Java Tuch上微调器上的NullPointerException

我正在制作一个应用程序，作为一个小型项目，用于计算一个人已经上过的课，以及显示他/她的出勤状态

但现在我在尝试使用微调器选择某个选项时遇到了一些空指针异常

这是我的Java文件：TimeTableFragment.Java

package in.teambhargavinilayam.abh.massbunk;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.List;


/**
 * A simple {@link Fragment} subclass.
 */
public class TimeTableFragment extends Fragment {

    public TimeTableFragment() {
        // Required empty public constructor
    }

    Spinner hour_1, hour_2, hour_3, hour_4, hour_5, hour_6;
    DBHelper myTimeTableDb;
    String hour_1_sub, hour_2_sub, hour_3_sub, hour_4_sub, hour_5_sub, hour_6_sub;
    TextView day_txt;
    int hour_no = 1;

    @Override
    public View onCreateView(final LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment

        final View view = inflater.inflate(R.layout.fragment_time_table, container, false);
        myTimeTableDb = new DBHelper(view.getContext());

        hour_1 = (Spinner) view.findViewById(R.id.hour_1_subj);
        hour_2 = (Spinner) view.findViewById(R.id.hour_2_subj);
        hour_3 = (Spinner) view.findViewById(R.id.hour_3_subj);
        hour_4 = (Spinner) view.findViewById(R.id.hour_4_subj);
        hour_5 = (Spinner) view.findViewById(R.id.hour_5_subj);
        hour_6 = (Spinner) view.findViewById(R.id.hour_6_subj);

        String[] subj = GetAllSubjects();

        // Hour 1 List
        List<String> hour_1_list = new ArrayList<String>();
        hour_1_list.add("Select Subject..");
        hour_1_list.add(subj[0]);
        hour_1_list.add(subj[1]);
        hour_1_list.add(subj[2]);
        hour_1_list.add(subj[3]);
        hour_1_list.add(subj[4]);
        hour_1_list.add(subj[5]);

        ArrayAdapter<String> hour_1_ListAdapter = new ArrayAdapter<String>(view.getContext(), R.layout.support_simple_spinner_dropdown_item, hour_1_list);
        hour_1_ListAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        hour_1.setAdapter(hour_1_ListAdapter);

        hour_1.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                hour_1_sub = parent.getItemAtPosition(position).toString();
            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {
                hour_1_sub = null;
            }
        });

        // Hour 2 List
        List<String> hour_2_list = new ArrayList<String>();
        hour_2_list.add("Select Subject..");
        hour_2_list.add(subj[0]);
        hour_2_list.add(subj[1]);
        hour_2_list.add(subj[2]);
        hour_2_list.add(subj[3]);
        hour_2_list.add(subj[4]);
        hour_2_list.add(subj[5]);

        ArrayAdapter<String> hour_2_ListAdapter = new ArrayAdapter<String>(view.getContext(), R.layout.support_simple_spinner_dropdown_item, hour_2_list);
        hour_2_ListAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        hour_2.setAdapter(hour_2_ListAdapter);

        hour_2.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                hour_2_sub = parent.getItemAtPosition(position).toString();
            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {
                hour_2_sub = null;
            }
        });

        // Hour 3 List
        List<String> hour_3_list = new ArrayList<String>();
        hour_3_list.add("Select Subject..");
        hour_3_list.add(subj[0]);
        hour_3_list.add(subj[1]);
        hour_3_list.add(subj[2]);
        hour_3_list.add(subj[3]);
        hour_3_list.add(subj[4]);
        hour_3_list.add(subj[5]);

        ArrayAdapter<String> hour_3_ListAdapter = new ArrayAdapter<String>(view.getContext(), R.layout.support_simple_spinner_dropdown_item, hour_3_list);
        hour_3_ListAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        hour_3.setAdapter(hour_3_ListAdapter);

        hour_3.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                hour_3_sub = parent.getItemAtPosition(position).toString();
            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {
                hour_3_sub = null;
            }
        });

        // Hour 4 List
        List<String> hour_4_list = new ArrayList<String>();
        hour_4_list.add("Select Subject..");
        hour_4_list.add(subj[0]);
        hour_4_list.add(subj[1]);
        hour_4_list.add(subj[2]);
        hour_4_list.add(subj[3]);
        hour_4_list.add(subj[4]);
        hour_4_list.add(subj[5]);

        ArrayAdapter<String> hour_4_ListAdapter = new ArrayAdapter<String>(view.getContext(), R.layout.support_simple_spinner_dropdown_item, hour_4_list);
        hour_4_ListAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        hour_4.setAdapter(hour_4_ListAdapter);


        hour_4.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                hour_4_sub = parent.getItemAtPosition(position).toString();
            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {
                hour_4_sub = null;
            }
        });

        // Hour 5 List
        List<String> hour_5_list = new ArrayList<String>();
        hour_5_list.add("Select Subject..");
        hour_5_list.add(subj[0]);
        hour_5_list.add(subj[1]);
        hour_5_list.add(subj[2]);
        hour_5_list.add(subj[3]);
        hour_5_list.add(subj[4]);
        hour_5_list.add(subj[5]);

        ArrayAdapter<String> hour_5_ListAdapter = new ArrayAdapter<String>(view.getContext(), R.layout.support_simple_spinner_dropdown_item, hour_5_list);
        hour_5_ListAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        hour_5.setAdapter(hour_5_ListAdapter);

        hour_5.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                hour_5_sub = parent.getItemAtPosition(position).toString();
            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {
                hour_5_sub = null;
            }
        });

        // Hour 6 List
        List<String> hour_6_list = new ArrayList<String>();
        hour_6_list.add("Select Subject..");
        hour_6_list.add(subj[0]);
        hour_6_list.add(subj[1]);
        hour_6_list.add(subj[2]);
        hour_6_list.add(subj[3]);
        hour_6_list.add(subj[4]);
        hour_6_list.add(subj[5]);

        ArrayAdapter<String> hour_6_ListAdapter = new ArrayAdapter<String>(view.getContext(), R.layout.support_simple_spinner_dropdown_item, hour_6_list);
        hour_6_ListAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        hour_6.setAdapter(hour_6_ListAdapter);

        hour_6.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                hour_6_sub = parent.getItemAtPosition(position).toString();
            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {
                hour_6_sub = null;
            }
        });


        day_txt = (TextView) view.findViewById(R.id.day_string);
        FloatingActionButton nextBtn = (FloatingActionButton) view.findViewById(R.id.nextBtn);
        final FloatingActionButton previousBtn = (FloatingActionButton) view.findViewById(R.id.previousBtn);
        nextBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                if (hour_1_sub.isEmpty() || hour_1_sub.equals("Select Subject..")){
                    Toast.makeText(view.getContext(), "Choose A subject", Toast.LENGTH_SHORT).show();
                }
                else if (hour_2_sub.isEmpty() || hour_2_sub.equals("Select Subject..")){
                    Toast.makeText(view.getContext(), "Choose A subject", Toast.LENGTH_SHORT).show();
                }
                else if (hour_3_sub.isEmpty() || hour_3_sub.equals("Select Subject..")){
                    Toast.makeText(view.getContext(), "Choose A subject", Toast.LENGTH_SHORT).show();
                }
                else if (hour_4_sub.isEmpty() || hour_4_sub.equals("Select Subject..")){
                    Toast.makeText(view.getContext(), "Choose A subject", Toast.LENGTH_SHORT).show();

                }
                else if (hour_5_sub.isEmpty() || hour_5_sub.equals("Select Subject..")){
                    Toast.makeText(view.getContext(), "Choose A subject", Toast.LENGTH_SHORT).show();

                }
                else if (hour_6_sub.isEmpty() || hour_6_sub.equals("Select Subject..")){
                    Toast.makeText(view.getContext(), "Choose A subject", Toast.LENGTH_SHORT).show();

                }
                else {
                    String[] hours = {
                            hour_1_sub,
                            hour_2_sub,
                            hour_3_sub,
                            hour_4_sub,
                            hour_5_sub,
                            hour_6_sub,
                    };
                    boolean isSaved = SaveTimeTableRow(hours,hour_no);
                    if (isSaved){

                        hour_no++;
                        if (hour_no == 6) {
                            ((MainActivity) getActivity()).callFragment(4);      //calling Current Status Fragment
                        }
                        hour_1.setSelection(0);
                        hour_2.setSelection(0);
                        hour_3.setSelection(0);
                        hour_4.setSelection(0);
                        hour_5.setSelection(0);
                        hour_6.setSelection(0);
                        previousBtn.show();
                        SetDay();
                    }
                    else {
                        Toast.makeText(view.getContext(), "Not Saved", Toast.LENGTH_SHORT).show();
                    }
                }
            }
        });

        previousBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                hour_no--;
                if (hour_no == 1)
                    previousBtn.hide();
                SetDay();
            }
        });
        return view;
    }

    public String[] GetAllSubjects(){
        String[] subjects = myTimeTableDb.ShowAllSubjects();
        return subjects;
    }

    public boolean SaveTimeTableRow(String[] hours,int hour_no){
        boolean isInserted = myTimeTableDb.InsertOrUpdateTimeTable(hours, Integer.toString(hour_no));
        return isInserted;
    }

    public void SetDay(){
        switch (hour_no){
            case 1:
                day_txt.setText("Monday");
                break;
            case 2:
                day_txt.setText("Tuesday");
                break;
            case 3:
                day_txt.setText("Wednesday");
                break;
            case 4:
                day_txt.setText("Thursday");
                break;
            case 5:
                day_txt.setText("Friday");
                break;
        }
    }
}

请帮助我修复此错误

尝试

hour_1_sub = hour_1_list .get(position).toString();

代替

hour_1_sub = parent.getItemAtPosition(position).toString();

---

在每个微调器的onSelectListner中。

显然subc[X]为空，我认为String[]subjects=myTimeTableDb.ShowAllSubjects；是null@Anonymous不SUBK不能为null，因为他将使用SUBK[0]获得NPE。。。sub[X]为空，我的意思是myTimeTableDb.ShowAllSubjects；复述null看起来像是一个。。。显然不是答案，因为堆栈跟踪没有指向SelectListner抱歉，它不起作用：

hour_1_sub = parent.getItemAtPosition(position).toString();