Location Updates with FusedLocationProviderClient produces memory leaks

Question

I can't understand why this very simple activity produces memory leaks.

It follows the guidelines given here: https://developer.android.com/training/location/receive-location-updates.html and the example code given here: https://github.com/googlesamples/android-play-location/tree/master/LocationUpdates

I also noticed that the memory leak is solved if I don't override the onLocationResult method of the LocationCallback class. But in this ways the LocationCallback is completely useless.

Thank you for your help!

public class TestLeaks extends Activity {
    private FusedLocationProviderClient mFusedLocationClient;   // Access to Fused Loc. Provider API
    private LocationRequest mLocationRequest;         // Stores parameters for requests to F.L.P.Api
    private LocationCallback mLocationCallback;                      // Callback for Location events

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.test_leaks);

        mFusedLocationClient = LocationServices.getFusedLocationProviderClient(this);
        mLocationCallback = new LocationCallback() {
            @Override
            public void onLocationResult(LocationResult locationResult) {
                super.onLocationResult(locationResult);
                Location loc = locationResult.getLastLocation();
                ((TextView) findViewById(R.id.latitude)).setText(String.format(Locale.US, "%.6f", loc.getLatitude()));
                ((TextView) findViewById(R.id.longitude)).setText(String.format(Locale.US, "%.6f", loc.getLongitude()));
            }
        };

        mLocationRequest = new LocationRequest()
                .setInterval(5000)
                .setFastestInterval(2000)
                .setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
    }

    @SuppressLint("MissingPermission")
    @Override
    public void onResume() {
        super.onResume();
        mFusedLocationClient.requestLocationUpdates(mLocationRequest, mLocationCallback, Looper.myLooper());
    }

    @Override
    protected void onPause() {
        super.onPause();
        mFusedLocationClient.removeLocationUpdates(mLocationCallback);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        mLocationCallback = null;
    }
}

This is the output of LeakCanary about the detected memory leak:

In it.myapp.app:1.0.4:10004.
* it.myapp.app.activities.TestLeaks has leaked:
* GC ROOT com.google.android.gms.internal.zzcfe.zzfus
* references com.google.android.gms.common.api.internal.zzci.zzful
* references com.google.android.gms.common.api.internal.zzck.zzfuk
* references it.myapp.app.activities.TestLeaks$1.this$0 (anonymous subclass of com.google.android.gms.location.LocationCallback)
* leaks it.myapp.app.activities.TestLeaks instance

* Retaining: 35 KB.
* Reference Key: 969b4256-81ff-4b01-b0d4-63e27e49b764
* Device: samsung samsung SM-G920F zerofltexx
* Android Version: 7.0 API: 24 LeakCanary: 1.5.4 74837f0
* Durations: watch=637463ms, gc=258ms, heap dump=2766ms, analysis=46757ms

* Details:
* Instance of com.google.android.gms.internal.zzcfe
|   static $classOverhead = byte[768]@317861889 (0x12f23001)
|   zzfus = com.google.android.gms.common.api.internal.zzci@318105032 (0x12f5e5c8)
|   mDescriptor = java.lang.String@317290744 (0x12e978f8)
|   mObject = 511599546432
|   mOwner = com.google.android.gms.internal.zzcfe@317359520 (0x12ea85a0)
|   shadow$_klass_ = com.google.android.gms.internal.zzcfe
|   shadow$_monitor_ = 0
* Instance of com.google.android.gms.common.api.internal.zzci
|   static $classOverhead = byte[648]@316776449 (0x12e1a001)
|   zzfuj = com.google.android.gms.common.api.internal.zzcj@317594368 (0x12ee1b00)
|   zzfuk = null
|   zzful = com.google.android.gms.common.api.internal.zzck@318185888 (0x12f721a0)
|   shadow$_klass_ = com.google.android.gms.common.api.internal.zzci
|   shadow$_monitor_ = 0
* Instance of com.google.android.gms.common.api.internal.zzck
|   static $classOverhead = byte[608]@316789761 (0x12e1d401)
|   zzfuk = it.myapp.app.activities.TestLeaks$1@318185648 (0x12f720b0)
|   zzfun = java.lang.String@317049344 (0x12e5ca00)
|   shadow$_klass_ = com.google.android.gms.common.api.internal.zzck
|   shadow$_monitor_ = 0
* Instance of it.myapp.app.activities.TestLeaks$1
|   static $classOverhead = byte[640]@316606465 (0x12df0801)
|   static serialVersionUID = -1641506329145588052
|   static $change = null
|   this$0 = it.myapp.app.activities.TestLeaks@317686496 (0x12ef82e0)
|   shadow$_klass_ = it.myapp.app.activities.TestLeaks$1
|   shadow$_monitor_ = -1897236332
* Instance of it.myapp.app.activities.TestLeaks
|   static $classOverhead = byte[4336]@316567553 (0x12de7001)
|   static serialVersionUID = 2740572635131010457
|   static $change = null
|   mFusedLocationClient = com.google.android.gms.location.FusedLocationProviderClient@317049680 (0x12e5cb50)
|   mLocationCallback = null
|   mLocationRequest = com.google.android.gms.location.LocationRequest@318159496 (0x12f6ba88)
|   mActionBar = null
|   mActionModeTypeStarting = 0
|   mActivityInfo = android.content.pm.ActivityInfo@317696896 (0x12efab80)
|   mActivityTransitionState = android.app.ActivityTransitionState@317736656 (0x12f046d0)
|   mAppLockCheckRunnable = android.app.Activity$1@318057504 (0x12f52c20)
|   mAppLockIsInMultiWindowMode = false
|   mApplication = it.myapp.app.CanaryLeak@315492064 (0x12ce06e0)
|   mCalled = true
|   mChangeCanvasToTranslucent = false
|   mChangingConfigurations = false
|   mComponent = android.content.ComponentName@318099536 (0x12f5d050)
|   mConfigChangeFlags = 0
|   mCurrentConfig = android.content.res.Configuration@317764560 (0x12f0b3d0)
|   mDecor = null
|   mDefaultKeyMode = 0
|   mDefaultKeySsb = null
|   mDestroyed = true
|   mDoReportFullyDrawn = false
|   mEatKeyUpEvent = false
|   mEmbeddedID = null
|   mEnableDefaultActionBarUp = false
|   mEnterTransitionListener = android.app.SharedElementCallback$1@1899179144 (0x71332c88)
|   mExitTransitionListener = android.app.SharedElementCallback$1@1899179144 (0x71332c88)
|   mFinished = true
|   mFlipfont = 0
|   mFragments = android.app.FragmentController@318057472 (0x12f52c00)
|   mHandler = android.os.Handler@317542688 (0x12ed5120)
|   mHasCurrentPermissionsRequest = false
|   mIdent = 165309401
|   mInstanceTracker = android.os.StrictMode$InstanceTracker@318057488 (0x12f52c10)
|   mInstrumentation = android.app.Instrumentation@315494968 (0x12ce1238)
|   mIntent = android.content.Intent@314929344 (0x12c570c0)
|   mLastNonConfigurationInstances = null
|   mMainThread = android.app.ActivityThread@315314736 (0x12cb5230)
|   mManagedCursors = java.util.ArrayList@318035832 (0x12f4d778)
|   mManagedDialogs = null
|   mMenuInflater = null
|   mParent = null
|   mPolicyManager = null
|   mReferrer = java.lang.String@314929856 (0x12c572c0)
|   mResultCode = 0
|   mResultData = null
|   mResumed = false
|   mScreenChangeListener = null
|   mSearchEvent = null
|   mSearchManager = null
|   mStartedActivity = false
|   mStopped = true
|   mTaskDescription = android.app.ActivityManager$TaskDescription@317542720 (0x12ed5140)
|   mTemporaryPause = false
|   mTitle = java.lang.String@315505152 (0x12ce3a00)
|   mTitleColor = 0
|   mTitleReady = true
|   mToken = android.os.BinderProxy@315387808 (0x12cc6fa0)
|   mTranslucentCallback = null
|   mUiThread = java.lang.Thread@2004343960 (0x7777dc98)
|   mVisibleBehind = false
|   mVisibleFromClient = true
|   mVisibleFromServer = true
|   mVoiceInteractor = null
|   mWindow = com.android.internal.policy.PhoneWindow@315451968 (0x12cd6a40)
|   mWindowAdded = true
|   mWindowManager = android.view.WindowManagerImpl@318034248 (0x12f4d148)
|   mInflater = com.android.internal.policy.PhoneLayoutInflater@316645632 (0x12dfa100)
|   mOverrideConfiguration = null
|   mResources = android.content.res.Resources@316047040 (0x12d67ec0)
|   mTheme = android.content.res.Resources$Theme@318057696 (0x12f52ce0)
|   mThemeResource = 2131820551
|   mBase = android.app.ContextImpl@316473008 (0x12dcfeb0)
|   shadow$_klass_ = it.myapp.app.activities.TestLeaks
|   shadow$_monitor_ = 1073742768
* Excluded Refs:
| Field: android.view.inputmethod.InputMethodManager.mNextServedView
| Field: android.view.inputmethod.InputMethodManager.mServedView
| Field: android.view.inputmethod.InputMethodManager.mServedInputConnection
| Field: android.view.textservice.SpellCheckerSession$1.this$0
| Field: com.samsung.android.content.clipboard.SemClipboardManager.mContext
| Field: com.samsung.android.emergencymode.SemEmergencyManager.mContext
| Field: android.view.Choreographer$FrameDisplayEventReceiver.mMessageQueue (always)
| Thread:FinalizerWatchdogDaemon (always)
| Thread:main (always)
| Thread:LeakCanary-Heap-Dump (always)
| Class:java.lang.ref.WeakReference (always)
| Class:java.lang.ref.SoftReference (always)
| Class:java.lang.ref.PhantomReference (always)
| Class:java.lang.ref.Finalizer (always)
| Class:java.lang.ref.FinalizerReference (always)

Answer 1

I face the same issue, and then is my fixed code for someone else if needed .

class WeakLocationCallback(locationCallback: LocationCallback) : LocationCallback() {

    private val weakLocationCallback = WeakReference<LocationCallback>(locationCallback)
    override fun onLocationResult(result: LocationResult) {
        super.onLocationResult(result)
        weakLocationCallback.get()?.onLocationResult(result)
    }
}  

and

        fusedLocationClient = LocationServices.getFusedLocationProviderClient(this)
        val locationRequest = LocationRequest()
        locationRequest.priority = LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY
        locationCallback = object : LocationCallback() {
            override fun onLocationResult(result: LocationResult) {
                super.onLocationResult(result)
                currentLocation = result.lastLocation
            }
        }
        val weakLocationCallback = WeakLocationCallback(locationCallback)
        fusedLocationClient.requestLocationUpdates(locationRequest, weakLocationCallback, Looper.myLooper())