Question

我正在尝试获取从mySQL数据库接收的数据，并使用onclicklistener在回收器视图中显示它们。回收者视图仅显示标题，当用户单击视图时，会将其带到“详细信息”页面以获取所有其他信息。到目前为止，所有操作均有效，但当我单击查看卡时，应用程序崩溃了。在onclick方法调用上，我一直得到空指针。

E / Android运行时：致命异常：主要流程：com.example.fit，PID：28226 java.lang.NullPointerException：尝试在空对象引用上调用接口方法'java.lang.Object java.util.List.get（int）' 在com.example.fit.WorkoutLogFragment.onItemClick（WorkoutLogFragment.java:69）在com.example.fit.WorkoutLogAdapter $ WorkoutLogViewHolder $ 1.onClick（WorkoutLogAdapter.java:59）

这是引发异常的类的代码。

public class WorkoutLogFragment extends Fragment implements   WorkoutLogAdapter.OnItemClickListener {

public static final String EXTRA_AUTOMATIC_THOUGHT = "automaticThought";
public static final String EXTRA_DISTORTIONS = "distortions";
public static final String EXTRA_CHALLENGE_THOUGHT = "challengeThought";
public static final String EXTRA_ALTERNATIVE_THOUGHT = "alternativeThought";
private SharedPreferences loginPref;
private RecyclerView recyclerView;
private WorkoutLogAdapter adapter;
private List<WorkoutLogRecycler> workoutLogList;

@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    return inflater.inflate(R.layout.fragment_workout_log, container, false);
}

@Override
public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);

    loginPref = getContext().getSharedPreferences("loginPref", Context.MODE_PRIVATE);
    int userId = loginPref.getInt("userId", 0);

    recyclerView = view.findViewById(R.id.recyclerView);
    recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
    recyclerView.setAdapter(adapter);

    Call<List<WorkoutLogRecycler>> call = RetrofitClient.getInstance()
            .getApi()
            .getLogs(userId);
    call.enqueue(new Callback<List<WorkoutLogRecycler>>() {
        @Override
        public void onResponse(Call<List<WorkoutLogRecycler>> call, Response<List<WorkoutLogRecycler>>response) {


            List<WorkoutLogRecycler> workoutLogRecyclers = response.body();
            adapter = new WorkoutLogAdapter(getActivity(),workoutLogRecyclers);
            recyclerView.setAdapter(adapter);
            adapter.setOnItemClickListener(WorkoutLogFragment.this);
        }
        @Override
        public void onFailure(Call<List<WorkoutLogRecycler>> call, Throwable t) {
        }
    });
}
@Override
public void onItemClick(int position) {

    **WorkoutLogRecycler clickedItem = workoutLogList.get(position);**
    Fragment workoutLogDetails = new WorkoutLogDetailsFragment();
    Bundle args = new Bundle();
    args.putString(EXTRA_AUTOMATIC_THOUGHT, clickedItem.getAutomaticThought());
    args.putString(EXTRA_CHALLENGE_THOUGHT, clickedItem.getChallengeThought());
    args.putString(EXTRA_ALTERNATIVE_THOUGHT, clickedItem.getAlternativeThought());
    args.putInt(EXTRA_DISTORTIONS, clickedItem.getDistortions());
    workoutLogDetails.setArguments(args);
    FragmentTransaction workoutLogTransaction = getActivity().getSupportFragmentManager().beginTransaction();
    workoutLogTransaction.replace(R.id.fragment_container, workoutLogDetails);
    workoutLogTransaction.commit();
}

}

此行代码根据调试日志触发错误。 WorkoutLogRecycler clickedItem = trainingLogList.get（position）;

调试帮助：回收器视图中的空指针

0 个答案: