyrights and license headers from Nokia to Digia Change-Id: If1cc974286d29fd01ec6c19dd4719a67f4c3f00e Reviewed-by: Lars Knoll <lars.knoll@digia.com> Reviewed-by: Sergio Ahumada <sergio.ahumada@digia.com>
95 lines
4.4 KiB
Plaintext
95 lines
4.4 KiB
Plaintext
/****************************************************************************
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**
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** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies).
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** Copyright (C) 2012 Rick Stockton <rickstockton@reno-computerhelp.com>
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** Contact: http://www.qt-project.org/legal
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**
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** This file is part of the documentation of the Qt Toolkit.
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**
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** $QT_BEGIN_LICENSE:FDL$
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** Commercial License Usage
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** Licensees holding valid commercial Qt licenses may use this file in
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** accordance with the commercial license agreement provided with the
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** Software or, alternatively, in accordance with the terms contained in
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** a written agreement between you and Digia. For licensing terms and
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** conditions see http://qt.digia.com/licensing. For further information
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** use the contact form at http://qt.digia.com/contact-us.
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**
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** GNU Free Documentation License Usage
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** Alternatively, this file may be used under the terms of the GNU Free
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** Documentation License version 1.3 as published by the Free Software
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** Foundation and appearing in the file included in the packaging of
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** this file. Please review the following information to ensure
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** the GNU Free Documentation License version 1.3 requirements
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** will be met: http://www.gnu.org/copyleft/fdl.html.
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** $QT_END_LICENSE$
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**
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****************************************************************************/
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/*!
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\example widgets/mousebuttons
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\title Mouse Button Tester
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\brief The 'Mouse Button Tester' example demonstrates how to reimplement
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mouse events within a custom class. You can also use this program to
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verify that Qt is actually receiving mouse events from your mouse.
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Many 'gamer' mouse devices are configured with high-numbered "buttons"
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sending text shortcuts for certain games. With such a mouse, no mouse
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button events occur: The "mouse" sends keystrokes, and the
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'Mouse Button Tester' Window will not see the event. Receiving no event,
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it will not repaint the Window with new text describing a button event.
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And so, in addition to it's use as Qt example code, the program may be
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useful s a mouse device tester. Note that there is another example
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mouse buttons example which provides the same function, written in QML.
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This program (the Widget-based example) consists of three classes,
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in addition to the main() parent program:
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\list
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\li \c A QPushButton, "Quit".
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\li \c ButtonTester. This is derived from Qt's TextArea class, for
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purpose of customizing/re-implementing the mouse and wheel event
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member functions.
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\li \c A simple QVBoxLayout layout.
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\endlist
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First we will review the main program, with it's layout and "Quit"
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QPushButton. Then we will take a look at the \c ButtonTester class.
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\section1 The Main Program
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Note that the QPushButton, "Quit", is defined directly within the main()
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program, rather than another class. This is a correct way of defining a
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"Quit" QPushButton: A "Quit" Button defined inside another
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class would result in the destructor of that second class being
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called twice. This "Quit" Button uses the traditional Signal/Slot
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connection to invoke termination of the QApp, which will properly destroy
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its child classes before terminating itself.
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The remainder of the main() program is concerned with defining the layout,
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and applying a minimum size to the customized ButtonTester.
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\section1 ButtonTester Class Definition
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The \c ButtonTester class inherits from QTextEdit, and listens for
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mouse events on all possible Qt::MouseButton values. It also listens for
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wheel events from the mouse, and indicates the direction of wheel motion
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("up", down", "left", or "right"). It prints short debug messages into
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the Window, and also on the console QDebug() stream, when mouse button
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and wheel events occur. Our reimplementation of mousePressEvent(),
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mouseReleaseEvent(), mouseDoubleClickEvent(), and wheelEvent() "drive"
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the program; the other functions simply convert the Qt::MouseButton
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values into text strings.
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You should call the ignore() function on any mouse event (or other event)
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which your widget-based classes do not use and consume. This function
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assures that Qt will propagate the event through each parent widget,
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until it is used or propagated to the Window Manager. (Qt attempts to do
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this automatically, but it is better programming practice to explicitly
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invoke the function.)
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\image mousebutton-buttontester.png
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*/
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