android SQLite数据库..没有这样的表：

Question

我又遇到了另一个问题:( 我遇到的错误是它没有创建一个名为contacts的表，但我有创建数据库的代码，但它没有创建它。如何解决这个问题？再次感谢您的回答。

package com.mobilebasedsignlanguage;

import java.io.ByteArrayOutputStream;
import java.util.ArrayList;
import java.util.List;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.util.Log;
import android.widget.ListView;

public class alphaconv extends Activity {
ArrayList<Contact> imageArry = new ArrayList<Contact>();
ContactImageAdapter adapter;

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.alphabetview);

    DataBaseHandler db = new DataBaseHandler(this);
    //get image from drawable..
    Bitmap image = BitmapFactory.decodeResource(getResources(), R.drawable.a);

    //convert bitmap to byte
    ByteArrayOutputStream stream = new ByteArrayOutputStream();
    image.compress(Bitmap.CompressFormat.JPEG, 100, stream);
    byte imageInByte[] = stream.toByteArray();
    //Inserting Contacts
    Log.d("Insert: ", "Inserting ..");
    db.addContact(new Contact("A", imageInByte));

    //Read all contacts from db
    List<Contact> contacts = db.getAllContacts();
    for(Contact cn: contacts) {
        String log = "ID: " + cn.getID() + "Name: " + cn.getName() + ", Image: " + cn.getImage();

        Log.d("Result: ", log);
        imageArry.add(cn);
    }

    adapter = new ContactImageAdapter(this, R.layout.screen_list, imageArry);
    ListView dataList = (ListView)findViewById(R.id.list);
    dataList.setAdapter(adapter);

}

}

这是其他java类：

Contact.java

package com.mobilebasedsignlanguage;

public class Contact {

int _id;
String _name;
byte[] _image;

public Contact() {

}

public Contact(int keyId, String name, byte[] image) {
    this._id = keyId;
    this._name = name;
    this._image = image;
}

public Contact(String contactID, String name, byte[] image) {
    this._name = name;
    this._image = image;
}

public Contact(String name, byte[] image) {
    this._name = name;
    this._image = image;
}

public int getID() {
    return this._id;
}

public void setID(int keyId ) {
    this._id = keyId;
}

public String getName() {
    return this._name;
}

public void setName(String name) {
    this._name = name;
}

public byte[] getImage() {
    return this._image;
}

public void setImage(byte[] image) {
    this._image = image;
}

}

ContactImageAdapter.java

package com.mobilebasedsignlanguage;

import java.io.ByteArrayInputStream;
import java.util.ArrayList;

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;

public class ContactImageAdapter extends ArrayAdapter<Contact>{
Context context;
int layoutResourceId;

ArrayList<Contact> data=new ArrayList<Contact>();
public ContactImageAdapter(Context context, int layoutResourceId, ArrayList<Contact> data) {
    super(context, layoutResourceId, data);
    this.layoutResourceId = layoutResourceId;
    this.context = context;
    this.data = data;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    View row = convertView;
    ImageHolder holder = null;

    if(row == null)
    {
        LayoutInflater inflater = ((Activity)context).getLayoutInflater();
        row = inflater.inflate(layoutResourceId, parent, false);

        holder = new ImageHolder();
        holder.txtTitle = (TextView)row.findViewById(R.id.txtTitle);
        holder.imgIcon = (ImageView)row.findViewById(R.id.imgIcon);
        row.setTag(holder);
    }
    else
    {
        holder = (ImageHolder)row.getTag();
    }

    Contact picture = data.get(position);
    holder.txtTitle.setText(picture._name);

    byte[] outImage = picture._image;
    ByteArrayInputStream imageStream = new ByteArrayInputStream(outImage);
    Bitmap theImage = BitmapFactory.decodeStream(imageStream);
    holder.imgIcon.setImageBitmap(theImage);
    return row;
}

static class ImageHolder
{
    ImageView imgIcon;
    TextView txtTitle;
}


}

DbHandler.java

package com.mobilebasedsignlanguage;

import java.util.ArrayList;
import java.util.List;

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

public class DataBaseHandler extends SQLiteOpenHelper {

private static final int DATABASE_VERSION = 1;

private static final String DATABASE_NAME = "SLdb";

private static final String TABLE_CONTACTS = "contacts";

private static final String KEY_ID = "id";
private static final String KEY_NAME = "name";
private static final String KEY_IMAGE = "image";

public DataBaseHandler(Context context) {
    super(context, DATABASE_NAME, null, DATABASE_VERSION);
}

public void onCreate(SQLiteDatabase db) {
    String CREATE_CONTACTS_TABLE = "CREATE TABLE " + TABLE_CONTACTS + "("
            + KEY_ID + " INTEGER PRIMARY KEY," + KEY_NAME + " TEXT,"
            + KEY_IMAGE + " BLOB" + ")";
    db.execSQL(CREATE_CONTACTS_TABLE);
}

public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    db.execSQL("DROP TABLE IF EXISTS " + TABLE_CONTACTS);

    onCreate(db);
}

public void addContact(Contact contact) {
    SQLiteDatabase db = this.getWritableDatabase();

    ContentValues values = new ContentValues();
    values.put(KEY_NAME, contact._name);
    values.put(KEY_IMAGE, contact._image);

    db.insert(TABLE_CONTACTS, null, values);
    db.close();
}

Contact getContact(int id) {
    SQLiteDatabase db = this.getWritableDatabase();

    Cursor cursor = db.query(TABLE_CONTACTS, new String[] { KEY_ID,
            KEY_NAME, KEY_IMAGE }, KEY_ID + "=?",
            new String[] { String.valueOf(id) }, null,null,null,null);
    if(cursor != null)
        cursor.moveToFirst();

    Contact contact = new Contact(Integer.parseInt(cursor.getString(0)),
            cursor.getString(1), cursor.getBlob(1));

    return contact;
    }

public List<Contact> getAllContacts() {
    List<Contact> contactlist = new ArrayList<Contact>();
    String selectQuery = "SELECT * FROM contacts ORDER BY name";
    SQLiteDatabase db = this.getWritableDatabase();
    Cursor cursor = db.rawQuery(selectQuery, null);

    if(cursor.moveToFirst()) {
        do {
            Contact contact = new Contact();
            contact.setID(Integer.parseInt(cursor.getString(0)));
            contact.setName(cursor.getString(1));
            contact.setImage(cursor.getBlob(2));

            contactlist.add(contact);
        }while (cursor.moveToNext());
    }

    db.close();

    return contactlist;
}

public int updateContact(Contact contact) {
    SQLiteDatabase db = this.getWritableDatabase();

    ContentValues values = new ContentValues();
    values.put(KEY_NAME, contact.getName());
    values.put(KEY_IMAGE, contact.getImage());

    return db.update(TABLE_CONTACTS, values, KEY_ID + " = ?",
            new String[] { String.valueOf(contact.getID()) });      
}

public void deleteContact(Contact contact) {
    SQLiteDatabase db = this.getWritableDatabase();
    db.delete(TABLE_CONTACTS, KEY_ID + " = ?",
            new String[] {String.valueOf(contact.getID()) });
    db.close();
}

public int getContactsCount() {
    String countQuery = "SELECT * FROM " + TABLE_CONTACTS;
    SQLiteDatabase db = this.getReadableDatabase();
    Cursor cursor = db.rawQuery(countQuery, null);
    cursor.close();

    return cursor.getCount();
}

}

log cat的错误是：

02-18 11:49:25.938: E/SQLiteLog(6044): (1) no such table: contacts
02-18 11:49:26.078: E/SQLiteDatabase(6044): Error inserting image=[B@40e29b40 name=A
02-18 11:49:26.078: E/SQLiteDatabase(6044): android.database.sqlite.SQLiteException: no such table: contacts (code 1): , while compiling: INSERT INTO contacts(image,name) VALUES (?,?)

Answer 1

在onCreate方法中执行日志或toast以查看是否已调用它，如果是，则删除旧表，因为只调用一次，如果表已经存在，则不会再次执行。

另外，请尝试使用以下查询，有时create语句中的空格会导致问题。

 String CREATE_CONTACTS_TABLE = "CREATE TABLE " + TABLE_CONTACTS + " ("
        + KEY_ID + " INTEGER PRIMARY KEY, " + KEY_NAME + " TEXT, "
        + KEY_IMAGE + " BLOB" + ");";

Answer 2

问题是您没有覆盖SQLiteOpenHelper onCreate方法，因此没有被调用。

尝试在override和onCreate方法上添加onUpgrade注释：

@Override
public void onCreate(SQLiteDatabase db) {
     String CREATE_CONTACTS_TABLE = "CREATE TABLE " + TABLE_CONTACTS + "("
        + KEY_ID + " INTEGER PRIMARY KEY," + KEY_NAME + " TEXT,"
        + KEY_IMAGE + " BLOB" + ")";
     db.execSQL(CREATE_CONTACTS_TABLE);
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
     db.execSQL("DROP TABLE IF EXISTS " + TABLE_CONTACTS);

     onCreate(db);
}