Simple Barcode and QR code scanner using Zxing or Zbar libraries

         When a requirement in your app to scan bar codes and QR codes, in this tutorial we will see how to scanning bar codes and QR codes. Here I am using Zxing and Zbar open source libraries. you can choose any one of the library.

Screen Shots:

Download Source Code

Step 1:  Build Gradle
              To start this application we need to include Zxing and Zbar dependencies in our build.gradle file.Check the below my build.gradle file.

build.gradle:

apply plugin: 'com.android.application'

android {
    compileSdkVersion 25
    buildToolsVersion "25.0.2"
    defaultConfig {
        applicationId "com.prasad.zxingscannerex"
        minSdkVersion 15
        targetSdkVersion 25
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    compile 'com.android.support:appcompat-v7:25.1.0'
    compile 'com.android.support.constraint:constraint-layout:1.0.0-beta4'
    testCompile 'junit:junit:4.12'

    compile 'me.dm7.barcodescanner:zxing:1.9'
    compile 'me.dm7.barcodescanner:zbar:1.9'


}

Step 2: XML Layouts
             Open activity_main.xml file and do the below changes.

activity_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#ffffff">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:layout_margin="10dp"
        android:orientation="vertical">

        <Button
            android:id="@+id/btn_scanner"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Zxing Scanner"
            android:textAllCaps="false" />

        <Button
            android:id="@+id/btn_zbar_scanner"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="20dp"
            android:text="Zbar Scanner"
            android:textAllCaps="false" />

    </LinearLayout>


</RelativeLayout>

Create a new layout resource name as activity_zxing_scanner.xml and modify below changes.

activity_zxing_scanner.xml:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#ffffff">


    <FrameLayout
        android:id="@+id/content_frame"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</RelativeLayout>

Create a new layout resource name as activity_zbar_scanner.xml and modify below changes.

activity_zbar_scanner.xml:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#ffffff">
    <FrameLayout
        android:id="@+id/content_frame"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</RelativeLayout>

Step 3: Java Classes
             Open MainActivity.java class and do the below changes.

MainActivity.java:

package com.prasad.zxingscannerex;

import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;

public class MainActivity extends AppCompatActivity {


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

        Button scannerBtn = (Button) findViewById(R.id.btn_scanner);
        Button zbarScannerBtn = (Button) findViewById(R.id.btn_zbar_scanner);

        scannerBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                Intent intent = new Intent(v.getContext(), ZxingScannerActivity.class);
                startActivity(intent);
            }
        });

        zbarScannerBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                Intent intent = new Intent(v.getContext(), ZbarScannerActivity.class);
                startActivity(intent);
            }
        });
    }
}

   Create a new Activity java class name as ZxingScannerActivity.java and modify below changes.

ZxingScannerActivity.java:

package com.prasad.zxingscannerex;

import android.Manifest;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.os.Handler;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.view.ViewGroup;
import android.widget.Toast;

import com.google.zxing.Result;

import me.dm7.barcodescanner.zxing.ZXingScannerView;

public class ZxingScannerActivity extends AppCompatActivity implements ZXingScannerView.ResultHandler {

    private ZXingScannerView mScannerView;
    static final Integer CAMERA = 0x1;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_zxing_scanner);

        ViewGroup contentFrame = (ViewGroup) findViewById(R.id.content_frame);
        mScannerView = new ZXingScannerView(this);
        contentFrame.addView(mScannerView);
        askForPermission(Manifest.permission.CAMERA, CAMERA);
    }

    private void askForPermission(String permission, Integer requestCode) {

        if (ContextCompat.checkSelfPermission(ZxingScannerActivity.this, permission) != PackageManager.PERMISSION_GRANTED) {

            // Should we show an explanation?
            if (ActivityCompat.shouldShowRequestPermissionRationale(ZxingScannerActivity.this, permission)) {

                //This is called if user has denied the permission before
                //In this case I am just asking the permission again
                ActivityCompat.requestPermissions(ZxingScannerActivity.this, new String[]{permission}, requestCode);

            } else {

                ActivityCompat.requestPermissions(ZxingScannerActivity.this, new String[]{permission}, requestCode);
            }
        } else {

            // Toast.makeText(this, "" + permission + " is already granted.", Toast.LENGTH_SHORT).show();
            mScannerView.setResultHandler(this);
            mScannerView.startCamera();
        }
    }


    @Override
    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        if (ActivityCompat.checkSelfPermission(this, permissions[0]) == PackageManager.PERMISSION_GRANTED) {
            switch (requestCode) {
                //Camera
                case 1:
                    mScannerView.setResultHandler(this);
                    mScannerView.startCamera();
                    break;


            }

            Toast.makeText(this, "Permission granted", Toast.LENGTH_SHORT).show();
        } else {
            Toast.makeText(this, "Permission denied", Toast.LENGTH_SHORT).show();
        }

    }


    @Override
    public void onPause() {
        super.onPause();
        mScannerView.stopCamera();
    }

    @Override
    public void handleResult(Result result) {

        Toast.makeText(this, "Contents = " + result.getText() +
                ", Format = " + result.getBarcodeFormat().toString(), Toast.LENGTH_SHORT).show();

        // * Wait 3 seconds to resume the preview.
        Handler handler = new Handler();
        handler.postDelayed(new Runnable() {
            @Override
            public void run() {
                mScannerView.resumeCameraPreview(ZxingScannerActivity.this);
            }
        }, 3000);

    }
}

  Create a new Activity java class name as ZbarScannerActivity.java and modify below changes.

ZbarScannerActivity.java:

package com.prasad.zxingscannerex;

import android.Manifest;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.os.Handler;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.view.ViewGroup;
import android.widget.Toast;

import me.dm7.barcodescanner.zbar.Result;
import me.dm7.barcodescanner.zbar.ZBarScannerView;


public class ZbarScannerActivity extends AppCompatActivity implements ZBarScannerView.ResultHandler {

    private ZBarScannerView mScannerView;
    static final Integer CAMERA = 0x1;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_zbar_scanner);

        ViewGroup contentFrame = (ViewGroup) findViewById(R.id.content_frame);
        mScannerView = new ZBarScannerView(this);
        contentFrame.addView(mScannerView);
        askForPermission(Manifest.permission.CAMERA, CAMERA);

    }

    private void askForPermission(String permission, Integer requestCode) {

        if (ContextCompat.checkSelfPermission(ZbarScannerActivity.this, permission) != PackageManager.PERMISSION_GRANTED) {

            // Should we show an explanation?
            if (ActivityCompat.shouldShowRequestPermissionRationale(ZbarScannerActivity.this, permission)) {

                //This is called if user has denied the permission before
                //In this case I am just asking the permission again
                ActivityCompat.requestPermissions(ZbarScannerActivity.this, new String[]{permission}, requestCode);

            } else {

                ActivityCompat.requestPermissions(ZbarScannerActivity.this, new String[]{permission}, requestCode);
            }
        } else {

            // Toast.makeText(this, "" + permission + " is already granted.", Toast.LENGTH_SHORT).show();
            mScannerView.setResultHandler(this);
            mScannerView.startCamera();
        }
    }


    @Override
    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        if (ActivityCompat.checkSelfPermission(this, permissions[0]) == PackageManager.PERMISSION_GRANTED) {
            switch (requestCode) {
                //Camera
                case 1:
                    mScannerView.setResultHandler(this);
                    mScannerView.startCamera();
                    break;


            }

            Toast.makeText(this, "Permission granted", Toast.LENGTH_SHORT).show();
        } else {
            Toast.makeText(this, "Permission denied", Toast.LENGTH_SHORT).show();
        }

    }


    @Override
    public void onPause() {
        super.onPause();
        mScannerView.stopCamera();
    }

    @Override
    public void handleResult(Result result) {

        Toast.makeText(this, "Contents = " + result.getContents() +
                ", Format = " + result.getBarcodeFormat().getName(), Toast.LENGTH_SHORT).show();
        
        // * Wait 3 seconds to resume the preview.       
        Handler handler = new Handler();
        handler.postDelayed(new Runnable() {
            @Override
            public void run() {
                mScannerView.resumeCameraPreview(ZbarScannerActivity.this);
            }
        }, 3000);
    }
}

4. Android Manifest
    Open AndroidManifest.xml add the Camera permission and declare activity classes.

    AndroidManifest.xml:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.prasad.zxingscannerex">

    <uses-permission android:name="android.permission.CAMERA" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name=".ZxingScannerActivity" />
        <activity android:name=".ZbarScannerActivity"></activity>
    </application>

</manifest>

5. Reference:
     Credits goes to this GitHub link.