如何将Android SQLite数据库存储到SD卡中

Question

如何将Android SQLite数据库存储到SD卡中

6

我刚刚创建了一个数据库，默认情况下它存储在data/data/database文件夹中。现在我想将数据库存储在sdcard中，我使用了以下代码，请建议在哪里添加代码。谢谢

代码:

    public class DataBaseHandler {
    SQLiteDatabase database;
    private static DataBaseHandler obj;
    private final String TABLE_NAME = "main_db";
    private final String COLUMN_FIRST = "_id";
    MovieDetails md = new MovieDetails();

    private DataBaseHandler(Context context) {
        DataBase dbobj = new DataBase(context, "Id_db.db", null, 1);
        database = dbobj.getWritableDatabase();
    }

    public static DataBaseHandler getinstance(Context context) {
        if (obj == null) {
            obj = new DataBaseHandler(context);
        }
        return obj;
    }

    public void insertData(String id) {
        try {
            ContentValues values = new ContentValues();
            values.put(COLUMN_FIRST, id);
            database.insert(TABLE_NAME, null, values);
        } catch (Exception er) {
            Log.d("Error is===", er.toString());
        }
    }

    public void deleteData(String id) {
        database.delete(TABLE_NAME, BaseColumns._ID + "=" + id, null);
    }

    public Cursor getData() {
        String[] columns = { BaseColumns._ID, COLUMN_FIRST };
        return database
                .query(TABLE_NAME, columns, null, null, null, null, null);
    }

    private class DataBase extends SQLiteOpenHelper {
        public DataBase(Context context, String name, CursorFactory factory,
                int version) {
            super(context, name, factory, version);
        }

        @Override
        public void onCreate(SQLiteDatabase db) {
            db.execSQL("CREATE TABLE " + TABLE_NAME + "(" + BaseColumns._ID
                    + " INTEGER PRIMARY KEY AUTOINCREMENT, " + COLUMN_FIRST
                    + " varchar(50)NOT NULL UNIQUE);");
        }

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        }
    }
}

- Dilip

可能是将内部数据库移动到SD卡上的可能性的重复问题。 - jfs

谢谢@jfs的回复，但是你能告诉我在我的上面的代码中哪里需要放置代码以将数据库存储在Sdcard中吗？ - Dilip

1个回答

网页内容由stack overflow 提供, 点击上面的

可以查看英文原文，
原文链接

- Lazy Ninja · Accepted Answer

使用这个类来复制您的数据库：

public class MyDatabaseTools {
  private String appName = "";
  private String packageName = "";

  public boolean backup() {
    boolean rc = false;

    boolean writeable = isSDCardWriteable();
    if (writeable) {
      File file = new File(Environment.getDataDirectory() + "/data/" + packageName + "/databases/" + MySQLiteOpenHelper.getDatabaseName());

      File fileBackupDir = new File(Environment.getExternalStorageDirectory(), appName + "/backup");
      if (!fileBackupDir.exists()) {
        fileBackupDir.mkdirs();
      }

      if (file.exists()) {
        File fileBackup = new File(fileBackupDir, MySQLiteOpenHelper.getDatabaseName());
        try {
          fileBackup.createNewFile();
          FileUtils.copyFile(file, fileBackup);
          rc = true;
        } catch (IOException ioException) {
          //
        } catch (Exception exception) {
          //
        }
      }
    }

    return rc;
  }

  private boolean isSDCardWriteable() {
    boolean rc = false;

    String state = Environment.getExternalStorageState();
    if (Environment.MEDIA_MOUNTED.equals(state)) {
      rc = true;
    }

    return rc;
  }

    public MyDatabaseTools(final Context context, final String appName) {
        this.appName = appName;
        packageName = context.getPackageName();
    }
}

如果您不了解如何使用它，请参考源。