Google Vision API Demo - BarCode Reader Using Android Studio

Introduction

Today, you are going to learn about the Google Vision API using Android Studio and we are going to build a barcode reader app to scan the barcodes. Please follow the below steps carefully to build the Barcode Reader App.

Google API

• Google Vision API is used to find the objects like images, faces in photos, and videos, and barcodes.
• It recognizes the texts and other things which are digitally captured; thus, it is very useful to build our barcode reader app.

Barcode API Overview

• This app will let us to detect the information from a barcode with the help of Vision API.
• A barcode is classified into 1d Barcode and 2d Barcode.
• To know more about it, you can visit the Barcode API information page from Google Developers portal.

Requirements

•  Android Studio
• How to code 
• Understanding basic functionlaities of how API works
• Free to learn 

Steps to follow

Add the below code in "build gradle" to add library files to our Barcode reader.

compile 'com.google.android.gms:play-services-vision:11.0.2'

Now, we are going to include Barcode Reader library to work correctly. First, we need to build the gradle codes and Android Hive. Then, add Barcode Reader code to it.

build.gradle
dependencies {

    implementation 'info.androidhive:barcode-reader:1.1.5'
    implementation 'com.google.android.gms:play-services-vision:11.0.2'
}

It is time to add Activity fragment to which we can invoke the Camera fragment.

<fragment
        android:id="@+id/barcode_scanner"
        android:name="info.androidhive.barcode.BarcodeReader"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:auto_focus="true"
        app:use_flash="false" />
This is code for Camera Actvity

Now, let's add the following code to work our project correctly and name it as BarcodeReader.BarcodeReader.java in class library.

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.SparseArray;
import com.google.android.gms.vision.barcode.Barcode;
import java.util.List;

import info.androidhive.barcode.BarcodeReader;

public class MainActivity extends AppCompatActivity implements BarcodeReader.BarcodeReaderListener {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_scan);
    }

    @Override
    public void onScanned(Barcode barcode) {
        // single barcode scanned
    }

    @Override
    public void onScannedMultiple(List<Barcode> list) {
        // multiple barcodes scanned
    }

    @Override
    public void onBitmapScanned(SparseArray<Barcode> sparseArray) {

    }

    @Override
    public void onScanError(String s) {
        // now scan error
    }

    @Override
    public void onCameraPermissionDenied() {
        // camera permission actually denied
    }
}

Add this following Java Code MyClass java file in iy.

import android.app.Application;
import android.text.TextUtils;
import com.android.volley.Request;
public class MyApplication extends Application {

    public static final String TAG = MyApplication.class
            .getSimpleName();

    private RequestQueue mRequestQueue;

    private static MyApplication mInstance;

    @Override
    public void onCreate() {
        super.onCreate();
        mInstance = this;
    }

    public static synchronized MyApplication getInstance() {
        return mInstance;
    }

    public RequestQueue getRequestQueue() {
        if (mRequestQueue == null) {
            mRequestQueue = Volley.newRequestQueue(getApplicationContext());
        }

        return mRequestQueue;
    }

    public <T> void addToRequestQueue(Request<T> req, String tag) {
        // set the default tag if tag is empty
        req.setTag(TextUtils.isEmpty(tag) ? TAG : tag);
        getRequestQueue().add(req);
    }

    public <T> void addToRequestQueue(Request<T> req) {
        req.setTag(TAG);
        getRequestQueue().add(req);
    }

    public void cancelPendingRequests(Object tag) {
        if (mRequestQueue != null) {
            mRequestQueue.cancelAll(tag);
        }
    }
}

Now, add the following XAML code to add the user interface in activity.main.xaml page. 

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/bg_gradient"
    tools:context="info.androidhive.movietickets.MainActivity">
 //akshayrao code
    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerInParent="true"
        android:gravity="center"
        android:orientation="vertical"
        android:paddingLeft="40dp"
        android:paddingRight="40dp">

        <ImageView
            android:id="@+id/icon"
            android:layout_width="100dp"
            android:layout_height="100dp"
            android:layout_centerHorizontal="true"
            android:clickable="true"
            android:foreground="?attr/selectableItemBackground"
            android:src="@drawable/qrcode"
            android:tint="@android:color/white" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="30dp"
            android:fontFamily="sans-serif-light"
            android:gravity="center"
            android:text="Scan the QR code on the poster and book your movie tickets"
            android:textColor="@android:color/white"
            android:textSize="16dp" />
    </LinearLayout>

    <Button
        android:id="@+id/btn_scan"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:layout_marginBottom="40dp"
        android:background="@android:color/transparent"
        android:foreground="?attr/selectableItemBackground"
        android:paddingLeft="20dp"
        android:paddingRight="20dp"
        android:fontFamily="sans-serif-medium"
        android:text="Scan QR Code"
        android:textColor="@android:color/white"
        android:textSize="18sp" />

</RelativeLayout>

Now, the application has been successully created. Debug it to get the certain output.

 

 

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