contextMenu dosent work and crash when played

Question

My code crashes in the line registerForContextMenu(lv);

Can you see the problem? i am stuck for hours.

i am trying to connect a listview i know its something small but i cant find it please need some help the code:

 protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_boss);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        datasource = new TableInfoDataSource(this);
        datasource.open();
        userPreferences = null;
        userPreferences = datasource.getAllPublications();
        lv = (ListView) findViewById(android.R.id.list);
        registerForContextMenu(lv); // for context menu!
        adapter = new CustomAdapter(Boss.this, R.layout.simple_list_item_2, userPreferences);
        lv.setAdapter(adapter);
        datasource.close();
        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
//                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
//                        .setAction("Action", null).show();
                Intent intent_employee = new Intent(Boss.this, BossAddJob.class);
                startActivity(intent_employee);
            }
        });


    }

    class CustomAdapter extends ArrayAdapter<TableInfo> {

        Context context;
        int layoutResourceId;
        ArrayList<TableInfo> data = null;
        private LayoutInflater mInflater;


        public CustomAdapter(Context context, int layoutResourceId, ArrayList<TableInfo> data) {
            super(context, layoutResourceId, data);
            this.layoutResourceId = layoutResourceId;
            this.context = context;
            this.data = data;
            this.mInflater = LayoutInflater.from(context);
        }

 @Override
    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
        super.onCreateContextMenu(menu, v, menuInfo);
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.context_menu, menu);
    }

    @Override
    public boolean onContextItemSelected(MenuItem item) {
        //final SharedPreferences.Editor editor = getSharedPreferences(MY_PREFS_NAME, MODE_PRIVATE).edit();
        AdapterView.AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo) item.getMenuInfo();

        switch (item.getItemId()) {
            case R.id.ViewInContextMenu:

                return true;

            case R.id.DeleteInContextMenu:

                return true;
            default:
                return super.onContextItemSelected(item);
        }

Possible duplicate of [What is a NullPointerException, and how do I fix it?](https://stackoverflow.com/questions/218384/what-is-a-nullpointerexception-and-how-do-i-fix-it) — Shubham Shukla, Jun 13 '17 at 20:33
@EvaZana I presume that your ListView is a field, correct? If so, initialize it like this instead: lv = (ListView) findViewById(R.id.list); — DaveNOTDavid, Jun 13 '17 at 20:36
its already initialize :lv = (ListView) findViewById(android.R.id.list); — Eva Zana, Jun 13 '17 at 20:39
@EvaZana Try getting rid of the "android" part, and leave it as "R.id.list". Does it compile? Because, based on the logcat error, your ListView is still null. — DaveNOTDavid, Jun 13 '17 at 20:46
i need to use android list it dosent work without or to configure a list in this activity — Eva Zana, Jun 13 '17 at 20:49
found the problem was configure of list in xml tnx for the help @DaveNOTDavid — Eva Zana, Jun 13 '17 at 20:53
@EvaZana No problem. Check out my answer as I explain it there. — DaveNOTDavid, Jun 13 '17 at 21:00

DaveNOTDavid · Accepted Answer · 2017-06-13T21:12:15.820

The problem lies in your ListView initialization:

lv = (ListView) findViewById(android.R.id.list);

... since you only use the "android" keyword for standard android features that come shipped with the SDK. That said you need to use only "R.id.list" instead which implies that you're referring to a resource file (layout XML file in this case) within your res directory assuming that you have the ListView configured properly in your layout, R.layout.activity_boss.

contextMenu dosent work and crash when played

1 Answers1