Android Development: Generating an EAN13 Barcode

Android Development Device

Introduction

The European Article Number, or EAN, is a standard European barcode which is designed to encode the identification of a product and its manufacturer and is a superset of the American standard, UPC. The format of the EAN13 barcode encodes a string of 12 characters followed by a 13th character which acts as the control number and is calculated through a formula based on the first 12 characters. 

Nowadays, barcodes are used everywhere. If you earn a living as a programmer, sooner or later the need of support of barcodes in your applications will come up. For example, it may be supermarket bonus system, where user is identified by barcode from his phone to get discount, or such payment systems as Starbucks moble payment network. In this article will be explained how to generate EAN13 barcodes on Android screen.  

The Russian version of this article can be found at  http://plaincodesource.blogspot.com/2011/02/android-ean13.html 

EAN13 Calculation Basics

EAN13 barcode uses  a 12 digits product code, the thirteenth digit is a control number, which is calculated on the basis of first 12 digits. Calculation of control number ( digits numbered from right to left ) looks like this:

  • P1 = the sum of even digits 
  • P2 = the sum of odd digits
  • Z = P1 + 3 * P2 
  • R = the number divisible by 10 immediately superior to Z
  • Control number = R – Z

Next, let’s see on EAN13 encoding system:

  • The first digit is not encoded
  • Each 6 following digit is encoded according to the first digit
  • The 6 last digits are converted by the strict rule
First digit  Left 6 digits  Right 6 digits 
LLLLLL  RRRRRR 
LLGLGG  RRRRRR  
LLGGLG  RRRRRR  
LLGGGL  RRRRRR  
LGLLGG  RRRRRR  
LGGLLG  RRRRRR  
LGGGLL  RRRRRR  
LGLGLG  RRRRRR  
LGLGGL  RRRRRR  
LGGLGL  RRRRRR  

Encoding for the digits:

Digit  L – code  G – code  R – code 
0001101  0100111  1110010 
0011001  0110011  1100110 
0010011  0011011  1101100 
0111101  0100001  1000010 
0100011  0011101  1011100 
0110001  0111001  1001110 
0101111  0000101  1010000 
0111011  0010001  1000100 
0110111  0001001  1001000 
0001011  0010111  1110100 

More by Author

Must Read