LeakCanary investigation to find memory leaks

build.gradle

@@ -1,5 +1,5 @@
 buildscript {
-    ext.kotlin_version = '1.3.61'
+    ext.kotlin_version = '1.3.72'
     repositories {
         google()
         jcenter()
@@ -122,7 +122,7 @@ android {
         sourceCompatibility JavaVersion.VERSION_1_8
         targetCompatibility JavaVersion.VERSION_1_8
     }
-    
+
      kotlinOptions {
         jvmTarget = "1.8"
     }
@@ -145,10 +145,10 @@ dependencies {
     implementation 'androidx.appcompat:appcompat:1.1.0'
     implementation 'androidx.constraintlayout:constraintlayout:2.0.0-beta4'
     implementation "androidx.coordinatorlayout:coordinatorlayout:1.1.0"
-    implementation 'androidx.preference:preference:1.1.0'
+    implementation 'androidx.preference:preference:1.1.1'
     implementation 'androidx.multidex:multidex:2.0.1'
     implementation 'androidx.annotation:annotation:1.1.0'
-    implementation 'com.google.android.material:material:1.2.0-alpha03'
+    implementation 'com.google.android.material:material:1.2.0-alpha06'
     implementation 'com.google.code.gson:gson:2.8.6'
     implementation 'com.wdullaer:materialdatetimepicker:4.2.3'
     implementation 'com.github.guardianproject:signal-cli-android:v0.6.0-android-beta-1'
@@ -178,6 +178,7 @@ dependencies {
     kapt "android.arch.persistence.room:compiler:2.1.0"
     implementation "android.arch.lifecycle:runtime:2.1.0"
     implementation "android.arch.lifecycle:extensions:2.1.0"
+    implementation "androidx.lifecycle:lifecycle-common-java8:2.2.0"
 
     testImplementation 'junit:junit:4.13'
     androidTestImplementation 'androidx.test:runner:1.2.0'
@@ -193,5 +194,5 @@ dependencies {
     // new camera view: https://github.com/natario1/CameraView
     implementation 'com.otaliastudios:cameraview:2.4.0'
 
-
+    debugImplementation 'com.squareup.leakcanary:leakcanary-android:2.2'
 }

src/main/java/org/havenapp/main/MonitorActivity.java

@@ -17,15 +17,13 @@
 package org.havenapp.main;
 
 import android.Manifest;
-import android.animation.ValueAnimator;
 import android.app.PictureInPictureParams;
 import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
 import android.content.pm.PackageManager;
 import android.content.res.Configuration;
-import android.graphics.Color;
 import android.os.Build;
 import android.os.Bundle;
 import android.os.CountDownTimer;
@@ -40,7 +38,11 @@
 import android.view.animation.AnimationUtils;
 import android.widget.Button;
 import android.widget.TextView;
-import android.widget.Toast;
+
+import androidx.appcompat.app.AppCompatActivity;
+import androidx.core.app.ActivityCompat;
+import androidx.core.content.ContextCompat;
+import androidx.localbroadcastmanager.content.LocalBroadcastManager;
 
 import com.wdullaer.materialdatetimepicker.time.TimePickerDialog;
 
@@ -55,11 +57,6 @@
 import java.io.FileOutputStream;
 import java.io.IOException;
 
-import androidx.appcompat.app.AppCompatActivity;
-import androidx.core.app.ActivityCompat;
-import androidx.core.content.ContextCompat;
-import androidx.localbroadcastmanager.content.LocalBroadcastManager;
-
 import static org.havenapp.main.Utils.getTimerText;
 
 public class MonitorActivity extends AppCompatActivity implements TimePickerDialog.OnTimeSetListener {
@@ -233,8 +230,6 @@ private void initSetupLayout() {
     }
 
     private void configCamera() {
-
-        mFragmentCamera.stopCamera();
         startActivityForResult(new Intent(this, CameraConfigureActivity.class),REQUEST_CAMERA);
     }
 
@@ -317,15 +312,6 @@ else if (requestCode == REQUEST_CAMERA)
         }
     }
 
-    @Override
-    protected void onDestroy() {
-        if (!mIsMonitoring)
-        {
-            mFragmentCamera.stopCamera();
-        }
-        super.onDestroy();
-    }
-
     private void initTimer() {
         txtTimer.setTextColor(getResources().getColor(R.color.colorAccent));
         cTimer = new CountDownTimer((preferences.getTimerDelay()) * 1000, 1000) {

src/main/java/org/havenapp/main/sensors/MicrophoneMonitor.java

@@ -102,7 +102,7 @@ public void stop (Context context)
     {
         context.unbindService(mConnection);
         if (microphone != null)
-            microphone.cancel(true);
+            microphone.cancelTask();
     }
 
 

src/main/java/org/havenapp/main/sensors/media/MicSamplerTask.java

@@ -13,10 +13,14 @@
 import android.os.AsyncTask;
 import android.util.Log;
 
+import androidx.annotation.Nullable;
+
 import java.io.IOException;
 
+
 public class MicSamplerTask extends AsyncTask<Void,Object,Void> {
 
+	@Nullable
 	private MicListener listener = null;
 	private AudioCodec volumeMeter = new AudioCodec();
 	private boolean sampling = true;
@@ -30,10 +34,6 @@ public  interface MicListener {
 	public void setMicListener(MicListener listener) {
 		this.listener = listener;
 	}
-
-	protected Void onPreExecute(Void...params) {
-		return null;
-	}
 
 	@Override
 	protected Void doInBackground(Void... params) {
@@ -106,6 +106,13 @@ public void pause() {
 	@Override
     protected void onProgressUpdate(Object... progress) {
 		short[] data = (short[]) progress[0];
-        listener.onSignalReceived(data);
-    }
+		if (listener != null) {
+			listener.onSignalReceived(data);
+		}
+	}
+
+    public void cancelTask() {
+		cancel(true);
+		listener = null;
+	}
 }

src/main/java/org/havenapp/main/service/SignalSender.java

@@ -40,7 +40,7 @@ public class SignalSender {
 
     private SignalSender(Context context, String username)
     {
-        mContext = context;
+        mContext = context.getApplicationContext();
         mUsername = username;
         mAlertCount = 0;
         preferences = new PreferenceManager(mContext);

src/main/java/org/havenapp/main/ui/CameraConfigureActivity.java

@@ -26,17 +26,16 @@
 import android.view.MenuItem;
 import android.view.View;
 import android.widget.TextView;
-import android.widget.Toast;
-
-import org.havenapp.main.PreferenceManager;
-import org.havenapp.main.R;
 
 import androidx.appcompat.app.AppCompatActivity;
 import androidx.appcompat.widget.Toolbar;
 import androidx.core.app.ActivityCompat;
 import androidx.core.content.ContextCompat;
 import androidx.localbroadcastmanager.content.LocalBroadcastManager;
-import me.angrybyte.numberpicker.listener.OnValueChangeListener;
+
+import org.havenapp.main.PreferenceManager;
+import org.havenapp.main.R;
+
 import me.angrybyte.numberpicker.view.ActualNumberPicker;
 
 
@@ -111,7 +110,6 @@ else if (camera.equals(PreferenceManager.BACK))
     public boolean onOptionsItemSelected(MenuItem item) {
         switch (item.getItemId()) {
             case android.R.id.home:
-                mFragment.stopCamera();
                 finish();
                 break;
         }
@@ -124,7 +122,6 @@ public boolean onOptionsItemSelected(MenuItem item) {
      */
     @Override
     public void onBackPressed() {
-        mFragment.stopCamera();
         finish();
     }
 

src/main/java/org/havenapp/main/ui/CameraFragment.java

@@ -19,6 +19,9 @@
 import androidx.fragment.app.Fragment;
 import androidx.localbroadcastmanager.content.LocalBroadcastManager;
 
+import androidx.fragment.app.Fragment;
+import androidx.localbroadcastmanager.content.LocalBroadcastManager;
+
 import com.otaliastudios.cameraview.CameraView;
 import com.otaliastudios.cameraview.controls.Audio;
 
@@ -76,13 +79,6 @@ public void updateCamera ()
         }
     }
 
-    public void stopCamera ()
-    {
-        if (cameraViewHolder != null) {
-            cameraViewHolder.stopCamera();
-        }
-    }
-
     public void initCamera ()
     {
 
@@ -94,6 +90,7 @@ public void initCamera ()
 
             CameraView cameraView = getActivity().findViewById(R.id.camera_view);
             cameraView.setAudio(Audio.OFF);
+            cameraView.setLifecycleOwner(this);
 
             if (cameraViewHolder == null) {
                 cameraViewHolder = new CameraViewHolder(getActivity(), cameraView);

src/main/java/org/havenapp/main/ui/CameraViewHolder.java

@@ -229,7 +229,6 @@ public List<Size> select(@NonNull List<Size> source) {
                 return result;
             }
         });
-        cameraView.open();
 
         cameraView.addFrameProcessor(new FrameProcessor() {
             @Override
@@ -390,21 +389,12 @@ private synchronized boolean recordVideo() {
     }
 
 
-    public synchronized void stopCamera ()
-    {
-        if (cameraView != null) {
-           cameraView.close();
-        }
-    }
-
-
     public void destroy ()
     {
         if (mConnection != null) {
             this.context.unbindService(mConnection);
             mConnection = null;
         }
-        stopCamera();
     }
 
     public int getCorrectCameraOrientation(Facing facing, int orientation) {

src/main/java/org/havenapp/main/ui/MicrophoneConfigureActivity.java

@@ -192,7 +192,7 @@ public void onRequestPermissionsResult(int requestCode, String[] permissions, in
     protected void onDestroy() {
         super.onDestroy();
         if (microphone != null)
-            microphone.cancel(true);
+            microphone.cancelTask();
 
     }
 

src/main/java/org/havenapp/main/ui/widget/HavenCameraView.kt

@@ -0,0 +1,51 @@
+package org.havenapp.main.ui.widget
+
+import android.content.Context
+import android.util.AttributeSet
+import androidx.annotation.NonNull
+import androidx.annotation.Nullable
+import androidx.lifecycle.DefaultLifecycleObserver
+import androidx.lifecycle.LifecycleOwner
+import com.otaliastudios.cameraview.CameraView
+
+/**
+ * A subclass of [CameraView] which implements [DefaultLifecycleObserver]
+ *
+ * According to https://developer.android.com/reference/androidx/lifecycle/DefaultLifecycleObserver
+ * [DefaultLifecycleObserver] should *always* be preferred over [androidx.lifecycle.LifecycleObserver]
+ * if we use Java 8. [CameraView] library targets Java 7 hence this implementation aims to ignore
+ * [androidx.lifecycle.OnLifecycleEvent] annotated methods in the super class and replace them with
+ * the callbacks implemeted in this sub class
+ */
+class HavenCameraView : CameraView, DefaultLifecycleObserver {
+    constructor(context: Context) : super(context)
+
+    constructor(@NonNull context: Context, @Nullable attrs: AttributeSet) : super(context, attrs)
+
+    override fun onCreate(owner: LifecycleOwner) {
+        super.onCreate(owner)
+    }
+
+    override fun onResume(owner: LifecycleOwner) {
+        super.onResume(owner)
+        open()
+    }
+
+    override fun onPause(owner: LifecycleOwner) {
+        close()
+        super.onPause(owner)
+    }
+
+    override fun onStart(owner: LifecycleOwner) {
+        super.onStart(owner)
+    }
+
+    override fun onStop(owner: LifecycleOwner) {
+        super.onStop(owner)
+    }
+
+    override fun onDestroy(owner: LifecycleOwner) {
+        destroy()
+        super.onDestroy(owner)
+    }
+}

src/main/res/layout/camera_fragment.xml

@@ -6,8 +6,7 @@
     android:foreground="@color/translucentOverlay25">
 
     <!-- Camera -->
-    <com.otaliastudios.cameraview.CameraView
-        xmlns:app="http://schemas.android.com/apk/res-auto"
+    <org.havenapp.main.ui.widget.HavenCameraView
         android:id="@+id/camera_view"
         android:layout_width="match_parent"
         android:layout_height="match_parent"