java-java.lang.IllegalStateException:无法从CursorWindow读取行0，col -1 [英] java - java.lang.IllegalStateException: Couldn't read row 0, col -1 from CursorWindow
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问题描述
我正在创建一个使用SQLiteDatabase存储ListView项目的应用程序.但是，从数据库填充ListView中的数据时出现错误，并且应用程序崩溃.
I'm creating an app which uses SQLiteDatabase to store items of a ListView. But, I get an error while populating the data in the ListView from the Database, and the app crashes.
这是我的数据库-
import java.util.ArrayList;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class NotesDatabase extends SQLiteOpenHelper {
private static final String NOTE_NAME = "name";
private static final String NOTE_ID = "id";
private static final String NOTE_SUBJECT = "subject";
private static final String DATABASE_NAME = "notesDatabase";
private static final String TABLE_NOTES = "notes";
private static final int DATABASE_VERSION = 1;
private static final String CREATE_NOTES_TABLE = "CREATE TABLE " + TABLE_NOTES + "("
+ NOTE_ID + " INTEGER PRIMARY KEY," + NOTE_NAME + " TEXT,"
+ NOTE_SUBJECT + " TEXT" + ")";
public NotesDatabase(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
try {
db.execSQL(CREATE_NOTES_TABLE);
}
catch(SQLException e) {
e.printStackTrace();
}
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXSISTS topics");
onCreate(db);
}
public void addNote(Note note) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues notes = new ContentValues();
notes.put(NOTE_NAME, note.getNote());
notes.put(NOTE_SUBJECT, note.getSubject());
db.insert(TABLE_NOTES, null, notes);
db.close();
}
public void removeNote(Note note) {
SQLiteDatabase db = this.getWritableDatabase();
db.delete(TABLE_NOTES, NOTE_NAME + " = ?",
new String[] {note.getNote()});
db.close();
}
public ArrayList<Note> getNotes(){
ArrayList<Note> notes = new ArrayList<Note>();
String selectQuery = "SELECT * FROM " + TABLE_NOTES;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cur = db.rawQuery(selectQuery, null);
if(cur.moveToFirst()) {
do {
Note note = new Note();
note.setId(Integer.parseInt(cur.getString(0)));
note.setNote(cur.getString(cur.getColumnIndex(NOTE_NAME)));
note.setSubject(cur.getString(cur.getColumnIndex(NOTE_SUBJECT)));
notes.add(note);
} while(cur.moveToNext());
}
db.close();
return notes;
}
public void updateNote(String old_name, String new_name) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues topic = new ContentValues();
topic.put(NOTE_NAME, new_name);
db.update(TABLE_NOTES, topic, NOTE_NAME + " = ?",
new String[] {old_name});
db.close();
}
}
Note.java-
Note.java -
public class Note {
String _Note;
int _id;
String subject;
public String getSubject() {
return subject;
}
public void setSubject(String subject) {
this.subject = subject;
}
public Note() {
}
public Note(int id, String Note, String Subject) {
this._id = id;
this._Note = Note;
this.subject = Subject;
}
public Note(String Note, String Subject) {
this._Note = Note;
this.subject = Subject;
}
public Note(String Note) {
this._Note = Note;
}
public String getNote() {
return _Note;
}
public void setNote(String _Note) {
this._Note = _Note;
}
public int getId() {
return _id;
}
public void setId(int _id) {
this._id = _id;
}
}
NotesDatabase.java-
NotesDatabase.java -
import java.util.ArrayList;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
public class Notes_page extends Activity {
ArrayList<Note> notes = new ArrayList<Note>();
NotesDatabase ndb = new NotesDatabase(this);
private NoteAdapter adapter;
private ListView notes_list;
private TextView subject_display;
String subject;
int requestCode = 1;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_notes_page);
notes_list = (ListView) findViewById(R.id.notes);
ndb.getWritableDatabase();
notes = ndb.getNotes();
adapter = new NoteAdapter(this, notes);
subject = getIntent().getStringExtra("SUBJECT_NAME");
notes_list.setAdapter(adapter);
subject_display = (TextView) findViewById(R.id.subject_name);
subject_display.setText(subject);
}
public void onClickAddNewNote(View v) {
startActivityForResult(new Intent("com.Swap.Add_New_Note"), requestCode);
}
public void onActivityResult(int request_Code, int result_Code, Intent i) {
if(request_Code == requestCode) {
if(result_Code == RESULT_OK) {
Note mNote = new Note(i.getStringExtra("NOTE"), getIntent().getStringExtra("SUBJECT_NAME"));
ndb.getWritableDatabase();
ndb.addNote(mNote);
Log.d("AddNote", "Note Succesfully Added to Database");
adapter.add(mNote);
adapter.notifyDataSetChanged();
Toast.makeText(getBaseContext(), mNote.getNote(), Toast.LENGTH_SHORT).show();
}
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_notes_page, menu);
return true;
}
}
这是LogCat错误日志-
Here's the LogCat Error log -
04-13 22:17:10.766: E/linker(25692): load_library(linker.cpp:759): library "libmaliinstr.so" not found
04-13 22:17:14.816: E/CursorWindow(25692): Failed to read row 0, column -1 from a CursorWindow which has 1 rows, 2 columns.
04-13 22:17:14.869: E/AndroidRuntime(25692): FATAL EXCEPTION: main
04-13 22:17:14.869: E/AndroidRuntime(25692): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.Swap.RR/com.Swap.RR.Notes_page}: java.lang.IllegalStateException: Couldn't read row 0, col -1 from CursorWindow. Make sure the Cursor is initialized correctly before accessing data from it.
04-13 22:17:14.869: E/AndroidRuntime(25692): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2364)
04-13 22:17:14.869: E/AndroidRuntime(25692): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2416)
04-13 22:17:14.869: E/AndroidRuntime(25692): at android.app.ActivityThread.access$600(ActivityThread.java:174)
04-13 22:17:14.869: E/AndroidRuntime(25692): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1382)
04-13 22:17:14.869: E/AndroidRuntime(25692): at android.os.Handler.dispatchMessage(Handler.java:107)
04-13 22:17:14.869: E/AndroidRuntime(25692): at android.os.Looper.loop(Looper.java:194)
04-13 22:17:14.869: E/AndroidRuntime(25692): at android.app.ActivityThread.main(ActivityThread.java:5409)
04-13 22:17:14.869: E/AndroidRuntime(25692): at java.lang.reflect.Method.invokeNative(Native Method)
04-13 22:17:14.869: E/AndroidRuntime(25692): at java.lang.reflect.Method.invoke(Method.java:525)
04-13 22:17:14.869: E/AndroidRuntime(25692): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
04-13 22:17:14.869: E/AndroidRuntime(25692): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:606)
04-13 22:17:14.869: E/AndroidRuntime(25692): at dalvik.system.NativeStart.main(Native Method)
04-13 22:17:14.869: E/AndroidRuntime(25692): 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.
04-13 22:17:14.869: E/AndroidRuntime(25692): at android.database.CursorWindow.nativeGetString(Native Method)
04-13 22:17:14.869: E/AndroidRuntime(25692): at android.database.CursorWindow.getString(CursorWindow.java:434)
04-13 22:17:14.869: E/AndroidRuntime(25692): at android.database.AbstractWindowedCursor.getString(AbstractWindowedCursor.java:51)
04-13 22:17:14.869: E/AndroidRuntime(25692): at com.Swap.RR.NotesDatabase.getNotes(NotesDatabase.java:78)
04-13 22:17:14.869: E/AndroidRuntime(25692): at com.Swap.RR.Notes_page.onCreate(Notes_page.java:41)
04-13 22:17:14.869: E/AndroidRuntime(25692): at android.app.Activity.performCreate(Activity.java:5122)
04-13 22:17:14.869: E/AndroidRuntime(25692): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1146)
04-13 22:17:14.869: E/AndroidRuntime(25692): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2328)
04-13 22:17:14.869: E/AndroidRuntime(25692): ... 11 more
请帮助我弄清楚我的代码出了什么问题.在此先感谢！
Please help me figure out what's wrong with me code. Thanks in advance!!
推荐答案
您的主题行具有误导性.您的堆栈跟踪中的异常提示
Your subject line is misleading. The exception in your stacktrace says
Couldn't read row 0, col -1 from CursorWindow
这实际上意味着getColumnIndex()在Cursor中找不到指定的列，并且-1作为列索引返回.
which essentially means that getColumnIndex() could not find the specified column in the Cursor and -1 was returned as column index.
您的选择SELECT *包含表中的所有列.
Your selection SELECT * contains all columns from the table.
您的CREATE TABLE似乎包含您要在getNotes()中使用getColumnIndex()进行索引的所有列.
Your CREATE TABLE seems to contain all columns you're requesting the index of with getColumnIndex() in getNotes().
可能是您已添加一列，但测试设备仍具有不带该列的数据库文件.只需卸载您的应用程序或清除其数据即可删除旧的数据库文件，并在下一次运行时使onCreate()重新创建数据库.
Chances are that you've added a column but the test device still has a database file without that column. Just uninstall your app or clear its data to remove the old database file and make your onCreate() recreate the database on the next run.
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