我失败了所有的 CREATE TABLE；和带有错误的 INSERT 语句no such a table。
Android 2.3 不会发生这种情况。取而代之的是3.2。这是为什么？创建数据库时出错？
我的课堂示例：
public class MainActivity extends Activity {
DatabaseHelper databaseHelper = new DatabaseHelper(this);
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
String queryTest="create table TEST_TABLE(ID integer,T_MESSAGE text)";
databaseHelper.executeQuery(queryTest);
queryTest="INSERT INTO TEST_TABLE (ID,T_MESSAGE) VALUES (1,'1');";
databaseHelper.executeQuery(queryTest);
}
}
我的数据库：
public class DatabaseHelper extends SQLiteOpenHelper {
private static String DATABASE_NAME = "pro.db";
private static String DATABASE_PATH = "/data/data/it.sysman.mobile.contactpro/databases/";
private static final int SCHEMA_VERSION = 2;
public DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, SCHEMA_VERSION);
}
@Override
public void onCreate(SQLiteDatabase sqlDB) {
try {
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
}
private SQLiteDatabase openDataBase(int flag) {
SQLiteDatabase checkDB = null;
try {
Environment.getExternalStorageDirectory();
Environment.getDataDirectory();
Environment.getRootDirectory();
Environment.getExternalStorageState();
checkDB = getWritableDatabase();
} catch (Exception e) {
e.printStackTrace();
}
return checkDB;
}
public String executeQuery(String query) {
SQLiteDatabase sqlDB = null;
Cursor data = null;
try {
sqlDB = openDataBase(SQLiteDatabase.NO_LOCALIZED_COLLATORS);
data = sqlDB.rawQuery(query, null);
if (data.getCount() == 0)
return null;
} catch (Exception e) {
e.printStackTrace();
} finally {
if (data != null)
data.close();
if (sqlDB != null)
sqlDB.close();
}
return null;
}
}