Retrofit2 Android：BEGIN_ARRAYが期待されていましたが、BEGIN_OBJECTが1行目の2行目$

Question

これは初めての問題ですが、Retrofit2では私の問題の解決策を見つけることができません。私はオンラインのチュートリアルに続き、うまくいった。私が自分のエンドポイントに同じコードを適用したとき、私はこの例外を受け取ります：java.lang.IllegalStateException: Expected BEGIN_ARRAY but was BEGIN_OBJECT at line 1 column 2 path $私はこれを解決する方法を知らない。

インタフェース：

public interface MyApiService { 

// Is this right place to add these headers? 
@Headers({"application-id: MY-APPLICATION-ID", 
     "secret-key: MY-SECRET-KEY", 
     "application-type: REST"}) 
@GET("Music") 
Call<List<Music>> getMusicList(); 



Retrofit retrofit = new Retrofit.Builder() 
     .baseUrl(MySettings.REST_END_POINT) 
     .addConverterFactory(GsonConverterFactory.create()) 
     .build(); 
} 

クライアントコード：

MyApiService service = MyApiService.retrofit.create(MyApiService.class); 
Call<List<Music>> call = service.getMusicList(); 
call.enqueue(new Callback<List<Music>>() { 

    @Override 
    public void onResponse(Call<List<Music>> call, Response<List<Music>> response) { 
     Log.e("MainActivity", response.body(). 
    } 

    @Override 
    public void onFailure(Call<List<Music>> call, Throwable t) { 
     Log.e("MainActivity", t.toString()); 
    } 
}); 

このペイロードでの作業このコード：

[ 
{ 
    "login": "JakeWharton", 
    "id": 66577, 
    "avatar_url": "https://avatars.githubusercontent.com/u/66577?v=3", 
    "gravatar_id": "", 
    "url": "https://api.github.com/users/JakeWharton", 
    "html_url": "https://github.com/JakeWharton", 
    "followers_url": "https://api.github.com/users/JakeWharton/followers", 
    "following_url": "https://api.github.com/users/JakeWharton/following{/other_user}", 
    "gists_url": "https://api.github.com/users/JakeWharton/gists{/gist_id}", 
    "starred_url": "https://api.github.com/users/JakeWharton/starred{/owner}{/repo}", 
    "subscriptions_url": "https://api.github.com/users/JakeWharton/subscriptions", 
    "organizations_url": "https://api.github.com/users/JakeWharton/orgs", 
    "repos_url": "https://api.github.com/users/JakeWharton/repos", 
    "events_url": "https://api.github.com/users/JakeWharton/events{/privacy}", 
    "received_events_url": "https://api.github.com/users/JakeWharton/received_events", 
    "type": "User", 
    "site_admin": false, 
    "contributions": 741 
}, 
{.... 

ではなく、1本付き：

{ 
"offset": 0, 
"data": [ 
    { 
     "filename": "E743_1458662837071.mp3", 
     "created": 1458662854000, 
     "publicUrl": "https://api.backendless.com/dbb77803-1ab8-b994-ffd8-65470fa62b00/v1/files/music/E743_1458662837071.mp3", 
     "___class": "Music", 
     "description": "", 
     "likeCount": 0, 
     "title": "hej Susanne. ", 
     "ownerId": "E743756F-E114-6892-FFE9-BCC8C072E800", 
     "updated": null, 
     "objectId": "DDD8CB3D-ED66-0D6F-FFA5-B14543ABC800", 
     "__meta": "{\"relationRemovalIds\":{},\"selectedProperties\":[\"filename\",\"created\",\"publicUrl\",\"___class\",\"description\",\"likeCount\",\"title\",\"ownerId\",\"updated\",\"objectId\"],\"relatedObjects\":{}}" 
    }, 
    {... 

予想だと、それが動作するようにするとしています方法です

マイミュージッククラス：

あなたが言う

public class Music { 

    private String ownerId; 
    private String filename; 
    private String title; 
    private String description; 
    private String publicUrl; 
    private int likeCount; 

    // Getters & Setters 

} 

Answer 1

「...このコードは、このペイロードで作業されています：この1に...ではなく」。実際には、エラーメッセージは、jsonをJavaオブジェクトに変換する際に、呼び出しがjsonの配列を期待していたが、代わりにオブジェクトを取得していることを示しています。

このコール：

@GET("Music") 
Call<List<Music>> getMusicList(); 

が、それはJSONで動作する理由です、Musicオブジェクトのリストを期待：JSON自体はあなたのMusicオブジェクトの配列であるため

[ 
    { 
    "login": "JakeWharton", 
    ... 
    }, 
    ... 
] 

（レトロフィットすることができますjson配列間をJavaリストに変換する）。 2番目のjsonの場合は、オブジェクトではなく、配列ではありません（[...]の欠落に気づく）。このためには、そのjsonにマップする別のモデルで別の呼び出しを作成する必要があります。モデル名をMusicListとしましょう。

@GET("Music") 
Call<MusicList> getMusicList(); 

（あなたが最初の呼び出しと、この1の両方を維持したい場合は、メソッド名を変更する必要があるかもしれないことに注意してください）：ここでは呼び出しは次のようになりますか。

MusicListモデルはこのような何か見ることができます：

public class MusicList { 
    @SerializedName("data") 
    private List<Music> musics; 
    // ... 
} 

を私はdata配列はMusicオブジェクトのリストであることを仮定しているが、私はjsonsが完全に異なっていることがわかりました。これも同様に適応する必要があるかもしれませんが、私はあなたがここで画像を取得すると思います。

Answer 2

private List<Message> messages = new ArrayList<>(); 

private void getInbox() { 
     ApiInterface apiService = 
       ApiClient.getClient().create(ApiInterface.class); 

     Call<List<Message>> call = apiService.getInbox(); 
     call.enqueue(new Callback<List<Message>>() { 
      @Override 
      public void onResponse(Call<List<Message>> call, Response<List<Message>> response) { 
       // clear the inbox 
       messages.clear(); 

       // add all the messages 
//     messages.addAll(response.body()); 

       // TODO - avoid looping 
       // the loop was performed to add colors to each message 

       mAdapter.notifyDataSetChanged(); 
       swipeRefreshLayout.setRefreshing(false); 
      } 

      @Override 
      public void onFailure(Call<List<Message>> call, Throwable t) { 
       Toast.makeText(getApplicationContext(), "Unable to fetch json: " + t.getMessage(), Toast.LENGTH_LONG).show(); 
      } 
     }); 
    } 


import retrofit2.Retrofit; 
import retrofit2.converter.gson.GsonConverterFactory; 

public class ApiClient { 
    public static final String BASE_URL = "http://api.androidhive.info/json/"; 
    private static Retrofit retrofit = null; 

    public static Retrofit getClient() { 
     if (retrofit == null) { 
      retrofit = new Retrofit.Builder() 
        .baseUrl(BASE_URL) 
        .addConverterFactory(GsonConverterFactory.create()) 
        .build(); 
     } 
     return retrofit; 
    } 
} 


import com.keshav.gmailretrofitexampleworking.models.Message; 

import java.util.List; 

import retrofit2.Call; 
import retrofit2.http.GET; 

public interface ApiInterface { 
    @GET("inbox.json") 
    Call<List<Message>> getInbox(); 
} 

======================================================= 
package com.keshav.gmailretrofitexampleworking.models; 

public class Message { 
    private int id; 
    private String from; 
    private String subject; 
    private String message; 
    private String timestamp; 
    private String picture; 
    private boolean isImportant; 
    private boolean isRead; 
    private int color = -1; 

    public Message() { 
    } 

    public int getId() { 
     return id; 
    } 

    public void setId(int id) { 
     this.id = id; 
    } 

    public String getFrom() { 
     return from; 
    } 

    public void setFrom(String from) { 
     this.from = from; 
    } 

    public String getSubject() { 
     return subject; 
    } 

    public void setSubject(String subject) { 
     this.subject = subject; 
    } 

    public String getMessage() { 
     return message; 
    } 

    public void setMessage(String message) { 
     this.message = message; 
    } 

    public String getTimestamp() { 
     return timestamp; 
    } 

    public void setTimestamp(String timestamp) { 
     this.timestamp = timestamp; 
    } 

    public boolean isImportant() { 
     return isImportant; 
    } 

    public void setImportant(boolean important) { 
     isImportant = important; 
    } 

    public String getPicture() { 
     return picture; 
    } 

    public void setPicture(String picture) { 
     this.picture = picture; 
    } 

    public boolean isRead() { 
     return isRead; 
    } 

    public void setRead(boolean read) { 
     isRead = read; 
    } 

    public int getColor() { 
     return color; 
    } 

    public void setColor(int color) { 
     this.color = color; 
    } 
} 

======================================= 
Response 
========================================= 
[ 
    { 
     "id": 1, 
     "isImportant": false, 
     "picture": "http://api.androidhive.info/json/google.png", 
     "from": "Google Alerts", 
     "subject": "Google Alert - android", 
     "message": "Now android supports multiple voice recogonization", 
     "timestamp": "10:30 AM", 
     "isRead": false 
    }, 
    { 
     "id": 2, 
     "isImportant": true, 
     "picture": "", 
     "from": "Amazon.in", 
     "subject": "Apple Macbook Pro", 
     "message": "Your Amazon.in Today's Deal Get Macbook Pro", 
     "timestamp": "9:20 AM", 
     "isRead": false 
    }, 
    { 
     "id": 3, 
     "isImportant": false, 
     "picture": "http://api.androidhive.info/json/imdb.png", 
     "from": "IMDB", 
     "subject": "Check out top rated movies this week", 
     "message": "Find out the top rated movies this week by editor choice", 
     "timestamp": "9:15 AM", 
     "isRead": false 
    }, 
    { 
     "id": 4, 
     "isImportant": false, 
     "picture": "https://scontent-frt3-1.xx.fbcdn.net/v/t1.0-1/p160x160/16298485_10208198778434887_8511207535440105240_n.jpg?oh=37c747b74709ff3bbdec6102c189cea5&oe=5929B733", 
     "from": "Dinesh Reddy, Me", 
     "subject": "Let's get started", 
     "message": "I started working on project proposals. Wanted to know", 
     "timestamp": "9:00 AM", 
     "isRead": true 
    }, 
    { 
     "id": 5, 
     "isImportant": false, 
     "picture": "", 
     "from": "BookMyShow", 
     "subject": "Will the lost boy find his family?", 
     "message": "LION a movie that humanity needs. Online version report spam 97%", 
     "timestamp": "8:55 AM", 
     "isRead": false 
    }, 
    { 
     "id": 6, 
     "isImportant": false, 
     "picture": "", 
     "from": "MakeMyTrip", 
     "subject": "A joyous Train Ride in North East!", 
     "message": "North East Package starting from Rs31,999/- only!", 
     "timestamp": "8:10 AM", 
     "isRead": false 
    }, 
    { 
     "id": 7, 
     "isImportant": false, 
     "picture": "", 
     "from": "Disqus 14", 
     "subject": "Re: Comment on Android Working with", 
     "message": "Hey Ravi, after following your article I am getting this error", 
     "timestamp": "8:10 AM", 
     "isRead": true 
    }, 
    { 
     "id": 8, 
     "isImportant": true, 
     "picture": "", 
     "from": "Evans, Ravi 3", 
     "subject": "Advertisement Enquiry", 
     "message": "Hello, I want to buy the advertising space on", 
     "timestamp": "7:59 AM", 
     "isRead": false 
    }, 
    { 
     "id": 9, 
     "isImportant": false, 
     "picture": "https://lh3.googleusercontent.com/9JKVlFDCj9VVIbI66z_JEXGXvQpUXc-EwXfDmYP9c-8Lwb6Bd_zZ9i6VygPpyXLj3PkNCtpmTvaKKw=w300-h300-rw-no", 
     "from": "Karthik Tamada", 
     "subject": "Call Me", 
     "message": "I am going home because I am not feeling well!", 
     "timestamp": "4:05 AM", 
     "isRead": false 
    }, 
    { 
     "id": 10, 
     "isImportant": false, 
     "picture": "", 
     "from": "Order-Update", 
     "subject": "Your Amazon order #408-2878882019", 
     "message": "Your Orders | Amazon.in shipment of pendrive", 
     "timestamp": "5:00 AM", 
     "isRead": true 
    }, 
    { 
     "id": 11, 
     "isImportant": false, 
     "picture": "", 
     "from": "Instapage", 
     "subject": "Lead notification from Instapage", 
     "message": "Congratulations! You just aquired a new lead", 
     "timestamp": "3:00 AM", 
     "isRead": false 
    }, 
    { 
     "id": 12, 
     "isImportant": false, 
     "picture": "", 
     "from": "Droid5", 
     "subject": "Droid5 Android Project", 
     "message": "Planning to start an android app for droid5", 
     "timestamp": "5:00 AM", 
     "isRead": false 
    }, 
    { 
     "id": 13, 
     "isImportant": true, 
     "picture": "", 
     "from": "Gmail Team", 
     "subject": "Gmail Business Suite", 
     "message": "Your Gmail business suite is expiring today!", 
     "timestamp": "Feb 20", 
     "isRead": true 
    }, 
    { 
     "id": 14, 
     "isImportant": false, 
     "picture": "", 
     "from": "Medium Daily Digest", 
     "subject": "6 Things You need to know to Recover", 
     "message": "Daily Digest Your daily three recommendations", 
     "timestamp": "8:15 AM", 
     "isRead": false 
    }, 
    { 
     "id": 15, 
     "isImportant": false, 
     "picture": "", 
     "from": "Alex, Ravi 24", 
     "subject": "Advertisement proposal to promote my android app", 
     "message": "Hello Ravi, Thanks for your link. Here is the proposal", 
     "timestamp": "Feb 17", 
     "isRead": false 
    } 
]