qt-everywhere-src-5.14.1/qtbase/examples/widgets/doc/src/licensewizard.qdoc

/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:FDL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** GNU Free Documentation License Usage
** Alternatively, this file may be used under the terms of the GNU Free
** Documentation License version 1.3 as published by the Free Software
** Foundation and appearing in the file included in the packaging of
** this file. Please review the following information to ensure
** the GNU Free Documentation License version 1.3 requirements
** will be met: https://www.gnu.org/licenses/fdl-1.3.html.
** $QT_END_LICENSE$
**
****************************************************************************/

/*!
    \example dialogs/licensewizard
    \title License Wizard Example
    \ingroup examples-dialogs

    \brief The License Wizard example shows how to implement complex wizards in
    Qt.

    \image licensewizard-example.png Screenshot of the License Wizard example

    Most wizards have a linear structure, with page 1 followed by
    page 2 and so on until the last page. The
    \l{dialogs/classwizard}{Class Wizard} example shows how to create
    such wizards.

    Some wizards are more complex in that they allow different
    traversal paths based on the information provided by the user.
    The License Wizard example illustrates this. It provides five
    wizard pages; depending on which options are selected, the user
    can reach different pages.

    \image licensewizard-flow.png The License Wizard pages

    The example consists of the following classes:

    \list
    \li \c LicenseWizard inherits QWizard and implements a non-linear
       five-page wizard that leads the user through the process of
       choosing a license agreement.
    \li \c IntroPage, \c EvaluatePage, \c RegisterPage, \c
       DetailsPage, and \c ConclusionPage are QWizardPage subclasses
       that implement the wizard pages.
    \endlist

    \section1 The LicenseWizard Class

    The \c LicenseWizard class derives from QWizard and provides a
    five-page wizard that guides the user through the process of
    registering their copy of a fictitious software product. Here's
    the class definition:

    \snippet dialogs/licensewizard/licensewizard.h 1

    The class's public API is limited to a constructor and an enum.
    The enum defines the IDs associated with the various pages:

    \table
    \header \li Class name \li Enum value \li Page ID
    \row \li \c IntroPage \li \c Page_Intro \li 0
    \row \li \c EvaluatePage \li \c Page_Evaluate \li 1
    \row \li \c RegisterPage \li \c Page_Register \li 2
    \row \li \c DetailsPage \li \c Page_Details \li 3
    \row \li \c ConclusionPage \li \c Page_Conclusion \li 4
    \endtable

    For this example, the IDs are arbitrary. The only constraints are
    that they must be unique and different from -1. IDs allow us to
    refer to pages.

    \snippet dialogs/licensewizard/licensewizard.cpp 2

    In the constructor, we create the five pages, insert them into
    the wizard using QWizard::setPage(), and set \c Page_Intro to be
    the first page.

    \snippet dialogs/licensewizard/licensewizard.cpp 3
    \snippet dialogs/licensewizard/licensewizard.cpp 4

    We set the style to \l{QWizard::}{ModernStyle} on all platforms
    except \macos,

    \snippet dialogs/licensewizard/licensewizard.cpp 5
    \snippet dialogs/licensewizard/licensewizard.cpp 6

    We configure the QWizard to show a \uicontrol Help button, which is
    connected to our \c showHelp() slot. We also set the
    \l{QWizard::}{LogoPixmap} for all pages that have a header (i.e.,
    \c EvaluatePage, \c RegisterPage, and \c DetailsPage).

    \snippet dialogs/licensewizard/licensewizard.cpp 9
    \snippet dialogs/licensewizard/licensewizard.cpp 11
    \dots
    \snippet dialogs/licensewizard/licensewizard.cpp 13

    In \c showHelp(), we display help texts that are appropriate for
    the current page. If the user clicks \uicontrol Help twice for the same
    page, we say, "Sorry, I already gave what help I could. Maybe you
    should try asking a human?"

    \section1 The IntroPage Class

    The pages are defined in \c licensewizard.h and implemented in \c
    licensewizard.cpp, together with \c LicenseWizard.

    Here's the definition and implementation of \c{IntroPage}:

    \snippet dialogs/licensewizard/licensewizard.h 4
    \codeline
    \snippet dialogs/licensewizard/licensewizard.cpp 16

    A page inherits from QWizardPage. We set a
    \l{QWizardPage::}{title} and a
    \l{QWizard::WatermarkPixmap}{watermark pixmap}. By not setting
    any \l{QWizardPage::}{subTitle}, we ensure that no header is
    displayed for this page. (On Windows, it is customary for wizards
    to display a watermark pixmap on the first and last pages, and to
    have a header on the other pages.)

    \snippet dialogs/licensewizard/licensewizard.cpp 17
    \snippet dialogs/licensewizard/licensewizard.cpp 19

    The \c nextId() function returns the ID for \c EvaluatePage if
    the \uicontrol{Evaluate the product for 30 days} option is checked;
    otherwise it returns the ID for \c RegisterPage.

    \section1 The EvaluatePage Class

    The \c EvaluatePage is slightly more involved:

    \snippet dialogs/licensewizard/licensewizard.h 5
    \codeline
    \snippet dialogs/licensewizard/licensewizard.cpp 20
    \dots
    \snippet dialogs/licensewizard/licensewizard.cpp 21
    \dots
    \snippet dialogs/licensewizard/licensewizard.cpp 22

    First, we set the page's \l{QWizardPage::}{title}
    and \l{QWizardPage::}{subTitle}.

    Then we create the child widgets, create \l{Registering and Using
    Fields}{wizard fields} associated with them, and put them into
    layouts. The fields are created with an asterisk (\c
    *) next to their name. This makes them \l{mandatory fields}, that
    is, fields that must be filled before the user can press the
    \uicontrol Next button (\uicontrol Continue on \macos). The fields' values
    can be accessed from any other page using QWizardPage::field().

    Resetting the page amounts to clearing the two text fields.

    \snippet dialogs/licensewizard/licensewizard.cpp 23

    The next page is always the \c ConclusionPage.

    \section1 The ConclusionPage Class

    The \c RegisterPage and \c DetailsPage are very similar to \c
    EvaluatePage. Let's go directly to the \c ConclusionPage:

    \snippet dialogs/licensewizard/licensewizard.h 6

    This time, we reimplement QWizardPage::initializePage() and
    QWidget::setVisible(), in addition to
    \l{QWizardPage::}{nextId()}. We also declare a private slot:
    \c printButtonClicked().

    \snippet dialogs/licensewizard/licensewizard.cpp 18

    The default implementation of QWizardPage::nextId() returns
    the page with the next ID, or -1 if the current page has the
    highest ID. This behavior would work here, because \c
    Page_Conclusion equals 5 and there is no page with a higher ID,
    but to avoid relying on such subtle behavior, we reimplement
    \l{QWizardPage::}{nextId()} to return -1.

    \snippet dialogs/licensewizard/licensewizard.cpp 27

    We use QWizard::hasVisitedPage() to determine the type of
    license agreement the user has chosen. If the user filled the \c
    EvaluatePage, the license text refers to an Evaluation License
    Agreement. If the user filled the \c DetailsPage, the license
    text is a First-Time License Agreement. If the user provided an
    upgrade key and skipped the \c DetailsPage, the license text is
    an Update License Agreement.

    \snippet dialogs/licensewizard/licensewizard.cpp 28

    We want to display a \uicontrol Print button in the wizard when the \c
    ConclusionPage is up. One way to accomplish this is to reimplement
    QWidget::setVisible():

    \list
    \li If the page is shown, we set the \l{QWizard::}{CustomButton1} button's
       text to \uicontrol{\underline{P}rint}, we enable the \l{QWizard::}{HaveCustomButton1}
       option, and we connect the QWizard's \l{QWizard::}{customButtonClicked()}
       signal to our \c printButtonClicked() slot.
    \li If the page is hidden, we disable the \l{QWizard::}{HaveCustomButton1}
       option and disconnect the \c printButtonClicked() slot.
    \endlist

    \sa QWizard, {Class Wizard Example}, {Trivial Wizard Example}
*/