Question

这个问题是我早期的一个问题的后续问题，可以在这里找到：Android GSON: Parsing several different objects from the same response

我按照那里发布的答案，为我的JSON响应创建了4个单独的类。但是，在解析此响应时，会生成对象（或者我认为，因为没有发生解析错误），但是当试图找出这些对象的数据时，会发生NullPointers。

我的JSON响应如下：

    {
  "Home": {
    "Icon": [
      {
        "ScreenID": 533,
        "ScreenIndex": 1,
        "IconName": "mainIcon_news",
        "Title": "News",
        "FK_ModuleID": 6,
        "FormID": 567,
        "ModName": "News",
        "MediaType": "",
        "New_Icon": 0
      },
      {
        "ScreenID": 528,
        "ScreenIndex": 2,
        "IconName": "mainIcon_music",
        "Title": "Music",
        "FK_ModuleID": 3,
        "FormID": 562,
        "ModName": "Media",
        "MediaType": "Music",
        "New_Icon": 0
      }
    ],
    "Header": [
      {
        "ModHomeRotationID": 183,
        "image_url": "*****/Media/68/1216_5.jpg",
        "flg_RotationEnabled": false,
        "flg_RotateOnlyOnReturn": true,
        "flg_RotationRandomize": false,
        "flg_RotationDelayMS": 5000,
        "flg_RotationDelayFadeMS": 3000,
        "HomeRotationIndex": null
      }
    ],
    "Player": [
      {
        "MediaID": 1219,
        "Track_Name": "***",
        "song_url": "*****/Media/68/1219.mp3",
        "song_remote_url": null,
        "FileSize": 4700502
      },
      {
        "MediaID": 1220,
        "Track_Name": "**** ",
        "song_url": "*****/Media/68/1220.mp3",
        "song_remote_url": null,
        "FileSize": 4350222
      }
    ]
  }
}

我解析此响应的代码如下：

package com.mobowski.app.menusections;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import com.mobowski.app.json.WebService;

import com.mobowski.app.listitems.Item;
import com.google.gson.Gson;

import android.app.Activity;

import android.os.Bundle;

//import android.widget.Toast;

public class TestMain extends Activity {

    ArrayList<Item> items = new ArrayList<Item>();

    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        // setContentView(R.layout.mainlinks);
        retrieveLinks();

    }

    public void retrieveLinks() {
        // Instantiate the Web Service Class with he URL of the web service not
        // that you must pass

        WebService webService = new WebService(
                "http://editedduetosecurityreasons");

        // Pass the parameters
        Map<String, String> params = new HashMap<String, String>();
        params.put("iAppID", "59");
        params.put("iUserID", "1");
        params.put("strCulName", "");
        // params.put("var", "");

        // Get JSON response from server the "" are where the method name would
        // normally go if needed example
        // webService.webGet("getMoreAllerts", params);
        String response = webService.webGet("", params);
        System.out.println("Returns: " + response);

        try {

            Home collection = new Gson().fromJson(response, Home.class);

            for (Icon icon : collection.icons) {
                System.out.println(icon.title);
            }

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public class Home {

        public List<Icon> icons;
        public Header header;
        public Player player[];

        public List<Icon> getIcons() {
            return icons;
        }

        public void setIcons(List<Icon> icons) {
            this.icons = icons;
        }

        public Header getHeader() {
            return header;
        }

        public void setHeader(Header header) {
            this.header = header;
        }

        public Player[] getPlayer() {
            return player;
        }

        public void setPlayer(Player[] player) {
            this.player = player;
        }

        public Player getSinglePlayer(int i) {
            return player[i];
        }

        public Icon getSingleIcon(int i) {
            return icons.get(i);
        }
    }

    public class Icon {

        public int ScreenID;
        public int ScreenIndex;
        public String IconName;
        public String title;
        public int FK_ModuleID;
        public int FormID;
        public String ModName;
        public String MediaType;
        public int New_Icon;

        public int getScreenID() {
            return ScreenID;
        }

        public void setScreenID(int screenID) {
            ScreenID = screenID;
        }

        public int getScreenIndex() {
            return ScreenIndex;
        }

        public void setScreenIndex(int screenIndex) {
            ScreenIndex = screenIndex;
        }

        public String getIconName() {
            return IconName;
        }

        public void setIconName(String iconName) {
            IconName = iconName;
        }

        public String getTitle() {
            return title;
        }

        public void setTitle(String title) {
            this.title = title;
        }

        public int getFK_ModuleID() {
            return FK_ModuleID;
        }

        public void setFK_ModuleID(int fK_ModuleID) {
            FK_ModuleID = fK_ModuleID;
        }

        public int getFormID() {
            return FormID;
        }

        public void setFormID(int formID) {
            FormID = formID;
        }

        public String getModName() {
            return ModName;
        }

        public void setModName(String modName) {
            ModName = modName;
        }

        public String getMediaType() {
            return MediaType;
        }

        public void setMediaType(String mediaType) {
            MediaType = mediaType;
        }

        public int getNew_Icon() {
            return New_Icon;
        }

        public void setNew_Icon(int new_Icon) {
            New_Icon = new_Icon;
        }

    }

    public class Player {

        public int MediaID;
        public String Track_Name;
        public String song_url;
        public String song_remote_url;
        public int FileSize;

        public int getMediaID() {
            return MediaID;
        }

        public void setMediaID(int mediaID) {
            MediaID = mediaID;
        }

        public String getTrack_Name() {
            return Track_Name;
        }

        public void setTrack_Name(String track_Name) {
            Track_Name = track_Name;
        }

        public String getSong_url() {
            return song_url;
        }

        public void setSong_url(String song_url) {
            this.song_url = song_url;
        }

        public String getSong_remote_url() {
            return song_remote_url;
        }

        public void setSong_remote_url(String song_remote_url) {
            this.song_remote_url = song_remote_url;
        }

        public int getFileSize() {
            return FileSize;
        }

        public void setFileSize(int fileSize) {
            FileSize = fileSize;
        }

    }

    public class Header {

        public int ModHomeRotationID;
        public String image_url;
        public boolean flg_RotationEnabled;
        public boolean flg_RotateOnlyOnReturn;
        public boolean flg_RotationRandomize;
        public int flg_RorationDelayMS;
        public int flg_RotationDelayFadeMS;
        public int HomeRotationIndex;

        public int getModHomeRotationID() {
            return ModHomeRotationID;
        }

        public void setModHomeRotationID(int modHomeRotationID) {
            ModHomeRotationID = modHomeRotationID;
        }

        public String getImage_url() {
            return image_url;
        }

        public void setImage_url(String image_url) {
            this.image_url = image_url;
        }

        public boolean isFlg_RotationEnabled() {
            return flg_RotationEnabled;
        }

        public void setFlg_RotationEnabled(boolean flg_RotationEnabled) {
            this.flg_RotationEnabled = flg_RotationEnabled;
        }

        public boolean isFlg_RotateOnlyOnReturn() {
            return flg_RotateOnlyOnReturn;
        }

        public void setFlg_RotateOnlyOnReturn(boolean flg_RotateOnlyOnReturn) {
            this.flg_RotateOnlyOnReturn = flg_RotateOnlyOnReturn;
        }

        public boolean isFlg_RotationRandomize() {
            return flg_RotationRandomize;
        }

        public void setFlg_RotationRandomize(boolean flg_RotationRandomize) {
            this.flg_RotationRandomize = flg_RotationRandomize;
        }

        public int getFlg_RorationDelayMS() {
            return flg_RorationDelayMS;
        }

        public void setFlg_RorationDelayMS(int flg_RorationDelayMS) {
            this.flg_RorationDelayMS = flg_RorationDelayMS;
        }

        public int getFlg_RotationDelayFadeMS() {
            return flg_RotationDelayFadeMS;
        }

        public void setFlg_RotationDelayFadeMS(int flg_RotationDelayFadeMS) {
            this.flg_RotationDelayFadeMS = flg_RotationDelayFadeMS;
        }

        public int getHomeRotationIndex() {
            return HomeRotationIndex;
        }

        public void setHomeRotationIndex(int homeRotationIndex) {
            HomeRotationIndex = homeRotationIndex;
        }

    }

}

但是这段代码似乎不起作用。调用for (Icon icon : collection.icons) {时会出现nullpointer。当任何方法用于实际应该实现的任何项目时，会出现NullPointer，但Home对象除外。

我确信这意味着我做错了什么，但我不知道我做错了什么或在哪里。有人可以给我一些指示吗？

提前感谢任何愿意尝试的人

在尝试Venky的建议之后，现在数据似乎正在解析得更好。但是我仍然面临一个问题。在尝试解析Header对象时，LogCat向我显示以下错误：

com.google.gson.JsonParseException: Expecting object found: [{"ModHomeRotationID":162,"image_url":"***********/1020_5.jpg","flg_RotationEnabled":false,"flg_RotateOnlyOnReturn":true,"flg_RotationRandomize":false,"flg_RotationDelayMS":5000,"flg_RotationDelayFadeMS":3000,"HomeRotationIndex":null}]

我知道这意味着它希望收到一个对象，但却得到了一个数组。但是，我的代码是这样的：

    public class Header {
        List<Header_info> header;
    }

    public class Header_info {
        public int ModHomeRotationID;
        public String image_url;
        public boolean flg_RotationEnabled;
        public boolean flg_RotateOnlyOnReturn;
        public boolean flg_RotationRandomize;
        public int flg_RorationDelayMS;
        public int flg_RotationDelayFadeMS;

    public int HomeRotationIndex;
}

我对Icon对象使用了相同的方法，这些方法似乎解析得很好（没有错误）。有什么建议为什么这不适用于Header对象？它似乎与图标格式相同。

Answer 1

选中此GSON Response

使用JSONLint

验证上述回复

检查Logcat中的输出：由于使用Log命令打印输出：

相同类型的输出是Parsed，根据您的需要进行更改。

只需检查响应和群组对象

Java代码：

Gson gson = new Gson();
RecordResponse cashResponse = null;
try {
cashResponse = gson.fromJson(response_data, RecordResponse.class);
} 
catch (JsonSyntaxException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} 
catch (JsonIOException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
}
List<Result> results = cashResponse.response.groups;
for (Result cashResult : results){
for(Result_items rest : cashResult.items ){
    if(rest!=null && !rest.equals("")){
        Log.v("IDSSSSS", rest.name);
        Log.v("IDSSSSS", rest.id);
        Log.v("IDSSSSS", rest.location.distance);
        Log.v("IDSSSSS", rest.location.lat);
        Log.v("IDSSSSS", rest.location.lng);
        try{
            for(Result_category cat : rest.categories ){
                Log.v("category_icon", cat.id);
                Log.v("category_name", cat.icon);
                Log.v("category_id", cat.name);
            }
        }catch(Exception e){}

    }
}
}

用于获取数据的相应类文件：

 class RecordResponse{
    CashGamesContainer response;
 }

  class CashGamesContainer{
     List<Result> groups;
  }

 class Result{
 List<Result_items> items;
 }
 class Result_items{
    String id;
String name;
String verified;
Locations location;
Stats  stats;
List<Result_category> categories;
  }

 class Locations{
String address;
String lat;
String lng;
String distance;
  }

  class Stats{
String checkinsCount;
String usersCount;
String tipCount;
   }

   class Result_category{
   String id;
   String name;
   String icon;
   }

Android GSON：对象未填充，但不会发生错误

1 个答案: