2017-10-12 105 views
0

我是新来改造和获取此错误(预计BEGIN_ARRAY,但BEGIN_OBJECT第1行第2列)在简单的HTTP获取请求。这里是code.Help me..`RETROFIT 2预计BEGIN_ARRAY,但是BEGIN_OBJECT在第1行第2列

主要活动

private ListView listView; 

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

    listView = (ListView) findViewById(R.id.pagination_list); 


    Retrofit.Builder builder = new Retrofit.Builder() 
      .baseUrl("https://www.googleapis.com/books/v1/") 
      .addConverterFactory(GsonConverterFactory.create()); 

    Retrofit retrofit = builder.build(); 

    String apiKey = getResources().getString(R.string.API_KEY); 

    GitHubClient client = retrofit.create(GitHubClient.class); 
    Call<List<Volumes>> call = client.reposForUser(apiKey); 

    call.enqueue(new Callback<List<Volumes>>() { 
     @Override 
     public void onResponse(Call<List<Volumes>> call, Response<List<Volumes>> response) { 
      List<Volumes> repos = response.body(); 
      int responseCode = response.code(); 
      Log.v("Volumeinfo", "onResponse: "+ responseCode); 

      listView.setAdapter(new GitHubRepoAdapter(MainActivity.this, repos)); 
     } 

     @Override 
     public void onFailure(Call<List<Volumes>> call, Throwable t) { 

      Log.v("Volumeinfo", "onResponse: "+ t.getMessage()); 
      Toast.makeText(MainActivity.this, t.getMessage()+"error :(", Toast.LENGTH_LONG).show(); 
     } 
    }); 
} 

接口

{ 

@GET("volumes?q=Android+intitle") 
Call<List<Volumes>> reposForUser(@Query("key")String ApiKey); 
} 




public class Volumes { 




@SerializedName("title") 
@Expose 
private String title; 


public String getTitle() { 
    return title; 
} 

}

适配器

private Context context; 
private List<Volumes> values; 

public GitHubRepoAdapter(Context context, List<Volumes> values) { 
    super(context, R.layout.list_item_pagination, values); 

    this.context = context; 
    this.values = values; 
} 

@Override 
public View getView(int position, View convertView, ViewGroup parent) { 
    View row = convertView; 

    if (row == null) { 
     LayoutInflater inflater = 
       (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
     row = inflater.inflate(R.layout.list_item_pagination, parent, false); 
    } 

    TextView textView = (TextView) row.findViewById(R.id.list_item_pagination_text); 

    Volumes item = values.get(position); 
    String message = item.getTitle(); 
    textView.setText(message); 

    return row; 
} 
} 

的Json

{ 
    "kind": "books#volumes", 
    "totalItems": 3395, 
    "items": [ 
    { 
    "kind": "books#volume", 
    "id": "1igDDgAAQBAJ", 
    "etag": "oS4LeBsRcfg", 
    "selfLink": "https://www.googleapis.com/books/v1/volumes/1igDDgAAQBAJ", 
    "volumeInfo": { 
"title": "Android Programming", 
"subtitle": "The Big Nerd Ranch Guide", 
"authors": [ 
"Bill Phillips", 
"Chris Stewart", 
"Kristin Marsicano" 
], 
"publisher": "Pearson Technology Group", 
"publishedDate": "2017-01-30", 
"description": "This is the eBook of the printed book and may not include 
", 
"industryIdentifiers": [ 
{ 
    "type": "ISBN_13", 
    "identifier": "9780134706078" 
}, 
{ 
    "type": "ISBN_10", 
    "identifier": "0134706072" 
} 
], 
"readingModes": { 
"text": true, 
"image": true 
}, 
"pageCount": 624, 
"printType": "BOOK", 
"categories": [ 
"Computers" 
], 
"maturityRating": "NOT_MATURE", 
"allowAnonLogging": true, 
"contentVersion": "1.1.1.0.preview.3", 
"panelizationSummary": { 
"containsEpubBubbles": false, 
"containsImageBubbles": false 
    }, 
    "imageLinks": { 
    "smallThumbnail": "http://books.google.com/books/content? 
id=1igDDgAAQBAJ&printsec=frontcover&img=1&zoom=5&edge=curl&source=gbs_api", 
"thumbnail": "http://books.google.com/books/content? 
id=1igDDgAAQBAJ&printsec=frontcover&img=1&zoom=1&edge=curl&source=gbs_api" 
    }, 
     "language": "en", 
     "previewLink": "http://books.google.com/books? 

完整的Json https://www.googleapis.com/books/v1/volumes?q=Android+intitle

几乎找遍..help将非常感激

回答

0

您有安装似乎已安装改造解析JSON,所以这个答案也假设了这一点。

你得到的错误来自Gson,如果你看看它 - Expected BEGIN_ARRAY but was BEGIN_OBJECT - 它告诉你,当解析json时期望一个数组,但得到了一个对象。

错误的第二部分很容易理解。如果你看看你的json,它开始于{这是一个对象,而不是一个数组(这将开始于[)。那么,为什么期待一个数组?

为此,您必须转向您的改造界面声明。你说你的电话会返回一个List<Volumes>(Gson可以在json数组和java列表之间转换)。问题是返回的json(如前所述)是一个对象而不是一个列表,所以gson无法将其转换为列表。

再看看您的模型,将其更改为仅返回Volumes将是不够的,将导致更多的错误。你必须基本上直接将你的json映射到java对象(除非你想使用非常不必要的自定义反序列化器)。

通过直接映射到java我的意思是你必须拿出一个代表根json元素的对象,然后代表项目(它可以只是一个对象列表)等等。

下面是一个很棒的website,它不仅可以帮助您理解我的意思,还可以根据您的json为您生成模型。你将json粘贴到字段中,确保你选择了正确的选项 - 源类型json,注释样式gson等。甚至还有android studio的插件。

希望它有帮助

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