如何存储在SD卡的Andr​​oid SQLite数据库

问题描述

我刚刚创建的数据库，它通过default.Now存储在数据/数据​​/数据​​库文件夹我想在SD卡存储数据库中，我使用下面的code.手电筒建议我在哪里都添加$ C $下that.Thanks

code：

 公共类数据库处理器{
    SQLiteDatabase数据库;
    私有静态数据库处理器OBJ;
    私人最终字符串TABLE_NAME =main_db;
    私人最终字符串COLUMN_FIRST =_id;
    MovieDetails MD =新MovieDetails（）;

    私人数据库处理器（上下文的背景下）{
        数据库dbobj =新的数据库（背景下，Id_db.db，NULL，1）;
        数据库= dbobj.getWritableDatabase（）;
    }

    公共静态数据库处理器的getInstance（上下文的背景下）{
        如果（OBJ == NULL）{
            OBJ =新的数据库处理器（上下文）;
        }
        返回OBJ;
    }

    公共无效insertData（字符串ID）{
        尝试 {
            ContentValues​​值=新ContentValues​​（）;
            values​​.put（COLUMN_FIRST，ID）;
            database.insert（TABLE_NAME，空，价值观）;
        }赶上（例外ER）{
            Log.d（错误是===，er.toString（））;
        }
    }

    公共无效deleteData（字符串ID）{
        database.delete（TABLE_NAME，BaseColumns._ID +=+ ID，NULL）;
    }

    公共光标的getData（）{
        的String []列= {BaseColumns._ID，COLUMN_FIRST};
        回数据库
                .query（TABLE_NAME，列，NULL，NULL，NULL，NULL，NULL）;
    }

    私有类数据库扩展SQLiteOpenHelper {
        公共数据库（上下文的背景下，字符串名称，CursorFactory厂，
                INT版）{
            超（背景下，名称，厂家，版本）;
        }

        @覆盖
        公共无效的onCreate（SQLiteDatabase DB）{
            db.execSQL（CREATE TABLE+ TABLE_NAME +（+ BaseColumns._ID
                    +INTEGER PRIMARY KEY AUTOINCREMENT，+ COLUMN_FIRST
                    +VARCHAR（50）NOT NULL UNIQUE）;）;
        }

        @覆盖
        公共无效onUpgrade（SQLiteDatabase分贝，INT oldVersion，诠释静态网页）{
        }
    }
}
 

解决方案

使用这个类来复制你的数据库：

 公共类MyDatabaseTools {
  私人字符串的appName =;
  私人字符串的packageName =;

  公共布尔备份（）{
    布尔RC = FALSE;

    布尔可写= isSDCardWriteable（）;
    如果（写）{
      档案文件=新的文件（Environment.getDataDirectory（）+/数据/+的packageName +/数据库/+ MySQLiteOpenHelper.getDatabaseName（））;

      文件fil​​eBackupDir =新的文件（Environment.getExternalStorageDirectory（）的appName +/备份）;
      如果（！fileBackupDir.exists（））{
        fileBackupDir.mkdirs（）;
      }

      如果（file.exists（））{
        文件文件备份=新的文件（fileBackupDir，MySQLiteOpenHelper.getDatabaseName（））;
        尝试 {
          fileBackup.createNewFile（）;
          FileUtils.copyFile（文件，文件备份）;
          RC = TRUE;
        }赶上（IOException异常IOException异常）{
          //
        }赶上（例外的例外）{
          //
        }
      }
    }

    返回RC;
  }

  私人布尔isSDCardWriteable（）{
    布尔RC = FALSE;

    字符串状态= Environment.getExternalStorageState（）;
    如果（Environment.MEDIA_MOUNTED.equals（州））{
      RC = TRUE;
    }

    返回RC;
  }

    公共MyDatabaseTools（最终上下文的背景下，最终字符串的appName）{
        this.appName =的appName;
        的packageName = context.getPackageName（）;
    }
}
 

请参考，如果你不知道如何使用它的来源。

I have just created database,its stored in data/data/database folder by default.Now i wanna store database in sdcard,I have used following code.please suggest me where have to add code for that.Thanks

Code:

    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) {
        }
    }
}

解决方案

Use this class to copy your DB:

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();
    }
}

Please refer to the Source if you dont understand how to use it.

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