我正在 Android 中开发客户端-服务器项目。我需要从给定的 URL 解析 JSON 并将其放在 ExpandableListView 中。在 JSON 响应中，我正在获取包含数组的节点的数据。因此，我必须将主要的 JsonArray 放置到 ExpandableListView 中的组中。它工作正常。

我可以从 JSON 中找出有多少组，但是当我试图根据来自服务器的数据将 child 放入每个组时，问题就出现了。我的代码只将第一个 child 放在第一组中，但是当我点击第二个 child 时，它显示错误。

我需要将“ID”和“用户名”放在相应的组中(例如:电子邮件、传真、上传)。我的代码可以将一个 child 的信息放在一组中，但是当我单击第二组时，它崩溃了。我们将不胜感激任何形式的帮助。

那么，我的问题是，如何根据服务器数据动态创建组并将子数据放入每个子项中？

这是日志中的错误:

04-07 17:49:02.194: E/AndroidRuntime(13285): FATAL EXCEPTION: main
04-07 17:49:02.194: E/AndroidRuntime(13285): java.lang.IndexOutOfBoundsException: Invalid index 1, size is 1
04-07 17:49:02.194: E/AndroidRuntime(13285):    at java.util.ArrayList.throwIndexOutOfBoundsException(ArrayList.java:251)
04-07 17:49:02.194: E/AndroidRuntime(13285):    at java.util.ArrayList.get(ArrayList.java:304)
04-07 17:49:02.194: E/AndroidRuntime(13285):    at android.widget.SimpleExpandableListAdapter.getChildrenCount(SimpleExpandableListAdapter.java:255)
04-07 17:49:02.194: E/AndroidRuntime(13285):    at android.widget.ExpandableListConnector.refreshExpGroupMetadataList(ExpandableListConnector.java:561)
04-07 17:49:02.194: E/AndroidRuntime(13285):    at android.widget.ExpandableListConnector.expandGroup(ExpandableListConnector.java:682)
04-07 17:49:02.194: E/AndroidRuntime(13285):    at android.widget.ExpandableListView.handleItemClick(ExpandableListView.java:561)
04-07 17:49:02.194: E/AndroidRuntime(13285):    at android.widget.ExpandableListView.performItemClick(ExpandableListView.java:521)
04-07 17:49:02.194: E/AndroidRuntime(13285):    at android.widget.AbsListView$PerformClick.run(AbsListView.java:2514)
04-07 17:49:02.194: E/AndroidRuntime(13285):    at android.widget.AbsListView$1.run(AbsListView.java:3168)
04-07 17:49:02.194: E/AndroidRuntime(13285):    at android.os.Handler.handleCallback(Handler.java:605)
04-07 17:49:02.194: E/AndroidRuntime(13285):    at android.os.Handler.dispatchMessage(Handler.java:92)
04-07 17:49:02.194: E/AndroidRuntime(13285):    at android.os.Looper.loop(Looper.java:137)
04-07 17:49:02.194: E/AndroidRuntime(13285):    at android.app.ActivityThread.main(ActivityThread.java:4424)
04-07 17:49:02.194: E/AndroidRuntime(13285):    at java.lang.reflect.Method.invokeNative(Native Method)
04-07 17:49:02.194: E/AndroidRuntime(13285):    at java.lang.reflect.Method.invoke(Method.java:511)

JSON 响应

{   "email":[   
    {"ID":"123","username":"dipakadmin"},
    {"ID":"3233","username":"raju"},
    {"ID":"5445","username":"hussain"}
    ]
,
"fax":[ 
    {"ID":"6665","username":"mohammad"},
    {"ID":"9877","username":"raj"},
    {"ID":"87655","username":"aryan"}
    ]
,
"upload":
    [   
    {"ID":"132322","username":"raja"},
    {"ID":"544333","username":"bala"},
    ]
}

这只是一个 JSON 响应的例子。真实的回复有很多标签。

ExpandableListActivity 的代码示例如下:

package com.ExpandableListActivity;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.ExpandableListActivity;
import android.os.Bundle;
import android.util.Log;
import android.widget.SimpleExpandableListAdapter;
import android.widget.TextView;

public class DocumentCenter extends ExpandableListActivity {

    public static JSONObject  jsonDocu=null;
    JSONArray jArray = null;
    JSONObject json_data = null;
    JSONObject root = null;

    List<List<Map<String, String>>> childs;

    List<Map<String, String>> child1;
    List<Map<String, String>> child2;
    List<Map<String, String>> child3;
    SimpleExpandableListAdapter adapter;

    Map<String, String> childdata1;

    public static String url3=null;
    String strEmailNull=null;
    String strFaxNull=null;
    String strUploadNull=null;
    public String user=null;
    TextView txtMLSID;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main2);

        user= TabBarExample.getJsonUser;
        Log.e("log_tag","USERNAME On Document : "+user); 

        List<Map<String, String>> groups = new ArrayList<Map<String, String>>();

        child1 = new ArrayList<Map<String, String>>();
        child2 = new ArrayList<Map<String, String>>();
        child3 = new ArrayList<Map<String, String>>();  

        url3 ="xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
        Log.e("log_tag","URL on DOCUMENT : "+url3); 
        try {
            jsonDocu = JSONfunctions1.getJSONfromURL(url3);
            JSONArray ary = jsonDocu.names();

            Log.e("log_tag","ary : "+ary .toString()); 

            for (int i1 = 0; i1 < ary.length(); i1++) {
                String value =      ary.get(i1).toString();
                Log.e("log_tag","value : "+value); 
                strEmailNull=   jsonDocu.getString(value);
                if (!strEmailNull.equals("null")){
                    try{
                        Map<String, String> group1 = new HashMap<String, String>();
                        group1.put("group", value);
                        //group1.put("group", value+(i1+1));
                        groups.add(group1);

                        JSONArray  email = jsonDocu.getJSONArray(value);
                        for(int i=0;i<email.length() ;i++){                     
                            childdata1 = new HashMap<String, String>();

                            JSONObject e = email.getJSONObject(i+1);
                            childdata1.put("child", e.getString("ID"));
                            childdata1.put("child1",  "Name:  "+e.getString("name"));
                            childdata1.put("child2", "Size:  "+e.getString("size"));
                            childdata1.put("child3",  "Update:  "+e.getString("lastUpdate"));

                            child1.add(childdata1); 
                            childs = new ArrayList<List<Map<String, String>>>();
                        }
                    }catch(JSONException e){
                        Log.e("log_tag", "Error parsing data "+e.toString());
                    }
                }
            }
            childs.add(child1);
        } catch (JSONException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        adapter = new SimpleExpandableListAdapter(
            this, groups, R.layout.groups2, new String[] { "group" },
            new int[] { R.id.group }, childs, R.layout.childs2,
            new String[] { "child1","child2" ,"child3"}, new int[] { R.id.child1, R.id.child2, R.id.child3});
        setListAdapter(adapter);
    }

    @Override
    public boolean setSelectedChild(int groupPosition, int childPosition,
        boolean shouldExpandGroup) {
        //do something
        Log.e("log_tag","setSelectedChild: "); 
        return super.setSelectedChild(groupPosition, childPosition,
            shouldExpandGroup);
    }

    @Override
    public void setSelectedGroup(int groupPosition) {
        //do something

        Log.e("log_tag","setSelectedGroup: "); 
        super.setSelectedGroup(groupPosition);
    }
}

最佳答案

下面是我的做法。当然，您可以像解析一样使用解析。但是，我会使用 jackson 库并根据响应创建一个对象类，并使用 ObjectMapper，它看起来更优雅并且可以节省您的解析时间。您可以根据需要在此处添加更多字段，例如内部传真和电子邮件类和列表:

public class ResponseObject {

private List<Email> email;

/**
 * @return the email
 */
public List<Email> getEmail() {
    return email;
}

/**
 * @param email
 *            the email to set
 */
public void setEmail(List<Email> email) {
    this.email = email;
}

public static class Email {
    private Integer ID;
    private String username;

    /**
     * @return the ID
     */
    public Integer getID() {
        return ID;
    }

    /**
     * @param ID
     *            the ID to set
     */
    public void setID(Integer ID) {
        ID = ID;
    }

    /**
     * @return the username
     */
    public String getUsername() {
        return username;
    }

    /**
     * @param username
     *            the username to set
     */
    public void setUsername(String username) {
        this.username = username;
    }
}
}

然后像这样使用 BaseExpandableListAdapter，根据需要进行更改和添加 View :

import java.util.ArrayList;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;

public class ResponseAdapter extends BaseExpandableListAdapter {
private ArrayList<ResponseObject> responseList = new ArrayList<ResponseObject>();

public ResponseAdapter(ArrayList<ResponseObject> responseObject) {
    this.responseList = responseObject;
}

@Override
public Object getChild(int groupPosition, int childPosition) {
    // TODO Auto-generated method stub
    return null;
}

@Override
public long getChildId(int groupPosition, int childPosition) {
    // TODO Auto-generated method stub
    return 0;
}

@Override
public View getChildView(int groupPosition, int childPosition,
        boolean isLastChild, View convertView, ViewGroup parent) {
    int ID = responseList.get(groupPosition).getEmail().get(childPosition)
            .getID();
    String username = responseList.get(groupPosition).getEmail()
            .get(childPosition).getUsername();
    return null;
}

@Override
public int getChildrenCount(int groupPosition) {
    return responseList.get(groupPosition).getEmail().size();
}

@Override
public Object getGroup(int groupPosition) {
    // TODO Auto-generated method stub
    return null;
}

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

@Override
public long getGroupId(int groupPosition) {
    // TODO Auto-generated method stub
    return 0;
}

@Override
public View getGroupView(int groupPosition, boolean isExpanded,
        View parent, ViewGroup viewGroup) {
    // Email group goes here
    return null;
}

@Override
public boolean hasStableIds() {
    // TODO Auto-generated method stub
    return false;
}

@Override
public boolean isChildSelectable(int arg0, int arg1) {
    // TODO Auto-generated method stub
    return false;
}

}

关于android - 如何在 android 中从 json 动态创建可扩展 ListView 中的组和子项？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/10054711/