Apps Scanning QR code using Android's Mobile Vision API

[isurujn]

I followed this tutorial on how to build an Android app that can scan QR codes.

Here's the full code. I added the Google Play services using grade like so

compile 'com.google.android.gms:play-services:7.8.0'

AndroidManifest.xml

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

    <meta-data android:name="com.google.android.gms.vision.DEPENDENCIES" android:value="barcode"/>
    <uses-permission android:name="android.permission.INTERNET"/>
    <uses-permission android:name="android.permission.CAMERA"/>

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        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>
    </application>

</manifest>

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">

    <SurfaceView
        android:id="@+id/cameraView"
        android:layout_width="640px"
        android:layout_height="480px"
        android:layout_centerVertical="true"
        android:layout_alignParentLeft="true"/>

    <TextView
        android:id="@+id/infoTextView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_toRightOf="@+id/cameraView"
        android:layout_marginLeft="16dp"
        android:text="Nothing to read"
        android:textSize="20sp"/>

</RelativeLayout>

MainActivity.java

package bitinvent.io.qrscanner;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.util.SparseArray;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.widget.TextView;

import com.google.android.gms.vision.CameraSource;
import com.google.android.gms.vision.Detector;
import com.google.android.gms.vision.barcode.Barcode;
import com.google.android.gms.vision.barcode.BarcodeDetector;

import java.io.IOException;

public class MainActivity extends Activity {

    private SurfaceView cameraView;
    private TextView barcodeInfo;
    private CameraSource cameraSource;

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

        cameraView = (SurfaceView) findViewById(R.id.cameraView);
        barcodeInfo = (TextView) findViewById(R.id.infoTextView);

        BarcodeDetector detector = new BarcodeDetector.Builder(this).setBarcodeFormats(Barcode.QR_CODE).build();
        cameraSource = new CameraSource.Builder(this, detector).setRequestedPreviewSize(640, 480).build();

        cameraView.getHolder().addCallback(new SurfaceHolder.Callback() {
            @Override
            public void surfaceCreated(SurfaceHolder holder) {
                try {
                    cameraSource.start(cameraView.getHolder());
                } catch (IOException e) {
                    Log.e("CAMERA SOURCE", e.getMessage());
                }
            }

            @Override
            public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {

            }

            @Override
            public void surfaceDestroyed(SurfaceHolder holder) {
                cameraSource.stop();
            }
        });

        detector.setProcessor(new Detector.Processor<Barcode>() {
            @Override
            public void release() {

            }

            @Override
            public void receiveDetections(Detector.Detections<Barcode> detections) {
                final SparseArray<Barcode> barcodes = detections.getDetectedItems();
                if (barcodes.size() != 0) {
                    barcodeInfo.post(new Runnable() {
                        @Override
                        public void run() {
                            barcodeInfo.setText(barcodes.valueAt(0).displayValue);
                        }
                    });
                }
            }
        });
    }
}

I tested this on a HTC Desire 816 running Android 4.4.2. But it doesn't seem to work. The camera view is active but when pointed at a QR code, it doesn't detect anything. But no errors or crashes occur either.

Am I missing something?

 

[MLSDev]

Hi,
You could try using one of these two libraries instead of Android's Mobile Vision API:
https://github.com/dm77/barcodescanner
http://www.scandit.com/developers/

The second one is not free, but there is a community edition.

 

[isurujn]

Hi,
You could try using one of these two libraries instead of Android's Mobile Vision API:
https://github.com/dm77/barcodescanner
http://www.scandit.com/developers/

The second one is not free, but there is a community edition.

Thanks but I try not to use third-party libraries when native options are available.