嗨，我不知道如何修复此游标错误，“java.lang.IllegalStateException：无法从 CursorWindow 读取第 0 行，第 1 列。”
Posted
技术标签:
【中文标题】嗨，我不知道如何修复此游标错误，“java.lang.IllegalStateException：无法从 CursorWindow 读取第 0 行，第 1 列。”【英文标题】：Hi, I can't figure out how to fix this cursor error, "java.lang.IllegalStateException: Couldn't read row 0, col 1 from CursorWindow." 【发布时间】：2019-09-13 00:08:26 【问题描述】：我对使用 android studio 还是很陌生，我不确定我什至可以做我想要在这里运行的事情。 我正在尝试运行从同一个表中提取的一些列表视图，当程序运行时，它会在这部分崩溃，说明光标。有什么想法吗？
日志猫
--------- beginning of crash
04-23 19:18:55.749 3100-3100/com.example.j3 E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.j3, PID: 3100
java.lang.RuntimeException: Unable to start activity ComponentInfocom.example.j3/com.example.j3.GroupList2: java.lang.IllegalStateException: Couldn't read row 0, col 1 from CursorWindow. Make sure the Cursor is initialized correctly before accessing data from it.
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
at android.app.ActivityThread.-wrap11(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.IllegalStateException: Couldn't read row 0, col 1 from CursorWindow. Make sure the Cursor is initialized correctly before accessing data from it.
at android.database.CursorWindow.nativeGetString(Native Method)
at android.database.CursorWindow.getString(CursorWindow.java:438)
at android.database.AbstractWindowedCursor.getString(AbstractWindowedCursor.java:51)
at com.example.j3.GroupList2.onViewData(GroupList2.java:61)
at com.example.j3.GroupList2.onCreate(GroupList2.java:38)
at android.app.Activity.performCreate(Activity.java:6237)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
at android.app.ActivityThread.-wrap11(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
主要代码
package com.example.j3;
import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.ListView;
import java.util.ArrayList;
public class GroupList2 extends AppCompatActivity
ListView listView, listView2, listView3, listView4;
SQLiteDatabase db;
Button clear;
ArrayList<String> listname, listLearningstyle;
@Override
protected void onCreate(Bundle savedInstanceState)
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_group_list);
clear = (Button) findViewById(R.id.clear);
listView = (ListView) findViewById(R.id.lv1);
listView2 = (ListView) findViewById(R.id.lv2);
listView3 = (ListView) findViewById(R.id.lv3);
listView4 = (ListView) findViewById(R.id.lv4);
db = openOrCreateDatabase("Mydata", Context.MODE_PRIVATE, null);
onViewData();
onViewData2();
onViewData3();
onViewData4();
clear.setOnClickListener(new View.OnClickListener()
@Override
public void onClick(View v)
deleteAll();
openStudents();
);
public void onViewData()
listname = new ArrayList<String>();
listLearningstyle = new ArrayList<String>();
listname.clear();
listLearningstyle.clear();
Cursor c = db.rawQuery("select NAME from id where LEARNINGSTYLE ='Visual' or LEARNINGSTYLE='VA' order by NAME desc, LEARNINGSTYLE desc ", null);
while (c.moveToNext())
listname.add(c.getString(1));
listLearningstyle.add(c.getString(2));
listView.setAdapter(new AdapterList2(GroupList2.this, listname, listLearningstyle)
);
//shows the 1st list view
public void onViewData2()
listname = new ArrayList<String>();
listLearningstyle = new ArrayList<String>();
listname.clear();
listLearningstyle.clear();
Cursor c = db.rawQuery("select NAME from id where LEARNINGSTYLE ='Kinesthetic' or LEARNINGSTYLE='VK' order by NAME desc, LEARNINGSTYLE desc ", null);
while (c.moveToNext())
listname.add(c.getString(1));
listLearningstyle.add(c.getString(2));
listView2.setAdapter(new AdapterList2(GroupList2.this, listname, listLearningstyle)
);
//shows the 2nd list view
public void onViewData3()
listname = new ArrayList<String>();
listLearningstyle = new ArrayList<String>();
listname.clear();
listLearningstyle.clear();
Cursor c = db.rawQuery("select NAME from id where LEARNINGSTYLE ='Aural' or LEARNINGSTYLE='VA' order by NAME desc, LEARNINGSTYLE desc ", null);
while (c.moveToNext())
listname.add(c.getString(1));
listLearningstyle.add(c.getString(2));
listView3.setAdapter(new AdapterList2(GroupList2.this, listname, listLearningstyle)
);
//shows the 3rd list view
public void onViewData4()
listname = new ArrayList<String>();
listLearningstyle = new ArrayList<String>();
listname.clear();
listLearningstyle.clear();
Cursor c = db.rawQuery("select NAME from id where LEARNINGSTYLE ='VAK' order by NAME desc, LEARNINGSTYLE desc ", null);
while (c.moveToNext())
listname.add(c.getString(1));
listLearningstyle.add(c.getString(2));
listView4.setAdapter(new AdapterList2(GroupList2.this, listname, listLearningstyle)
);
//shows the 4th list view
public void deleteAll()
db.delete("id", null, null); //delete all rows in a table
public void openStudents()
Intent intent = new Intent(this, Students.class);
startActivity(intent);
适配器列表
package com.example.j3;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;
import java.util.ArrayList;
public class AdapterList2 extends BaseAdapter
ArrayList<String> n, p;
GroupList2 l;
LayoutInflater inflater;
public AdapterList2(GroupList2 data, ArrayList<String> name, ArrayList<String> learningstyle)
this.l = data;
this.n = name;
this.p = learningstyle;
this.inflater = LayoutInflater.from(data);
@Override public int getCount()
return n.size();
@Override public Object getItem(int i)
return n.get(i);
@Override public long getItemId(int i)
return i;
@Override public View getView(int i, View view, ViewGroup viewGroup)
view=inflater.inflate(R.layout.adapter,viewGroup,false);
TextView tvname=(TextView)view.findViewById(R.id.tvName);
TextView tvlearningstyle=(TextView)view.findViewById(R.id.tvlearningstyle);
tvname.setText(n.get(i));
tvlearningstyle.setText(p.get(i));
return view;
适配器 xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_
android:layout_
android:orientation="vertical">
<TextView
android:id="@+id/tvName"
android:layout_
android:layout_
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:layout_marginBottom="8dp"
android:layout_weight="1"
android:text="Name"
android:textSize="20sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.016"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.14" />
<TextView
android:id="@+id/tvlearningstyle"
android:layout_
android:layout_
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:layout_marginBottom="8dp"
android:layout_weight="1"
android:text="Name"
android:textSize="20sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.055"
app:layout_constraintStart_toEndOf="@+id/tvName"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.14" />
</android.support.constraint.ConstraintLayout>
我这几天一直在尝试解决这个问题，我希望能提供一些意见。
【问题讨论】：
【参考方案1】：在您的“主代码”中，有如下几行：
Cursor c = db.rawQuery("select NAME from id where LEARNINGSTYLE ='Visual'
or LEARNINGSTYLE='VA' order by NAME desc, LEARNINGSTYLE desc ", null);
仅选择 1 列：NAME 从表 id（这真的是表名吗？）。
然后是这样的行：
listname.add(c.getString(1));
listLearningstyle.add(c.getString(2));
Cursor 的列索引是基于0，也就是说第一列的索引是0，第二列的索引是1，但是你尝试访问1和2！
但是，请记住，查询只获取了 1 列。
改为：
Cursor c = db.rawQuery("select NAME, LEARNINGSTYLE from id where LEARNINGSTYLE ='Visual'
or LEARNINGSTYLE='VA' order by NAME desc, LEARNINGSTYLE desc ", null);
此查询获取 2 列：NAME 和 LEARNINGSTYLE。
并将值添加到列表中，如下所示：
..................................................
listname.add(c.getString(0));
listLearningstyle.add(c.getString(1));
【讨论】：
您好，谢谢您的回复。是的，解决了这个错误，但现在我有了一个新错误：（原因：java.lang.NullPointerException：尝试在在 com.example.j3.GroupList2.onCreate(GroupList2.java:41) 的 com.example.j3.GroupList2.onViewData4(GroupList2.java:111) 处的空对象引用 这篇文章回答了你的问题。对于任何其他问题，您必须使用所有相关代码发布另一个问题。以上是关于嗨，我不知道如何修复此游标错误，“java.lang.IllegalStateException：无法从 CursorWindow 读取第 0 行，第 1 列。”的主要内容，如果未能解决你的问题，请参考以下文章