我有一个json，里面有一个对象，我有一个json数组，我制作了pojo，但是像mvvm一样，我无法弄清楚如何解析它并在recyclerView中显示它（片段），请检查我的代码，谢谢 这是我的json
{
"response":{
"status":"ok",
"userTier":"developer",
"total":2157516,
"startIndex":1,
"pageSize":10,
"currentPage":1,
"pages":215752,
"orderBy":"newest",
"results":[
{
"id":"uk-news/2019/dec/02/killer-of-three-elderly-devon-men-found-not-guilty-due-to-insanity",
"type":"article",
"sectionId":"uk-news",
"sectionName":"UK news",
"webPublicationDate":"2019-12-02T17:53:26Z",
"webTitle":"Killer of three elderly Devon men found not guilty due to insanity",
"webUrl":"https://www.theguardian.com/uk-news/2019/dec/02/killer-of-three-elderly-devon-men-found-not-guilty-due-to-insanity",
"apiUrl":"https://content.guardianapis.com/uk-news/2019/dec/02/killer-of-three-elderly-devon-men-found-not-guilty-due-to-insanity",
"isHosted":false,
"pillarId":"pillar/news",
"pillarName":"News"
},
{
"id":"football/2019/dec/02/fa-homophobic-chants-west-ham-chelsea-kick-it-out",
"type":"article",
"sectionId":"football",
"sectionName":"Football",
"webPublicationDate":"2019-12-02T17:53:09Z",
"webTitle":"FA in discussions after homophobic chants by West Hams fans",
"webUrl":"https://www.theguardian.com/football/2019/dec/02/fa-homophobic-chants-west-ham-chelsea-kick-it-out",
"apiUrl":"https://content.guardianapis.com/football/2019/dec/02/fa-homophobic-chants-west-ham-chelsea-kick-it-out",
"isHosted":false,
"pillarId":"pillar/sport",
"pillarName":"Sport"
},
{
"id":"news/shortcuts/2019/dec/02/jeremy-corbyn-suit-fabric-labour-leader-for-the-many-not-the-few-pinstripes",
"type":"article",
"sectionId":"politics",
"sectionName":"Politics",
"webPublicationDate":"2019-12-02T17:42:03Z",
"webTitle":"Socialist pinstripe: the secret message stitched into Jeremy Corbyn’s new suit",
"webUrl":"https://www.theguardian.com/news/shortcuts/2019/dec/02/jeremy-corbyn-suit-fabric-labour-leader-for-the-many-not-the-few-pinstripes",
"apiUrl":"https://content.guardianapis.com/news/shortcuts/2019/dec/02/jeremy-corbyn-suit-fabric-labour-leader-for-the-many-not-the-few-pinstripes",
"isHosted":false,
"pillarId":"pillar/news",
"pillarName":"News"
},
{
"id":"uk-news/2019/dec/02/police-criticised-response-attack-rabbi-in-north-london",
"type":"article",
"sectionId":"uk-news",
"sectionName":"UK news",
"webPublicationDate":"2019-12-02T17:41:13Z",
"webTitle":"Police criticised over response to attack on rabbi in north London",
"webUrl":"https://www.theguardian.com/uk-news/2019/dec/02/police-criticised-response-attack-rabbi-in-north-london",
"apiUrl":"https://content.guardianapis.com/uk-news/2019/dec/02/police-criticised-response-attack-rabbi-in-north-london",
"isHosted":false,
"pillarId":"pillar/news",
"pillarName":"News"
},
{
"id":"artanddesign/2019/dec/02/les-tasses-war-and-pissoirs-how-the-debauched-urinals-of-paris-helped-to-beat-the-nazis",
"type":"article",
"sectionId":"artanddesign",
"sectionName":"Art and design",
"webPublicationDate":"2019-12-02T17:36:28Z",
"webTitle":"War and pissoirs: how the urinals of Paris helped beat the Nazis",
"webUrl":"https://www.theguardian.com/artanddesign/2019/dec/02/les-tasses-war-and-pissoirs-how-the-debauched-urinals-of-paris-helped-to-beat-the-nazis",
"apiUrl":"https://content.guardianapis.com/artanddesign/2019/dec/02/les-tasses-war-and-pissoirs-how-the-debauched-urinals-of-paris-helped-to-beat-the-nazis",
"isHosted":false,
"pillarId":"pillar/arts",
"pillarName":"Arts"
},
{
"id":"commentisfree/2019/dec/02/trust-in-politics-has-evaporated-now-it-offers-only-fantasy",
"type":"article",
"sectionId":"commentisfree",
"sectionName":"Opinion",
"webPublicationDate":"2019-12-02T17:36:01Z",
"webTitle":"Trust in politics has evaporated, now it offers only fantasy | Suzanne Moore",
"webUrl":"https://www.theguardian.com/commentisfree/2019/dec/02/trust-in-politics-has-evaporated-now-it-offers-only-fantasy",
"apiUrl":"https://content.guardianapis.com/commentisfree/2019/dec/02/trust-in-politics-has-evaporated-now-it-offers-only-fantasy",
"isHosted":false,
"pillarId":"pillar/opinion",
"pillarName":"Opinion"
},
{
"id":"film/2019/dec/02/2019-braddies-peter-bradshaw-films-of-the-year",
"type":"article",
"sectionId":"film",
"sectionName":"Film",
"webPublicationDate":"2019-12-02T17:29:48Z",
"webTitle":"And the 2019 Braddies go to … Peter Bradshaw's film picks of the year",
"webUrl":"https://www.theguardian.com/film/2019/dec/02/2019-braddies-peter-bradshaw-films-of-the-year",
"apiUrl":"https://content.guardianapis.com/film/2019/dec/02/2019-braddies-peter-bradshaw-films-of-the-year",
"isHosted":false,
"pillarId":"pillar/arts",
"pillarName":"Arts"
},
{
"id":"world/2019/dec/02/christine-lagarde-ecb-should-do-more-to-tackle-climate-emergency",
"type":"article",
"sectionId":"world",
"sectionName":"World news",
"webPublicationDate":"2019-12-02T17:23:28Z",
"webTitle":"Lagarde: ECB should do more to tackle climate emergency",
"webUrl":"https://www.theguardian.com/world/2019/dec/02/christine-lagarde-ecb-should-do-more-to-tackle-climate-emergency",
"apiUrl":"https://content.guardianapis.com/world/2019/dec/02/christine-lagarde-ecb-should-do-more-to-tackle-climate-emergency",
"isHosted":false,
"pillarId":"pillar/news",
"pillarName":"News"
},
{
"id":"food/2019/dec/02/robert-neame-obituary",
"type":"article",
"sectionId":"food",
"sectionName":"Food",
"webPublicationDate":"2019-12-02T17:19:32Z",
"webTitle":"Robert Neame obituary",
"webUrl":"https://www.theguardian.com/food/2019/dec/02/robert-neame-obituary",
"apiUrl":"https://content.guardianapis.com/food/2019/dec/02/robert-neame-obituary",
"isHosted":false,
"pillarId":"pillar/lifestyle",
"pillarName":"Lifestyle"
},
{
"id":"politics/live/2019/dec/02/general-election-swinson-condemns-johnson-over-trump-friendship-ahead-of-london-visit-live",
"type":"liveblog",
"sectionId":"politics",
"sectionName":"Politics",
"webPublicationDate":"2019-12-02T17:13:40Z",
"webTitle":"General election: Johnson insists he opposed early release for terrorists long before London Bridge attack – live news",
"webUrl":"https://www.theguardian.com/politics/live/2019/dec/02/general-election-swinson-condemns-johnson-over-trump-friendship-ahead-of-london-visit-live",
"apiUrl":"https://content.guardianapis.com/politics/live/2019/dec/02/general-election-swinson-condemns-johnson-over-trump-friendship-ahead-of-london-visit-live",
"isHosted":false,
"pillarId":"pillar/news",
"pillarName":"News"
}
]
}
}
现在这是我的pojo课程。
public class NewsResponse {
@SerializedName("response")
private NewsArticle response;
public NewsArticle getResponse() {
return response;
}
public void setResponse(NewsArticle response) {
this.response = response;
}
}
public class NewsArticle {
@SerializedName("results")
private List<Result> results = null;
public List<Result> getResults() {
return results;
}
public void setResults(List<Result> results) {
this.results = results;
}
}
public class Result {
@SerializedName("sectionName")
private String sectionName;
@SerializedName("webTitle")
private String webTitle;
@SerializedName("webUrl")
private String webUrl;
public String getSectionName() {
return sectionName;
}
public void setSectionName(String sectionName) {
this.sectionName = sectionName;
}
public String getWebTitle() {
return webTitle;
}
public void setWebTitle(String webTitle) {
this.webTitle = webTitle;
}
public String getWebUrl() {
return webUrl;
}
public void setWebUrl(String webUrl) {
this.webUrl = webUrl;
}
}
这是我的新存储库
public class NewsRepository {
private static NewsRepository newsRepository;
public static NewsRepository getInstance(){
if (newsRepository == null){
newsRepository = new NewsRepository();
}
return newsRepository;
}
private NewsApi newsApi;
public NewsRepository(){
newsApi = RetrofitService.cteateService(NewsApi.class);
}
public MutableLiveData<NewsResponse> getNews(String key){
final MutableLiveData<NewsResponse> newsData = new MutableLiveData<>();
newsApi.getNewsList( key).enqueue(new Callback<NewsResponse>() {
@Override
public void onResponse(Call<NewsResponse> call,
Response<NewsResponse> response) {
if (response.isSuccessful()){
newsData.setValue(response.body());
}
}
@Override
public void onFailure(Call<NewsResponse> call, Throwable t) {
newsData.setValue(null);
}
});
return newsData;
}
}
现在是片段
ublic class NewsFragment extends Fragment {
ArrayList<NewsResponse> articleArrayList = new ArrayList<>();
NewsAdapter newsAdapter;
RecyclerView rvHeadline;
private static final String TAG = "NewsFragment";
private PageViewModel pageViewModel;
public NewsFragment() {
// Required empty public constructor
}
/**
* @return A new instance of fragment SpeedDialFragment.
*/
public static NewsFragment newInstance() {
return new NewsFragment();
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
pageViewModel = ViewModelProviders.of(this).get(PageViewModel.class);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View root = inflater.inflate(R.layout.news_fragment, container, false);
rvHeadline = root.findViewById(R.id.rvNews);
pageViewModel.init();
pageViewModel.getNewsRepository().observe(this, new Observer<NewsResponse>() {
@Override
public void onChanged(NewsResponse newsResponse) {
** ****** List<NewsArticle> newsArticles = newsResponse.getResponse(); ******
******* articleArrayList.addAll(newsArticles); ********
newsAdapter.notifyDataSetChanged();
}
});
setupRecyclerView();
return root;
}
private void setupRecyclerView() {
if (newsAdapter == null) {
newsAdapter = new NewsAdapter(getActivity(), articleArrayList);
rvHeadline.setLayoutManager(new LinearLayoutManager(getActivity()));
rvHeadline.setAdapter(newsAdapter);
rvHeadline.setItemAnimator(new DefaultItemAnimator());
rvHeadline.setNestedScrollingEnabled(true);
} else {
newsAdapter.notifyDataSetChanged();
}
}
}
好吧，我的错误是在pageViewModel.getNewsRepository（）内部，我不知道该怎么办 如果我将泛型更改为结果类，则第一行中已修复错误，但第二行无法接受我丢失的结果列表，请帮助
ViewModel类
public class PageViewModel extends ViewModel {
private MutableLiveData<NewsResponse> mutableLiveData;
private NewsRepository newsRepository;
public void init(){
if (mutableLiveData != null){
return;
}
newsRepository = NewsRepository.getInstance();
mutableLiveData = newsRepository.getNews( "***************");
}
public LiveData<NewsResponse> getNewsRepository() {
return mutableLiveData;
}
}
答案 0 :(得分：0)
直接将NewsRepository的{{1}}从您的MutableLiveData传递到View。
ViewModel当前，您public class PageViewModel extends ViewModel {
private NewsRepository newsRepository = NewsRepository.getInstance();
public MutableLiveData<NewsResponse> getNewsRepository() {
return newsRepository.getNews( "***************");
}
}
的ViewModel的observe不会发出任何值。 MutableLiveData的{{1}}发出的数据在ViewModel中丢失了，因为它没有被观察到。您必须维护NewsRepository的单个实例才能观察到更改。
除此之外，您还必须更新“片段和适配器”以使用“列表”而不是“列表”，因为MutableLiveData不包含文章列表。它包含结果列表。检查下面
LiveData答案 1 :(得分：0)
编辑
我将列表更改为结果
ArrayList<Result> articleArrayList = new ArrayList<>();
加上我在这里更改了
@Override
public void onChanged(NewsResponse newsResponse) {
List<Result> newsArticles = newsResponse.getResponse().getResults();
articleArrayList.addAll(newsArticles);
就像阿萨杜扎曼博士说的那样，我也更换了适配器，一切正常