Android QR Code Scanner using third party Library

Objective : In this tutorial we will learn how to use QR code scanning using third party library ZXingScanner in Android Application.

We will follow the steps ass below.

Step-1:
               Basic introduction of the QR code scanner.

-QR stands for Quick Response code which is a two dimensional barcode (matrix codes) that allows contents to be decoded at a high speed. QR code system is invented in 1994 by japanese company Denso-Wave.

-Quick Response code is a licence free and QR have the square dots which are arranged in a grid with white color background which are easily read by the scanner or camera which are called the imaging devices.

-QR code have the different different sizes which are starts from the 21X21 pixels which is version 1,25X25 pixels is version 2 and go on up to 177X177 which is version 40.

-QR codes storing the addresses and URLS may appear in newspapers,books,business cards..etc or any type of entity which user want the information.

-QR scanner decode the code so for mobile device its use the camera for decoding the       codes.

Step-2 
             Create new Project in Android Studio go to file new Project.


Step -3   Add library into Dependencies
               Open the build.gradle file and add the following library into file

  compile ' me.dm7.barcodescanner:zxing:1.8.4';

            Add this library and click on sync now.

Step -4  Creating Layout
              - For open camera and getting the QR code decoding we will take one buttong and click on the buttong we will open the camera for getting the QR codes.

  <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="QR Scanner"
        android:layout_margin="20dp"
        android:id="@+id/scanner"
        android:background="@color/colorPrimary"
        android:padding="5dp"
        android:textColor="@android:color/white"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintHorizontal_bias="0.501"
        app:layout_constraintVertical_bias="0.14" />

Step-5   Add following code  in java file 
      
     You have to implement the ZXingScannerView

       public void QrScanner(View view){


        mScannerView = new ZXingScannerView(this);   // Programmatically initialize the scanner view
        setContentView(mScannerView);

        mScannerView.setResultHandler(this); // Register ourselves as a handler for scan results.
        mScannerView.startCamera();         // Start camera

    }



 @Override
    public void handleResult(Result rawResult) {
        // Do something with the result here

        Log.e("handler", rawResult.getText()); // Prints scan results
        Log.e("handler", rawResult.getBarcodeFormat().toString()); // Prints the scan format (qrcode)

        // show the scanner result into dialog box.
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle("Scan Result");
        builder.setMessage(rawResult.getText());
        AlertDialog alert1 = builder.create();
        alert1.show();

        // If you would like to resume scanning, call this method below:
        // mScannerView.resumeCameraPreview(this);
    }



Here You can get full code


package com.qrcode.app;

import android.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;

import com.google.zxing.Result;
import me.dm7.barcodescanner.zxing.ZXingScannerView;

public class MainActivity extends AppCompatActivity implements ZXingScannerView.ResultHandler {
    private ZXingScannerView mScannerView;


    private Button scannerbtn;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        scannerbtn = (Button)findViewById(R.id.scanner);

        scannerbtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                QrScanner(view);
            }
        });

    }

    public void QrScanner(View view){


        mScannerView = new ZXingScannerView(this);   // Programmatically initialize the scanner view
        setContentView(mScannerView);

        mScannerView.setResultHandler(this); // Register ourselves as a handler for scan results.
        mScannerView.startCamera();         // Start camera

    }

    @Override
    public void onPause() {
        super.onPause();
        mScannerView.stopCamera();           // Stop camera on pause
    }

    @Override
    public void handleResult(Result rawResult) {
        // Do something with the result here

        Log.e("handler", rawResult.getText()); // Prints scan results
        Log.e("handler", rawResult.getBarcodeFormat().toString()); // Prints the scan format (qrcode)

        // show the scanner result into dialog box.
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle("Scan Result");
        builder.setMessage(rawResult.getText());
        AlertDialog alert1 = builder.create();
        alert1.show();

        // If you would like to resume scanning, call this method below:
        // mScannerView.resumeCameraPreview(this);
    }

}

output : 

I hope this tutorial is useful for all