creator-mobile-app-tutorial.qdoc

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/*!
    \contentspage {Qt Creator Manual}
    \previouspage creator-writing-program.html
    \example accelbubble
    \nextpage {Using Qt Quick UI Forms}

    \title Creating a Mobile Application

    This tutorial describes developing Qt Quick applications for Android and iOS
    devices using Qt Quick Controls.
    We use \QC to implement a Qt Quick application
    that accelerates an SVG (Scalable Vector Graphics) image based on the
    changing accelerometer values.

    \image creator_android_tutorial_ex_app.png

    \section1 Setting up the Development Environment

    To be able to build the application for and run it on a mobile device, you must
    set up the development environment for the device platform and configure a
    connection between \QC and the mobile device.

    To develop for Android  devices, you must download and install
    the latest Android NDK and SDK, and update the SDK to get the API and tools
    needed for development. In addition, you must install the
    Java SE Development Kit (JDK) and Apache Ant. After you have installed all
    these tools, you must specify the paths to them in \QC.
    For detailed instructions, see \l{Qt for Android} and
    \l{Connecting Android Devices}.

    To develop for iOS devices, you must install Xcode and use it to configure
    a device. For this, you need an Apple developer account and iOS Developer
    Program certificate that you receive from Apple. For more information, see
    \l{Connecting iOS Devices}.

    \include creator-tutorial-create-qq-project.qdocinc qt quick application

    \section1 Creating the Accelbubble Main View

    The main view of the application displays an SVG bubble image that moves
    around the screen when you tilt the device.

    To use \l{accelbubble/Bluebubble.svg}{Bluebubble.svg} in your project,
    copy it to the project directory (same subdirectory as the QML file).
    The image appears in \uicontrol Resources. You can also use any other
    image or a QML type, instead.

    To create the UI in the \uicontrol Design mode:

    \list 1

        \li In the \uicontrol Projects view, double-click the MainForm.ui.qml
            file to open it in \QMLD.

        \li In the \uicontrol Navigator, select \uicontrol RowLayout and press
            \key Delete to delete it.

        \li In \uicontrol Library > \uicontrol {QML Types}, select
            \uicontrol Rectangle and drag and drop it to the \uicontrol Item in
            the navigator.

        \li Select the rectangle in the navigator to edit its properties:

            \list a

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

                \li Select the \uicontrol Layout tab, and then click
                    the \inlineimage anchor_fill.png
                    (\uicontrol {Fill to Parent}) button to anchor the rectangle
                    to the item.

            \endlist

        \li In \uicontrol Library > \uicontrol Resources, select Bluebubble.svg
            and drag and drop it to \e mainWindow in the navigator.

        \li In the \uicontrol Properties pane, \uicontrol Id field, enter
            \e bubble to be able to reference the image from other places.

        \li Select the \inlineimage export_unchecked.png
            (\uicontrol Export) button in the navigator to export the
            \e mainWindow and \e bubble as properties.

    \endlist

    We want to modify the properties of the bubble in ways that are not
    supported by \QMLD, and therefore we create a custom QML type for it:

    \list 1

        \li Select \uicontrol Edit to open MainForm.ui.qml in the code editor.

        \li Right-click \uicontrol Image and select \uicontrol Refactoring >
            \uicontrol {Move Component into Separate File}.

        \li In the \uicontrol {Component name} field, enter \e Bubble and
            select \uicontrol OK to create \e Bubble.qml.

    \endlist

    \QC creates a reference to Bubble.qml in MainForm.ui.qml.

    To check your code, you can compare MainForm.ui.qml with the
    \l{accelbubble/MainForm.ui.qml}{MainForm.ui.qml} example file and Bubble.qml
    with the \l{accelbubble/Bubble.qml}{Bubble.qml} example file.

    The UI is now ready and you can switch to editing the main.qml and
    Bubble.qml files in the \uicontrol Edit mode, as described in the
    following section.

    \section1 Moving the Bubble

    The new project wizard adds boilerplate code to the main.qml file to create
    menu items and push buttons. Modify the boilerplate code by removing
    obsolete code and by adding new code. You removed the push buttons from the
    UI Form, so you also need to remove the corresponding code from main.qml (or
    the application cannot be built).

    In the code editor, edit Bubble.qml to add properties that we will use to
    position the image:

    \quotefromfile accelbubble/Bubble.qml
    \skipto Image
    \printuntil }

    In the code editor, edit the main.qml to specify the application title, as
    illustrated by the following code snippet:

    \quotefromfile accelbubble/main.qml
    \skipto ApplicationWindow
    \printuntil title

    Use the bubble properties to position the image:

    \printuntil bubbleCenter

    Then set the x and y position of the image based on the new properties:

    \printuntil centerY
    \skipto /^\}/
    \printuntil }

    Then add code to move the bubble based on Accelerometer sensor values:

    \list 1
        \li Add the following import statement to main.qml:

            \code
            import QtSensors 5.5
            \endcode

        \li Add the \l{Accelerometer} type with the necessary properties:

            \quotefromfile accelbubble/main.qml
            \skipto Accelerometer
            \printuntil true
            \skipto }
            \printuntil }

        \li Add the following JavaScript functions that calculate the
            x and y position of the bubble based on the current Accelerometer
            values:

            \quotefromfile accelbubble/main.qml
            \skipto function
            \printuntil Math.atan(x
            \printuntil }

        \li Add the following JavaScript code for \c onReadingChanged signal of
            Accelerometer type to make the bubble move when the Accelerometer
            values change:

            \quotefromfile accelbubble/main.qml
            \skipto onReadingChanged
            \printuntil }

            We want to ensure that the position of the bubble is always within
            the bounds of the screen. If the Accelerometer returns not a number
            (NaN), the value is ignored and the bubble position is not updated.
        \li Add SmoothedAnimation behavior on the \c x and \c y properties of
            the bubble to make its movement look smoother.

            \quotefromfile accelbubble/main.qml
            \skipto Behavior
            \printuntil x
            \printuntil }
            \printuntil }
     \endlist

     \section1 Locking Device Orientation

     The device display is rotated by default when the device orientation
     changes between portrait and landscape. For this example, it would be
     better for the screen orientation to be fixed.

    To lock the orientation to portrait or landscape on Android, specify it in
    an AndroidManifest.xml that you can generate in \QC. For more information,
    see \l{Editing Manifest Files}.

    On iOS, you can lock the device orientation in a Info.plist file that you
    specify in the .pro file as the value of the QMAKE_INFO_PLIST variable.

    \section1 Adding Dependencies

    Update the accelbubble.pro file with the following library dependency
    information:

    \code
    QT += quick sensors svg xml
    \endcode

    On iOS, you must link to the above libraries statically, by adding the
    plugin names explicitly as values of the QTPLUGIN variable. Specify a
    qmake scope for iOS builds (which can also contain the QMAKE_INFO_PLIST
    variable):

    \code
    ios {
    QTPLUGIN += qsvg qsvgicon qtsensors_ios
    QMAKE_INFO_PLIST = Info.plist
    }
    \endcode

    After adding the dependencies, select \uicontrol Build > \uicontrol {Run qmake} to apply
    the changes to the Makefile of the project.

    \section1 Adding Resources

    You need to add the Bluebubble.svg image file to the application resources
    for deployment to mobile devices:

    \list 1

        \li In the \uicontrol Projects view, double-click the qml.qrc file to open it
            in the resource editor.

        \li Select \uicontrol Add to add Bluebubble.svg.

    \endlist

    \section1 Running the Application

    The application is complete and ready to be deployed to a device:

    \list 1

        \li Enable \e{USB Debugging} on the Android device or \e{developer mode}
            on the iOS device.

        \li Connect the device to the development PC.

    If you are using a device running Android v4.2.2, it should prompt you to
    verify the connection to allow USB debugging from the PC it is connected
    to. To avoid such prompts every time you connect the device, select the
    \uicontrol {Always allow from the computer} check box, and then select
    \uicontrol OK.

        \li To run the application on the device, press \key {Ctrl+R}.

    \endlist
*/