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我试图从Web API获取数据，但在我的onResponse()方法中出现错误，我找不到它。改造onResponse方法不工作，抛出NullPointerException
我的JSON看起来像这样
[
"partner1",
"partner2",
"partner3",
... ,
"partner150"
]
我有表的合作伙伴（ActiveAndroid）中，我想保存来自API的所有合作伙伴。
@Table(name = "Partners")
public class Partners extends Model {
@Column(name = "Name")
String name;
public Partners() {}
public Partners(String name) {
this.name = name;
}
}
这里是我的POJO模型类：
public class Partners extends ArrayList<String> {
@SerializedName("partners")
@Expose
public List<String> partners = new ArrayList<String>();
public List<String> getPartners() {
return partners;
}
public void setName(List<String> partners) {
this.partners = partners;
}
}
这是我的接口
public interface APIService {
@GET("Partners")
Call<Partners> getPartners();
}
这是我APIHelper类
public class APIHelper {
public static final String PARTNERS_URL = "https://part-of-link.com/partners.json/";
public static APIService apiService;
public static APIService getApiService() {
if (apiService == null) {
Retrofit retrofit = new Retrofit.Builder().baseUrl(PARTNERS_URL)
.addConverterFactory(GsonConverterFactory.create()).build();
apiService = retrofit.create(APIService.class);
}
return apiService;
}
}
这是片段，我有一个按钮，我想在其上执行onClick()方法以从API获取数据并将其保存到合作伙伴表中。
public class DownloadMain extends Fragment implements Callback<Partners> {
private Button dloadPartners;
private Call<Partners> callPartners;
public static APIService apiService;
public DownloadMain() {}
public DownloadMain newInstance() { return new DownloadMain(); }
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.download_main, container, false);
dloadPartners = (Button) view.findViewById(R.id.downloadPartners);
dloadPartners.setOnClickListener(btnListener);
callPartners = APIHelper.getApiService().getPartners();
callPartners.enqueue(this);
return view;
}
Button.OnClickListener btnListener = (new View.OnClickListener() {
@Override
public void onClick(View v) {
APIHelper helper = new APIHelper();
apiService = helper.getApiService();
Call<Partners> call = apiService.getPartners();
call.enqueue(new Callback<Partners>() {
@Override
public void onResponse(Call<Partners> call, Response<Partners> response) {
Call<Partners> call = apiService.getPartners();
call.enqueue(new Callback<Partners>() {
@Override
public void onResponse(Call<Partners> call, Response<Partners> response) {
List<String> partners = response.body().getPartners();
Log.d(TAG, "Number of partners received: " + partners.size());
}
@Override
public void onFailure(Call<Partners> call, Throwable t) {
Toast.makeText(getActivity(), "FAIL!!!", Toast.LENGTH_SHORT).show();
}
});
}
});
@Override
public void onResponse(Call<Partners> call, Response<Partners> response) {
}
@Override
public void onFailure(Call<Partners> call, Throwable t) {
}
}
这里onResponse()方法引发我一个错误：Attempt to invoke virtual method 'java.util.List com.example...pojo.Partners.getPartners()' on a null object reference
我想要的是让来自网络的所有合作伙伴，并保存到我的合作伙伴表上按一下按钮。
我找不到这个错误的解决方案，所以如果有人可以帮助我，我将不胜感激。
问题：有人可以指导我，告诉我什么是错的，并帮助我解决这个问题吗？
什么是JSON响应的完整模式？由于您使用GSON将JSON映射到POJO，我怀疑您可能错误地声明了POJO。 – crymson
@crymson JSON在我的网页API URL看起来像这样'[ “合作伙伴1”， “合作伙伴2”， “partner3”， ......， “partner150” ]' – RubyDigger19
我只是想指出的是，你连续调用你的Retrofit方法两次...并且根本不需要合作伙伴类 –