Merge pull request #24598 from AleksandrPanov:add_android_qr_sample

Add android QR detection sample #24598

Android QR detection sample was added.

![image](https://github.com/opencv/opencv/assets/22337800/0aaf6689-36ee-4201-b609-256d3278641a)
![image](https://github.com/opencv/opencv/assets/22337800/1cf54758-2c96-4108-888b-4796d8825340)
![image](https://github.com/opencv/opencv/assets/22337800/4ecc0933-a2e6-4cc0-abae-7525213c4145)

current interface:
![image](https://github.com/opencv/opencv/assets/22337800/aff5b06d-6a9d-4762-be6e-ce20ff2c2271)


### Pull Request Readiness Checklist

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [x] The PR is proposed to the proper branch
- [x] There is a reference to the original bug report and related work
- [ ] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
      Patch to opencv_extra has the same branch name.
- [ ] The feature is well documented and sample code can be built with the project CMake

samples/android/CMakeLists.txt

@@ -8,6 +8,7 @@ ocv_warnings_disable(CMAKE_CXX_FLAGS -Wmissing-declarations)
 
 add_subdirectory(15-puzzle)
 add_subdirectory(face-detection)
+add_subdirectory(qr-detection)
 add_subdirectory(image-manipulations)
 add_subdirectory(camera-calibration)
 add_subdirectory(color-blob-detection)

samples/android/qr-detection/AndroidManifest.xml

@@ -0,0 +1,34 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="org.opencv.samples.qrdetection"
+    android:versionCode="301"
+    android:versionName="3.01" >
+
+    <uses-sdk android:minSdkVersion="8"/>
+
+    <application
+        android:icon="@drawable/icon"
+        android:label="@string/app_name" >
+
+        <activity
+            android:name=".QRdetectionActivity"
+            android:label="@string/app_name"
+            android:screenOrientation="landscape"
+            android:configChanges="keyboardHidden|orientation" >
+
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+
+    <uses-permission android:name="android.permission.CAMERA"/>
+
+    <uses-feature android:name="android.hardware.camera" android:required="false"/>
+    <uses-feature android:name="android.hardware.camera.autofocus" android:required="false"/>
+    <uses-feature android:name="android.hardware.camera.front" android:required="false"/>
+    <uses-feature android:name="android.hardware.camera.front.autofocus" android:required="false"/>
+
+</manifest>

samples/android/qr-detection/CMakeLists.txt

@@ -0,0 +1,6 @@
+set(sample example-qr-detection)
+
+add_android_project(${sample} "${CMAKE_CURRENT_SOURCE_DIR}" LIBRARY_DEPS "${OPENCV_ANDROID_LIB_DIR}" SDK_TARGET 11 "${ANDROID_SDK_TARGET}")
+if(TARGET ${sample})
+  add_dependencies(opencv_android_examples ${sample})
+endif()

samples/android/qr-detection/build.gradle.in

@@ -0,0 +1,36 @@
+apply plugin: 'com.android.application'
+
+android {
+    namespace 'org.opencv.samples.qrdetection'
+    compileSdkVersion @ANDROID_COMPILE_SDK_VERSION@
+    defaultConfig {
+        applicationId "org.opencv.samples.qrdetection"
+        minSdkVersion @ANDROID_MIN_SDK_VERSION@
+        targetSdkVersion @ANDROID_TARGET_SDK_VERSION@
+        versionCode 301
+        versionName "3.01"
+    }
+    buildTypes {
+        release {
+            minifyEnabled false
+            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
+        }
+    }
+    sourceSets {
+        main {
+            java.srcDirs = @ANDROID_SAMPLE_JAVA_PATH@
+            aidl.srcDirs = @ANDROID_SAMPLE_JAVA_PATH@
+            res.srcDirs = @ANDROID_SAMPLE_RES_PATH@
+            manifest.srcFile '@ANDROID_SAMPLE_MANIFEST_PATH@'
+        }
+    }
+}
+
+dependencies {
+    //implementation fileTree(dir: 'libs', include: ['*.jar'])
+    if (gradle.opencv_source == "sdk_path") {
+        implementation project(':opencv')
+    } else if (gradle.opencv_source == "maven_local" || gradle.opencv_source == "maven_cenral") {
+        implementation 'org.opencv:opencv:@OPENCV_VERSION_PLAIN@'
+    }
+}

samples/android/qr-detection/gradle/AndroidManifest.xml

@@ -0,0 +1,31 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="org.opencv.samples.qrdetection">
+
+    <application
+        android:icon="@drawable/icon"
+        android:label="@string/app_name">
+
+        <activity
+            android:exported="true"
+            android:name=".QRdetectionActivity"
+            android:label="@string/app_name"
+            android:screenOrientation="landscape"
+            android:configChanges="keyboardHidden|orientation" >
+
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+
+    <uses-permission android:name="android.permission.CAMERA"/>
+
+    <uses-feature android:name="android.hardware.camera" android:required="false"/>
+    <uses-feature android:name="android.hardware.camera.autofocus" android:required="false"/>
+    <uses-feature android:name="android.hardware.camera.front" android:required="false"/>
+    <uses-feature android:name="android.hardware.camera.front.autofocus" android:required="false"/>
+
+</manifest>

samples/android/qr-detection/res/values/strings.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <string name="app_name">OpenCV QR Detector</string>
+</resources>

samples/android/qr-detection/src/org/opencv/samples/qrdetection/QRProcessor.java

@@ -0,0 +1,87 @@
+package org.opencv.samples.qrdetection;
+
+import org.opencv.core.Core;
+import org.opencv.core.Mat;
+import org.opencv.core.MatOfPoint;
+import org.opencv.core.Scalar;
+import org.opencv.core.Size;
+import org.opencv.core.Point;
+import org.opencv.imgproc.Imgproc;
+import org.opencv.objdetect.GraphicalCodeDetector;
+import org.opencv.objdetect.QRCodeDetector;
+import org.opencv.objdetect.QRCodeDetectorAruco;
+
+import android.util.Log;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class QRProcessor {
+    private GraphicalCodeDetector detector;
+    private static final String TAG = "QRProcessor";
+    private Scalar LineColor = new Scalar(255, 0, 0);
+    private Scalar FontColor = new Scalar(0, 0, 255);
+
+    public QRProcessor(boolean useArucoDetector) {
+        if (useArucoDetector)
+            detector = new QRCodeDetectorAruco();
+        else
+            detector = new QRCodeDetector();
+    }
+
+    private boolean findQRs(Mat inputFrame, List<String> decodedInfo, MatOfPoint points,
+                           boolean tryDecode, boolean multiDetect) {
+        boolean result = false;
+        if (multiDetect) {
+            if (tryDecode)
+                result = detector.detectAndDecodeMulti(inputFrame, decodedInfo, points);
+            else
+                result = detector.detectMulti(inputFrame, points);
+        }
+        else {
+            if(tryDecode) {
+                String s = detector.detectAndDecode(inputFrame, points);
+                result = !points.empty();
+                if (result)
+                    decodedInfo.add(s);
+            }
+            else {
+                result = detector.detect(inputFrame, points);
+            }
+        }
+        return result;
+    }
+
+    private void renderQRs(Mat inputFrame, List<String> decodedInfo, MatOfPoint points) {
+        for (int i = 0; i < points.rows(); i++) {
+            for (int j = 0; j < points.cols(); j++) {
+                Point pt1 = new Point(points.get(i, j));
+                Point pt2 = new Point(points.get(i, (j + 1) % 4));
+                Imgproc.line(inputFrame, pt1, pt2, LineColor, 3);
+            }
+            if (!decodedInfo.isEmpty()) {
+                String decode = decodedInfo.get(i);
+                if (decode.length() > 15) {
+                    decode = decode.substring(0, 12) + "...";
+                }
+                int baseline[] = {0};
+                Size textSize = Imgproc.getTextSize(decode, Imgproc.FONT_HERSHEY_COMPLEX, .95, 3, baseline);
+                Scalar sum = Core.sumElems(points.row(i));
+                Point start = new Point(sum.val[0] / 4. - textSize.width / 2., sum.val[1] / 4. - textSize.height / 2.);
+                Imgproc.putText(inputFrame, decode, start, Imgproc.FONT_HERSHEY_COMPLEX, .95, FontColor, 3);
+            }
+        }
+    }
+
+    /* this method to be called from the outside. It processes the frame to find QR codes. */
+    public synchronized Mat handleFrame(Mat inputFrame, boolean tryDecode, boolean multiDetect) {
+        List<String> decodedInfo = new ArrayList<String>();
+        MatOfPoint points = new MatOfPoint();
+        boolean result = findQRs(inputFrame, decodedInfo, points, tryDecode, multiDetect);
+        if (result) {
+            renderQRs(inputFrame, decodedInfo, points);
+        }
+        points.release();
+        return inputFrame;
+    }
+}

samples/android/qr-detection/src/org/opencv/samples/qrdetection/QRdetectionActivity.java

@@ -0,0 +1,130 @@
+package org.opencv.samples.qrdetection;
+
+import org.opencv.android.CameraActivity;
+import org.opencv.android.OpenCVLoader;
+import org.opencv.core.Mat;
+import org.opencv.android.CameraBridgeViewBase;
+import org.opencv.android.CameraBridgeViewBase.CvCameraViewListener;
+import org.opencv.android.JavaCameraView;
+
+import android.os.Bundle;
+import android.util.Log;
+import android.view.Menu;
+import android.view.MenuItem;
+import android.view.WindowManager;
+import android.widget.Toast;
+
+import java.util.Collections;
+import java.util.List;
+
+public class QRdetectionActivity extends CameraActivity implements CvCameraViewListener {
+
+    private static final String  TAG = "QRdetection::Activity";
+
+    private CameraBridgeViewBase mOpenCvCameraView;
+    private QRProcessor    mQRDetector;
+    private MenuItem             mItemQRCodeDetectorAruco;
+    private MenuItem             mItemQRCodeDetector;
+    private MenuItem             mItemTryDecode;
+    private MenuItem             mItemMulti;
+
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
+
+        if (OpenCVLoader.initLocal()) {
+            Log.i(TAG, "OpenCV loaded successfully");
+        } else {
+            Log.e(TAG, "OpenCV initialization failed!");
+            (Toast.makeText(this, "OpenCV initialization failed!", Toast.LENGTH_LONG)).show();
+            return;
+        }
+
+        Log.d(TAG, "Creating and setting view");
+        mOpenCvCameraView = new JavaCameraView(this, -1);
+        setContentView(mOpenCvCameraView);
+        mOpenCvCameraView.setVisibility(CameraBridgeViewBase.VISIBLE);
+        mOpenCvCameraView.setCvCameraViewListener(this);
+        mQRDetector = new QRProcessor(true);
+    }
+
+    @Override
+    public void onPause()
+    {
+        super.onPause();
+        if (mOpenCvCameraView != null)
+            mOpenCvCameraView.disableView();
+    }
+
+    @Override
+    public void onResume()
+    {
+        super.onResume();
+        if (mOpenCvCameraView != null) {
+            mOpenCvCameraView.enableView();
+        }
+    }
+
+    @Override
+    protected List<? extends CameraBridgeViewBase> getCameraViewList() {
+        return Collections.singletonList(mOpenCvCameraView);
+    }
+
+    public void onDestroy() {
+        super.onDestroy();
+        if (mOpenCvCameraView != null)
+            mOpenCvCameraView.disableView();
+    }
+
+    @Override
+    public boolean onCreateOptionsMenu(Menu menu) {
+        Log.i(TAG, "called onCreateOptionsMenu");
+        mItemQRCodeDetectorAruco = menu.add("Aruco-based QR code detector");
+        mItemQRCodeDetectorAruco.setCheckable(true);
+        mItemQRCodeDetectorAruco.setChecked(true);
+
+        mItemQRCodeDetector = menu.add("Legacy QR code detector");
+        mItemQRCodeDetector.setCheckable(true);
+        mItemQRCodeDetector.setChecked(false);
+
+        mItemTryDecode = menu.add("Try to decode QR codes");
+        mItemTryDecode.setCheckable(true);
+        mItemTryDecode.setChecked(true);
+
+        mItemMulti = menu.add("Use multi detect/decode");
+        mItemMulti.setCheckable(true);
+        mItemMulti.setChecked(true);
+
+        return true;
+    }
+
+    @Override
+    public boolean onOptionsItemSelected(MenuItem item) {
+        Log.i(TAG, "Menu Item selected " + item);
+        if (item == mItemQRCodeDetector && !mItemQRCodeDetector.isChecked()) {
+            mQRDetector = new QRProcessor(false);
+            mItemQRCodeDetector.setChecked(true);
+            mItemQRCodeDetectorAruco.setChecked(false);
+        } else if (item == mItemQRCodeDetectorAruco && !mItemQRCodeDetectorAruco.isChecked()) {
+            mQRDetector = new QRProcessor(true);
+            mItemQRCodeDetector.setChecked(false);
+            mItemQRCodeDetectorAruco.setChecked(true);
+        } else if (item == mItemTryDecode) {
+            mItemTryDecode.setChecked(!mItemTryDecode.isChecked());
+        } else if (item == mItemMulti) {
+            mItemMulti.setChecked(!mItemMulti.isChecked());
+        }
+        return true;
+    }
+
+    public void onCameraViewStarted(int width, int height) {
+    }
+
+    public void onCameraViewStopped() {
+    }
+
+    public Mat onCameraFrame(Mat inputFrame) {
+        return mQRDetector.handleFrame(inputFrame, mItemTryDecode.isChecked(), mItemMulti.isChecked());
+    }
+}