我有几个月的时间开发Android作为hobbie,这是我第一次尝试使用数据库。我把这个类作为数据库助手:
public class ContactsDbAdapter {
public static final String KEY_NAME = "name";
public static final String KEY_CONTACT_ID = "contactID";
public static final String KEY_ROWID = "_id";
private static final String TAG = "ContactsDbAdapter";
private DatabaseHelper mDbHelper;
private SQLiteDatabase mDb;
private static final String DATABASE_CREATE = "create table contacts (_id integer primary key autoincrement, "
+ "name text not null, contactID text not null);";
private final Context mCtx;
private static final String DATABASE_NAME = "data";
private static final String DATABASE_TABLE = "contacts";
private static final int DATABASE_VERSION = 2;
private static class DatabaseHelper extends SQLiteOpenHelper {
DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
Log.v("t", "super(context,DATABSENAME,null..etc)");
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(DATABASE_CREATE);
Log.v("t", "db.execSQL(database_create)");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
//TODO
}
}
public ContactsDbAdapter(Context ctx) {
this.mCtx = ctx;
Log.v("t", "Constructor, this.mCtx=ctx");
}
public ContactsDbAdapter open() throws SQLException {
mDbHelper = new DatabaseHelper(mCtx);
mDb = mDbHelper.getWritableDatabase();
return this;
}
public void close() {
mDbHelper.close();
}
public long addContact(String name, String contactId) {
ContentValues initialValues = new ContentValues();
initialValues.put(KEY_NAME, name);
initialValues.put(KEY_CONTACT_ID, contactId);
return mDb.insert(DATABASE_TABLE, null, initialValues);
}
}
并在主要的Activity onCreate()方法上用
初始化数据库 mDbHelper = new ContactsDbAdapter(this);
mDbHelper.open();
然后在我的代码的某处我调用数据库
mDbHelper.addContact(name, contactId);
失败,因为数据库显然找不到名为contacts的表:
12-19 19:48:50.436: I/Database(276): sqlite returned: error code = 1, msg = no such table: contacts
任何想法我做错了,也许我在创建数据库时做错了。
谢谢!