Android: context menu not displayed native

#include <QApplication>
#include <QMenuBar>
#include <QMenu>
#include <QAction>
#include <QPushButton>
#include <QVBoxLayout>
#include <QMainWindow>

int main( int argc, char* argv[] )
{
    QApplication app(argc, argv);
    
    QMainWindow wnd;
    wnd.setMenuBar( new QMenuBar( &wnd ) );

    wnd.menuBar()->addMenu( "File" )->addAction( "Hello World native action" )->setCheckable( true );

    QPushButton* button = new QPushButton( "Show menu", &wnd );
    wnd.setCentralWidget( button );

    QMenu contextMenu;
    QAction* action = contextMenu.addAction( "Hello World not native action" );

    QObject::connect( button, SIGNAL(clicked()), &contextMenu, SLOT(show()) );

    wnd.show();

    return app.exec();
}