如何将数据插入assets文件夹中的数据库文件

Question

我创建了一个SQLite文件并将其放在assets文件夹中.现在我能够从该文件中读取数据,但我不知道如何写入此数据库文件.我需要获取用户名和分数并将其存储到该数据库文件中.我在网上和SO上搜索了但是有正常数据库插入的例子.

任何人都可以告诉我如何将值存储到数据库文件中.我需要存储用户名和分数.想想这就像字符串一样,请给我一个例子吧.

Answer 1

您不应该在assets文件夹中创建数据库,因为我们只能从assets文件夹中读取数据.

实际上你应该在默认的内部文件夹中创建数据库,即data/data/[package-name]/databases 或者你也可以在sdcard中创建你的数据库,并且可以执行读写操作,但当然如果有的话它将无法运行没有SD卡.

以下是在SD卡中创建数据库的代码: -

    private SQLiteDatabase db;
    private static Context cntxt;

    public static File filename = null;
    public static String DATABASE_FILE_PATH_EXTERNAL = null;

    public DBHelper(Context context) {
            super(context, DATABASE_NAME, null,1);
            cntxt = context;
            try{
                try{
                    filename = Environment.getExternalStorageDirectory();
                }catch(Exception e){
                    Toast.makeText(DbHelper.cntxt, "Please Insert SD card To create Database", Toast.LENGTH_LONG).show();
                    Log.e("Log",e.getMessage(),e.fillInStackTrace());
                }

                DATABASE_FILE_PATH_EXTERNAL = filename.getAbsolutePath()+File.separator+DATABASE_NAME;

                //  db = SQLiteDatabase.openDatabase(DATABASE_FILE_PATH_EXTERNAL, null, SQLiteDatabase.OPEN_READWRITE + SQLiteDatabase.CREATE_IF_NECESSARY);
            }catch(Exception e){

                Log.e("Log",e.getMessage(),e.fillInStackTrace());
            }
        }



        @Override
        public synchronized SQLiteDatabase getWritableDatabase() {
            // TODO Auto-generated method stub
            try{
                db = SQLiteDatabase.openDatabase(DATABASE_FILE_PATH_EXTERNAL, null, SQLiteDatabase.OPEN_READWRITE + SQLiteDatabase.CREATE_IF_NECESSARY);
                try{
                    onCreate(db);
                }catch(Exception e){
                    Log.e("Log",e.getMessage(),e.fillInStackTrace());
                }
                return db;
            }catch(Exception e){
                Log.e("Log",e.getMessage(),e.fillInStackTrace());
                if(db!=null)
                    db.close();
            }
            return db;
        }// End of getWritableDatabase()



**Inserting  and Retrieving data from database:-**


public void insertIntoTable(String[] userName,int[] score)
    {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues cv = new ContentValues();

        try {
            db.beginTransaction();
            for (int i = 0; i < beatID.length; i++) {
                cv.put("UserName",userName[i]);
                cv.put("Score",score[i]);

                db.insert("TableName", "UserName",
                        cv);
            }
            db.setTransactionSuccessful();
        } catch (Exception ex) {

        } finally {
            db.endTransaction();
            db.close();
        }
    }


public void getUserNamePswd(){
        Cursor c = null;
        SQLiteDatabase db = null;
        try{
            db = this.getReadableDatabase();     
            c = db.rawQuery("Select UserName,Score from TableName",null);
            c.moveToFirst();
            String[] username = new String[c.getCount()];
            int[] score = new int[c.getCount()];            
            int counter = 0;
            c.moveToFirst();
            while(!c.isAfterLast()){
            username[counter] = c.getString(0);
            score[counter] = c.getInt(1);
            c.moveToNext();
            counter++;
            }


        }catch(Exception e){
            Log.e("Log", e.getMessage(), e.fillInStackTrace());
            return null;      
        }finally{
            c.close();
            db.close();
        }
    }