android.content.Context.getSystemService(java.lang.String)' on a null object reference

Question

when click button on 'listview', I want to use Push Notification. But there is Error..

'ListViewAdapter'

 public class ListViewAdapter extends BaseAdapter{
private Context con;
public ListViewAdapter(Context con) {
        this.con = con;
        getData("http://117.17.158.240/test/GpsSender.php");
    }
....
... 
 @Override
    public View getView(final int position, View convertView, final ViewGroup parent) {
        final int pos = position;
        final Context context = parent.getContext();

        if (convertView == null) {
            LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = inflater.inflate(com.satt.mjbus.R.layout.listview_item, parent, false);

        }
 final ImageButton btn = (ImageButton)convertView.findViewById(com.satt.mjbus.R.id.button);
        btn.setTag(position);
        btn.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                int poss = (Integer) v.getTag();
                int check_num = 0;

                btn.setSelected(true);
                if (check_num == 0) {
                    btn.setSelected(true);
                    check_num = 1;
                } else if (check_num == 1) {
                    btn.setSelected(false);
                    check_num = 0;
                }
                NotificationManager notificationManager = (NotificationManager) con.getSystemService(con.NOTIFICATION_SERVICE);
                Intent intent1 = new Intent(con.getApplicationContext(), ListViewAdapter.class); 

                Notification.Builder builder = new Notification.Builder(con.getApplicationContext());
                intent1.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP | Intent.FLAG_ACTIVITY_CLEAR_TOP);

                PendingIntent pendingNotificationIntent = PendingIntent.getActivity(con, 0, intent1, PendingIntent.FLAG_UPDATE_CURRENT);

                builder.setSmallIcon(R.drawable.bus)
                        .setTicker("HETT")
                        .setWhen(System.currentTimeMillis())
                        .setNumber(1)
                        .setContentTitle("푸쉬 제목")
                        .setContentText("푸쉬내용")
                        .setDefaults(Notification.DEFAULT_SOUND | Notification.DEFAULT_VIBRATE)
                        .setContentIntent(pendingNotificationIntent)
                        .setAutoCancel(true)
                        .setOngoing(true);

                notificationManager.notify(1, builder.build());

            }

        });
        btn.setFocusable(false);

....
}

And I got error is java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Object android.content.Context.getSystemService(java.lang.String)' on a null object reference

plz help..

Your context is null. Put the code of the activity or fragment when you're calling ListViewAdapter please — Dany Pop
– Dany Pop, Commented Jun 6, 2017 at 8:55

Abdul Saleem · Accepted Answer · 2018-09-12 16:03:48Z

2

Replace this line of code

LayoutInflater inflater = 
    (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);

with

LayoutInflater inflater = 
    (LayoutInflater) con.getSystemService(Context.LAYOUT_INFLATER_SERVICE);

edited Sep 12, 2018 at 16:03

Abdul Saleem

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answered Jun 6, 2017 at 8:55

Rohit

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3 Comments

B.Sung Over a year ago

it's not work.. Attempt to invoke virtual method 'java.lang.Object android.content.Context.getSystemService(java.lang.String)'

Rohit Over a year ago

remove this line too final Context context = parent.getContext();

B.Sung Over a year ago

i got it. thk you

Linh Nguyen · Accepted Answer · 2017-06-06 09:32:07Z

0

replace LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); with

LayoutInflater inflater = (LayoutInflater) con.getSystemService(Context.LAYOUT_INFLATER_SERVICE);

answered Jun 6, 2017 at 9:32

Linh Nguyen

1,2641 gold badge10 silver badges23 bronze badges

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