qt-creator/doc/src/qtquick/qtquick-app-tutorial.qdoc

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/*!
    \contentspage index.html
    \previouspage creator-tutorials.html
    \page creator-qml-application.html
    \nextpage creator-writing-program.html

    \title Creating a Qt Quick Application

    This tutorial uses built-in QML types and illustrates basic concepts of
    \l{Qt Quick}.

    This tutorial describes how to use \QC to implement Qt states and transitions. We use
    \l{Animation}{Qt example code} to
    create an application that displays a Qt logo that moves between three rectangles on the
    page when you click them.

    \image qmldesigner-tutorial.png "States and transitions example"

    For more information about using \QMLD, see
    \l{Developing Qt Quick Applications}.

    \section1 Creating the Project

    \list 1

        \li Select \gui{File > New File or Project > Applications >
            Qt Quick Application > Choose}.

        \li In the \gui{Name} field, type \b {Transitions}.

        \li In the \gui {Create in} field, enter the path for the project files.
            For example, \c {C:\Qt\examples}, and then click \gui{Next} (on
            Windows and Linux) or \gui Continue (on Mac OS).

        \li In the \gui {Qt Quick component set} field, select
            \gui {Qt Quick 2.0}.

            \note The QML types used in this example are also supported in
            Qt Quick 1.1. To create this example application for platforms that
            run Qt 4, select \gui {Qt Quick 1.1}.

        \li Select \l{glossary-buildandrun-kit}{kits} for running and building your project,
            and then click \gui{Next}.

            \note Kits are listed if they have been specified in \gui Tools >
            \gui Options > \gui {Build & Run} > \gui Kits.

        \li Select \gui Next in the following dialogs to use the default
            settings.

        \li Review the project settings, and click \gui{Finish} (on Windows and
            Linux) or \gui Done (on Mac OS) to create the project.

        \li Press \key {Ctrl+R} (or \key {Cmd+R}) to run the application.

    \endlist

    \QC generates a default QML file that you can modify to create the main view
    of the application.

    \image qmldesigner-tutorial-project.png "Transitions project in Edit mode"

    \section1 Creating the Main View

    The main view of the application displays a Qt logo in the top left corner
    of the screen and two empty rectangles.

    To use the states.png image in your application, you must copy it to the
    project directory (same subdirectory as the QML file) from the examples
    directory in the Qt installation directory. For example:
    \c {C:\Qt\Qt5.0.1\5.0.1\msvc2010\examples\declarative\animation\states}. The image appears
    in the \gui Resources pane. You can also use any other image or a QML
    type, instead.

    \list 1

        \li In the \gui Projects view, double-click the main.qml file
            to open it in the code editor.

        \li Click \gui Design to open the file in \QMLD.

            \image qmldesigner-tutorial-desing-mode.png "Transitions project in Design Mode"

        \li In the \gui Navigator pane, select \gui Text and press \key Delete to
            delete it.

        \li Select \gui Rectangle to edit its properties.

            \image qmldesigner-tutorial-page.png "Page properties"

        \list a

            \li In the \gui Id field, enter \e page, to be able to reference the
                rectangle from other places.

            \li In the \gui Color field, set the color to #343434.

            \li In the code editor, delete the \c {Qt.quit();} command.

        \endlist

        \li In the \gui Library view, \gui Resources tab, select states.png and
            drag and drop it to the canvas.

            \image qmldesigner-tutorial-user-icon.png "Image properties"

        \list a

            \li In the \gui Id field, enter \e icon.

            \li In the \gui Position field, set \gui X to 10 and \gui Y to 20.

        \endlist

        \li In the \gui Library view, \gui {QML Types} tab, select \gui Rectangle,
            drag and drop it to the canvas, and edit its properties.

            \image qmldesigner-tutorial-topleftrect.png "Rectangle properties"

        \list a

            \li In the \gui Id field, enter \e topLeftRect.

            \li In the \gui Size field, set \gui W and \gui H to 64, for the
                rectangle size to match the image size.

            \li In the \gui Color field, click the
                \inlineimage qmldesigner-transparent-button.png
                (\gui Transparent) button to make the rectangle transparent.

            \li In the \gui Border field, set the border color to #808080.

            \li In the \gui Rectangle group, \gui Border field, set the border
                width to 1.

                \note If the \gui Border field does not appear after you set the
                border color, try setting the border color to solid by clicking
                the
                \inlineimage qmldesigner-solid-color-button.png
                (\gui {Solid Color}) button.

            \li In the \gui Radius field, select 6 to create rounded corners for
                the rectangle.

            \li Click \gui {Layout}, and then click the top and left anchor
                buttons to anchor the rectangle to the top left corner of the
                page.

                \image qmldesigner-tutorial-topleftrect-layout.png "Layout tab"

            \li In the \gui Margin field, select 20 for the top anchor and 10
                for the left anchor.

        \endlist

        \li In the \gui Navigator pane, drag and drop the \gui {Mouse Area}
            from \e page to \e topLeftRect to make it apply only to the
            rectangle and not to the whole page.

        \li  Edit the \gui {Mouse Area} properties:

        \list a

            \li Click \gui {Layout}, and then click the
                \inlineimage qmldesigner-anchor-fill-screen.png
                (\gui {Fill to Parent}) button to anchor the mouse area to the
                rectangle.

            \li In the code editor, edit the pointer to the clicked expression
                in the mouse area, as illustrated by the following code
                snippet:

                \qml
                MouseArea {
                    anchors.fill: parent
                    onClicked: page.state = ''
                }
                \endqml

                The expression sets the state to the base state and returns the
                image to its initial position.

        \endlist

            The qml.main file should now look as follows:

            \snippet transitions/main.qml 0

        \li In the \gui Navigator pane, copy topLeftRect (by pressing
            \key {Ctrl+C}) and paste it to the canvas twice (by pressing
            \key {Ctrl+V}). \QC renames the new instances of the type
            topLeftRect1 and topLeftRect2.

        \li  Select topLeftRect1 and edit its properties:

        \list a

            \li In the \gui Id field, enter \e middleRightRect.

            \li In \gui {Layout}, select the vertical center anchor button and
                then the right anchor button to
                anchor the rectangle to the middle right margin of the screen.

            \li In the \gui Margin field, select 10 for the right anchor and 0
                for the vertical center anchor.

            \li In the code editor, add a pointer to a clicked expression to the
                mouse area. The following expression sets the state to
                \e State1:

                \c {onClicked: page.state = 'State1'}

                You will create State1 later.

        \endlist

        \li Select topLeftRect2 and edit its properties:

        \list a

            \li In the \gui Id field, enter \e bottomLeftRect.

            \li In \gui {Layout}, select the bottom and left anchor buttons to
                anchor the rectangle to the bottom left margin of the screen.

            \li In the \gui Margin field, select 20 for the bottom anchor and 10
                for the left anchor.

            \li In the code editor, add a pointer to a clicked expression to the
                mouse area. The following expression sets the state to
                \e State2:

                \c {onClicked: page.state = 'State2'}

                You will create State2 later.

            The qml.main file should now look as follows:

            \snippet transitions/main.qml 1

        \endlist

        \li Press \key {Ctrl+S} to save the changes.

        \li Press \key {Ctrl+R} to run the application.

    \endlist

    \image qmldesigner-tutorial.png "States and transitions example"

    You should see the Qt logo in the top left rectangle, and two additional
    rectangles in the center right and bottom left of the screen.

    You can now create additional states to add views to the application.

    \section1 Adding Views

    In the .qml file, you already created pointers to two additional states:
    State1 and State2. To create the states:

    \list 1

        \li Click the empty slot in the \gui States pane to create State1.

        \li Click the empty slot in the \gui States pane to create State2.

        \li In the code editor, bind the position of the Qt logo to the
            rectangle to make sure that the logo is displayed within the
            rectangle when the view is scaled on different sizes of screens. Set
            expressions for the x and y properties, as illustrated by the
            following code snippet:

            \snippet qml/states-properties.qml states

            \image qmldesigner-tutorial-state1.png "States"

            \note When you set the expressions, drag and drop is disabled for
            the icon in \QMLD.

        \li Press \key {Ctrl+R} to run the application.

    \endlist

    Click the rectangles to move the Qt logo from one rectangle to another.

    \section1 Adding Animation to the View

    Add transitions to define how the properties change when the Qt logo moves
    between states. The transitions apply animations to the Qt logo. For example,
    the Qt logo bounces back when it moves to the middleRightRect and eases into
    bottomLeftRect. Add the transitions in the code editor.

    \list 1

        \li In the code editor, add the following code to specify that when
            moving to State1, the x and y coordinates of the Qt logo change
            linearly over a duration of 1 second:

            \snippet qml/list-of-transitions.qml first transition

        \li You can use the Qt Quick toolbar for animation to change the easing
            curve type from linear to OutBounce:

        \list a

            \li Click \gui NumberAnimation in the code editor to display the
                \inlineimage qml-toolbar-indicator.png
                icon, and then click the icon to open the toolbar:

                \image qmldesigner-tutorial-quick-toolbar.png "Qt Quick toolbar for animation"

            \li In the \gui Easing field, select \gui Bounce.

            \li In the \gui Subtype field, select \gui Out.

        \endlist

        \li Add the following code to specify that when moving to State2, the x
            and y coordinates of the Qt logo change over a duration of 2
            seconds, and an InOutQuad easing function is used:

            \snippet qml/list-of-transitions.qml second transition

        \li Add the following code to specify that for any other state changes,
            the x and y coordinates of the Qt logo change linearly over a
            duration of 200 milliseconds:

            \snippet qml/list-of-transitions.qml default transition

        \li Press \key {Ctrl+R} to run the application.

    \endlist

    Click the rectangles to view the animated transitions.

    \section1 Example Code

    When you have completed the steps, the main.qml file should look as follows:

    \snippet transitions/main.qml 2

*/