java - 如何使用多级数组遍历 Gson 对象

Question

我正在尝试使用 Gson 库获取 jSon items>item>image>images>transparent 内的参数。这个想法是捕获 transparent、transparent_blank 和 transparent_dark。但我不知道如何获得这些值，目前我创建了以下内容:

Json

{ 
  "date_layout":"day-month-year",
  "lastupdate":1547596830,
    "items":[{
      "name":"Cleans Cuts",
      "featured":"true",
      "item":{
        "image":"http:www.domain.com/unwanted_image.jpg",
           "images":{
              "transparent":"http:www.domain.com/desired_image1.jpg",
              "transparent_blank":"http:www.domain.com/desired_image2.jpg",
              "transparent_dark":"http:www.domain.com/desired_image3.jpg"
             }
          }
    },
    {
      "name":"Cleans Cuts",
      "featured":"true",
      "item":{
        "image":"http:www.domain.com/unwanted_image.jpg",
           "images":{
              "transparent":"http:www.domain.com/desired_image1.jpg",
              "transparent_blank":"http:www.domain.com/desired_image2.jpg",
              "transparent_dark":"http:www.domain.com/desired_image3.jpg"
             }
          }
    }]
}

.MainActivity

public class MainActivity extends AppCompatActivity {
@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

String url = "http://www.example.com/file.json";

Request request = new Request.Builder()
       .url(url)
       .build();

Response response = client.newCall(request).execute();
       if(response.isSuccessful()){
          String response_jSon = response.body().string();
          Gson gson = new Gson();
          Datos datosFinal = gson.fromJson(response_jSon, Datos.class);
              for (int i=0; i<datosFinal.items.size(); i++){
                Log.d("msg_2", datosFinal.items.get(i).name);
              }
}

我只能访问您在 .MainActivity 日志中看到的项目。

Json 的类对象

Datos.java

public class Datos {
    public String date_layout;
    public Int lastupdate;
     List<items> items;
}

items.java

public class items {
    public String name;
}

Answer 1

json 不是很干净，我建议您重新设计该 json 字符串的生成方式，但如果您仍然想在不重新设计 json 的情况下获取这些值，则需要更改您的 Items 类:

`public class items {
    public String name;
    public String featured;
    public Item item;
}` 

然后您需要创建另一个名为Item的类

`public class Item{
    public String image;
    public Image images;
}`

您还需要创建一个 Image 类，如下所示:

`public class Image {
    public String transparent;
    public String transparent_blank;
    public String transparent_dark;
}`

然后您可以在循环中记录这些值:

`Datos datosFinal = gson.fromJson(response_jSon, Datos.class);
 for (int i=0; i<datosFinal.items.size(); i++){
        Log.d("msg_2", datosFinal.items.get(i).item.images.transparent);
        Log.d("msg_2", datosFinal.items.get(i).item.images.transparent_blank);
        Log.d("msg_2", datosFinal.items.get(i).item.images.transparent_dark);
}`

虽然这可能有效，但我强烈建议您重新设计您的 json 并使其更易于维护。