Question

我正在尝试将我的sqlite数据库保存到SD卡。我尝试了一些事情，但我无法弄清楚，有些人给了我错误，例如它虽然创建了它但找不到表SD卡上的数据库。我最终删除了所有内容......

我需要添加或更改以保存到SD卡？为了说清楚，我不是要把它复制到SD卡，我试图把它保存在SD卡而不是内部存储器上。

到目前为止，这是我的数据库。

public class Backup_DB extends SQLiteOpenHelper {
private static final String DB_NAME = "backup.db";
private static final int DB_VERSION_NUMBER = 1;
private static final String DB_TABLE_NAME = "backup";
private static final String TAG = "CountriesDbAdapter";
private final Context mCtx;
private Backup_DB mDbHelper;
public static final String KEY_ROWID = "_id";
static final String DB_COLUMN_1_NAME = "country_name";

static final String DB_COLUMN_3_NAME = "country_price";

private static final String DB_CREATE_SCRIPT = "create table "
        + DB_TABLE_NAME
        + " ( _id INTEGER PRIMARY KEY AUTOINCREMENT,country_name text unique,country_price REAL)";

private SQLiteDatabase sqliteDBbackup = null;

public Backup_DB(Context context) {
    super(context, DB_NAME, null, DB_VERSION_NUMBER);
    this.mCtx = context;
}

public Backup_DB open() throws SQLException {
    mDbHelper = new Backup_DB(mCtx);
    sqliteDBbackup = mDbHelper.getWritableDatabase();
    return this;
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    // TODO: Implement onUpgrade

}

@Override
public void onCreate(SQLiteDatabase sqliteDBbackup) {
    Log.i("onCreate", "Creating the database...");
    sqliteDBbackup.execSQL(DB_CREATE_SCRIPT);
}

public void openDB() throws SQLException {
    Log.i("openDB", "Checking sqliteDBbackup...");
    if (this.sqliteDBbackup == null) {
        Log.i("openDB", "Creating sqliteDBbackup...");
        this.sqliteDBbackup = this.getWritableDatabase();

    }
}

public void closeDB() {
    if (this.sqliteDBbackup != null) {
        if (this.sqliteDBbackup.isOpen())
            this.sqliteDBbackup.close();
    }
}

public void insertCountry(String countryName, String countryPrice) {

    sqliteDBbackup.execSQL("INSERT OR IGNORE INTO " + DB_TABLE_NAME
            + "(country_name) VALUES('" + countryName + "')");

    sqliteDBbackup.execSQL("UPDATE " + DB_TABLE_NAME
            + " SET country_price=" + countryPrice
            + " WHERE country_name='" + countryName + "';");
}

Answer 1

SQLiteOpenHelper不是为创建外部数据库而构建的。在SQLiteOpenHelper构造函数中，传入上下文，它用于在包文件夹中创建文件。看一下源代码SQLiteOpenHelper。但是，您可以先在内部创建，然后再将其导出。请记住添加权限。

尝试我写的DBAssetHelper

这个助手类

导出：

new AssetDatabaseHelper(this,"test.sqlite").exportDatabase("/flder_toExport/canBerenamedhere.sqlite");

将数据库保存到SD卡

1 个答案: