NullPointerException 和跳过 110 帧

Question

我通过 Jsoup 从网站获取数据，大约 60-70 行 table 并使用它来创建一个包含团队成员子名的 ListView。当我调试时，一切正常，但不知从哪里出现 NullPointerException。我认为我的代码很好，这不应该发生。在错误描述中，我有一个关于跳过帧的声明。

错误：

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.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.

和我的代码：

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;
    }

}

我不知道我能做什么？我在网上找，但没有找到任何有意义的东西:(

Answer 1

您没有初始化 names。您需要添加 names = new ArrayList<>(); 作为声明的一部分或在代码中使用它之前。如果您希望它只包含您检索到的两个团队的名称，请在 names.add(team1);.

之前添加该语句

Answer 2

跳过帧 与您的问题无关。 null object reference 未初始化导致的错误 names。

所以首先：

AlertDialog dialog;
Button btnGetData;
Document doc;
List<String> names = new ArrayList<>();

然后：

names.clear(); 
for(Element row:rows) {

NullPointerException 和跳过 110 帧

NullPointerException and Skipped 110 frames

android

listview

frames

nullpointerexception

jsoup