Update Navigation and Lifecycle libraries.

- Updated the Navigation architecture component library to the latest stable version, with no big changes required.
- Updated the Lifecycle architecture component library to the latest stable version, along with a bunch of changes related to the deprecation of some methods and the addition of others.

app/build.gradle

@@ -63,7 +63,7 @@ android {
 }
 
 dependencies {
-    def lifecycle_version = "2.2.0"
+    def lifecycle_version = "2.3.0"
     def arch_version = "2.1.0"
     def room_version = "2.2.6"
     def rx_bindings_version = '3.0.0'
@@ -83,8 +83,8 @@ dependencies {
     implementation 'com.google.android.gms:play-services-maps:17.0.0'
     implementation 'com.google.maps.android:android-maps-utils:0.5'
     // AAC Lifecycle
-    implementation "androidx.lifecycle:lifecycle-extensions:$lifecycle_version"
+    implementation "androidx.lifecycle:lifecycle-livedata-ktx:$lifecycle_version"
-    implementation "androidx.lifecycle:lifecycle-viewmodel-ktx:$lifecycle_version" // viewModelScope
+    implementation "androidx.lifecycle:lifecycle-viewmodel-ktx:$lifecycle_version"
     implementation "androidx.lifecycle:lifecycle-common-java8:$lifecycle_version"
     // AAC Room
     implementation "androidx.room:room-runtime:$room_version"

app/src/main/java/cy/agorise/bitsybitshareswallet/activities/ConnectedActivity.kt

@@ -7,10 +7,9 @@ import android.os.Handler
 import android.preference.PreferenceManager
 import android.util.Log
 import android.widget.Toast
+import androidx.activity.viewModels
 import androidx.appcompat.app.AppCompatActivity
 import androidx.core.content.pm.PackageInfoCompat
-import androidx.lifecycle.Observer
-import androidx.lifecycle.ViewModelProviders
 import com.google.firebase.crashlytics.FirebaseCrashlytics
 import cy.agorise.bitsybitshareswallet.database.entities.Balance
 import cy.agorise.bitsybitshareswallet.database.entities.Transfer
@@ -69,10 +68,11 @@ abstract class ConnectedActivity : AppCompatActivity() {
         private const val RESPONSE_GET_MARKET_HISTORY = 6
     }
 
-    private lateinit var mUserAccountViewModel: UserAccountViewModel
+    // TODO consolidate ViewModels
-    private lateinit var mBalanceViewModel: BalanceViewModel
+    private val userAccountViewModel: UserAccountViewModel by viewModels()
-    private lateinit var mTransferViewModel: TransferViewModel
+    private val balanceViewModel: BalanceViewModel by viewModels()
-    private lateinit var mConnectedActivityViewModel: ConnectedActivityViewModel
+    private val transferViewModel: TransferViewModel by viewModels()
+    private val connectedActivityViewModel: ConnectedActivityViewModel by viewModels()
 
     private lateinit var mAssetRepository: AssetRepository
 
@@ -114,42 +114,38 @@ abstract class ConnectedActivity : AppCompatActivity() {
         mAssetRepository = AssetRepository(this)
 
         // Configure ConnectedActivityViewModel to obtain missing equivalent values
-        mConnectedActivityViewModel = ViewModelProviders.of(this).get(ConnectedActivityViewModel::class.java)
-
         val currencyCode = Helper.getCoingeckoSupportedCurrency(Locale.getDefault())
         Log.d(TAG, "Using currency: ${currencyCode.toUpperCase(Locale.ROOT)}")
-        mConnectedActivityViewModel.observeMissingEquivalentValuesIn(currencyCode)
+        connectedActivityViewModel.observeMissingEquivalentValuesIn(currencyCode)
 
         // Configure UserAccountViewModel to obtain the missing account ids
-        mUserAccountViewModel = ViewModelProviders.of(this).get(UserAccountViewModel::class.java)
+        userAccountViewModel.getMissingUserAccountIds().observe(this, { userAccountIds ->
-
-        mUserAccountViewModel.getMissingUserAccountIds().observe(this, Observer<List<String>>{ userAccountIds ->
             if (userAccountIds.isNotEmpty()) {
                 missingUserAccounts.clear()
                 for (userAccountId in userAccountIds)
                     missingUserAccounts.add(UserAccount(userAccountId))
 
-                mHandler.postDelayed(mRequestMissingUserAccountsTask, Constants.NETWORK_SERVICE_RETRY_PERIOD)
+                mHandler.postDelayed(
+                    mRequestMissingUserAccountsTask,
+                    Constants.NETWORK_SERVICE_RETRY_PERIOD
+                )
             }
         })
 
         // Configure UserAccountViewModel to obtain the missing account ids
-        mBalanceViewModel = ViewModelProviders.of(this).get(BalanceViewModel::class.java)
+        balanceViewModel.getMissingAssetIds().observe(this, { assetIds ->
-
-        mBalanceViewModel.getMissingAssetIds().observe(this, Observer<List<String>>{ assetIds ->
             if (assetIds.isNotEmpty()) {
                 missingAssets.clear()
                 for (assetId in assetIds)
                     missingAssets.add(Asset(assetId))
 
-                mHandler.postDelayed(mRequestMissingAssetsTask, Constants.NETWORK_SERVICE_RETRY_PERIOD)
+                mHandler
+                    .postDelayed(mRequestMissingAssetsTask, Constants.NETWORK_SERVICE_RETRY_PERIOD)
             }
         })
 
         //Configure TransferViewModel to obtain the Transfer's block numbers with missing time information, one by one
-        mTransferViewModel = ViewModelProviders.of(this).get(TransferViewModel::class.java)
+        transferViewModel.getTransferBlockNumberWithMissingTime().observe(this, { blockNumber ->
-
-        mTransferViewModel.getTransferBlockNumberWithMissingTime().observe(this, Observer<Long>{ blockNumber ->
             if (blockNumber != null && blockNumber != blockNumberWithMissingTime) {
                 blockNumberWithMissingTime = blockNumber
                 mHandler.post(mRequestBlockMissingTimeTask)
@@ -167,13 +163,14 @@ abstract class ConnectedActivity : AppCompatActivity() {
         mCompositeDisposable.add(disposable)
 
 
-        val info = this.packageManager.getPackageInfo(this.packageName, PackageManager.GET_ACTIVITIES)
+        val info =
+            this.packageManager.getPackageInfo(this.packageName, PackageManager.GET_ACTIVITIES)
         val versionCode = PackageInfoCompat.getLongVersionCode(info)
         val hasPurgedEquivalentValues = PreferenceManager.getDefaultSharedPreferences(this)
             .getBoolean(Constants.KEY_HAS_PURGED_EQUIVALENT_VALUES, false)
         if (versionCode > 11 && !hasPurgedEquivalentValues) {
             thread {
-                mConnectedActivityViewModel.purgeEquivalentValues()
+                connectedActivityViewModel.purgeEquivalentValues()
                 PreferenceManager.getDefaultSharedPreferences(this)
                     .edit()
                     .putBoolean(Constants.KEY_HAS_PURGED_EQUIVALENT_VALUES, true)
@@ -261,8 +258,8 @@ abstract class ConnectedActivity : AppCompatActivity() {
                 // If we got an API update
                 if (message.api == ApiAccess.API_HISTORY) {
                     // Starts the procedure that will obtain the missing equivalent values
-                    mTransferViewModel
+                    transferViewModel
-                        .getTransfersWithMissingBtsValue().observe(this, Observer<Transfer> {
+                        .getTransfersWithMissingBtsValue().observe(this, {
                             if (it != null) handleTransfersWithMissingBtsValue(it)
                         })
                 }
@@ -280,7 +277,10 @@ abstract class ConnectedActivity : AppCompatActivity() {
             val bucket: Long = TimeUnit.SECONDS.convert(1, TimeUnit.DAYS)
             val end: Long = transfer.timestamp * 1000L
             val start: Long = (transfer.timestamp - bucket) * 1000L
-            val id = mNetworkService!!.sendMessage(GetMarketHistory(base, quote, bucket, start, end), GetMarketHistory.REQUIRED_API)
+            val id = mNetworkService!!.sendMessage(
+                GetMarketHistory(base, quote, bucket, start, end),
+                GetMarketHistory.REQUIRED_API
+            )
             responseMap[id] = RESPONSE_GET_MARKET_HISTORY
             this.transfer = transfer
         }
@@ -292,11 +292,17 @@ abstract class ConnectedActivity : AppCompatActivity() {
      */
     private fun handleAccountDetails(accountDetails: FullAccountDetails) {
         val latestOpCount = accountDetails.statistics.total_ops
-        Log.d(TAG, "handleAccountDetails. prev count: $storedOpCount, current count: $latestOpCount")
+        Log.d(
+            TAG,
+            "handleAccountDetails. prev count: $storedOpCount, current count: $latestOpCount"
+        )
 
         if (latestOpCount == 0L) {
-            Log.d(TAG, "The node returned 0 total_ops for current account and may not have installed the history plugin. " +
+            Log.d(
-                    "\nAsk the NetworkService to remove the node from the list and connect to another one.")
+                TAG,
+                "The node returned 0 total_ops for current account and may not have installed the history plugin. " +
+                        "\nAsk the NetworkService to remove the node from the list and connect to another one."
+            )
             mNetworkService?.reconnectNode()
         } else if (storedOpCount == -1L) {
             // Initial case when the app starts
@@ -317,7 +323,8 @@ abstract class ConnectedActivity : AppCompatActivity() {
      * create a list of BiTSy's UserAccount objects and stores them into the database
      */
     private fun handleAccountProperties(accountPropertiesList: List<AccountProperties>) {
-        val userAccounts = ArrayList<cy.agorise.bitsybitshareswallet.database.entities.UserAccount>()
+        val userAccounts =
+            ArrayList<cy.agorise.bitsybitshareswallet.database.entities.UserAccount>()
 
         for (accountProperties in accountPropertiesList) {
             val userAccount = cy.agorise.bitsybitshareswallet.database.entities.UserAccount(
@@ -329,7 +336,7 @@ abstract class ConnectedActivity : AppCompatActivity() {
             userAccounts.add(userAccount)
         }
 
-        mUserAccountViewModel.insertAll(userAccounts)
+        userAccountViewModel.insertAll(userAccounts)
         missingUserAccounts.clear()
     }
 
@@ -346,7 +353,7 @@ abstract class ConnectedActivity : AppCompatActivity() {
             balances.add(balance)
         }
 
-        mBalanceViewModel.insertAll(balances)
+        balanceViewModel.insertAll(balances)
     }
 
     /**
@@ -382,7 +389,7 @@ abstract class ConnectedActivity : AppCompatActivity() {
 
         try {
             val date = dateFormat.parse(blockHeader.timestamp)
-            mTransferViewModel.setBlockTime(blockNumber, date.time / 1000)
+            transferViewModel.setBlockTime(blockNumber, date.time / 1000)
         } catch (e: ParseException) {
             Log.e(TAG, "ParseException. Msg: " + e.message)
         }
@@ -395,22 +402,25 @@ abstract class ConnectedActivity : AppCompatActivity() {
             val pair = Pair(transfer, bucket)
             val disposable = Observable.just(pair)
                 .subscribeOn(Schedulers.computation())
-                .map { mTransferViewModel.updateBtsValue(it.first!!, it.second) }
+                .map { transferViewModel.updateBtsValue(it.first!!, it.second) }
                 .subscribe({}, {
                     Log.e(TAG, "Error at updateBtsValue. Msg: ${it.message}")
-                    for(line in it.stackTrace) Log.e(TAG, "${line.className}#${line.methodName}:${line.lineNumber}")
+                    for (line in it.stackTrace)
+                        Log.e(TAG, "${line.className}#${line.methodName}:${line.lineNumber}")
                 })
             mCompositeDisposable.add(disposable)
         } else {
             Log.i(TAG, "handleMarketData. Bucket IS empty")
-            AsyncTask.execute { mTransferViewModel.updateBtsValue(transfer!!, Transfer.ERROR) }
+            AsyncTask.execute { transferViewModel.updateBtsValue(transfer!!, Transfer.ERROR) }
         }
     }
 
     private fun updateBalances() {
         if (mNetworkService?.isConnected == true) {
-            val id = mNetworkService!!.sendMessage(GetAccountBalances(mCurrentAccount, ArrayList()),
+            val id = mNetworkService!!.sendMessage(
-                GetAccountBalances.REQUIRED_API)
+                GetAccountBalances(mCurrentAccount, ArrayList()),
+                GetAccountBalances.REQUIRED_API
+            )
 
             responseMap[id] = RESPONSE_GET_ACCOUNT_BALANCES
         }
@@ -447,7 +457,10 @@ abstract class ConnectedActivity : AppCompatActivity() {
     private val mRequestMissingUserAccountsTask = object : Runnable {
         override fun run() {
             if (mNetworkService?.isConnected == true) {
-                val id = mNetworkService!!.sendMessage(GetAccounts(missingUserAccounts), GetAccounts.REQUIRED_API)
+                val id = mNetworkService!!.sendMessage(
+                    GetAccounts(missingUserAccounts),
+                    GetAccounts.REQUIRED_API
+                )
 
                 responseMap[id] = RESPONSE_GET_ACCOUNTS
             } else if (missingUserAccounts.isNotEmpty()) {
@@ -462,7 +475,8 @@ abstract class ConnectedActivity : AppCompatActivity() {
     private val mRequestMissingAssetsTask = object : Runnable {
         override fun run() {
             if (mNetworkService?.isConnected == true) {
-                val id = mNetworkService!!.sendMessage(GetAssets(missingAssets), GetAssets.REQUIRED_API)
+                val id =
+                    mNetworkService!!.sendMessage(GetAssets(missingAssets), GetAssets.REQUIRED_API)
 
                 responseMap[id] = RESPONSE_GET_ASSETS
             } else if (missingAssets.isNotEmpty()) {
@@ -480,13 +494,17 @@ abstract class ConnectedActivity : AppCompatActivity() {
                 if (mCurrentAccount != null) {
                     val userAccounts = ArrayList<String>()
                     userAccounts.add(mCurrentAccount!!.objectId)
-                    val id = mNetworkService!!.sendMessage(GetFullAccounts(userAccounts, false),
+                    val id = mNetworkService!!.sendMessage(
-                        GetFullAccounts.REQUIRED_API)
+                        GetFullAccounts(userAccounts, false),
+                        GetFullAccounts.REQUIRED_API
+                    )
 
                     responseMap[id] = RESPONSE_GET_FULL_ACCOUNTS
                 }
             } else {
-                Log.w(TAG, "NetworkService is null or is not connected. mNetworkService: $mNetworkService")
+                val msg = "NetworkService is null or is not connected. " +
+                        "mNetworkService: $mNetworkService"
+                Log.w(TAG, msg)
             }
             mHandler.postDelayed(this, Constants.MISSING_PAYMENT_CHECK_PERIOD)
 
@@ -500,8 +518,10 @@ abstract class ConnectedActivity : AppCompatActivity() {
         override fun run() {
 
             if (mNetworkService?.isConnected == true) {
-                val id = mNetworkService!!.sendMessage(GetBlockHeader(blockNumberWithMissingTime),
+                val id = mNetworkService!!.sendMessage(
-                    GetBlockHeader.REQUIRED_API)
+                    GetBlockHeader(blockNumberWithMissingTime),
+                    GetBlockHeader.REQUIRED_API
+                )
 
                 responseMap[id] = RESPONSE_GET_BLOCK_HEADER
                 requestIdToBlockNumberMap[id] = blockNumberWithMissingTime
@@ -521,7 +541,7 @@ abstract class ConnectedActivity : AppCompatActivity() {
     override fun onPause() {
         super.onPause()
         mNetworkService?.nodeLatencyVerifier?.nodeList?.let { nodes ->
-            mConnectedActivityViewModel.updateNodeLatencies(nodes as List<FullNode>)
+            connectedActivityViewModel.updateNodeLatencies(nodes as List<FullNode>)
         }
 
         mHandler.removeCallbacks(mCheckMissingPaymentsTask)

app/src/main/java/cy/agorise/bitsybitshareswallet/fragments/BalancesFragment.kt

@@ -5,22 +5,20 @@ import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
 import androidx.fragment.app.Fragment
-import androidx.lifecycle.Observer
+import androidx.fragment.app.viewModels
-import androidx.lifecycle.ViewModelProviders
 import androidx.recyclerview.widget.DividerItemDecoration
 import androidx.recyclerview.widget.LinearLayoutManager
 import cy.agorise.bitsybitshareswallet.adapters.BalancesAdapter
-import cy.agorise.bitsybitshareswallet.database.joins.BalanceDetail
 import cy.agorise.bitsybitshareswallet.databinding.FragmentBalancesBinding
 import cy.agorise.bitsybitshareswallet.viewmodels.BalanceDetailViewModel
 
 class BalancesFragment : Fragment() {
 
+    private val viewModel: BalanceDetailViewModel by viewModels()
+
     private var _binding: FragmentBalancesBinding? = null
     private val binding get() = _binding!!
 
-    private lateinit var mBalanceDetailViewModel: BalanceDetailViewModel
-
     override fun onCreateView(
         inflater: LayoutInflater, container: ViewGroup?,
         savedInstanceState: Bundle?
@@ -40,18 +38,14 @@ class BalancesFragment : Fragment() {
         super.onViewCreated(view, savedInstanceState)
 
         // Configure BalanceDetailViewModel to show the current balances
-        mBalanceDetailViewModel =
+        val balancesAdapter = BalancesAdapter(requireContext())
-            ViewModelProviders.of(this).get(BalanceDetailViewModel::class.java)
-
-        val balancesAdapter = BalancesAdapter(context!!)
         binding.rvBalances.adapter = balancesAdapter
-        binding.rvBalances.layoutManager = LinearLayoutManager(context!!)
+        binding.rvBalances.layoutManager = LinearLayoutManager(requireContext())
         binding.rvBalances.addItemDecoration(
-            DividerItemDecoration(context!!, DividerItemDecoration.VERTICAL)
+            DividerItemDecoration(requireContext(), DividerItemDecoration.VERTICAL)
         )
 
-        mBalanceDetailViewModel.getAll()
+        viewModel.getAll().observe(viewLifecycleOwner, { balancesDetails ->
-            .observe(this, Observer<List<BalanceDetail>> { balancesDetails ->
             balancesAdapter.replaceAll(balancesDetails)
         })
     }

app/src/main/java/cy/agorise/bitsybitshareswallet/fragments/BaseAccountFragment.kt

@@ -3,6 +3,7 @@ package cy.agorise.bitsybitshareswallet.fragments
 import android.preference.PreferenceManager
 import androidx.navigation.fragment.findNavController
 import cy.agorise.bitsybitshareswallet.R
+import cy.agorise.bitsybitshareswallet.activities.ConnectedActivity
 import cy.agorise.bitsybitshareswallet.database.entities.Authority
 import cy.agorise.bitsybitshareswallet.repositories.AuthorityRepository
 import cy.agorise.bitsybitshareswallet.repositories.UserAccountRepository
@@ -13,7 +14,6 @@ import cy.agorise.graphenej.BrainKey
 import cy.agorise.graphenej.PublicKey
 import cy.agorise.graphenej.models.AccountProperties
 import org.bitcoinj.core.ECKey
-import cy.agorise.bitsybitshareswallet.activities.ConnectedActivity
 
 
 abstract class BaseAccountFragment : ConnectedFragment() {
@@ -36,7 +36,7 @@ abstract class BaseAccountFragment : ConnectedFragment() {
         val hashedPIN = CryptoUtils.createSHA256Hash(salt + pin)
 
         // Stores the user selected PIN, hashed
-        PreferenceManager.getDefaultSharedPreferences(context!!).edit()
+        PreferenceManager.getDefaultSharedPreferences(requireContext()).edit()
             .putString(Constants.KEY_HASHED_PIN_PATTERN, hashedPIN)
             .putString(Constants.KEY_PIN_PATTERN_SALT, salt)
             .putInt(Constants.KEY_SECURITY_LOCK_SELECTED, 1).apply() // 1 -> PIN
@@ -44,15 +44,17 @@ abstract class BaseAccountFragment : ConnectedFragment() {
         // Stores the accounts this key refers to
         val id = accountProperties.id
         val name = accountProperties.name
-        val isLTM = accountProperties.membership_expiration_date == Constants.LIFETIME_EXPIRATION_DATE
+        val isLTM =
+            accountProperties.membership_expiration_date == Constants.LIFETIME_EXPIRATION_DATE
 
-        val userAccount = cy.agorise.bitsybitshareswallet.database.entities.UserAccount(id, name, isLTM)
+        val userAccount =
+            cy.agorise.bitsybitshareswallet.database.entities.UserAccount(id, name, isLTM)
 
-        val userAccountRepository = UserAccountRepository(context!!.applicationContext)
+        val userAccountRepository = UserAccountRepository(requireContext().applicationContext)
         userAccountRepository.insert(userAccount)
 
         // Stores the id of the currently active user account
-        PreferenceManager.getDefaultSharedPreferences(context!!).edit()
+        PreferenceManager.getDefaultSharedPreferences(requireContext()).edit()
             .putString(Constants.KEY_CURRENT_ACCOUNT_ID, accountProperties.id).apply()
 
         // Trying to store all possible authorities (owner, active and memo) into the database
@@ -65,13 +67,25 @@ abstract class BaseAccountFragment : ConnectedFragment() {
             val publicKey = PublicKey(ECKey.fromPublicOnly(mBrainKey!!.privateKey.pubKey))
 
             if (ownerAuthority.keyAuths.keys.contains(publicKey)) {
-                addAuthorityToDatabase(accountProperties.id, AuthorityType.OWNER.ordinal, mBrainKey!!)
+                addAuthorityToDatabase(
+                    accountProperties.id,
+                    AuthorityType.OWNER.ordinal,
+                    mBrainKey!!
+                )
             }
             if (activeAuthority.keyAuths.keys.contains(publicKey)) {
-                addAuthorityToDatabase(accountProperties.id, AuthorityType.ACTIVE.ordinal, mBrainKey!!)
+                addAuthorityToDatabase(
+                    accountProperties.id,
+                    AuthorityType.ACTIVE.ordinal,
+                    mBrainKey!!
+                )
             }
             if (options.memoKey == publicKey) {
-                addAuthorityToDatabase(accountProperties.id, AuthorityType.MEMO.ordinal, mBrainKey!!)
+                addAuthorityToDatabase(
+                    accountProperties.id,
+                    AuthorityType.MEMO.ordinal,
+                    mBrainKey!!
+                )
             }
         }
 
@@ -91,13 +105,21 @@ abstract class BaseAccountFragment : ConnectedFragment() {
         val wif = brainKey.walletImportFormat
         val sequenceNumber = brainKey.sequenceNumber
 
-        val encryptedBrainKey = CryptoUtils.encrypt(context!!, brainKeyWords)
+        val encryptedBrainKey = CryptoUtils.encrypt(requireContext(), brainKeyWords)
-        val encryptedSequenceNumber = CryptoUtils.encrypt(context!!, sequenceNumber.toString())
+        val encryptedSequenceNumber =
-        val encryptedWIF = CryptoUtils.encrypt(context!!, wif)
+            CryptoUtils.encrypt(requireContext(), sequenceNumber.toString())
+        val encryptedWIF = CryptoUtils.encrypt(requireContext(), wif)
 
-        val authority = Authority(0, userId, authorityType, encryptedWIF, encryptedBrainKey, encryptedSequenceNumber)
+        val authority = Authority(
+            0,
+            userId,
+            authorityType,
+            encryptedWIF,
+            encryptedBrainKey,
+            encryptedSequenceNumber
+        )
 
-        val authorityRepository = AuthorityRepository(context!!)
+        val authorityRepository = AuthorityRepository(requireContext())
         authorityRepository.insert(authority)
     }
 }

app/src/main/java/cy/agorise/bitsybitshareswallet/fragments/CreateAccountFragment.kt

@@ -362,8 +362,9 @@ class CreateAccountFragment : BaseAccountFragment() {
         var reader: BufferedReader? = null
         val dictionary: String
         try {
-            reader =
+            reader = BufferedReader(
-                BufferedReader(InputStreamReader(context!!.assets.open(BRAINKEY_FILE), "UTF-8"))
+                InputStreamReader(requireContext().assets.open(BRAINKEY_FILE), "UTF-8")
+            )
             dictionary = reader.readLine()
 
             val brainKeySuggestion = BrainKey.suggest(dictionary)

app/src/main/java/cy/agorise/bitsybitshareswallet/fragments/EReceiptFragment.kt

@@ -12,8 +12,7 @@ import android.view.*
 import androidx.core.content.ContextCompat
 import androidx.core.os.ConfigurationCompat
 import androidx.fragment.app.Fragment
-import androidx.lifecycle.Observer
+import androidx.fragment.app.viewModels
-import androidx.lifecycle.ViewModelProviders
 import androidx.navigation.fragment.navArgs
 import com.google.firebase.crashlytics.FirebaseCrashlytics
 import cy.agorise.bitsybitshareswallet.R
@@ -38,12 +37,13 @@ class EReceiptFragment : Fragment() {
         private const val REQUEST_WRITE_EXTERNAL_STORAGE_PERMISSION = 100
     }
 
+    private val args: EReceiptFragmentArgs by navArgs()
+
+    private val viewModel: EReceiptViewModel by viewModels()
+
     private var _binding: FragmentEReceiptBinding? = null
     private val binding get() = _binding!!
 
-    private val args: EReceiptFragmentArgs by navArgs()
-
-    private lateinit var mEReceiptViewModel: EReceiptViewModel
     private lateinit var mLocale: Locale
 
     override fun onCreateView(
@@ -75,10 +75,7 @@ class EReceiptFragment : Fragment() {
 
         val transferId = args.transferId
 
-        mEReceiptViewModel = ViewModelProviders.of(this).get(EReceiptViewModel::class.java)
+        viewModel.get(userId, transferId).observe(viewLifecycleOwner, { transferDetail ->
-
-        mEReceiptViewModel.get(userId, transferId)
-            .observe(this, Observer<TransferDetail> { transferDetail ->
             bindTransferDetail(transferDetail)
         })
     }
@@ -165,7 +162,7 @@ class EReceiptFragment : Fragment() {
      * shares it but if it is not then it asks the user for that permission */
     private fun verifyStoragePermission() {
         if (ContextCompat
-                .checkSelfPermission(activity!!, Manifest.permission.WRITE_EXTERNAL_STORAGE)
+                .checkSelfPermission(requireActivity(), Manifest.permission.WRITE_EXTERNAL_STORAGE)
             != PackageManager.PERMISSION_GRANTED
         ) {
             // Permission is not already granted

app/src/main/java/cy/agorise/bitsybitshareswallet/fragments/FilterOptionsDialog.kt

@@ -10,8 +10,7 @@ import android.widget.TextView
 import androidx.core.os.ConfigurationCompat
 import androidx.fragment.app.DialogFragment
 import androidx.fragment.app.Fragment
-import androidx.lifecycle.Observer
+import androidx.fragment.app.viewModels
-import androidx.lifecycle.ViewModelProviders
 import com.google.firebase.crashlytics.FirebaseCrashlytics
 import cy.agorise.bitsybitshareswallet.R
 import cy.agorise.bitsybitshareswallet.adapters.BalancesDetailsAdapter
@@ -42,6 +41,8 @@ class FilterOptionsDialog : DialogFragment(), DatePickerFragment.OnDateSetListen
         const val END_DATE_PICKER = 1
     }
 
+    private val viewModel: BalanceDetailViewModel by viewModels()
+
     private var _binding: DialogFilterOptionsBinding? = null
     private val binding get() = _binding!!
 
@@ -56,8 +57,6 @@ class FilterOptionsDialog : DialogFragment(), DatePickerFragment.OnDateSetListen
 
     private var mBalanceDetails = ArrayList<BalanceDetail>()
 
-    private lateinit var mBalanceDetailViewModel: BalanceDetailViewModel
-
     private var mBalancesDetailsAdapter: BalancesDetailsAdapter? = null
 
     private lateinit var mCurrency: Currency
@@ -117,7 +116,7 @@ class FilterOptionsDialog : DialogFragment(), DatePickerFragment.OnDateSetListen
     override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
         super.onViewCreated(view, savedInstanceState)
 
-        onAttachToParentFragment(parentFragment!!)
+        onAttachToParentFragment(requireParentFragment())
 
         val crashlytics = FirebaseCrashlytics.getInstance()
         crashlytics.setCustomKey(Constants.CRASHLYTICS_KEY_LAST_SCREEN, TAG)
@@ -150,18 +149,12 @@ class FilterOptionsDialog : DialogFragment(), DatePickerFragment.OnDateSetListen
         binding.cbAsset.isChecked = mFilterOptions.assetAll
 
         // Configure BalanceDetailViewModel to obtain the user's Balances
-        mBalanceDetailViewModel =
+        viewModel.getAll().observe(viewLifecycleOwner, { balancesDetails ->
-            ViewModelProviders.of(this).get(BalanceDetailViewModel::class.java)
-
-        mBalanceDetailViewModel.getAll()
-            .observe(this, Observer<List<BalanceDetail>> { balancesDetails ->
             mBalanceDetails.clear()
             mBalanceDetails.addAll(balancesDetails)
-                mBalanceDetails.sortWith(
+            mBalanceDetails.sortWith { a, b -> a.toString().compareTo(b.toString(), true) }
-                    Comparator { a, b -> a.toString().compareTo(b.toString(), true) }
-                )
             mBalancesDetailsAdapter = BalancesDetailsAdapter(
-                    context!!,
+                requireContext(),
                 android.R.layout.simple_spinner_item,
                 mBalanceDetails
             )

app/src/main/java/cy/agorise/bitsybitshareswallet/fragments/HomeFragment.kt

@@ -6,16 +6,15 @@ import android.view.*
 import androidx.appcompat.app.AppCompatActivity
 import androidx.appcompat.widget.Toolbar
 import androidx.core.content.ContextCompat
+import androidx.core.content.res.ResourcesCompat
 import androidx.fragment.app.Fragment
 import androidx.fragment.app.FragmentManager
 import androidx.fragment.app.FragmentPagerAdapter
-import androidx.lifecycle.Observer
+import androidx.fragment.app.viewModels
-import androidx.lifecycle.ViewModelProviders
 import androidx.navigation.Navigation
 import androidx.navigation.fragment.findNavController
 import com.google.firebase.crashlytics.FirebaseCrashlytics
 import cy.agorise.bitsybitshareswallet.R
-import cy.agorise.bitsybitshareswallet.database.entities.UserAccount
 import cy.agorise.bitsybitshareswallet.databinding.FragmentHomeBinding
 import cy.agorise.bitsybitshareswallet.utils.Constants
 import cy.agorise.bitsybitshareswallet.viewmodels.UserAccountViewModel
@@ -27,11 +26,11 @@ class HomeFragment : Fragment() {
         private const val TAG = "HomeFragment"
     }
 
+    private val viewModel: UserAccountViewModel by viewModels()
+
     private var _binding: FragmentHomeBinding? = null
     private val binding get() = _binding!!
 
-    private lateinit var mUserAccountViewModel: UserAccountViewModel
-
     override fun onCreateView(
         inflater: LayoutInflater,
         container: ViewGroup?,
@@ -47,7 +46,8 @@ class HomeFragment : Fragment() {
         // MerchantsFragment (visibility)
         val toolbar: Toolbar? = activity?.findViewById(R.id.toolbar)
         (activity as AppCompatActivity).setSupportActionBar(toolbar)
-        toolbar?.navigationIcon = resources.getDrawable(R.drawable.ic_bitsy_logo_2, null)
+        toolbar?.navigationIcon =
+            ResourcesCompat.getDrawable(resources, R.drawable.ic_bitsy_logo_2, null)
         toolbar?.setBackgroundResource(if (!nightMode) R.color.colorPrimary else R.color.colorToolbarDark)
         toolbar?.visibility = View.VISIBLE
         toolbar?.title = getString(R.string.app_name)
@@ -94,10 +94,7 @@ class HomeFragment : Fragment() {
         }
 
         // Configure UserAccountViewModel to show the current account
-        mUserAccountViewModel = ViewModelProviders.of(this).get(UserAccountViewModel::class.java)
+        viewModel.getUserAccount(userId).observe(viewLifecycleOwner, { userAccount ->
-
-        mUserAccountViewModel.getUserAccount(userId)
-            .observe(this, Observer<UserAccount> { userAccount ->
             if (userAccount != null) {
                 binding.tvAccountName.text = userAccount.name
                 if (userAccount.isLtm) {
@@ -149,11 +146,11 @@ class HomeFragment : Fragment() {
         }
 
         override fun getPageTitle(position: Int): CharSequence {
-            return listOf(
+            return when (position) {
-                getString(R.string.title_balances),
+                0 -> getString(R.string.title_balances)
-                getString(R.string.title_net_worth),
+                1 -> getString(R.string.title_net_worth)
-                ""
+                else -> ""
-            )[position]
+            }
         }
 
         override fun getCount(): Int {

app/src/main/java/cy/agorise/bitsybitshareswallet/fragments/ImportBrainkeyFragment.kt

@@ -402,7 +402,7 @@ class ImportBrainkeyFragment : BaseAccountFragment() {
                 for (accountProperties in accountPropertiesList) {
                     candidates.add(accountProperties.name)
                 }
-                MaterialDialog(context!!)
+                MaterialDialog(requireContext())
                     .title(R.string.dialog__account_candidates_title)
                     .message(R.string.dialog__account_candidates_content)
                     .listItemsSingleChoice(

app/src/main/java/cy/agorise/bitsybitshareswallet/fragments/MerchantsFragment.kt

@@ -18,8 +18,7 @@ import androidx.appcompat.widget.Toolbar
 import androidx.core.content.ContextCompat
 import androidx.cursoradapter.widget.SimpleCursorAdapter
 import androidx.fragment.app.Fragment
-import androidx.lifecycle.Observer
+import androidx.fragment.app.viewModels
-import androidx.lifecycle.ViewModelProviders
 import com.afollestad.materialdialogs.MaterialDialog
 import com.afollestad.materialdialogs.customview.customView
 import com.google.android.gms.maps.CameraUpdateFactory
@@ -73,13 +72,13 @@ class MerchantsFragment : Fragment(), OnMapReadyCallback, SearchView.OnSuggestio
         private const val SUGGEST_COLUMN_IMAGE_RESOURCE = "suggest_image_resource"
     }
 
+    private val viewModel: MerchantViewModel by viewModels()
+
     private var _binding: FragmentMerchantsBinding? = null
     private val binding get() = _binding!!
 
     private var mMap: GoogleMap? = null
 
-    private lateinit var mMerchantViewModel: MerchantViewModel
-
     private var mMarkerManager: MarkerManager? = null
 
     /** Keeps track of all RxJava disposables, to make sure they are all disposed when the fragment is destroyed */
@@ -166,8 +165,6 @@ class MerchantsFragment : Fragment(), OnMapReadyCallback, SearchView.OnSuggestio
         val mapFragment = childFragmentManager.findFragmentById(R.id.map) as SupportMapFragment
         mapFragment.getMapAsync(this)
 
-        mMerchantViewModel = ViewModelProviders.of(this).get(MerchantViewModel::class.java)
-
         setupPopupWindow()
 
         // Gets the screen width to correctly place the merchants and tellers popup menu
@@ -245,12 +242,12 @@ class MerchantsFragment : Fragment(), OnMapReadyCallback, SearchView.OnSuggestio
 
     private fun updateSearchViewSuggestions(query: String) {
         // Obtain observable of the list of merchants matching the query
-        val merchantsObs = mMerchantViewModel.queryMerchants(query)
+        val merchantsObs = viewModel.queryMerchants(query)
             .subscribeOn(Schedulers.io())
             .observeOn(AndroidSchedulers.mainThread()).toObservable()
 
         // Obtain observable of the list of tellers matching the query
-        val tellerObs = mMerchantViewModel.queryTellers(query)
+        val tellerObs = viewModel.queryTellers(query)
             .subscribeOn(Schedulers.io())
             .observeOn(AndroidSchedulers.mainThread()).toObservable()
 
@@ -449,7 +446,10 @@ class MerchantsFragment : Fragment(), OnMapReadyCallback, SearchView.OnSuggestio
     }
 
     private fun verifyLocationPermission() {
-        if (ContextCompat.checkSelfPermission(activity!!, Manifest.permission.ACCESS_FINE_LOCATION)
+        if (ContextCompat.checkSelfPermission(
+                requireActivity(),
+                Manifest.permission.ACCESS_FINE_LOCATION
+            )
             != PackageManager.PERMISSION_GRANTED
         ) {
             // Permission is not already granted
@@ -482,7 +482,7 @@ class MerchantsFragment : Fragment(), OnMapReadyCallback, SearchView.OnSuggestio
         // Force marker to use a custom info window
         mMerchantClusterManager?.markerCollection?.setOnInfoWindowAdapter(MerchantInfoWindowAdapter())
 
-        mMerchantViewModel.getAllMerchants().observe(this, Observer<List<Merchant>> { merchants ->
+        viewModel.getAllMerchants().observe(viewLifecycleOwner, { merchants ->
             this.merchants.clear()
             this.merchants.addAll(merchants)
             showHideMerchantsMarkers()
@@ -508,7 +508,7 @@ class MerchantsFragment : Fragment(), OnMapReadyCallback, SearchView.OnSuggestio
         // Force marker to use a custom info window
         mTellerClusterManager?.markerCollection?.setOnInfoWindowAdapter(TellerInfoWindowAdapter())
 
-        mMerchantViewModel.getAllTellers().observe(this, Observer<List<Teller>> { tellers ->
+        viewModel.getAllTellers().observe(viewLifecycleOwner, { tellers ->
             this.tellers.clear()
             this.tellers.addAll(tellers)
             showHideTellersMarkers()

app/src/main/java/cy/agorise/bitsybitshareswallet/fragments/ReceiveTransactionFragment.kt

@@ -11,8 +11,7 @@ import android.widget.AdapterView
 import androidx.appcompat.widget.Toolbar
 import androidx.collection.LongSparseArray
 import androidx.core.content.ContextCompat
-import androidx.lifecycle.Observer
+import androidx.fragment.app.viewModels
-import androidx.lifecycle.ViewModelProviders
 import com.google.common.primitives.UnsignedLong
 import com.google.firebase.crashlytics.FirebaseCrashlytics
 import com.jakewharton.rxbinding3.widget.textChanges
@@ -52,11 +51,11 @@ class ReceiveTransactionFragment : ConnectedFragment() {
         private const val OTHER_ASSET = "other_asset"
     }
 
+    private val viewModel: ReceiveTransactionViewModel by viewModels()
+
     private var _binding: FragmentReceiveTransactionBinding? = null
     private val binding get() = _binding!!
 
-    private lateinit var mViewModel: ReceiveTransactionViewModel
-
     /** Current user account */
     private var mUserAccount: UserAccount? = null
 
@@ -118,18 +117,14 @@ class ReceiveTransactionFragment : ConnectedFragment() {
         crashlytics.setCustomKey(Constants.CRASHLYTICS_KEY_LAST_SCREEN, TAG)
 
         // Configure ViewModel
-        mViewModel = ViewModelProviders.of(this).get(ReceiveTransactionViewModel::class.java)
-
         val userId = PreferenceManager.getDefaultSharedPreferences(context)
             .getString(Constants.KEY_CURRENT_ACCOUNT_ID, "")
 
-        mViewModel.getUserAccount(userId!!).observe(this,
+        viewModel.getUserAccount(userId!!).observe(viewLifecycleOwner, { user ->
-            Observer<cy.agorise.bitsybitshareswallet.database.entities.UserAccount> { user ->
             mUserAccount = UserAccount(user.id, user.name)
         })
 
-        mViewModel.getAllNonZero().observe(this,
+        viewModel.getAllNonZero().observe(viewLifecycleOwner, { assets ->
-            Observer<List<cy.agorise.bitsybitshareswallet.database.entities.Asset>> { assets ->
             mAssets.clear()
             mAssets.addAll(assets)
 
@@ -152,7 +147,7 @@ class ReceiveTransactionFragment : ConnectedFragment() {
             mAssets.add(asset)
 
             mAssetsAdapter =
-                    AssetsAdapter(context!!, android.R.layout.simple_spinner_item, mAssets)
+                AssetsAdapter(requireContext(), android.R.layout.simple_spinner_item, mAssets)
             binding.spAsset.adapter = mAssetsAdapter
 
             // Try to select the selectedAssetSymbol
@@ -164,7 +159,7 @@ class ReceiveTransactionFragment : ConnectedFragment() {
             }
         })
 
-        mViewModel.qrCodeBitmap.observe(this, Observer { bitmap ->
+        viewModel.qrCodeBitmap.observe(viewLifecycleOwner, { bitmap ->
             binding.ivQR.setImageBitmap(bitmap)
         })
 
@@ -204,7 +199,7 @@ class ReceiveTransactionFragment : ConnectedFragment() {
 
         // Add adapter to the Assets AutoCompleteTextView
         mAutoSuggestAssetAdapter =
-            AutoSuggestAssetAdapter(context!!, android.R.layout.simple_dropdown_item_1line)
+            AutoSuggestAssetAdapter(requireContext(), android.R.layout.simple_dropdown_item_1line)
         binding.actvAsset.setAdapter(mAutoSuggestAssetAdapter)
 
         // Use RxJava Debounce to avoid making calls to the NetworkService on every text change event and also avoid
@@ -311,7 +306,7 @@ class ReceiveTransactionFragment : ConnectedFragment() {
         )
         Log.d(TAG, "invoice: " + invoice.toJsonString())
         try {
-            mViewModel.updateInvoice(invoice, min(binding.ivQR.width, binding.ivQR.height))
+            viewModel.updateInvoice(invoice, min(binding.ivQR.width, binding.ivQR.height))
             updateAmountAddressUI(amount, asset.symbol, asset.precision, mUserAccount!!.name)
         } catch (e: NullPointerException) {
             Log.e(TAG, "NullPointerException. Msg: " + e.message)
@@ -366,7 +361,7 @@ class ReceiveTransactionFragment : ConnectedFragment() {
 
     private fun verifyStoragePermission() {
         if (ContextCompat.checkSelfPermission(
-                activity!!,
+                requireActivity(),
                 android.Manifest.permission.WRITE_EXTERNAL_STORAGE
             )
             != PackageManager.PERMISSION_GRANTED
@@ -411,7 +406,7 @@ class ReceiveTransactionFragment : ConnectedFragment() {
 
         // Get Screenshot
         val screenshot = Helper.loadBitmapFromView(binding.container)
-        val imageUri = Helper.saveTemporalBitmap(context!!, screenshot)
+        val imageUri = Helper.saveTemporalBitmap(requireContext(), screenshot)
 
         // Prepare information for share intent
         val subject = getString(R.string.msg__invoice_subject, mUserAccount?.name)

app/src/main/java/cy/agorise/bitsybitshareswallet/fragments/SendTransactionFragment.kt

@@ -12,8 +12,7 @@ import android.widget.Toast
 import androidx.appcompat.widget.Toolbar
 import androidx.collection.LongSparseArray
 import androidx.core.content.ContextCompat
-import androidx.lifecycle.Observer
+import androidx.fragment.app.viewModels
-import androidx.lifecycle.ViewModelProviders
 import androidx.navigation.fragment.findNavController
 import androidx.navigation.fragment.navArgs
 import com.afollestad.materialdialogs.MaterialDialog
@@ -74,13 +73,15 @@ class SendTransactionFragment : ConnectedFragment(), ZXingScannerView.ResultHand
         private const val ACTION_SEND_TRANSFER = 1
     }
 
-    private var _binding: FragmentSendTransactionBinding? = null
-    private val binding get() = _binding!!
-
-    // Navigation AAC Safe Args
     private val args: SendTransactionFragmentArgs by navArgs()
 
-    private lateinit var mViewModel: SendTransactionViewModel
+    // TODO consolidate ViewModels
+    private val viewModel: SendTransactionViewModel by viewModels()
+
+    private val balanceDetailViewModel: BalanceDetailViewModel by viewModels()
+
+    private var _binding: FragmentSendTransactionBinding? = null
+    private val binding get() = _binding!!
 
     /** Variables used in field's validation */
     private var isCameraPreviewVisible = false
@@ -90,8 +91,6 @@ class SendTransactionFragment : ConnectedFragment(), ZXingScannerView.ResultHand
 
     private var mBalancesDetails = ArrayList<BalanceDetail>()
 
-    private lateinit var mBalanceDetailViewModel: BalanceDetailViewModel
-
     private var mBalancesDetailsAdapter: BalancesDetailsAdapter? = null
 
     /** Keeps track of the asset's symbol selected in the Asset spinner */
@@ -162,10 +161,8 @@ class SendTransactionFragment : ConnectedFragment(), ZXingScannerView.ResultHand
             mUserAccount = UserAccount(userId)
 
         // Configure ViewModel
-        mViewModel = ViewModelProviders.of(this).get(SendTransactionViewModel::class.java)
+        viewModel.getWIF(userId, AuthorityType.ACTIVE.ordinal)
-
+            .observe(viewLifecycleOwner, { encryptedWIF ->
-        mViewModel.getWIF(userId, AuthorityType.ACTIVE.ordinal).observe(this,
-            Observer<String> { encryptedWIF ->
                 context?.let {
                     try {
                         wifKey = CryptoUtils.decrypt(it, encryptedWIF)
@@ -186,18 +183,14 @@ class SendTransactionFragment : ConnectedFragment(), ZXingScannerView.ResultHand
         binding.fabOpenCamera.setOnClickListener { if (isCameraPreviewVisible) stopCameraPreview() else verifyCameraPermission() }
 
         // Configure BalanceDetailViewModel to show the current balances
-        mBalanceDetailViewModel =
+        balanceDetailViewModel.getAll().observe(viewLifecycleOwner, { balancesDetails ->
-            ViewModelProviders.of(this).get(BalanceDetailViewModel::class.java)
-
-        mBalanceDetailViewModel.getAll()
-            .observe(this, Observer<List<BalanceDetail>> { balancesDetails ->
             mBalancesDetails.clear()
             mBalancesDetails.addAll(balancesDetails)
             mBalancesDetails.sortWith(
                 Comparator { a, b -> a.toString().compareTo(b.toString(), true) }
             )
             mBalancesDetailsAdapter = BalancesDetailsAdapter(
-                    context!!,
+                requireContext(),
                 android.R.layout.simple_spinner_item,
                 mBalancesDetails
             )
@@ -387,7 +380,7 @@ class SendTransactionFragment : ConnectedFragment(), ZXingScannerView.ResultHand
 
     /** Verifies if the user has already granted the Camera permission, if not the asks for it */
     private fun verifyCameraPermission() {
-        if (ContextCompat.checkSelfPermission(activity!!, android.Manifest.permission.CAMERA)
+        if (ContextCompat.checkSelfPermission(requireActivity(), android.Manifest.permission.CAMERA)
             != PackageManager.PERMISSION_GRANTED
         ) {
             // Permission is not already granted
@@ -711,7 +704,7 @@ class SendTransactionFragment : ConnectedFragment(), ZXingScannerView.ResultHand
 
     override fun onOptionsItemSelected(item: MenuItem): Boolean {
         if (item.itemId == R.id.menu_info) {
-            MaterialDialog(context!!).show {
+            MaterialDialog(requireContext()).show {
                 customView(R.layout.dialog_send_transaction_info, scrollable = true)
                 positiveButton(android.R.string.ok) { dismiss() }
             }

app/src/main/java/cy/agorise/bitsybitshareswallet/fragments/SettingsFragment.kt

@@ -11,7 +11,7 @@ import android.view.ViewGroup
 import androidx.appcompat.widget.Toolbar
 import androidx.collection.LongSparseArray
 import androidx.core.content.res.ResourcesCompat
-import androidx.lifecycle.ViewModelProviders
+import androidx.fragment.app.viewModels
 import androidx.recyclerview.widget.LinearLayoutManager
 import com.afollestad.materialdialogs.MaterialDialog
 import com.afollestad.materialdialogs.callbacks.onDismiss
@@ -60,11 +60,11 @@ class SettingsFragment : ConnectedFragment(), BaseSecurityLockDialog.OnPINPatter
         private const val RESPONSE_BROADCAST_TRANSACTION = 3
     }
 
+    private val viewModel: SettingsFragmentViewModel by viewModels()
+
     private var _binding: FragmentSettingsBinding? = null
     private val binding get() = _binding!!
 
-    private lateinit var mViewModel: SettingsFragmentViewModel
-
     private var mUserAccount: UserAccount? = null
 
     private var privateKey: String? = null
@@ -119,10 +119,7 @@ class SettingsFragment : ConnectedFragment(), BaseSecurityLockDialog.OnPINPatter
             .getString(Constants.KEY_CURRENT_ACCOUNT_ID, "") ?: ""
 
         // Configure ViewModel
-        mViewModel = ViewModelProviders.of(this).get(SettingsFragmentViewModel::class.java)
+        viewModel.getUserAccount(userId).observe(viewLifecycleOwner, { userAccount ->
-
-        mViewModel.getUserAccount(userId).observe(this,
-            androidx.lifecycle.Observer<cy.agorise.bitsybitshareswallet.database.entities.UserAccount> { userAccount ->
             if (userAccount != null) {
                 mUserAccount = UserAccount(userAccount.id, userAccount.name)
                 binding.btnUpgradeToLTM.isEnabled =
@@ -130,8 +127,8 @@ class SettingsFragment : ConnectedFragment(), BaseSecurityLockDialog.OnPINPatter
             }
         })
 
-        mViewModel.getWIF(userId, AuthorityType.ACTIVE.ordinal).observe(this,
+        viewModel.getWIF(userId, AuthorityType.ACTIVE.ordinal)
-            androidx.lifecycle.Observer<String> { encryptedWIF ->
+            .observe(viewLifecycleOwner, { encryptedWIF ->
                 context?.let {
                     try {
                         privateKey = CryptoUtils.decrypt(it, encryptedWIF)
@@ -624,7 +621,7 @@ class SettingsFragment : ConnectedFragment(), BaseSecurityLockDialog.OnPINPatter
 
     private fun removeAccount(context: Context) {
         // Clears the database.
-        mViewModel.clearDatabase(context)
+        viewModel.clearDatabase(context)
 
         // Clears the shared preferences.
         val pref = PreferenceManager.getDefaultSharedPreferences(context)

app/src/main/java/cy/agorise/bitsybitshareswallet/fragments/TransactionsFragment.kt

@@ -11,8 +11,7 @@ import androidx.appcompat.widget.SearchView
 import androidx.core.content.ContextCompat
 import androidx.fragment.app.Fragment
 import androidx.fragment.app.FragmentActivity
-import androidx.lifecycle.Observer
+import androidx.fragment.app.viewModels
-import androidx.lifecycle.ViewModelProviders
 import androidx.recyclerview.widget.LinearLayoutManager
 import com.afollestad.materialdialogs.MaterialDialog
 import com.afollestad.materialdialogs.list.listItemsMultiChoice
@@ -20,7 +19,6 @@ import com.google.firebase.crashlytics.FirebaseCrashlytics
 import com.jakewharton.rxbinding3.appcompat.queryTextChangeEvents
 import cy.agorise.bitsybitshareswallet.R
 import cy.agorise.bitsybitshareswallet.adapters.TransfersDetailsAdapter
-import cy.agorise.bitsybitshareswallet.database.joins.TransferDetail
 import cy.agorise.bitsybitshareswallet.databinding.FragmentTransactionsBinding
 import cy.agorise.bitsybitshareswallet.models.FilterOptions
 import cy.agorise.bitsybitshareswallet.utils.*
@@ -42,11 +40,11 @@ class TransactionsFragment : Fragment(), FilterOptionsDialog.OnFilterOptionsSele
         private const val REQUEST_WRITE_EXTERNAL_STORAGE_PERMISSION = 100
     }
 
+    private val viewModel: TransactionsViewModel by viewModels()
+
     private var _binding: FragmentTransactionsBinding? = null
     private val binding get() = _binding!!
 
-    private lateinit var mViewModel: TransactionsViewModel
-
     private var mDisposables = CompositeDisposable()
 
     override fun onCreateView(
@@ -74,15 +72,12 @@ class TransactionsFragment : Fragment(), FilterOptionsDialog.OnFilterOptionsSele
         val userId = PreferenceManager.getDefaultSharedPreferences(context)
             .getString(Constants.KEY_CURRENT_ACCOUNT_ID, "") ?: ""
 
-        val transfersDetailsAdapter = TransfersDetailsAdapter(context!!)
+        val transfersDetailsAdapter = TransfersDetailsAdapter(requireContext())
         binding.rvTransactions.adapter = transfersDetailsAdapter
         binding.rvTransactions.layoutManager = LinearLayoutManager(context)
 
         // Configure TransactionsViewModel to fetch the transaction history
-        mViewModel = ViewModelProviders.of(this).get(TransactionsViewModel::class.java)
+        viewModel.getFilteredTransactions(userId).observe(viewLifecycleOwner, { transactions ->
-
-        mViewModel.getFilteredTransactions(userId).observe(this,
-            Observer<List<TransferDetail>> { transactions ->
             if (transactions.isEmpty()) {
                 binding.rvTransactions.visibility = View.GONE
                 binding.tvEmpty.visibility = View.VISIBLE
@@ -118,7 +113,7 @@ class TransactionsFragment : Fragment(), FilterOptionsDialog.OnFilterOptionsSele
                 .map { it.queryText.toString().toLowerCase() }
                 .observeOn(AndroidSchedulers.mainThread())
                 .subscribe {
-                    mViewModel.setFilterQuery(it)
+                    viewModel.setFilterQuery(it)
                 }
         )
 
@@ -133,7 +128,7 @@ class TransactionsFragment : Fragment(), FilterOptionsDialog.OnFilterOptionsSele
                 val args = Bundle()
                 args.putParcelable(
                     FilterOptionsDialog.KEY_FILTER_OPTIONS,
-                    mViewModel.getFilterOptions()
+                    viewModel.getFilterOptions()
                 )
                 filterOptionsDialog.arguments = args
                 filterOptionsDialog.show(childFragmentManager, "filter-options-tag")
@@ -163,13 +158,13 @@ class TransactionsFragment : Fragment(), FilterOptionsDialog.OnFilterOptionsSele
      * Gets called when the user selects some filter options in the [FilterOptionsDialog] and wants to apply them.
      */
     override fun onFilterOptionsSelected(filterOptions: FilterOptions) {
-        mViewModel.applyFilterOptions(filterOptions)
+        viewModel.applyFilterOptions(filterOptions)
     }
 
     /** Verifies that the storage permission has been granted before attempting to generate the export options */
     private fun verifyStoragePermission() {
         if (ContextCompat.checkSelfPermission(
-                activity!!,
+                requireActivity(),
                 Manifest.permission.WRITE_EXTERNAL_STORAGE
             )
             != PackageManager.PERMISSION_GRANTED
@@ -205,7 +200,7 @@ class TransactionsFragment : Fragment(), FilterOptionsDialog.OnFilterOptionsSele
     }
 
     private fun showExportOptionsDialog() {
-        MaterialDialog(context!!).show {
+        MaterialDialog(requireContext()).show {
             title(R.string.title_export_transactions)
             listItemsMultiChoice(
                 R.array.export_options,
@@ -228,7 +223,7 @@ class TransactionsFragment : Fragment(), FilterOptionsDialog.OnFilterOptionsSele
                 return
         }
 
-        mViewModel.getFilteredTransactionsOnce()?.let { filteredTransactions ->
+        viewModel.getFilteredTransactionsOnce()?.let { filteredTransactions ->
             if (exportPDF)
                 activity?.let { PDFGeneratorTask(it).execute(filteredTransactions) }
 

build.gradle

@@ -3,8 +3,8 @@
 buildscript {
 
     ext {
-        kotlin_version = '1.4.30'
+        kotlin_version = '1.4.31'
-        nav_version = '2.1.0'
+        nav_version = '2.3.4'
     }
 
     repositories {