为什么从 ArrayAdapter 中的 ListView 中获取项目时会出错？

Question

我为 ListView 创建了一个 ArrayAdapter，并用 ArrayList 的值“msg”定义了元素的 TextView 文本，到目前为止一切正常，但是当我创建另一个元素，第一个元素将文本更改为新的“msg”值，有人知道错误吗？ (文由葡译英，如有翻译错误请见谅)

Class ListViewAdapter

public class ListViewAdapter extends ArrayAdapter
    {
        ArrayList<HashMap<Object,Object>> items;

        public ListViewAdapter(Context context,ArrayList<HashMap<Object,Object>> items)
            {
                super(context, R.xml.chat, items);

                this.items = items;
            }

        @Override
        public View getView(int position, View view, ViewGroup parent)
            {
                if (view == null)
                    {
                        view = LayoutInflater.from(getContext()).inflate(R.xml.chat, parent, false);
                    }

                TextView text_name = view.findViewById(R.id.text_name);
                TextView text_message = view.findViewById(R.id.text_message);

                text_message.setText(items.get(position).get("msg").toString());

                return view;
                
            }
            
    }

主要活动：

public class MainActivity extends Activity
    {
        public static ListView list_chat;
        public static EditText edit_message;
        public static Button button_send;

        public static ArrayList<HashMap<Object,Object>> list_map = new ArrayList<>();
        public static HashMap<Object,Object> user_map;
        public static HashMap<Object,Object> chat_map;
        public static HashMap<Object,Object> send_map;

        public static LayoutInflater inflaterChat;
        public static String BUILD;

        public static Texture texture;
        public static ListViewAdapter chatAdapter;

        @Override
        protected void onCreate(Bundle savedInstanceState)
            {
                super.onCreate(savedInstanceState);
                setContentView(R.layout.main);


                list_chat = findViewById(R.id.list_chat);
                edit_message = findViewById(R.id.edit_message);
                button_send = findViewById(R.id.button_send);

                BUILD = Build.ID.replace(".", "");

                chatAdapter = new ListViewAdapter(this, list_map);

                list_chat.setAdapter(chatAdapter);

                button_send.setOnClickListener(new View.OnClickListener()
                        {
                            public void onClick(View view)
                                {
                                    chat_map = new HashMap<>();

                                    chat_map.put("msg", edit_message.getText());

                                    list_map.add(chat_map);

                                    chatAdapter.notifyDataSetChanged();
                                }
                        });
            }
    }

Answer 1

我发现了错误，我把“getText()”放在一个HashMap值中，当ListView被更新时，它没有得到一个已经定义的值，而是再次执行了getText()命令Ex: Set String to “.getText ()”而不是“HashMap” 我的解决方案是获取字符串中的文本，然后使用该字符串设置 HashMap 的值

  HashMap<Object,Object> chat_map = new HashMap<>();
  String message = String.valueOf(edit_message.getText());

  chat_map.put("msg", message);

  list_chat_map.add(chat_map);

为什么从 ArrayAdapter 中的 ListView 中获取项目时会出错？

Why is there an error when getting an item from a ListView in an ArrayAdapter?

java

hashmap

android-arrayadapter