使用来自 JSON 响应的数据填充 ExpandableListView

Question

我遇到了可展开列表视图的问题。我见过的所有关于父项的教程都只有一项。就我而言，我正在处理父母和孩子中的多个字段（名称和评论）。我应该如何进行？

我的 json 数据

[
{
    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: [ ]
}
]

还有我的评论活动代码

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");
    }

适配器

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;
    }

}

我尝试了几种方法来使这段代码工作，但都没有成功！

Answer 1

我添加了将解析 JSON 响应并为适配器填充数据的代码。这是一个完整的例子。但它需要一个带有名为“list”的 ExpandableListView 的 XML 文件。

我从另一个 stackoverflow 帖子中借用了一个基本适配器。它只显示基本文本，而不是整个对话。但这可能足以让您畅通无阻。但是您需要用您自己的视图替换简单的视图，例如：android.R.layout.simple_list_item_1。

在实际应用中，最好在 ASyncTask 中解析 JSON 数据。

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;
    }
}
}

以下是一些发出 HTTP 请求的示例： Using URLConnection

另外，您可能会考虑使用 Volley 框架： Volley

简单且非常流行的 HTTP 请求框架： OK HTTP

对于 Kotlin，我使用 Fuel： Fuel

注意，Stackoverflow 上关于下载项目的大多数答案都使用了一个名为 DefaultHttpClient 的类，它来自 Apache 库。 Google 决定在几个 Android 版本前删除 Apache 库。仍然可以通过调整 Gradle 文件来使用它们，但这仅适用于旧版应用程序。新应用程序应使用以下类：URLConnection。 Converting Apache to Current Android HTTP Classes