[JAVA] Read and generate QR code [Android]

Development environment

OS: macOS HighSierra Android Studio: 3.0.1

・ API level setting

build.gradle

android {
    compileSdkVersion 26
    defaultConfig {
        minSdkVersion 15
        targetSdkVersion 26
        }
}

Introducing the library

Library to use: zxing-android-embedded (3.6.0) https://github.com/journeyapps/zxing-android-embedded

How to add to the project: Add the following sentence to build.gradle (Module: app).

build.gradle

dependencies {
    ...
    compile 'com.journeyapps:zxing-android-embedded:3.6.0'
}

QR code reading

Start the reading camera

python

new IntentIntegrator(MainActivity.this).initiateScan();

Write the above code where you want to read. Change the part of MainActivity.this to the target Activity name and use it.

Acquisition of read results

@Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        IntentResult result = IntentIntegrator.parseActivityResult(requestCode, resultCode, data);
        if(result != null) {
            Log.d("readQR", result.getContents());
        } else {
            super.onActivityResult(requestCode, resultCode, data);
        }
    }

The read data can be received as a String type with getContents ().

QR code generation

python

//Character string to be QR coded
String data = "https://www.google.com";
//Specify the size of the QR code image(pixel)
int size = 500;


try {
    BarcodeEncoder barcodeEncoder = new BarcodeEncoder();
    //Create QR code with Bitmap
    Bitmap bitmap = barcodeEncoder.encodeBitmap(data,BarcodeFormat.QR_CODE, size, size);

    //Place the created QR code on the screen
    ImageView imageViewQrCode = (ImageView) findViewById(R.id.imageView);
    imageViewQrCode.setImageBitmap(bitmap);

} catch (WriterException e) {
    throw new AndroidRuntimeException("Barcode Error.", e);
}

-The contents of data are reflected in the QR code. -Specify the size of the image with size.

Prepare ImageView in the xml file corresponding to Acticity, Place the QR code created by Bitmap and display it on the screen.

** <If you want to specify the character code, error correction level, QR code version, etc.> **

python

String data = "https://www.google.com"; //Character string to be QR coded
//Specify the size of the QR code image(pixel)
int size = 500;

try {
    BarcodeEncoder barcodeEncoder = new BarcodeEncoder();

    HashMap hints = new HashMap();

    //Character code specification
    hints.put(EncodeHintType.CHARACTER_SET, "shiftjis");

    //Specify error correction level
        //L 7%Can be restored
        //M 15%Can be restored
        //Q 25%Can be restored
        //H 30%Can be restored
    hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.M);

    //Specify the QR code version
    hints.put(EncodeHintType.QR_VERSION, 20);

    Bitmap bitmap = barcodeEncoder.encodeBitmap(data, BarcodeFormat.QR_CODE, size, size, hints);

    ImageView imageViewQrCode = (ImageView) findViewById(R.id.imageView);
    imageViewQrCode.setImageBitmap(bitmap);

} catch (WriterException e) {
    throw new AndroidRuntimeException("Barcode Error.", e);
}

ʻEncode HintType` can be used to create a QR code with detailed specifications.