请修复错误我试图在数据库中显示textview中的数据 数据库已创建，但未在textview中显示数据 和代码数据库文件为...
package com.example.databasetest;
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;
import android.provider.BaseColumns;
import android.util.Log;
public class DBHelper extends SQLiteOpenHelper{
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "teacher";
private static final String TABLE_NAME = "teacher_table";
private static final String NAME = "teacher_name";
private static final String FATHER_NAME = "father_name";
private static final String MOTHER_NAME = "mother_name";
SQLiteDatabase data=this.getWritableDatabase();
Context ctx;
public DBHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
ctx=context;
Log.d("DATABASE OPERATION", "DATABASE CREATED");
}
@Override
public void onCreate(SQLiteDatabase db) {
data=db;
db.execSQL("CREATE TABLE " + TABLE_NAME + " ("
+ BaseColumns._ID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
+ NAME + " TEXT,"
+ FATHER_NAME + " TEXT,"
+ MOTHER_NAME + " TEXT"
+ ");");
Log.d("DATABASE OPERATION", "TABLE CREATED");
}
public void open() throws SQLException
{
DBHelper db1 = new DBHelper(ctx);
data = db1.getWritableDatabase();
}
public void close()
{
data.close();
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXCEPTION EXISTS");
onCreate(db);
}
public void onInsert(DBHelper db,String name,String f_name, String m_name)
{
SQLiteDatabase sql= db.getWritableDatabase();
ContentValues cv=new ContentValues();
cv.put("teacher_name",name);
cv.put("father_name", f_name);
cv.put("mother_name", m_name);
sql.insert(TABLE_NAME, null, cv);
Log.d("DATABASE OPERATION", "ONE ROW INSERTED.....");
}
public Cursor getInformation(DBHelper dop)
{
SQLiteDatabase SQ=dop.getReadableDatabase();
String[] coloumns={NAME,FATHER_NAME,MOTHER_NAME};
Cursor CR=SQ.query(TABLE_NAME, coloumns, null, null, null, null, null);
return CR;
}
}
java活动为......
package com.example.databasetest;
import android.app.Activity;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.widget.TextView;
public class ShowDetail extends Activity{
SQLiteDatabase db;
TextView NAME,FATHERNAME,MOTHERNAME;
String name,fathername,mothername;
Context ctxx=this;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.show_data);
NAME=(TextView)findViewById(R.id.name);
FATHERNAME=(TextView)findViewById(R.id.father_name);
MOTHERNAME=(TextView)findViewById(R.id.mother_name);
DBHelper DB= new DBHelper(ctxx);
DB.open();
Cursor CR=DB.getInformation(DB);
if (CR.moveToFirst()) {
do {
name=CR.getString(0);
fathername=CR.getString(1);
mothername=CR.getString(2);
NAME.setText(name);
FATHERNAME.setText(fathername);
MOTHERNAME.setText(mothername);
} while (CR.moveToNext());
}
if (CR != null && !CR.isClosed()) {
CR.close();
}
if(DB!=null)
{
DB.close();
}
}
}
运行此代码后，我发现错误，所以我将活动代码更改为
DBHelper DB= new DBHelper(ctxx);
DB.open();
Cursor CR=DB.getInformation(DB);
if (CR.moveToFirst()) {
do {
name=CR.getString(1);
fathername=CR.getString(2);
mothername=CR.getString(3);
NAME.setText(name);
FATHERNAME.setText(fathername);
MOTHERNAME.setText(mothername);
} while (CR.moveToNext());
}
if (CR != null && !CR.isClosed()) {
CR.close();
}
if(DB!=null)
{
DB.close();
}
}
}
显示运行时错误为...
05-11 02:30:06.273: D/DATABASE OPERATION(894): DATABASE CREATED
05-11 02:30:06.333: D/DATABASE OPERATION(894): DATABASE CREATED
05-11 02:30:06.373: D/DATABASE OPERATION(894): ONE ROW INSERTED.....
05-11 02:30:06.683: I/Choreographer(894): Skipped 42 frames! The application may be doing too much work on its main thread.
05-11 02:30:07.373: D/DATABASE OPERATION(894): DATABASE CREATED
05-11 02:30:07.623: D/DATABASE OPERATION(894): DATABASE CREATED
05-11 02:30:07.723: E/CursorWindow(894): Failed to read row 0, column 3 from a CursorWindow which has 21 rows, 3 columns.
05-11 02:30:07.723: E/CursorWindow(894): Failed to read row 0, column 3 from a CursorWindow which has 21 rows, 3 columns.
05-11 02:30:07.984: D/dalvikvm(894): GC_FOR_ALLOC freed 154K, 9% free 2865K/3136K, paused 136ms, total 213ms
05-11 02:30:07.993: D/AndroidRuntime(894): Shutting down VM
05-11 02:30:07.993: W/dalvikvm(894): threadid=1: thread exiting with uncaught exception (group=0x41465700)
05-11 02:30:08.113: E/AndroidRuntime(894): FATAL EXCEPTION: main
05-11 02:30:08.113: E/AndroidRuntime(894): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.databasetest/com.example.databasetest.ShowDetail}: java.lang.IllegalStateException: Couldn't read row 0, col 3 from CursorWindow. Make sure the Cursor is initialized correctly before accessing data from it.
05-11 02:30:08.113: E/AndroidRuntime(894): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
05-11 02:30:08.113: E/AndroidRuntime(894): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
05-11 02:30:08.113: E/AndroidRuntime(894): at android.app.ActivityThread.access$600(ActivityThread.java:141)
05-11 02:30:08.113: E/AndroidRuntime(894): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
05-11 02:30:08.113: E/AndroidRuntime(894): at android.os.Handler.dispatchMessage(Handler.java:99)
05-11 02:30:08.113: E/AndroidRuntime(894): at android.os.Looper.loop(Looper.java:137)
05-11 02:30:08.113: E/AndroidRuntime(894): at android.app.ActivityThread.main(ActivityThread.java:5103)
05-11 02:30:08.113: E/AndroidRuntime(894): at java.lang.reflect.Method.invokeNative(Native Method)
05-11 02:30:08.113: E/AndroidRuntime(894): at java.lang.reflect.Method.invoke(Method.java:525)
05-11 02:30:08.113: E/AndroidRuntime(894): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
05-11 02:30:08.113: E/AndroidRuntime(894): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
05-11 02:30:08.113: E/AndroidRuntime(894): at dalvik.system.NativeStart.main(Native Method)
05-11 02:30:08.113: E/AndroidRuntime(894): Caused by: java.lang.IllegalStateException: Couldn't read row 0, col 3 from CursorWindow. Make sure the Cursor is initialized correctly before accessing data from it.
05-11 02:30:08.113: E/AndroidRuntime(894): at android.database.CursorWindow.nativeGetString(Native Method)
05-11 02:30:08.113: E/AndroidRuntime(894): at android.database.CursorWindow.getString(CursorWindow.java:434)
05-11 02:30:08.113: E/AndroidRuntime(894): at android.database.AbstractWindowedCursor.getString(AbstractWindowedCursor.java:51)
05-11 02:30:08.113: E/AndroidRuntime(894): at com.example.databasetest.ShowDetail.onCreate(ShowDetail.java:38)
05-11 02:30:08.113: E/AndroidRuntime(894): at android.app.Activity.performCreate(Activity.java:5133)
05-11 02:30:08.113: E/AndroidRuntime(894): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
05-11 02:30:08.113: E/AndroidRuntime(894): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175)
05-11 02:30:08.113: E/AndroidRuntime(894): ... 11 more
答案 0 :(得分：0)
列索引出错。为避免这种情况，您应首先使用getColumnIndex（NAME_OF_FIELD）函数获取列索引，然后您可以使用正确的索引访问数据。
int nameFieldColumnIndex = CR.getColumnIndex("teacher_name");
name= CR.getString(nameFieldColumnIndex);