qt-everywhere-src-5.15.1/qtandroidextras/examples/androidextras/musiclist/doc/src/qtandroidextras-example-musiclist.qdoc

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/*!
\title Qt JNI Music List
    \ingroup examples-qtandroidextras
    \example musiclist
    \brief Demonstrates how to exchange data from complex Java objects.

    \image musiclist.png

    This example demonstrates how to move around data from a Java ArrayList of
    objects over to Qt. The example uses Android APIs to retrieve a list of music
    tracks, and displays some information about them with QML.

    When the application starts, it displays a list of music tracks, showing the
    track name, artist, and duration.

    \include examples-run.qdocinc

    \section1 Create the Music Classes

    Let's create a Java class, \c MusicTrack, that defines some of the basic
    information about a track. In the Java side, create the following:

    \quotefromfile musiclist/android/src/org/qtproject/example/musiclist/MusicList.java
    \skipto class MusicTrack
    \printuntil /^\}/

    Create another class with the same variables or information on the C++ side.
    The definition for \c MusicTrack class is the following:

    \quotefromfile musiclist/musiclist.h
    \skipto class MusicTrack
    \printuntil };

    \note The \c MusicTrack class must be a \l{QObject}-derived class to be used
        with as a QML context property. For more information, see
        \l{Overview - QML and C++ Integration}{QML and C++ Integration}.

    \section1 Fetch the Music List

    To retrieve the music list, the Android APIs are used. Add the following method
    to find music tracks that are available on the system. This method returns
    an ArrayList of \c MusicTrack.

    \quotefromfile musiclist/android/src/org/qtproject/example/musiclist/MusicList.java
    \skipto package
    \printuntil /^\ {4}\}/
    \printline }

    Using the JNI helpers provided with Qt, call the previous method to
    first get an \l{QAndroidJniObject} containing an ArrayList of objects. In the
    C++ code, you need to go through the Java ArrayList and create a parallel list
    on C++. Add the following lines to do that:

    \quotefromfile musiclist/musiclist.cpp
    \skipto QAndroidJniObject
    \printuntil /^\ {4}\}/

    Then, add a function to return the resulted \l{QList}:

    \quotefromfile musiclist/musiclist.cpp
    \skipto MusicList::assembledMusicList
    \printuntil }

    To display the music list, create a \l{ListView} that uses the \l{QList}
    as a property. Register the property as follows:

    \quotefromfile musiclist/main.cpp
    \skipto MusicList
    \printuntil assembledMusicList

    In the QML code, define the model of the \l{ListView} as follows:

    \quotefromfile musiclist/main.qml
    \skipto model
    \printline model

    \sa {Qt for Android}, {Qt Android Extras}
*/