任务应用程序上的游标索引超出边界异常

我正在开发一个tasks应用程序，我想用sqldatabase保存一些数据，但我遇到了一些问题，因为当我试图保存数据时，我的应用程序崩溃了。我还希望使用列表适配器在自定义列表视图（带有自定义列表项）中显示此数据。
这是错误消息：

android.database.CursorIndexOutOfBoundsException: Index -1 requested, with a size of 1

以下是dbhelper的代码：

package com.example.taskmasterv3;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

import androidx.annotation.Nullable;

public class DBHelper extends SQLiteOpenHelper {
    public DBHelper(Context context) {
        super(context, "Subtaskdata.db", null, 1);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {

        db.execSQL("create Table Subtaskdata(subtaskname TEXT primary key, pri TEXT, time TEXT)");
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("drop Table if exists Userdetails");
    }

    public Boolean insertSubtaskData(String subtaskName, String pri, String time){
            SQLiteDatabase db = this.getWritableDatabase();
            ContentValues contentValues = new ContentValues();
            contentValues.put("subtaskname", subtaskName);
            contentValues.put("pri", pri);
            contentValues.put("time", time);
            long result = db.insert("Subtaskdata", null, contentValues);
            if (result < 0){
                return false;
            }
            else
            {
                return true;
            } }

    public Boolean updateSubtaskData(String subtaskName, String pri, String time){
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put("subtaskname", subtaskName);
        contentValues.put("pri", pri);
        contentValues.put("time", time);
        Cursor cursor = db.rawQuery("Select * from Subtaskdata where subtaskname = ?", new String[]{subtaskName});
        if (cursor.getCount()> 0){
        long result = db.update("Subtaskdata", contentValues, "name=?", new String[]{subtaskName});
        if (result== -1){
            return false;
        }
        else
        {
            return true;
        } }
        else
        {
            return false;
        }}

    public Boolean deletedata(String subtaskName){
        SQLiteDatabase db = this.getWritableDatabase();
        Cursor cursor = db.rawQuery("Select * from Subtaskdata where subtaskname = ?", new String[]{subtaskName});
        if (cursor.getCount()> 0){
            long result = db.delete("Subtaskdata","name=?", new String[]{subtaskName});
            if (result== -1){
                return false;
            }
            else
            {
                return true;
            } }
        else
        {
            return false;
        }}

        public Cursor getdata (){
        SQLiteDatabase db = this.getWritableDatabase();
        Cursor cursor = db.rawQuery("Select * from Subtaskdata", null);
        return cursor;
        }

}

我的子任务类的代码（仅用于理解）

package com.example.taskmasterv3;

public class SubtaskPartTwo {

private String subtaskName;
private String pri;
private String time;

    public SubtaskPartTwo(String subtaskName, String pri, String time) {
        this.subtaskName = subtaskName;
        this.pri = pri;
        this.time = time;
    }

    public String getSubtaskName() {
        return subtaskName;
    }

    public void setSubtaskName(String subtaskName) {
        this.subtaskName = subtaskName;
    }

    public String getPri() {
        return pri;
    }

    public void setPri(String pri) {
        this.pri = pri;
    }

    public String getTime() {
        return time;
    }

    public void setTime(String time) {
        this.time = time;
    }
}

主类的代码：

package com.example.taskmasterv3;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Context;
import android.database.Cursor;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.widget.ListView;
import android.widget.TextView;

import java.util.ArrayList;

public class TaskSummary extends AppCompatActivity {

    ListView lvTaskList;
    TextView tvBreak, tvBreakAfterEvery, txt1, txt2, text1, hmm;
    TextView break_duration_mins;
    ArrayList<SubtaskPartTwo> subtaskList = new ArrayList<>();
    String subtname;
    String pri;
    String time;
    DBHelper dbHelper;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_task_summary);

        lvTaskList = findViewById(R.id.lvTaskList);
        tvBreak = findViewById(R.id.tvBreak);
        tvBreakAfterEvery = findViewById(R.id.tvBreakAfterEvery);
        txt1 = findViewById(R.id.txt1);
        txt2 = findViewById(R.id.txt2);
        break_duration_mins = findViewById(R.id.break_duration_mins);
        text1 = findViewById(R.id.text1);
        hmm = findViewById(R.id.hmm);
        dbHelper = new DBHelper(this);

        Cursor res = dbHelper.getdata();
        while(res.moveToNext()){
            subtname = dbHelper.getdata().getString(0);
            pri = dbHelper.getdata().getString(1);
            time = dbHelper.getdata().getString(2);
        }

        SubtaskDetailAdapter adapter = new SubtaskDetailAdapter(this, subtaskList);
        lvTaskList.setAdapter(adapter);
        SubtaskPartTwo subtaskPartTwo = new SubtaskPartTwo(subtname, pri, time);
        subtaskList.add(subtaskPartTwo);
        adapter.addANewSubTask(subtaskPartTwo);

        double working_hours = getIntent().getIntExtra("working_hours", 1);
        double working_minutes = getIntent().getIntExtra("working_minutes", 0);
        double without_break_hours = getIntent().getIntExtra("without_break_hours", 1);
        double without_break_minutes = getIntent().getIntExtra("without_break_minutes", 0);
        double break_duration = getIntent().getIntExtra("break_duration", 20);
        String a = working_hours + " h";
        txt1.setText(a);
        String b = working_minutes + " m";
        break_duration_mins.setText(b);
        String c = break_duration + " m";
        txt2.setText(c);

        //Mathematics

        double g = working_hours * 100;
        double h = g + working_minutes;
        double i = h + break_duration;
        double j = i / 60;
        double p = (int) j;
        double q = j - p;
        double r = q * 60;

        without_break_hours = p;
        without_break_minutes = r;

        String d = without_break_hours + " h";
        String e = without_break_minutes + " m";

        text1.setText(d);
        hmm.setText(e);

    }

}

列表适配器的代码：

package com.example.taskmasterv3;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;

import java.util.ArrayList;

public class SubtaskDetailAdapter extends ArrayAdapter<SubtaskPartTwo> {

    private final Context context;
    private ArrayList<SubtaskPartTwo> values;
    public boolean deleted;

    public SubtaskDetailAdapter(Context context, ArrayList<SubtaskPartTwo> list) {

        //since your are using custom view,pass zero and inflate the custom view by overriding getview

        super(context, 0 , list);
        this.context = context;
        this.values = list;

    }

    @Override
    public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {

        //check if its null, if so inflate it, else simply reuse it
        if (convertView == null) {
            LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = inflater.inflate(R.layout.task_summary_item, parent, false);
        }

        //use convertView to refer the childviews to populate it with data
        TextView tvSubtaskName = convertView.findViewById(R.id.tvlolitaskname);
        ImageView ivPri = convertView.findViewById(R.id.ivloliPri);
        ImageView ivTime = convertView.findViewById(R.id.ivloliTime);

        tvSubtaskName.setText(values.get(position).getSubtaskName());

        if (values.get(position).getPri().equals("h"))
        {
            ivPri.setImageResource(R.drawable.priority_high);
        }
        if (values.get(position).getPri().equals("m"))
        {
            ivPri.setImageResource(R.drawable.priority_med);
        }
        if (values.get(position).getPri().equals("l"))
        {
            ivPri.setImageResource(R.drawable.priority_low);
        }

        if (values.get(position).getTime().equals("more"))
        {
            ivPri.setImageResource(R.drawable.time_symbol_more);
        }
        if (values.get(position).getPri().equals("med"))
        {
            ivPri.setImageResource(R.drawable.time_symbol_med);
        }
        if (values.get(position).getPri().equals("less"))
        {
            ivPri.setImageResource(R.drawable.time_symbol_less);
        }

        //return the view you inflated
        return convertView;
    }

    //to keep adding the new subtasks try the following
    public void addANewSubTask(SubtaskPartTwo newSubTask){
        ArrayList<SubtaskPartTwo> newvalues = new ArrayList<>(this.values);
        newvalues.add(newSubTask);
        this.values = newvalues;
        notifyDataSetChanged();

    }

    }

任务应用程序上的游标索引超出边界异常

暂无答案！

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