private void collectNumbers()
	{
		mNumbers.clear();
		mNumberId = 0;
		TileValue value;
		final int size = mField.getWidth() * mField.getHeight();
		for (int tile = 0; tile < size; tile++ )
			if (mField.getMaskValue(tile).isOpen())
			{
				value = mField.getTileValue(tile);
				if ( !value.isBomb() && !value.isEmpty() && isBorder(tile)) addNumber(tile);
			}
	}