QR code Generator

This is how you can make a QR code .For my case, when you can scan the QR code and you will reach to the PayPal link with the total sum of the product in it)

Firstly by using ZXing you can create by using their ZXing web link : http://zxing.appspot.com/generator
or
you can write by using QRcodeWrite class:http://zxing.org/w/docs/javadoc/com/google/zxing/qrcode/QRCodeWriter.html
http://code.google.com/p/zxing/source/browse/trunk/core/src/com/google/zxing/qrcode/QRCodeWriter.java?r=1028

But first one is very limited.

1)Step by Step: notice the ZXing package: http://stackoverflow.com/questions/6376400/zxing-android-generate-1d-barcode
Then details inside : http://stackoverflow.com/questions/2489048/qr-code-encoding-and-decoding-using-zxing

2) image processing in ZXing library : http://code.google.com/p/zxing/source/browse/trunk/androidtest/src/com/google/zxing/client/androidtest/ZXingTestActivity.java

3) QR code writer in ZXing

http://cfsearching.blogspot.co.uk/2010/04/coldfusion-zxing-read-write-qrcode.html This is the CFC extention (not related with project)

4) Java android encoder (without using ZXing)

http://www.keepdynamic.com/barcode-for-android/

Encoding and Decoding through a web service:

http://groups.google.com/group/zxing/browse_thread/thread/ae31211ea7d70539/283b2878870ec66c?lnk=gst&q=endcoding+the+barcodes#283b2878870ec66c

BitMat (bit matrix) documentation

http://www.cs.rpi.edu/~atrem/papers/iswc_medha.pdf