Modernize Android qrcode module with CameraX and zxing-cpp

The qrcode module used deprecated APIs like android.hardware.Camera and Play Services Vision API. Replace these with AndroidX CameraX and open source zxing-cpp. zxing-cpp works on all devices, no matter if they have Play Services or not.

Author: nift4

hellocardboard-android/build.gradle

@@ -1,7 +1,7 @@
 apply plugin: 'com.android.application'
 
 android {
-    compileSdkVersion 33
+    compileSdk = 34
     lintOptions {
         abortOnError false
     }
@@ -16,7 +16,7 @@ android {
         //
         // See the release notes for details.
         minSdkVersion 26
-        targetSdkVersion 33
+        targetSdkVersion 34
         versionCode 1
         versionName "1.25.0"
         testInstrumentationRunner 'androidx.test.runner.AndroidJUnitRunner'
@@ -41,12 +41,14 @@ android {
 
 dependencies {
     implementation fileTree(dir: 'libs', include: ['*.jar'])
-    implementation 'androidx.appcompat:appcompat:1.6.1'
-    // Android Mobile Vision
-    // TODO(b/213613345) Migrate to ML Kit.
-    implementation 'com.google.android.gms:play-services-vision:20.1.3'
+    implementation 'androidx.appcompat:appcompat:1.7.0'
+    implementation 'io.github.zxing-cpp:android:2.2.0'
     implementation 'com.google.android.material:material:1.6.1'
     implementation 'com.google.protobuf:protobuf-javalite:3.19.4'
+    implementation 'androidx.camera:camera-core:1.3.4'
+    implementation 'androidx.camera:camera-view:1.3.4'
+    implementation 'androidx.camera:camera-lifecycle:1.3.4'
+    implementation 'androidx.camera:camera-camera2:1.3.4'
     implementation project(":sdk")
 }
 

sdk/build.gradle

@@ -2,7 +2,7 @@ apply plugin: 'com.android.library'
 apply plugin: 'com.google.protobuf'
 
 android {
-    compileSdkVersion 33
+    compileSdk = 34
     lintOptions {
         abortOnError false
     }
@@ -16,7 +16,7 @@ android {
         //
         // See the release notes for details.
         minSdkVersion 26
-        targetSdkVersion 33
+        targetSdkVersion 34
         testInstrumentationRunner 'androidx.test.runner.AndroidJUnitRunner'
         ndk {
             abiFilters 'armeabi-v7a', 'arm64-v8a'
@@ -69,10 +69,12 @@ protobuf {
 
 dependencies {
     implementation fileTree(dir: 'libs', include: ['*.jar'])
-    implementation 'androidx.appcompat:appcompat:1.6.1'
-    // Android Mobile Vision
-    // TODO(b/217176538) Migrate to ML Kit.
-    implementation 'com.google.android.gms:play-services-vision:20.1.3'
+    implementation 'androidx.appcompat:appcompat:1.7.0'
+    implementation 'io.github.zxing-cpp:android:2.2.0'
     implementation 'com.google.android.material:material:1.6.1'
     implementation 'com.google.protobuf:protobuf-javalite:3.19.4'
+    implementation 'androidx.camera:camera-core:1.3.4'
+    implementation 'androidx.camera:camera-view:1.3.4'
+    implementation 'androidx.camera:camera-lifecycle:1.3.4'
+    implementation 'androidx.camera:camera-camera2:1.3.4'
 }

sdk/qrcode/android/java/com/google/cardboard/sdk/QrCodeCaptureActivity.java

@@ -16,7 +16,6 @@
 package com.google.cardboard.sdk;
 
 import android.Manifest;
-import android.app.Dialog;
 import android.content.Context;
 import android.content.Intent;
 import android.content.pm.PackageManager;
@@ -30,19 +29,16 @@
 import android.widget.Toast;
 import androidx.annotation.NonNull;
 import androidx.appcompat.app.AppCompatActivity;
+import androidx.camera.view.PreviewView;
 import androidx.core.app.ActivityCompat;
-import com.google.android.gms.common.ConnectionResult;
-import com.google.android.gms.common.GoogleApiAvailability;
-import com.google.android.gms.vision.MultiProcessor;
-import com.google.android.gms.vision.barcode.Barcode;
-import com.google.android.gms.vision.barcode.BarcodeDetector;
+import zxingcpp.BarcodeReader;
 import com.google.cardboard.sdk.qrcode.CardboardParamsUtils;
 import com.google.cardboard.sdk.qrcode.QrCodeContentProcessor;
 import com.google.cardboard.sdk.qrcode.QrCodeTracker;
-import com.google.cardboard.sdk.qrcode.QrCodeTrackerFactory;
 import com.google.cardboard.sdk.qrcode.camera.CameraSource;
-import com.google.cardboard.sdk.qrcode.camera.CameraSourcePreview;
+
 import java.io.IOException;
+import java.util.HashSet;
 
 /**
  * Manages the QR code capture activity. It scans permanently with the camera until it finds a valid
@@ -52,17 +48,11 @@ public class QrCodeCaptureActivity extends AppCompatActivity
     implements QrCodeTracker.Listener, QrCodeContentProcessor.Listener {
   private static final String TAG = QrCodeCaptureActivity.class.getSimpleName();
 
-  // Intent request code to handle updating play services if needed.
-  private static final int RC_HANDLE_GMS = 9001;
-
   // Permission request codes
   private static final int PERMISSIONS_REQUEST_CODE = 2;
 
-  // Min sdk version required for google play services.
-  private static final int MIN_SDK_VERSION = 23;
-
   private CameraSource cameraSource;
-  private CameraSourcePreview cameraSourcePreview;
+  private PreviewView cameraSourcePreview;
 
   // Flag used to avoid saving the device parameters more than once.
   private static boolean qrCodeSaved = false;
@@ -154,26 +144,14 @@ private void launchPermissionsSettings() {
 
   /** Creates and starts the camera. */
   private void createCameraSource() {
-    Context context = getApplicationContext();
-
-    BarcodeDetector qrCodeDetector =
-        new BarcodeDetector.Builder(context).setBarcodeFormats(Barcode.QR_CODE).build();
-
-    QrCodeTrackerFactory qrCodeFactory = new QrCodeTrackerFactory(this);
-
-    qrCodeDetector.setProcessor(new MultiProcessor.Builder<>(qrCodeFactory).build());
-
-    // Check that native dependencies are downloaded.
-    if (!qrCodeDetector.isOperational()) {
-      Toast.makeText(this, R.string.missing_dependencies, Toast.LENGTH_LONG).show();
-      Log.w(
-          TAG,
-          "QR Code detector is not operational. Try connecting to WiFi and updating Google Play"
-              + " Services or checking that the device storage isn't low.");
-    }
-
-    // Creates and starts the camera.
-    cameraSource = new CameraSource(getApplicationContext(), qrCodeDetector);
+    BarcodeReader.Options options = new BarcodeReader.Options();
+    HashSet<BarcodeReader.Format> formats = new HashSet<>();
+    formats.add(BarcodeReader.Format.QR_CODE);
+    options.setFormats(formats);
+    options.setTextMode(BarcodeReader.TextMode.PLAIN);
+    BarcodeReader qrCodeDetector = new BarcodeReader(options);
+    QrCodeTracker tracker = new QrCodeTracker(this);
+    cameraSource = new CameraSource(this, this, qrCodeDetector, tracker);
   }
 
   /** Restarts the camera. */
@@ -197,27 +175,17 @@ protected void onResume() {
   @Override
   protected void onPause() {
     super.onPause();
-    if (cameraSourcePreview != null) {
-      cameraSourcePreview.stop();
-      cameraSourcePreview.release();
+    if (cameraSource != null) {
+      cameraSource.release();
+      cameraSource = null;
     }
   }
 
   /** Starts or restarts the camera source, if it exists. */
   private void startCameraSource() {
-    // Check that the device has play services available.
-    int code =
-        GoogleApiAvailability.getInstance()
-            .isGooglePlayServicesAvailable(getApplicationContext(), MIN_SDK_VERSION);
-    if (code != ConnectionResult.SUCCESS) {
-      Log.i(TAG, "isGooglePlayServicesAvailable() returned: " + new ConnectionResult(code));
-      Dialog dlg = GoogleApiAvailability.getInstance().getErrorDialog(this, code, RC_HANDLE_GMS);
-      dlg.show();
-    }
-
     if (cameraSource != null) {
       try {
-        cameraSourcePreview.start(cameraSource);
+        cameraSource.start(cameraSourcePreview);
       } catch (IOException e) {
         Log.e(TAG, "Unable to start camera source.", e);
         cameraSource.release();
@@ -248,7 +216,7 @@ public void skipQrCodeCapture(View view) {
    * @param qrCode Detected QR code.
    */
   @Override
-  public void onQrCodeDetected(Barcode qrCode) {
+  public void onQrCodeDetected(BarcodeReader.Result qrCode) {
     if (qrCode != null && !qrCodeSaved) {
       qrCodeSaved = true;
       QrCodeContentProcessor qrCodeContentProcessor = new QrCodeContentProcessor(this);
@@ -265,7 +233,10 @@ public void onQrCodeDetected(Barcode qrCode) {
   public void onQrCodeSaved(boolean status) {
     if (status) {
       Log.d(TAG, "Device parameters saved in external storage.");
-      cameraSourcePreview.stop();
+      if (cameraSource != null) {
+        cameraSource.release();
+        cameraSource = null;
+      }
       nativeIncrementDeviceParamsChangedCount();
       finish();
     } else {

sdk/qrcode/android/java/com/google/cardboard/sdk/qrcode/QrCodeContentProcessor.java

@@ -18,7 +18,7 @@
 import android.content.Context;
 import android.util.Log;
 import android.widget.Toast;
-import com.google.android.gms.vision.barcode.Barcode;
+import zxingcpp.BarcodeReader;
 import com.google.cardboard.sdk.R;
 
 /**
@@ -50,7 +50,7 @@ public interface Listener {
    *     Application. It is used to write device params to scoped storage via {@code
    *     Context.getFilesDir()}.
    */
-  public void processAndSaveQrCode(Barcode qrCode, Context context) {
+  public void processAndSaveQrCode(BarcodeReader.Result qrCode, Context context) {
     new ProcessAndSaveQrCodeTask(context).execute(qrCode);
   }
 
@@ -59,7 +59,7 @@ public void processAndSaveQrCode(Barcode qrCode, Context context) {
    * external storage.
    */
   public class ProcessAndSaveQrCodeTask
-      extends AsyncTask<Barcode, CardboardParamsUtils.UriToParamsStatus> {
+      extends AsyncTask<BarcodeReader.Result, CardboardParamsUtils.UriToParamsStatus> {
     private final Context context;
 
     /**
@@ -74,7 +74,7 @@ public ProcessAndSaveQrCodeTask(Context context) {
     }
 
     @Override
-    protected CardboardParamsUtils.UriToParamsStatus doInBackground(Barcode qrCode) {
+    protected CardboardParamsUtils.UriToParamsStatus doInBackground(BarcodeReader.Result qrCode) {
       UrlFactory urlFactory = new UrlFactory();
       return getParamsFromQrCode(qrCode, urlFactory);
     }
@@ -109,13 +109,13 @@ protected void onPostExecute(CardboardParamsUtils.UriToParamsStatus result) {
    * @return Cardboard device parameters, or null if there is an error.
    */
   private static CardboardParamsUtils.UriToParamsStatus getParamsFromQrCode(
-      Barcode barcode, UrlFactory urlFactory) {
-    if (barcode.valueFormat != Barcode.TEXT && barcode.valueFormat != Barcode.URL) {
-      Log.e(TAG, "Invalid QR code format: " + barcode.valueFormat);
+      BarcodeReader.Result barcode, UrlFactory urlFactory) {
+    if (barcode.getText() == null) {
+      Log.e(TAG, "Invalid QR code format: text is null");
       return CardboardParamsUtils.UriToParamsStatus.error(
           CardboardParamsUtils.UriToParamsStatus.STATUS_UNEXPECTED_FORMAT);
     }
 
-    return CardboardParamsUtils.getParamsFromUriString(barcode.rawValue, urlFactory);
+    return CardboardParamsUtils.getParamsFromUriString(barcode.getText(), urlFactory);
   }
 }

sdk/qrcode/android/java/com/google/cardboard/sdk/qrcode/QrCodeTracker.java

@@ -15,34 +15,42 @@
  */
 package com.google.cardboard.sdk.qrcode;
 
-import com.google.android.gms.vision.Tracker;
-import com.google.android.gms.vision.barcode.Barcode;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.List;
+
+import zxingcpp.BarcodeReader;
 
 /**
  * QrCodeTracker is used for tracking or reading a QR code. This is used to receive newly detected
  * items, add a graphical representation to an overlay, update the graphics as the item changes, and
  * remove the graphics when the item goes away.
  */
-public class QrCodeTracker extends Tracker<Barcode> {
+public class QrCodeTracker {
   private final Listener listener;
+  private final HashSet<BarcodeReader.Result> lastData = new HashSet<>();
 
   /**
    * Consume the item instance detected from an Activity or Fragment level by implementing the
    * Listener interface method onQrCodeDetected.
    */
   public interface Listener {
-    void onQrCodeDetected(Barcode qrCode);
+    void onQrCodeDetected(BarcodeReader.Result qrCode);
   }
 
-  QrCodeTracker(Listener listener) {
+  public QrCodeTracker(Listener listener) {
     this.listener = listener;
   }
 
-  /** Start tracking the detected item instance. */
-  @Override
-  public void onNewItem(int id, Barcode item) {
-    if (item.displayValue != null) {
-      listener.onQrCodeDetected(item);
+  public void onItemsDetected(List<BarcodeReader.Result> data) {
+    for (BarcodeReader.Result result : data) {
+      if (lastData.stream().anyMatch(otherResult -> Arrays.equals(result.getBytes(), otherResult.getBytes()))) {
+        // This QR code already was detected in last frame, it's not new.
+        continue;
+      }
+      listener.onQrCodeDetected(result);
     }
+    lastData.clear();
+    lastData.addAll(data);
   }
 }