使用來自 JSON 響應的數據填充 ExpandableListView

Question

我的可擴展列表視圖有問題。 我見過的所有關於父項的教程都只有一項。 在我的情況下，我在父和子中處理多個字段（名稱和評論）。 我應該如何進行？

我的json數據

[
{
    nome: "Carlos",
    comentario: "Esse dia foi show",
    resp: [ ]
},
{
    nome: "Andre",
    comentario: "Acho que não precisava disso",
    resp: [
    {
        nome: "inutil",
        comentario: "Sempre assim"
    },
    {
        nome: "Roberto",
        comentario: "Se não estivessem fazendo nada errado, não iam querer apagar a mídia."
    },
    {
        nome: "xumbinho",
        comentario: "André ! Para vai!"
    }
    ]
},
{
    nome: "Celso",
    comentario: "É pra acabar mesmo",
    resp: [ ]
}
]

還有我的 CommentariosActivity 代碼

private void makejsonobjreq() {
        PD.show();

        JsonObjectRequest jsonObjReq = new JsonObjectRequest(Method.GET, url+"284901",
                null, response -> {
                    ArrayList<Group> list = new ArrayList<Group>();
                    ArrayList<Child> ch_list;

                    Log.d("response", String.valueOf(response));
                    try {
                        Iterator<String> key = response.keys();
                        while (key.hasNext()) {
                            String k = key.next();
                            Log.d("KEY", String.valueOf(k));

                            Group gru = new Group();
                            gru.setNome(k);
                            ch_list = new ArrayList<Child>();

                            JSONArray ja = response.getJSONArray(k);
                            Log.d("QNT", String.valueOf(ja.length()));

                            for (int i = 0; i < ja.length(); i++) {

                                JSONObject jo = ja.getJSONObject(i);

                                Child ch = new Child();
                                Log.d("COMENTARIO NOME",jo.getString("nome"));
                                ch.setNome(jo.getString("nome"));
                                ch.setComentario(jo.getString("comentario"));

                                ch_list.add(ch);
                            } // for loop end
                            gru.setItems(ch_list);
                            list.add(gru);
                        } // while loop end

                        ExpAdapter = new ExpandListAdapter(ComentariosActivity.this, list);
                        ExpandList.setAdapter(ExpAdapter);

                        PD.dismiss();

                    } catch (JSONException e) {
                        e.printStackTrace();
                    }
                }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                PD.dismiss();
                Log.d("response", String.valueOf(error));
            }
        });
        MyApplication.getInstance().addToRequestQueue(jsonObjReq, "jreq");
    }

適配器

package br.inf.cgn.cgnapp;

import java.util.ArrayList;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.TextView;
import com.android.volley.toolbox.ImageLoader;

import br.inf.cgn.cgnapp.model.Child;
import br.inf.cgn.cgnapp.model.Group;

public class ExpandListAdapter extends BaseExpandableListAdapter {

    private Context context;
    private ArrayList<Group> groups;

    ImageLoader imageLoader = MyApplication.getInstance().getImageLoader();

    public ExpandListAdapter(Context context, ArrayList<Group> groups) {
        this.context = context;
        this.groups = groups;
    }

    @Override
    public Object getChild(int groupPosition, int childPosition) {
        ArrayList<Child> chList = groups.get(groupPosition).getItems();
        return chList.get(childPosition);
    }

    @Override
    public long getChildId(int groupPosition, int childPosition) {
        return childPosition;
    }

    @Override
    public View getChildView(int groupPosition, int childPosition,
                             boolean isLastChild, View convertView, ViewGroup parent) {

        Child child = (Child) getChild(groupPosition, childPosition);
        if (convertView == null) {
            LayoutInflater infalInflater = (LayoutInflater) context
                    .getSystemService(context.LAYOUT_INFLATER_SERVICE);
            convertView = infalInflater.inflate(R.layout.comentarios_resp, null);
        }

        if (imageLoader == null)
            imageLoader = MyApplication.getInstance().getImageLoader();

        TextView nome = (TextView) convertView.findViewById(R.id.nome_resp);
        nome.setText(child.getNome().toString());

        TextView comentario = (TextView) convertView.findViewById(R.id.comentario_resp);
        comentario.setText(child.getComentario().toString());

        return convertView;
    }

    @Override
    public int getChildrenCount(int groupPosition) {
        ArrayList<Child> chList = groups.get(groupPosition).getItems();
        return chList.size();
    }

    @Override
    public Object getGroup(int groupPosition) {
        return groups.get(groupPosition);
    }

    @Override
    public int getGroupCount() {
        return groups.size();
    }

    @Override
    public long getGroupId(int groupPosition) {
        return groupPosition;
    }

    @Override
    public View getGroupView(int groupPosition, boolean isExpanded,
                             View convertView, ViewGroup parent) {
        Group group = (Group) getGroup(groupPosition);
        if (convertView == null) {
            LayoutInflater inf = (LayoutInflater) context
                    .getSystemService(context.LAYOUT_INFLATER_SERVICE);
            convertView = inf.inflate(R.layout.comentarios_list, null);
        }
        TextView nome = (TextView) convertView.findViewById(R.id.nome);
        nome.setText(group.getNome());
        TextView comentario = (TextView) convertView.findViewById(R.id.comentario);
        comentario.setText(group.getComentario());

        return convertView;
    }

    @Override
    public boolean hasStableIds() {
        return true;
    }

    @Override
    public boolean isChildSelectable(int groupPosition, int childPosition) {
        return true;
    }

}

我嘗試了幾種方法來使這段代碼工作，但沒有成功！

Answer 1

我添加了將解析 JSON 響應並填充適配器數據的代碼。 這是一個完整的例子。 但它需要一個帶有名為“list”的 ExpandableListView 的 XML 文件。

我從另一個 stackoverflow 帖子中借用了一個基本的適配器。 它只顯示基本文本，而不是整個對話。 但這可能足以讓您暢通無阻。 但是你需要用你自己的視圖替換簡單的視圖，比如：android.R.layout.simple_list_item_1。

在實際應用中，最好在 ASyncTask 中解析 JSON 數據。

package com.example.elletlar.myapplication;
import android.content.Context;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.ExpandableListView;
import android.widget.TextView;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {

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

    List<Group> list = getList();
    ExpAdapter adapter = new ExpAdapter(this, list);
    ExpandableListView listView = findViewById(R.id.lst);
    listView.setAdapter(adapter);
}

public class Group {
    String name;
    private List<Child> childList;

    void setChildList(List<Child> list) {
        childList = list;
    }
    List<Child> getChildList() {
        return childList;
    }
}

public class Child {
    String name;
    String comment;
}

private ArrayList<Group> getList() {
    ArrayList<Group> list = new ArrayList<>();
    JSONArray groupArr;
    try {
        String TEST = "[" +
                "{" +
                "nome: \"Carlos\"," +
                "                comentario: \"Esse dia foi show\"," +
                "            resp: [ ]" +
                "    }," +
                "    {" +
                "        nome: \"Andre\"," +
                "                comentario: \"Acho que não precisava disso\"," +
                "            resp: [" +
                "        {" +
                "            nome: \"inutil\"," +
                "                    comentario: \"Sempre assim\"" +
                "        }," +
                "        {" +
                "            nome: \"Roberto\"," +
                "                    comentario: \"Se não estivessem fazendo nada errado, não iam querer apagar a mídia.\"\n" +
                "        }," +
                "        {" +
                "            nome: \"xumbinho\"," +
                "                    comentario: \"André ! Para vai!\"" +
                "        }" +
                "    ]" +
                "    }" +
                "]";

        groupArr = new JSONArray(TEST);
        ArrayList<Child> childList;

        for (int i = 0; i < groupArr.length(); ++i) {
            JSONObject groupObj= groupArr.getJSONObject(i);
            Group group = new Group();
            group.name = groupObj.getString("nome");

            childList = new ArrayList<>();
            JSONArray replyArr = groupObj.getJSONArray("resp");
            for (int j = 0; j < replyArr.length(); ++j) {
                JSONObject childObj = replyArr.getJSONObject(j);
                Child child = new Child();
                child.name = (childObj.getString("nome"));
                child.comment = (childObj.getString("comentario"));
                childList.add(child);
            } // for loop end

            group.setChildList(childList);
            list.add(group);
        }
    } catch (JSONException e) {
        e.printStackTrace();
    }

    return list;
}

public class ExpAdapter extends BaseExpandableListAdapter {

    private final class ViewHolder {
        TextView textLabel;
    }

    private final List<Group> itemList;
    private final LayoutInflater inflater;

    private ExpAdapter(Context context, List<Group> itemList) {
        this.inflater = LayoutInflater.from(context);
        this.itemList = itemList;
    }

    @Override
    public Child getChild(int groupPosition, int childPosition) {

        return itemList.get(groupPosition).getChildList().get(childPosition);
    }

    @Override
    public long getChildId(int groupPosition, int childPosition) {
        return childPosition;
    }

    @Override
    public int getChildrenCount(int groupPosition) {
        return itemList.get(groupPosition).getChildList().size();
    }

    @Override
    public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView,
                             final ViewGroup parent) {
        View resultView = convertView;
        ViewHolder holder;

        if (resultView == null) {
            resultView = inflater.inflate(android.R.layout.simple_list_item_1, null); //TODO change layout id
            holder = new ViewHolder();
            holder.textLabel = resultView.findViewById(android.R.id.text1); //TODO change view id
            resultView.setTag(holder);
        } else {
            holder = (ViewHolder) resultView.getTag();
        }

        final Child item = getChild(groupPosition, childPosition);

        holder.textLabel.setText(item.name);

        return resultView;
    }

    @Override
    public Group getGroup(int groupPosition) {
        return itemList.get(groupPosition);
    }

    @Override
    public int getGroupCount() {
        return itemList.size();
    }

    @Override
    public long getGroupId(final int groupPosition) {
        return groupPosition;
    }

    @Override
    public View getGroupView(int groupPosition, boolean isExpanded, View theConvertView, ViewGroup parent) {
        View resultView = theConvertView;
        ViewHolder holder;

        if (resultView == null) {
            resultView = inflater.inflate(android.R.layout.simple_list_item_1, null);
            holder = new ViewHolder();
            holder.textLabel = resultView.findViewById(android.R.id.text1);
            resultView.setTag(holder);
        } else {
            holder = (ViewHolder) resultView.getTag();
        }

        final Group item = getGroup(groupPosition);

        holder.textLabel.setText(item.name);

        return resultView;
    }

    @Override
    public boolean hasStableIds() {
        return true;
    }

    @Override
    public boolean isChildSelectable(int groupPosition, int childPosition) {
        return true;
    }
}
}

以下是發出 HTTP 請求的一些示例： 使用 URLConnection

此外，您可能會考慮使用 Volley 框架： Volley

簡單且非常流行的 HTTP 請求框架： OK HTTP

對於 Kotlin，我使用 Fuel： Fuel

請注意，Stackoverflow 上關於下載項目的大多數答案都使用了一個名為：DefaultHttpClient 的類，該類來自 Apache 庫。 谷歌決定在幾個 Android 版本之前刪除 Apache 庫。 仍然可以通過調整 Gradle 文件來使用它們，但這僅適用於舊版應用程序。 新應用應使用類似以下的類：URLConnection。 將 Apache 轉換為當前的 Android HTTP 類