Android：没有FCM的通知

Question

我已使用Firebase云消息传递（FCM）进行推送通知，但我想使用android服务而不是FCM。我该如何构建呢？

 import android.app.Activity;
    import android.app.NotificationManager;
    import android.app.PendingIntent;
    import android.content.Context;
    import android.content.Intent;
    import android.support.v4.app.NotificationCompat;
    import android.os.Bundle;
    import android.view.View;
    import android.widget.Button;

    public class MainActivity extends Activity {
        Button b1;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);

            b1 = (Button)findViewById(R.id.button);
            b1.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    addNotification();
                }
            });
        }

        private void addNotification() {
            NotificationCompat.Builder builder =
                    new NotificationCompat.Builder(this)
                            .setSmallIcon(R.mipmap.ic_launcher)
                            .setContentTitle("Notifications Example")
                            .setContentText("This is a test notification");

            Intent notificationIntent = new Intent(this, NotificationView.class);
            PendingIntent contentIntent = PendingIntent.getActivity(this, 0, notificationIntent,
                    PendingIntent.FLAG_UPDATE_CURRENT);
            builder.setContentIntent(contentIntent);

            // Add as notification
            NotificationManager manager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
            manager.notify(0, builder.build());
        }
    }

我想在不使用GCM和其他第三方库的情况下为Android应用构建推送通知服务。我想从我自己的应用程序服务器发送通知。