Fix code analytics

Signed-off-by: alperozturk <alper_ozturk@proton.me>

app/src/main/java/com/nextcloud/client/files/downloader/FileDownloadHelper.kt

@@ -45,10 +45,8 @@ class FileDownloadHelper {
         private var instance: FileDownloadHelper? = null
 
         fun instance(): FileDownloadHelper {
-            return if (instance == null) {
-                FileDownloadHelper()
-            } else {
-                instance!!
+            return instance ?: synchronized(this) {
+                instance ?: FileDownloadHelper().also { instance = it }
             }
         }
     }

app/src/main/java/com/nextcloud/client/files/downloader/FileDownloadWorker.kt

@@ -179,11 +179,11 @@ class FileDownloadWorker(
     }
 
     private fun setWorkerState(user: User?, file: DownloadFileOperation?) {
-        WorkerStateLiveData.instance?.setWorkState(WorkerState.Download(user, file))
+        WorkerStateLiveData.instance().setWorkState(WorkerState.Download(user, file))
     }
 
     private fun setIdleWorkerState() {
-        WorkerStateLiveData.instance?.setWorkState(WorkerState.Idle)
+        WorkerStateLiveData.instance().setWorkState(WorkerState.Idle)
     }
 
     private fun addAccountUpdateListener() {

app/src/main/java/com/nextcloud/model/WorkerStateLiveData.kt

@@ -30,13 +30,12 @@ class WorkerStateLiveData private constructor() : LiveData<WorkerState>() {
     }
 
     companion object {
-        var instance: WorkerStateLiveData? = null
-            get() {
-                if (field == null) {
-                    field = WorkerStateLiveData()
-                }
-                return field
+        private var instance: WorkerStateLiveData? = null
+
+        fun instance(): WorkerStateLiveData {
+            return instance ?: synchronized(this) {
+                instance ?: WorkerStateLiveData().also { instance = it }
             }
-            private set
+        }
     }
 }

app/src/main/java/com/owncloud/android/ui/activity/FileDisplayActivity.java

@@ -1563,7 +1563,7 @@ public class FileDisplayActivity extends FileActivity
     }
 
     private void observeWorkerState() {
-        WorkerStateLiveData.Companion.getInstance().observe(this, state -> {
+        WorkerStateLiveData.Companion.instance().observe(this, state -> {
             if (state instanceof WorkerState.Download) {
                 Log_OC.d(TAG, "Download worker started");
                 handleDownloadWorkerState();

app/src/main/java/com/owncloud/android/ui/activity/ManageAccountsActivity.java

@@ -518,7 +518,7 @@ public class ManageAccountsActivity extends FileActivity implements UserListAdap
     }
 
     private void observeWorkerState() {
-        WorkerStateLiveData.Companion.getInstance().observe(this, state -> {
+        WorkerStateLiveData.Companion.instance().observe(this, state -> {
             if (state instanceof WorkerState.Download) {
                 Log_OC.d(TAG, "Download worker started");
                 workerAccountName = ((WorkerState.Download) state).getUser().getAccountName();

app/src/main/java/com/owncloud/android/ui/preview/PreviewImageActivity.java

@@ -307,7 +307,7 @@ public class PreviewImageActivity extends FileActivity implements
     }
 
     private void observeWorkerState() {
-        WorkerStateLiveData.Companion.getInstance().observe(this, state -> {
+        WorkerStateLiveData.Companion.instance().observe(this, state -> {
             if (state instanceof WorkerState.Download) {
                 Log_OC.d(TAG, "Download worker started");
                 isDownloadWorkStarted = true;