IntelRealSense · ev-mp · Aug 4, 2020 · Jul 28, 2020 · Jul 28, 2020 · Jul 28, 2020
diff --git a/src/android/jni/device.cpp b/src/android/jni/device.cpp
@@ -57,7 +57,12 @@ Java_com_intel_realsense_librealsense_Device_nQuerySensors(JNIEnv *env, jclass t
         sensors.push_back(s);
     }
     jlongArray rv = env->NewLongArray(sensors.size());
-    env->SetLongArrayRegion(rv, 0, sensors.size(), reinterpret_cast<const jlong *>(sensors.data()));
+
+    for (auto i = 0; i < sensors.size(); i++)
+    {
+        env->SetLongArrayRegion(rv, i, 1, reinterpret_cast<const jlong *>(&sensors[i]));
+    }
+
     return rv;
 }
 

diff --git a/src/android/jni/sensor.cpp b/src/android/jni/sensor.cpp
@@ -36,8 +36,12 @@ Java_com_intel_realsense_librealsense_Sensor_nGetStreamProfiles(JNIEnv *env, jcl
         profiles.push_back(sp);
     }
 
+    // jlong is 64-bit, but pointer in profiles could be 32-bit, copy element by element
     jlongArray rv = env->NewLongArray(profiles.size());
-    env->SetLongArrayRegion(rv, 0, profiles.size(), reinterpret_cast<const jlong *>(profiles.data()));
+    for (auto i = 0; i < size; i++)
+    {
+        env->SetLongArrayRegion(rv, i, 1, reinterpret_cast<const jlong *>(&profiles[i]));
+    }
     return rv;
 }
 
@@ -97,4 +101,4 @@ Java_com_intel_realsense_librealsense_DepthSensor_nGetDepthScale(JNIEnv *env, jc
     float depthScale = rs2_get_depth_scale(reinterpret_cast<rs2_sensor *>(handle), &e);
     handle_error(env, e);
     return depthScale;
-}
+}
diff --git a/src/concurrency.h b/src/concurrency.h
@@ -266,14 +266,16 @@ class dispatcher
         auto func = std::move(item);
         invoke([&, func](dispatcher::cancellable_timer c)
         {
+            std::lock_guard<std::mutex> lk(_blocking_invoke_mutex);
             func(c);
+
             done = true;
             _blocking_invoke_cv.notify_one();
         }, is_blocking);
 
         //wait
         std::unique_lock<std::mutex> lk(_blocking_invoke_mutex);
-        while(_blocking_invoke_cv.wait_for(lk, std::chrono::milliseconds(10), [&](){ return !done && !exit_condition(); }));
+        _blocking_invoke_cv.wait(lk, [&](){ return done || exit_condition(); });
     }
 
     void start()
@@ -288,6 +290,9 @@ class dispatcher
     {
         {
             std::unique_lock<std::mutex> lock(_was_stopped_mutex);
+
+            if (_was_stopped.load()) return;
+
             _was_stopped = true;
             _was_stopped_cv.notify_all();
         }
@@ -310,6 +315,8 @@ class dispatcher
         stop();
         _queue.clear();
         _is_alive = false;
+
+        if (_thread.joinable())
         _thread.join();
     }
 
@@ -379,8 +386,10 @@ class active_object
 
     void stop()
     {
-        _stopped = true;
-        _dispatcher.stop();
+        if (!_stopped.load()) {
+            _stopped = true;
+            _dispatcher.stop();
+        }
     }
 
     ~active_object()

diff --git a/src/pipeline/pipeline.cpp b/src/pipeline/pipeline.cpp
@@ -20,11 +20,12 @@ namespace librealsense
 
         pipeline::~pipeline()
         {
-            try
-            {
-                unsafe_stop();
+            if (_active_profile) {
+                try {
+                    unsafe_stop();
+                }
+                catch (...) {}
             }
-            catch (...) {}
         }
 
         std::shared_ptr<profile> pipeline::start(std::shared_ptr<config> conf, frame_callback_ptr callback)
@@ -144,10 +145,13 @@ namespace librealsense
                 catch (...)
                 {
                 } // Stop will throw if device was disconnected. TODO - refactoring anticipated
+
+                // shared pointers initialized when pipeline running with _active_profile
+                // should be reset with _active_profile too
+                _active_profile.reset();
+                _prev_conf.reset();
+                _streams_callback.reset();
             }
-            _active_profile.reset();
-            _prev_conf.reset();
-            _streams_callback.reset();
         }
 
         std::shared_ptr<device_interface> pipeline::wait_for_device(const std::chrono::milliseconds& timeout, const std::string& serial)

diff --git a/src/uvc/uvc-device.cpp b/src/uvc/uvc-device.cpp
@@ -160,7 +160,7 @@ namespace librealsense
 
             stop_stream_cleanup(profile, elem);
 
-            if (_profiles.empty())
+            if (!_profiles.empty())
                 _streamers.clear();
         }
 

diff --git a/src/uvc/uvc-streamer.cpp b/src/uvc/uvc-streamer.cpp
@@ -157,7 +157,10 @@ namespace librealsense
 
                 _context.messenger->reset_endpoint(_read_endpoint, RS2_USB_ENDPOINT_DIRECTION_READ);
 
-                _running = true;
+                {
+                    std::lock_guard<std::mutex> lock(_running_mutex);
+                    _running = true;
+                }
 
                 for(auto&& r : _requests)
                 {
@@ -197,14 +200,25 @@ namespace librealsense
 
                 _publish_frame_thread->stop();
 
-                _running = false;
+                {
+                    std::lock_guard<std::mutex> lock(_running_mutex);
+                    _running = false;
+                    _stopped_cv.notify_one();
+                }
 
             }, [this](){ return !_running; });
         }
 
         void uvc_streamer::flush()
         {
-            stop();
+            if(_running)
+                stop();
+
+            // synchronized so do not destroy shared pointers while it's still being running
+            {
+                std::unique_lock<std::mutex> lock(_running_mutex);
+                _stopped_cv.wait_for(lock, std::chrono::seconds(1), [&]() { return !_running; });
+            }
 
             _read_endpoint.reset();
 

diff --git a/src/uvc/uvc-streamer.h b/src/uvc/uvc-streamer.h
@@ -44,6 +44,8 @@ namespace librealsense
             bool wait_for_first_frame(uint32_t timeout_ms);
 
         private:
+            std::mutex _running_mutex;
+            std::condition_variable _stopped_cv;
             bool _running = false;
             bool _frame_arrived = false;
             bool _publish_frames = true;

diff --git a/wrappers/android/tools/camera/src/main/AndroidManifest.xml b/wrappers/android/tools/camera/src/main/AndroidManifest.xml
@@ -24,6 +24,7 @@
         </activity>
         <activity
             android:name=".PreviewActivity"
+            android:launchMode="singleTop"
             android:theme="@style/AppTheme.NoActionBar" />
         <activity
             android:name=".SettingsActivity"
@@ -49,4 +50,4 @@
             android:theme="@style/AppTheme.NoActionBar" />
     </application>
 
-</manifest>
+</manifest>
diff --git a/wrappers/android/tools/camera/src/main/java/com/intel/realsense/camera/DetachedActivity.java b/wrappers/android/tools/camera/src/main/java/com/intel/realsense/camera/DetachedActivity.java
@@ -53,28 +53,7 @@ protected void onCreate(Bundle savedInstanceState) {
 
         requestPermissionsIfNeeded();
 
-        mPlaybackButton = findViewById(R.id.playbackButton);
-        mPlaybackButton.setOnClickListener(new View.OnClickListener() {
-            @Override
-            public void onClick(View view) {
-                mDetached = false;
-                finish();
-                Intent intent = new Intent(DetachedActivity.this, PlaybackActivity.class);
-                startActivityForResult(intent, PLAYBACK_REQUEST_CODE);
-            }
-        });
-
-        runOnUiThread(new Runnable() {
-            @Override
-            public void run() {
-                String appVersion = BuildConfig.VERSION_NAME;
-                String lrsVersion = RsContext.getVersion();
-                TextView versions = findViewById(R.id.versionsText);
-                versions.setText("librealsense version: " + lrsVersion + "\ncamera app version: " + appVersion);
-            }
-        });
-
-        mMinimalFirmwares.put(ProductLine.D400, MINIMAL_D400_FW_VERSION);
+        init();
     }
 
     private void requestPermissionsIfNeeded() {
@@ -93,7 +72,7 @@ private void requestPermissionsIfNeeded() {
     @Override
     protected void onResume() {
         super.onResume();
-        mDetached = true;
+
         if (isCameraPermissionGranted()) {
             RsContext.init(getApplicationContext());
             mRsContext.setDevicesChangedCallback(mListener);
@@ -109,12 +88,53 @@ private boolean isWritePermissionGranted() {
         return ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED;
     }
 
+    private synchronized void init()
+    {
+        mPlaybackButton = findViewById(R.id.playbackButton);
+        mPlaybackButton.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View view) {
+                mDetached = false;
+                finish();
+                Intent intent = new Intent(DetachedActivity.this, PlaybackActivity.class);
+                startActivityForResult(intent, PLAYBACK_REQUEST_CODE);
+            }
+        });
+
+        runOnUiThread(new Runnable() {
+            @Override
+            public void run() {
+                String appVersion = BuildConfig.VERSION_NAME;
+                String lrsVersion = RsContext.getVersion();
+                TextView versions = findViewById(R.id.versionsText);
+                versions.setText("librealsense version: " + lrsVersion + "\ncamera app version: " + appVersion);
+            }
+        });
+
+        mMinimalFirmwares.put(ProductLine.D400, MINIMAL_D400_FW_VERSION);
+    }
+
     private synchronized void validatedDevice(){
         if(mUpdating)
             return;
         try(DeviceList dl = mRsContext.queryDevices()){
-            if(dl.getDeviceCount() == 0)
+            if(dl.getDeviceCount() == 0) {
+                init();
+
+                // kill preview activity if device disconnected
+                if (mDetached) {
+                    mDetached = false;
+
+                    Intent intent = new Intent(this, PreviewActivity.class);
+                    intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
+                    intent.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);
+                    intent.putExtra("keepalive", false);
+                    startActivity(intent);
+                }
+
                 return;
+            }
+
             try(Device d = dl.createDevice(0)){
                 if(d == null)
                     return;
@@ -127,10 +147,17 @@ private synchronized void validatedDevice(){
                 else {
                     if (!validateFwVersion(d))
                         return;
+
                     mDetached = false;
 
-                    finish();
+
+                    // launch preview activity and keep it alive
+                    // the activity is single top instance, can be killed later the same instance
+                    // to prevent issues with multiple instances
                     Intent intent = new Intent(this, PreviewActivity.class);
+                    intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
+                    intent.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);
+                    intent.putExtra("keepalive", true);
                     startActivity(intent);
                 }
             }
@@ -201,11 +228,8 @@ public void onDeviceAttach() {
 
         @Override
         public void onDeviceDetach() {
-            if(mDetached)
-                return;
-            finish();
-            Intent intent = new Intent(mAppContext, DetachedActivity.class);
-            startActivity(intent);
+            mDetached = true;
+            validatedDevice();
         }
     };
 }
diff --git a/wrappers/android/tools/camera/src/main/java/com/intel/realsense/camera/PreviewActivity.java b/wrappers/android/tools/camera/src/main/java/com/intel/realsense/camera/PreviewActivity.java
@@ -54,6 +54,8 @@ public class PreviewActivity extends AppCompatActivity {
     private boolean statsToggle = false;
     private boolean mShow3D = false;
 
+    boolean keepalive = true;
+
     public synchronized void toggleStats(){
         statsToggle = !statsToggle;
         if(statsToggle){
@@ -72,6 +74,15 @@ public synchronized void toggleStats(){
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_preview);
+
+        keepalive = true;
+
+        Intent intent = this.getIntent();
+
+        if (intent != null && intent.getExtras() != null ) {
+            keepalive = intent.getExtras().getBoolean("keepalive");
+        }
+
         getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
 
         mGLSurfaceView = findViewById(R.id.glSurfaceView);
@@ -204,6 +215,11 @@ private void clearLables(){
     protected void onResume() {
         super.onResume();
 
+        if(keepalive == false)
+        {
+            return;
+        }
+
         mStreamingStats  = new StreamingStats();
         mStreamer = new Streamer(this, true, new Streamer.Listener() {
             @Override
@@ -298,4 +314,21 @@ private synchronized void pauseFwLogger(){
         }
         mFwLogsRunning = false;
     }
+
+    @Override
+    protected void onNewIntent(Intent intent)
+    {
+        super.onNewIntent(intent);
+
+        if (intent != null && intent.getExtras() != null ) {
+            keepalive = intent.getExtras().getBoolean("keepalive");
+        }
+
+        // destroy activity if requested
+        if(keepalive == false)
+        {
+            PreviewActivity.this.finish();
+        }
+    }
+
 }