Transcript Document
Cosc 5/4730
Blackberry and Andriod
QR codes
What is QR code?
• A QR code (abbreviated from Quick Response code) is a
type of matrix barcode (or two-dimensional code) first
designed for the automotive industry.
• More recently, the system has become popular outside of
the industry due to its fast readability and large storage
capacity compared to traditional UPC barcodes.
• The code consists of black modules arranged in a square
pattern on a white background.
• The information encoded can be made up of four
standardized kinds ("modes") of data (numeric,
alphanumeric, byte/binary, Kanji), or by supported
extensions virtually any kind of data
From Wikipedia, http://en.wikipedia.org/wiki/QR_code
Anatomy of a QR code
QR app’s
• The Main api for QR codes comes from the ZXing
(“Zebra Crossing”).
• Which is part of google.com code
• http://code.google.com/p/zxing/
• Blackberry supports the APIs directly in the
com.google.zxing, since API 6.0.0
• Android does not have any built-in API (for it’s
own code…). Instead you need to install the
barcode Scanner apk (in the market and on the
zxing website)
– Version 3.72 (as of Jan 25, 2012)
Creating QR codes
• You can use XYing website to create QR code
• http://zxing.appspot.com/generator/
QR code
BLACKBERRY
QR codes
• Uses the com.google.zxing packages.
– Allows you to create QR very quickly and easily.
– You can also scan for QR codes
• Uses the camera and viewfinder, so some what
complex if you don’t already under the camera calls.
Creating/displaying the QR code.
• First delcare a QRCode variable
QRCode qrCode = new QRCode();
• This encodes the text with a low level (%7) of error correction
Encoder.encode(barcodeTextField.getText(), ErrorCorrectionLevel.L,
qrCode);
• Where barcodeTextField is a the text to encode in the QRcode
• From there we get the actual data matrix and convert it into a
bitmap
ByteMatrix barcode = qrCode.getMatrix();
Bitmap bitmap = BarcodeBitmap.createBitmap(barcode,
BARCODE_WIDTH);
– Where BARCODE_WIDTH is a constant 300.
• Now display the barcode in a bitmapField
barcodeField.setBitmap(bitmap);
Scanning a QR code.
• Requires use of the camera.
– So if you’ll need to back to get camera lecture for
a lot of the information about what is going on
with the viewfinder.
– We create a BarcodeScanner and BarcodeDecoder
• The decoder is feed to the scanner as well as “hints”
• We provide this information to the viewfinder as well
to find the QR code automatically.
– IE the camera will focus, etc and “take the picture”.
Coding it up.
•
First we create a hashtable to hold all of the hints that we can give the API about
how we want to scan a barcode to improve speed and accuracy.
Hashtable hints = new Hashtable();
•
The first thing going in is a list of formats. We could look for more than one at a
time, but it's much slower.
Vector formats = new Vector();
formats.addElement(BarcodeFormat.QR_CODE);
– This is where we would add other formats to look for.
hints.put(DecodeHintType.POSSIBLE_FORMATS, formats);
• We will also use the "TRY_HARDER" flag to make sure we get an accurate scan
hints.put(DecodeHintType.TRY_HARDER, Boolean.TRUE);
• We create a new decoder using those hints
BarcodeDecoder decoder = new BarcodeDecoder(hints);
Coding it up. (2)
• Finally we can create the actual scanner with a decoder and
a listener that will handle the data stored in the barcode.
We put that in our view screen to handle the display.
scanner = new BarcodeScanner(decoder, new
MyBarcodeDecoderListener() );
barcodeScreen = new
MyBarcodeScannerViewScreen(scanner);
• Once we get here, all the barcode scanning infrastructure
should be set up, so all we have to do is start the scan and
display the viewfinder
scanner.startScan();
theApp.pushScreen(barcodeScreen); //the viewfinder screen
BarcodeDecoderListener
• The listener is call when a the QR code has been
decoded with the text string.
class MyBarcodeDecoderListener implements
BarcodeDecoderListener {
public void barcodeDecoded(final String rawText) {
//close the viewfinder
//and decide what to do with the rawText
//like launch a browser if it’s an http://…
}
}
You can use BB qrDemo code
• Which is located here:
• The res/img has a demo barcode img file for the
simulator
QR code
ANDROID
First
• You will need to install the
BarcodeScannerX.apk into the simulator
– And download it first of course.
– Adb.exe install BarcodeScanner3.72.apk
– We’ll use intents to call it.
• It should noted, you can also import their
code and then it looks a lot like the Blackberry
code.
– We are not covering this
Encoding.
• Create the intent and call the activity.
• So for a simple one, text encoding.
Intent intent = new Intent(
"com.google.zxing.client.android.ENCODE");
intent.putExtra("ENCODE_TYPE", “TEXT_TYPE”);
intent.putExtra("ENCODE_DATA",
“http://www.cs.uwyo.edu);
startActivity(intent);
• The encoded QR will show on the screen.
Scanning
• Again, create an intent, but we’ll need a
result.
Intent intent = new Intent(
"com.google.zxing.client.android.SCAN");
intent.putExtra("com.google.zxing.client.android.SCAN.
SCAN_MODE", "QR_CODE_MODE");
startActivityForResult(intent, 0);
Scanning (2)
• Add the onActivityResult method
if (requestCode == 0) { //code used to call Scanner.
if (resultCode == RESULT_OK) {
String contents = intent.getStringExtra("SCAN_RESULT");
String format = intent.getStringExtra(
"SCAN_RESULT_FORMAT");
// Handle successful scan
} else if (resultCode == RESULT_CANCELED) {
// Handle cancel
}
}
All well and good, EXCEPT
• What happens if the BarcodeScanner app is
not installed?
– FORCE CLOSE!
• But there is code to handle it.
– xying has two java class you can add to your
project.
• IntentIntegrator.java and IntentResult.java
IntentIntegrator
• It checks to make sure the app is installed.
– If not, then it asks the user to get it from the
Market.
• Now you code doesn’t force close.
Create with the Integrator
• We call the integrator code, we included in the
project
IntentIntegrator integrator = new
IntentIntegrator( qrDemoActivity.this);
• Where qrDemoActivity is the name of your activity.
integrator.shareText(“http://www.cs.uwyo.edu”
);
• Again shows the qrCode or an error message if
there is a problem with the text.
Scan with the Integrator
• Same idea as creating, but again we need a
result
IntentIntegrator integrator = new
IntentIntegrator(qrDemoActivity.this);
– Where qrDemoActivity is the name of your activity.
integrator.initiateScan(
IntentIntegrator.QR_CODE_TYPES);
• And wait for the result in onActivityResult
Scan with the Integrator (2)
• In the onActivityResult method
//code to handle the intentintegrator, then
IntentResult scanResult =
IntentIntegrator.parseActivityResult(requestCode, resultCode, intent);
if (scanResult != null) {
// handle scan result
String contents = scanResult.getContents();
if (contents != null) {
logthis("[II] Scan result is "+ scanResult.toString());
} else {
logthis("[II] Scan failed or canceled");
}
} //handle the other result codes as needed.
You can use Android qrDemo code
• Which is located here:
refrences
• http://zxing.appspot.com/generator
• http://code.google.com/p/zxing/
• http://supportforums.blackberry.com/t5/JavaDevelopment/How-to-use-the-Barcode-API/tap/574569
• http://devblog.blackberry.com/2010/10/barcode
-api/
• http://stackoverflow.com/questions/9795501/ho
w-do-i-use-zxings-qr-barcode-scanner-withintentintegrator-and-intentresult
Q&A