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在我的 Android 应用程序中,我想使用我现有的 sqlite 数据库。我遵循http://www.reigndesign.com/blog/using-your-own-sqlite-database-in-android-applications/本教程并成功复制数据库文件。但我的问题是我无法访问复制的数据库。任何人都可以检查我的代码并帮助我访问我的数据库吗?谢谢你..

这是我用来复制数据库的方法,

public class Databaseopenhelper extends SQLiteOpenHelper {



    //The Android's default system path of your application database.
    private static String DB_PATH = "/data/data/com.basim.database/databases/";

    private static String DB_NAME = "db3";

    private SQLiteDatabase myDataBase; 

    private final Context myContext;

    /**
     * Constructor
     * Takes and keeps a reference of the passed context in order to access to the application assets and resources.
     * @param context
     */
    public Databaseopenhelper(Context context) {

        super(context, DB_NAME, null, 1);
        this.myContext = context;
    }   

  /**
     * Creates a empty database on the system and rewrites it with your own database.
     * */
    public void createDataBase() throws IOException{

        boolean dbExist = checkDataBase();

        if(dbExist){
            //do nothing - database already exist
        }else{

            //By calling this method and empty database will be created into the default system path
               //of your application so we are gonna be able to overwrite that database with our database.
            this.getReadableDatabase();

            try {

                copyDataBase();

            } catch (IOException e) {

                throw new Error("Error copying database");

            }
        }

    }

    /**
     * Check if the database already exist to avoid re-copying the file each time you open the application.
     * @return true if it exists, false if it doesn't
     */
    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;
    }

    /**
     * Copies your database from your local assets-folder to the just created empty database in the
     * system folder, from where it can be accessed and handled.
     * This is done by transfering bytestream.
     * */
    private void copyDataBase() throws IOException{

        //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;
        myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);

    }

    @Override
    public synchronized void close() {

            if(myDataBase != null)
                myDataBase.close();

            super.close();

    }

    @Override
    public void onCreate(SQLiteDatabase db) {

    }

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

    }

        // Add your public helper methods to access and get content from the database.
       // You could return cursors by doing "return myDataBase.query(....)" so it'd be easy
       // to you to create adapters for your views.

}

我想知道如何访问复制的数据库文件。

4

2 回答 2

1

检查这个方法。这样你就可以像往常一样透明地使用你的 SQLiteOpenHelper 实现。无特殊处理。
使用带有 SQLiteOpenHelper 的预加载 sqlite 数据库

于 2012-09-30T13:51:38.770 回答
0

试试这个方法。

private DataBaseHelper dataBaseHelper;
    private SQLiteDatabase sqLiteDatabase;
sqLiteDatabase = dataBaseHelper.getReadableDatabase();
cursor = sqLiteDatabase.rawQuery("SELECT * FROM TABLE_NAME", null);
        if (cursor != null) {
            try {
                cursor.moveToFirst();
                do {
                    int abc=
                            cursor.getString(cursor.getColumnIndex("TABLE_COLOUM_NAME")),

                } while (cursor.moveToNext());
            } finally {
                cursor.close();
                sqLiteDatabase.close();
            }

        }

谢谢

于 2012-06-25T05:08:51.227 回答