Merge pull request #24622 from alexlyulkov:al/fixed-android-sample-img-save

Fixed problem with saving images in Android sample #24622

Fixes https://github.com/opencv/opencv/issues/24590

Current code for saving images in Android sample worked only on very old phones.
Added support for modern Android versions.

Required:
- https://github.com/opencv/ci-gha-workflow/pull/127
- https://github.com/opencv-infrastructure/opencv-gha-dockerfile/pull/27

cmake/android/android_gradle_projects.cmake

@@ -16,7 +16,7 @@ endif()
 set(GRADLE_VERSION "7.6.3" CACHE STRING "Gradle version")
 message(STATUS "Gradle version: ${GRADLE_VERSION}")
 
-set(ANDROID_COMPILE_SDK_VERSION "26" CACHE STRING "Android compileSdkVersion")
+set(ANDROID_COMPILE_SDK_VERSION "31" CACHE STRING "Android compileSdkVersion")
 if(ANDROID_NATIVE_API_LEVEL GREATER 21)
   set(ANDROID_MIN_SDK_VERSION "${ANDROID_NATIVE_API_LEVEL}" CACHE STRING "Android minSdkVersion")
 else()

platforms/android/build_java_shared_aar.py

@@ -157,7 +157,7 @@ def main(args):
 if __name__ == "__main__":
     parser = argparse.ArgumentParser(description="Builds AAR with Java and shared C++ libs from OpenCV SDK")
     parser.add_argument('opencv_sdk_path')
-    parser.add_argument('--android_compile_sdk', default="26")
+    parser.add_argument('--android_compile_sdk', default="31")
     parser.add_argument('--android_min_sdk', default="21")
     parser.add_argument('--android_target_sdk', default="31")
     parser.add_argument('--java_version', default="1_8")

platforms/android/build_static_aar.py

@@ -230,9 +230,9 @@ def main(args):
 if __name__ == "__main__":
     parser = argparse.ArgumentParser(description="Builds AAR with static C++ libs from OpenCV SDK")
     parser.add_argument('opencv_sdk_path')
-    parser.add_argument('--android_compile_sdk', default="26")
+    parser.add_argument('--android_compile_sdk', default="31")
     parser.add_argument('--android_min_sdk', default="21")
-    parser.add_argument('--android_target_sdk', default="26")
+    parser.add_argument('--android_target_sdk', default="31")
     parser.add_argument('--java_version', default="1_8")
     parser.add_argument('--ndk_location', default="")
     parser.add_argument('--cmake_location', default="")

samples/android/tutorial-3-cameracontrol/src/org/opencv/samples/tutorial3/Tutorial3Activity.java

@@ -13,8 +13,11 @@ import org.opencv.android.OpenCVLoader;
 import org.opencv.core.Mat;
 import org.opencv.android.CameraBridgeViewBase.CvCameraViewListener2;
 
+import android.Manifest;
 import android.annotation.SuppressLint;
+import android.content.pm.PackageManager;
 import android.hardware.Camera.Size;
+import android.os.Build;
 import android.os.Bundle;
 import android.os.Environment;
 import android.util.Log;
@@ -177,10 +180,17 @@ public class Tutorial3Activity extends CameraActivity implements CvCameraViewLis
     @Override
     public boolean onTouch(View v, MotionEvent event) {
         Log.i(TAG,"onTouch event");
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
+            if (checkSelfPermission(Manifest.permission.WRITE_EXTERNAL_STORAGE)
+                != PackageManager.PERMISSION_GRANTED) {
+                String[] permissions = {Manifest.permission.WRITE_EXTERNAL_STORAGE};
+                requestPermissions(permissions, 1);
+                return false;
+            }
+        }
         SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd_HH-mm-ss");
         String currentDateandTime = sdf.format(new Date());
-        String fileName = Environment.getExternalStorageDirectory().getPath() +
+        String fileName = "sample_picture_" + currentDateandTime + ".jpg";
-                               "/sample_picture_" + currentDateandTime + ".jpg";
         mOpenCvCameraView.takePicture(fileName);
         Toast.makeText(this, fileName + " saved", Toast.LENGTH_SHORT).show();
         return false;

samples/android/tutorial-3-cameracontrol/src/org/opencv/samples/tutorial3/Tutorial3View.java

@@ -1,14 +1,24 @@
 package org.opencv.samples.tutorial3;
 
 import java.io.FileOutputStream;
+import java.io.OutputStream;
 import java.util.List;
+import java.util.Objects;
 
 import org.opencv.android.JavaCameraView;
 
+import android.content.ContentResolver;
+import android.content.ContentValues;
 import android.content.Context;
+import android.graphics.Bitmap;
+import android.graphics.BitmapFactory;
 import android.hardware.Camera;
 import android.hardware.Camera.PictureCallback;
 import android.hardware.Camera.Size;
+import android.net.Uri;
+import android.os.Build;
+import android.os.Environment;
+import android.provider.MediaStore;
 import android.util.AttributeSet;
 import android.util.Log;
 
@@ -73,15 +83,36 @@ public class Tutorial3View extends JavaCameraView implements PictureCallback {
         mCamera.setPreviewCallback(this);
 
         // Write the image in a file (in jpeg format)
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
+            Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
+            new Thread(new Runnable() {
+                @Override
+                public void run() {
+                    ContentResolver resolver = getContext().getContentResolver();
+                    ContentValues contentValues = new ContentValues();
+                    contentValues.put(MediaStore.MediaColumns.DISPLAY_NAME, mPictureFileName);
+                    contentValues.put(MediaStore.MediaColumns.MIME_TYPE, "image/jpg");
+                    contentValues.put(MediaStore.MediaColumns.RELATIVE_PATH, Environment.DIRECTORY_PICTURES);
+                    Uri imageUri = resolver.insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, contentValues);
                     try {
-            FileOutputStream fos = new FileOutputStream(mPictureFileName);
+                        OutputStream fos = resolver.openOutputStream(Objects.requireNonNull(imageUri));
-
+                        bitmap.compress(Bitmap.CompressFormat.JPEG, 100, fos);
-            fos.write(data);
+                        Objects.requireNonNull(fos).close();
-            fos.close();
-
                     } catch (java.io.IOException e) {
                         Log.e("PictureDemo", "Exception in photoCallback", e);
                     }
-
+                }
+            }).start();
+        } else {
+            mPictureFileName = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES).getPath()
+                               + "/" + mPictureFileName;
+            try {
+                FileOutputStream fos = new FileOutputStream(mPictureFileName);
+                fos.write(data);
+                fos.close();
+            } catch (java.io.IOException e) {
+                Log.e("PictureDemo", "Exception in photoCallback", e);
+            }
+        }
     }
 }