android - 在 Android 2.2 中复制 SQLite 数据库时出现问题

Question

我必须设置 4.55Mb、2.2Mb 两个数据库。我们的目标是 2.2 版本。我尝试了一些方法，它设置了部分文件。(3096kb)。如果我们使用 API 10 那么它工作正常。如何才能我复制做什么？如何分块文件。

我这样试过:

private static String DB_PATH = "/data/data/com.android.xont.controller/databases/";
private static String DB_NAME = "";
private SQLiteDatabase ventura;
private final Context myContext;
// private SQLiteDatabase myDataBase=null;

    private DataBaseHelper myDbHelper;

public DataBaseHelper(Context context, String DB_NAME) {
    super(context, DB_NAME, null, 1);
    this.myContext = context;
    this.DB_NAME = DB_NAME;
}

/**
 * Creates a empty database on the system and rewrites it with your own
 * database.
 **/
public void createDataBase() throws IOException {
    boolean dbExist = checkDataBase();
    File Path = myContext.getDir("Data", 0);
    File DBFile = new File(Path, "DEMOUserVentura_HEMA.db");

    if (dbExist) {
    } else {
        this.getReadableDatabase().close();
        //this.getReadableDatabase().getPath();
        //System.out.println( " ===== " +   this.getReadableDatabase().getPath());
        try {
            copyDataBase();
        } catch (IOException e) {
            throw new Error(e);
        }
    }

}

private boolean checkDataBase() {
    SQLiteDatabase checkDB = null;
    try {
        String myPath = DB_PATH + DB_NAME;
        checkDB = SQLiteDatabase.openDatabase(myPath, null,SQLiteDatabase.OPEN_READONLY);
    } catch (SQLiteException e) {
        // database does't exist yet.
    }

    if (checkDB != null) {
        checkDB.close();
    }

    return checkDB != null ? true : false;
}

private void copyDataBase() throws IOException {
         //AssetManager am = myContext.getAssets();
         //String outFileName = DB_PATH + DB_NAME;
         // OutputStream os = new FileOutputStream(outFileName);
    //outFileName.createNewFile();
        // byte []b = new byte[1024];
       //int i, r;
      //String []Files = am.list("");
      // Arrays.sort(Files);
       //for(i=1;i<10;i++)
       //{
         // String fn = String.format("%d.db", i);
        //if(Arrays.binarySearch(Files, fn) < 0)
          // break;
        //InputStream is = am.open(fn);
       //  while((r = is.read(b)) != -1)
       //os.write(b, 0, r);
      //is.close();
       //  }
     //  os.close();

    // Open your local db as the input stream
    InputStream myInput = myContext.getAssets().open(DB_NAME);

    // Path to the just created empty db
    String outFileName = DB_PATH + DB_NAME;

    // Open the empty db as the output stream
    OutputStream myOutput = new FileOutputStream(outFileName);

    // transfer bytes from the inputfile to the outputfile
    byte[] buffer = new byte[1024];
    int length;
    while ((length = myInput.read(buffer)) > 0) {
        myOutput.write(buffer, 0, length);
    }

    // Close the streams
    myOutput.flush();
    myOutput.close();
    myInput.close();

}

public void openDataBase() throws SQLException {

    // Open the database
    String myPath = DB_PATH + DB_NAME;
    ventura = SQLiteDatabase.openDatabase(myPath, null,
            SQLiteDatabase.OPEN_READONLY);

}

@Override
public synchronized void close() {
    if (ventura != null)
        ventura.close();
        super.close();
}

请提供一些解决方案。请帮助我。

Answer 1

您看过 SQLite 备份 API 了吗:SQLite Backup API

它允许您使用 SQLite 本身以 block 的形式复制数据库文件，这可能会有所帮助。提供的链接包括一个简单的、有据可查的示例，尽管是用 C 语言编写的。