Android notification don't appear

[kamelEddine]

hello , I have problem with android notification , i just copied the java and notificationClient class from qt notification example ,and register new type in my main

     qmlRegisterType<NotificationClient>("notification",1,0,"Notification");

of course i added

QT +=androidextras
ANDROID_PACKAGE_SOURCE_DIR = $$PWD/android-sources

and changed the package name in java code
this is the java code

package org.qtproject.example.androidpi;

import android.app.Notification;
import android.app.NotificationManager;
import android.content.Context;

public class NotificationClient extends org.qtproject.qt5.android.bindings.QtActivity
{
    private static NotificationManager m_notificationManager;
    private static Notification.Builder m_builder;
    private static NotificationClient m_instance;

    public NotificationClient()
    {
        m_instance = this;
    }

    public static void notify(String s)
    {
        if (m_notificationManager == null) {
            m_notificationManager = (NotificationManager)m_instance.getSystemService(Context.NOTIFICATION_SERVICE);
            m_builder = new Notification.Builder(m_instance);
            m_builder.setSmallIcon(R.drawable.icon);
            m_builder.setContentTitle("A message from Qt!");
        }

        m_builder.setContentText(s);
        m_notificationManager.notify(1, m_builder.build());
    }
}

when i compile all work fine but notification don't appear ,if you want more information i can give all the code