Question

我正在尝试从AsyncTask类中的API获取数据，并将数据返回到数据显示在RecyclerView中的片段。但是数据始终为空，并且片段始终为空。

看看我的代码。

我的AsyncTask类：

public class EmployeesData extends AsyncTask<Void, Void, List<Employee>>{

List<Employee> data = new ArrayList<>();
EmployeesFragment emp;

public EmployeesData (EmployeesFragment emp){
    this.emp= emp;
}


@Override
protected List<Employee> doInBackground(Void... arg0) {
    RestService restService = new RestService();
    try {

        restService.getService().getEmployees(new Callback<List<Employee>>() {

            @Override
            public void success(List<Employee> employee, Response response) {

                data = employee;
            }

            @Override
            public void failure(RetrofitError error) {
                Toast.makeText(emp.getContext(), error.getMessage().toString(), Toast.LENGTH_LONG).show();
            }
        });
    } catch (Exception ex) {
        Toast.makeText(emp.getContext(), ex.getMessage().toString(), Toast.LENGTH_LONG).show();

    }
    return data;
}

@Override
protected void onPostExecute(List<Employee> data) {
    super.onPostExecute(data);
    emp.setList(data);
}
}

我的片段：

public class EmployeesFragment extends Fragment {

RecyclerView rv;
List<Employee> employees= new ArrayList<>();
public EmployeesFragment () {
    // Required empty public constructor
}


@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment
    View view = inflater.inflate(R.layout.fragment_employees, container, false);

    rv = (RecyclerView) view.findViewById(R.id.emp_Rv);
    rv.setLayoutManager(new LinearLayoutManager(getContext()));

    fireYourAsyncTask();


   EmployeesRvAdapter adapter = new EmployeesRvAdapter (employees, getActivity());

    rv.setAdapter(adapter);

    return view;
}

public void setList(List<Employee> data) {
    employees= data;
}

public void fireYourAsyncTask() {
    new EmployeesData(this).execute();
}
}

我的RecyclerView适配器：

public class EmployeesRvAdapter extends RecyclerView.Adapter<EmployeesRvAdapter.EmployeesHolder> {
List<Employees> employees;
LayoutInflater inflater;
Context context;
public class EmployeesHolder extends RecyclerView.ViewHolder {
    TextView name, description;
    View container;
    public EmployeesHolder(View itemView) {
        super(itemView);
        name = (TextView) itemView.findViewById(R.id.name_tv);
        description = (TextView) itemView.findViewById(R.id.description_tv);
        container = itemView.findViewById(R.id. item_root);
    }
}
public EmployeesRvAdapter(List<Employees> employees, Context c) {
    this.inflater = LayoutInflater.from(c);
    this.employees = employees;
    context = c;
}
@Override
public EmployeesRvAdapter.EmployeesHolder onCreateViewHolder(ViewGroup parent, int viewType) {

    View v = inflater.inflate(R.layout.employees_rv_item, parent, false);
    return new EmployeesRvAdapter.EmployeesHolder(v);
}
@Override
public void onBindViewHolder(final EmployeesRvAdapter.EmployeesHolder holder, int position) {
    Employees employee = Employees.get(position);
    holder.name.setText(employee.getName());
    holder.description.setText(employee.getDescription());
}
@Override
public int getItemCount() {
    return employees.size();
}
}

我的RestService类：

public class RestService {
private static final String URL = "http://localhost:23000/";
private retrofit.RestAdapter restAdapter;
private EmployeesService apiService;

public RestService()
{
    restAdapter = new retrofit.RestAdapter.Builder()
            .setEndpoint(URL)
            .setLogLevel(retrofit.RestAdapter.LogLevel.FULL)
            .build();

    apiService = restAdapter.create(EmployeesService.class);
}

public EmployeesService getService()
{
    return apiService;
}
}

我的员工服务界面：

public interface EmployeesService {
    @GET("/api/employees")
    public void getEmployees(Callback<List<Employee>> callback);
}

有人指出我错了吗？我很感激帮助。

谢谢

Answer 1

首先，您不需要使用Retrofit的AsyncTask。

可能只是这个

private EmployeesRvAdapter adapter;

public void fireYourAsyncTask() {

    EmployeesService service = new RestService().getService();
    try {

        service.getEmployees(new Callback<List<Employee>>() {

            @Override
            public void success(List<Employee> employee, Response response) {
                employees.clear();
                employees.addAll(employee);
                adapter.notifyDatSetChanged();
            }

            @Override
            public void failure(RetrofitError error) {
                Toast.makeText(emp.getContext(), error.getMessage().toString(), Toast.LENGTH_LONG).show();
            }
        });

如果你这样做会更清洁，但这取决于你

public class EmployeesFragment extends Fragment implements Callback<List<Employee>> {

而且更清洁，我的意思是它只是

public void fireYourAsyncTask() {
    EmployeesService service = new RestService().getService();
    service.getEmployees(this);
}

无论您在何处添加数据，这都不是您添加到ArrayList的方式

employees= data;

这是重新分配。这是补充

employees.clear();
employees.addAll(data);

asynctask类不会将数据返回到片段

1 个答案: