Android Example Using Camera2 with Zxing for live scan of 1D and 2D barcodes

Johan Schoeman · Apr 12, 2020

This will show the "text" as well as the type of barcode that was scanned successfully. You still need to download and extract the jar from core-3.3.2.zip in post #1 above and copy the jar to your additional libs folder.

Some of the code:

B4X:

Sub t_tick
   
    Dim mbm As Bitmap = cam.GetPreviewBitmap(480, 640)
    ImageView1.Bitmap = mbm
    Dim s As String = nativeMe.RunMethod("decodeQRImage", Array(mbm))
    Label1.Text = s
    Log("S = " & s)
   
   
End Sub

#if Java

import com.google.zxing.MultiFormatWriter;
import android.graphics.Bitmap;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.BarcodeFormat;
import com.google.zxing.WriterException;
import com.google.zxing.qrcode.decoder.Version;

import android.graphics.BitmapFactory;

import com.google.zxing.BinaryBitmap;
import com.google.zxing.ChecksumException;
import com.google.zxing.FormatException;
import com.google.zxing.LuminanceSource;
import com.google.zxing.NotFoundException;
import com.google.zxing.RGBLuminanceSource;
import com.google.zxing.Reader;
import com.google.zxing.Result;
import com.google.zxing.common.HybridBinarizer;
import com.google.zxing.qrcode.QRCodeReader;
import com.google.zxing.MultiFormatReader;

public Result result;

public String decodeQRImage(Bitmap bMap) {

    String decoded = "";

    int[] intArray = new int[bMap.getWidth() * bMap.getHeight()];
    bMap.getPixels(intArray, 0, bMap.getWidth(), 0, 0, bMap.getWidth(),
            bMap.getHeight());
    LuminanceSource source = new RGBLuminanceSource(bMap.getWidth(),
            bMap.getHeight(), intArray);
    BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));

    Reader reader = new MultiFormatReader();
    try {
   
        result = reader.decode(bitmap);
        decoded = result.getText();
       
    } catch (NotFoundException e) {
         BA.Log("NotFoundException: " + e.getMessage());
    } catch (ChecksumException e) {
        BA.Log("ChecksumException: " + e.getMessage());
    } catch (FormatException e) {
        BA.Log("FormatException: " + e.getMessage());
    }
    if (decoded != "") {
       return decoded + "\r\n" + result.getBarcodeFormat().toString();
    } else {
       return decoded;  
    }  
}

#end if

Johan Schoeman · Apr 13, 2020

This update will add the resultpoints to the bitmap of the decoded barcode (1D / 2D). Have moved the imageview to (almost) bottom right hand side.

MARCO C. · Apr 18, 2020

hi everyone, but is it normal that I can only use the secondary camera ? is there any method to be able to use the primary one?
Thank you

Johan Schoeman · Apr 19, 2020

MARCO CORRIAS said:
hi everyone, but is it normal that I can only use the secondary camera ? is there any method to be able to use the primary one?
Thank you

Not sure I follow your question? What are you referring to with primary camera? The primary camera is usually the back facing camera. Or are you referring to the native Android camera?

MARCO C. · Apr 19, 2020

Johan Schoeman said:
The primary camera is usually the back facing camera.

Exact, instead, as I open the app, I do not start the "the back facing camera", but the front one .... the selfie one

Grazie

Johan Schoeman · Apr 19, 2020

MARCO CORRIAS said:
Exact, instead, as I open the app, I do not start the "the back facing camera", but the front one .... the selfie one

Grazie

See this in the code (frontCamera is set to false - so it will start the back facing camera. Change the value to True to start the front camera):

B4X:

Sub Process_Globals
    Private frontCamera As Boolean = False

B4X:

Sub OpenCamera (front As Boolean)
    rp.CheckAndRequest(rp.PERMISSION_CAMERA)
    Wait For Activity_PermissionResult (Permission As String, Result As Boolean)
    If Result = False Then
        ToastMessageShow("No permission!", True)
        Return
    End If
  
    SetState(False, False, VideoMode)
    Wait For (cam.OpenCamera(front)) Complete (TaskIndex As Int)
    If TaskIndex > 0 Then
        MyTaskIndex = TaskIndex 'hold this index. It will be required in later calls.
        Wait For(PrepareSurface) Complete (Success As Boolean)
        t.Enabled = True
    End If
    Log("Start success: " & Success)
    SetState(Success, False, VideoMode)
    If Success = False Then
        ToastMessageShow("Failed to open camera", True)
    End If
End Sub

MARCO C. · Apr 19, 2020

Johan Schoeman said:
Not sure I follow your question? What are you referring to with primary camera? The primary camera is usually the back facing camera. Or are you referring to the native Android camera?

solved, the smartphone does not allow me to switch the camera. thanks a lot

MARCO C. · Apr 19, 2020

Johan Schoeman said:

See this in the code (frontCamera is set to false - so it will start the back facing camera. Change the value to True to start the front camera):

B4X:

Sub Process_Globals
    Private frontCamera As Boolean = False

B4X:

Sub OpenCamera (front As Boolean)
    rp.CheckAndRequest(rp.PERMISSION_CAMERA)
    Wait For Activity_PermissionResult (Permission As String, Result As Boolean)
    If Result = False Then
        ToastMessageShow("No permission!", True)
        Return
    End If

    SetState(False, False, VideoMode)
    Wait For (cam.OpenCamera(front)) Complete (TaskIndex As Int)
    If TaskIndex > 0 Then
        MyTaskIndex = TaskIndex 'hold this index. It will be required in later calls.
        Wait For(PrepareSurface) Complete (Success As Boolean)
        t.Enabled = True
    End If
    Log("Start success: " & Success)
    SetState(Success, False, VideoMode)
    If Success = False Then
        ToastMessageShow("Failed to open camera", True)
    End If
End Sub

Thanks but
I think it's a hardware problem. On my Note 9 everything is ok. On an old Galaxy S4, which I use for testing, he answers me with
"Start success: false"
"NotFoundException: null"

Galaxy S4 : Version Android 5.0.1

Johan Schoeman · Apr 19, 2020

MARCO CORRIAS said:
Thanks but
I think it's a hardware problem. On my Note 9 everything is ok. On an old Galaxy S4, which I use for testing, he answers me with
"Start success: false"
"NotFoundException: null"

View attachment 92074

Galaxy S4 : Version Android 5.0.1

Change the code of OpenCamera(......) to:

B4X:

Sub OpenCamera (front As Boolean)
    rp.CheckAndRequest(rp.PERMISSION_CAMERA)
    Wait For Activity_PermissionResult (Permission As String, Result As Boolean)
    If Result = False Then
        ToastMessageShow("No permission!", True)
        Return
    End If
   
    SetState(False, False, VideoMode)
    Wait For (cam.OpenCamera(front)) Complete (TaskIndex As Int)
    If TaskIndex > 0 Then
        MyTaskIndex = TaskIndex 'hold this index. It will be required in later calls.
        Wait For(PrepareSurface) Complete (Success As Boolean)
    End If
    Log("Start success: " & Success)
    SetState(Success, False, VideoMode)
    If Success = False Then
        ToastMessageShow("Failed to open camera", True)
    Else
        t.Enabled = True
    End If  
End Sub

It should eliminate the NotFoundException: null error logged by the inline Java code.
The other error (Start success: false) is logged by the B4A code because opening the camera was not successful.

MARCO C. · Apr 19, 2020

negative,
same result.
If I understand correctly, it has moved
t.Enabled = True
in the IF block ??

hatzisn · Dec 2, 2020

MARCO CORRIAS said:
negative,
same result.
If I understand correctly, it has moved
t.Enabled = True
in the IF block ??

Maybe it is kind of a late response but better late than never.

Take a look at this link:

Samsung I9500 Galaxy S4 - Full phone specifications

www.gsmarena.com

In the link above you can see that the default Android is 4.2.2 and it is upgradeable to 5.0.1
Api version 4.2.2 is API level 17 and 5.0.1 is API level 21. Camera 2 API can be used from API level 21 so if you have not upgraded your phone's Android to 5.0.1 it is logical not to work.

I hope this helps.

Cristian Rufino · Aug 30, 2024

Hello everyone:

Is there a way to turn the flashlight on or off manually while trying to scan a code?
The example project works very well but would need to scan codes in low light conditions

Add the following code to the example, the idea is to leave the flashlight on only while touching the screen:

Torch On/Off:

Sub Process_Globals
' ...
' ...
' ...
    Private TorchOn As Boolean = False
End Sub

Private Sub pnlCamera_Touch (Action As Int, X As Float, Y As Float)
    Select Action
        Case 1
            If TorchOn Then
                TorchOn = False
                TurnTorchOnOff(False)
            End If
            
        Case 2
            If Not(TorchOn) Then
                TorchOn = True
                TurnTorchOnOff(True)
            End If
    End Select
End Sub

Private Sub TurnTorchOnOff(On As Boolean)
    Try
        Dim JOCam As JavaObject = cam.Camera
        Dim JOCamManager As JavaObject = JOCam.GetField("cameraManager")
        JOCamManager.RunMethod("setTorchMode", Array(cam.Camera.FindCameraId(False), On))
    Catch
        Log(LastException)
    End Try
End Sub

But the log returns the following error:

(ServiceSpecificException) android.os.ServiceSpecificException: setTorchMode:1628: Torch for camera "0" is not available due to an existing camera user (code 7)

Johan Schoeman · Aug 30, 2024

Cristian Rufino said:
Hello everyone:

Is there a way to turn the flashlight on or off manually while trying to scan a code?
The example project works very well but would need to scan codes in low light conditions

You will have to modify the CamEx2 class and add a button to the activity to control the torch (on/off). The inline Java code cannot be used to switch on/off the torch as the camera is already occupied by the Camera2 application. The inline java code only uses the preview frames from the Camera2 project to decode barcodes should there be any present in the preview frames passed from Carmera2 project to the inline java code.

xiaoyao · Nov 8, 2024

Johan Schoeman said:
This will show the "text" as well as the type of barcode that was scanned successfully. You still need to download and extract the jar from core-3.3.2.zip in post #1 above and copy the jar to your additional libs folder.

where is ( your additional libs folder.)? thank you

unpacked-core-1.9.0\res\values\values.xml:112: error: resource android:attr/lStar not found.
Originally SDK 28, replaced with SDK 33
Solution: core-33.2.jar needs to be placed in the libraries directory

it's ok,,thank you!

Android Example Using Camera2 with Zxing for live scan of 1D and 2D barcodes

Camera2 - Still images and videos

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Samsung I9500 Galaxy S4 - Full phone specifications

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