I get data from website by Jsoup, about 60-70 rows of table and use that to create a ListView with subnames of team members. When I debug it's all ok but from nowhere appears to me NullPointerException. I think my code is good and this should not happen. At the error description I have a statement about skipped frames.
Error:
W/System.err: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean java.util.ArrayList.add(java.lang.Object)' on a null object reference
                  at com.example.adam.rozpiskimeczowe.offical.GetDataFromBeachPzps$1.onClick(GetDataFromBeachPzps.java:104)
W/System.err:     at android.view.View.performClick(View.java:6256)
                  at android.view.View$PerformClick.run(View.java:24779)
                  at android.os.Handler.handleCallback(Handler.java:789)
                  at android.os.Handler.dispatchMessage(Handler.java:98)
                  at android.os.Looper.loop(Looper.java:180)
                  at android.app.ActivityThread.main(ActivityThread.java:6944)
                  at java.lang.reflect.Method.invoke(Native Method)
                  at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:853)
I/Choreographer: Skipped 110 frames!  The application may be doing too much work on its main thread.
and my code:
public class GetDataFromBeachPzps extends AppCompatActivity {
    AlertDialog dialog;
    Button btnGetData;
    Document doc;
    String teams;
    //add
    int quantityOfTeam=0;
    ArrayList<String> names;
    CustomAdapter customAdapter;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_get_data_from_beach_pzps);
        //ADD LIST
        final ListView list = findViewById(R.id.getDataListView);
        list.setItemsCanFocus(true);
        //GET DATA FROM WEBSITE
        StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
        StrictMode.setThreadPolicy(policy);
        btnGetData = findViewById(R.id.getDataBtn);
        btnGetData.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //Selecja turnieju za pomocą numeru na końcu URL
                try {
                    Connection.Response res = Jsoup.connect("http://beach.pzps.pl/pl/site/login")
                            .data("LoginForm[email]", "adamandrys7@gmail.com", "LoginForm[password]", "66romek6")
                            .method(Connection.Method.POST)
                            .execute();
                    Map<String, String> loginCookies = res.cookies();
                    doc = Jsoup.connect("http://beach.pzps.pl/pl/tournament/793")
                            .cookies(loginCookies)
                            .get();
                    Element innerTable = doc.select(".items tbody").first();
                    Elements  rows = innerTable.select("tr");
                    for(Element row:rows) {
                        Elements cells = row.select("td:eq(4)");
                        /*for (Element cell : cells) {*/
                            //MOŻLIWA ZMIANA DO TURNIEJU TO JEST ZROBIONE PO ZAKOŃCZENIU TURNIEJU
                            teams =cells.text();
                        /*}*/
                        quantityOfTeam++;
                        //convert
                        teams = teams.replaceAll("\\(.*?\\)","");
                        String team1 =teams.split("/")[0];
                        String team2 =teams.split("/")[1];
                        team1 = team1.substring(indexOfFirstCapitalLetter(team1));
                        team2 = team2.substring(indexOfFirstCapitalLetter(team2));
                        team1 = team1.split(" ")[0];
                        team2 = team2.split(" ")[0];
                            names.add(team1);
                            names.add(team2);
                    }
                    customAdapter = new CustomAdapter(getApplicationContext());
                    list.setAdapter(customAdapter);
                } catch (Exception e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        });
    }
    class CustomAdapter extends BaseAdapter {
        private Context context;
        private String[] rValues = new String[quantityOfTeam];
        CustomAdapter(Context context) {
            this.context = context;
        }
        @Override
        public int getViewTypeCount() {
            return getCount();
        }
        @Override
        public int getItemViewType(int position) {
            return position;
        }
        @Override
        public int getCount() {
            return quantityOfTeam;
        }
        @Override
        public String getItem(int position) {
            return names.get(position) +"\n" + names.get(position + quantityOfTeam);
        }
        @Override
        public long getItemId(int position) {
            return 0;
        }
        @Override
        public View getView(final int position, View convertView, ViewGroup parent) {
            final ViewHolder holder;
            for(int i =0;i<quantityOfTeam;i++){
                rValues[i]="R"+(i+1);
            }
            if (convertView == null) {
                holder = new ViewHolder();
                LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                convertView = inflater.inflate(R.layout.brazylian_item_list, null, true);
                holder.editText = convertView.findViewById(R.id.brazItemListEditTextName1);
                holder.editText2 = convertView.findViewById(R.id.brazItemListEditTextName2);
                holder.textView = convertView.findViewById(R.id.brazItemListtextViewR);
                holder.editText.setText(names.get(position));
                holder.editText2.setText(names.get(position+quantityOfTeam));
                convertView.setTag(holder);
            } else {
                // the getTag returns the viewHolder object set as a tag to the view
                holder = (ViewHolder) convertView.getTag();
            }
            holder.textView.setText(rValues[position]);
            holder.editText.setOnFocusChangeListener(new View.OnFocusChangeListener() {
                @Override
                public void onFocusChange(View view, boolean b) {
                    if (!b) {
                        names.set(position, holder.editText.getText().toString()) ;
                    }
                }
            });
            holder.editText2.setOnFocusChangeListener(new View.OnFocusChangeListener() {
                @Override
                public void onFocusChange(View view, boolean b) {
                    if (!b) {
                        names.set(position + quantityOfTeam, holder.editText2.getText().toString());
                    }
                }
            });
            return convertView;
        }
        private class ViewHolder {
            protected EditText editText;
            protected EditText editText2;
            protected TextView textView;
        }
    }
    int indexOfFirstCapitalLetter(String str){
        for(int i=0;i<str.length();i++){
            if(Character.isUpperCase(str.charAt(i))) return i;
        }
        return -1;
    }
}
I don't know what I can do? I was looking on the internet but I did not find anything meaningful :(
 
     
     
    