Question

I have created a database of objects. Each of these objects contains two strings and two bitmaps. When I do a getAllContacts() call to my database, the loading takes quite a while. For me its not a problem, but for the end-users, this would be annoying. When I load an object I set this options to my bitmaps saying:

  BitmapFactory.Options options=new BitmapFactory.Options();
  options.inSampleSize = 8;

Which will shrink the Bitmaps to 1/8 of the original height and width. But still, it takes around 10-15 seconds to load 50 records and fill this into a ListView. Is there any way I can check if the object I try to load is in the memory, also called paging? Or maybe I can load the Bitmaps, when the users presses one of the items in the ListView?

Thanks in advance!

Answer 1

The solution:

So, finally I found a solution to my problem. Instead of getting all of the Bitmaps when I do a getAllContact() call, the bitmap’s is loaded when the user presses a row in the ListView This is whats done in the setOnClickListener method in CustomAdapter for my ListView

String PCN = cases.get(position).getCaseNumber(); 
int tempPCN = Integer.valueOf(PCN); 
tempBitMapArray = dbHandler.getFinger(tempPCN); 

Bitmap left = tempBitMapArray[0]; 
Bitmap right = tempBitMapArray[1]; 

ByteArrayOutputStream bs1 = new ByteArrayOutputStream();
left.compress(Bitmap.CompressFormat.PNG, 100, bs1);

ByteArrayOutputStream bs2 = new ByteArrayOutputStream();
right.compress(Bitmap.CompressFormat.PNG, 100, bs2);

And the getFinger(...) method:

    public Bitmap[] getFinger(int pcn) {

    Bitmap[] fingers = new Bitmap[2]; 

    String SQLQUERY = "SELECT " + RIGHTFINGER + ", " + LEFTFINGER +" FROM " + TABLE_CASES  + " WHERE " + KEY_ID + "=" + pcn + ";"; 

    SQLiteDatabase db = this.getWritableDatabase(); 

    Cursor cursor = db.rawQuery(SQLQUERY, null); 
    BitmapFactory.Options options=new BitmapFactory.Options();
        options.inSampleSize = 2;
      if (cursor.moveToFirst()) {
            do {

                byte[] blob1 = cursor.getBlob(cursor.getColumnIndexOrThrow("leftFinger"));
                Bitmap bmp1 = BitmapFactory.decodeByteArray(blob1, 0, blob1.length, options);

                byte[] blob2 = cursor.getBlob(cursor.getColumnIndexOrThrow("rightFinger")); 
                Bitmap bmp2 = BitmapFactory.decodeByteArray(blob2, 0, blob2.length, options);

                fingers[0] = bmp1; 
                fingers[1] = bmp2;
                return fingers;

               } while(cursor.moveToNext());
      }
      return null; 
}

I hope this example will give other people a pinpoint in the right direction.