refactor code

samples/demo-app/app/src/main/java/cash/z/ecc/android/sdk/demoapp/demos/getbalance/GetBalanceFragment.kt

@@ -15,9 +15,13 @@ import cash.z.ecc.android.sdk.ext.collectWith
 import cash.z.ecc.android.sdk.ext.convertZatoshiToZecString
 import cash.z.ecc.android.sdk.tool.DerivationTool
 
+/**
+ * Displays the available balance && total balance associated with the seed defined by the default config.
+ * comments.
+ */
 class GetBalanceFragment : BaseDemoFragment<FragmentGetBalanceBinding>() {
 
-    private lateinit var synchronize: Synchronizer
+    private lateinit var synchronizer: Synchronizer
 
     override fun inflateBinding(layoutInflater: LayoutInflater): FragmentGetBalanceBinding =
         FragmentGetBalanceBinding.inflate(layoutInflater)
@@ -44,7 +48,7 @@ class GetBalanceFragment : BaseDemoFragment<FragmentGetBalanceBinding>() {
                 it.importWallet(viewingKey, config.birthdayHeight)
                 it.server(config.host, config.port)
             }.let { initializer ->
-                synchronize = Synchronizer(initializer)
+                synchronizer = Synchronizer(initializer)
             }
         }
     }
@@ -52,36 +56,39 @@ class GetBalanceFragment : BaseDemoFragment<FragmentGetBalanceBinding>() {
     override fun onResume() {
         super.onResume()
         // the lifecycleScope is used to dispose of the synchronize when the fragment dies
-        synchronize.start(lifecycleScope)
+        synchronizer.start(lifecycleScope)
         monitorChanges()
     }
 
     private fun monitorChanges() {
-        synchronize.status.collectWith(lifecycleScope, ::onStatus)
-        synchronize.balances.collectWith(lifecycleScope, ::onBalance)
+        synchronizer.status.collectWith(lifecycleScope, ::onStatus)
+        synchronizer.balances.collectWith(lifecycleScope, ::onBalance)
     }
 
-    private var isSyncing = true
-
     private fun onBalance(balance: CompactBlockProcessor.WalletBalance) {
-        this.balance = balance
-        if (!isSyncing) {
             binding.textBalance.text = """
                 Available balance: ${balance.availableZatoshi.convertZatoshiToZecString(12)}
                 Total balance: ${balance.totalZatoshi.convertZatoshiToZecString(12)}
             """.trimIndent()
-        }
+
     }
 
-    private var balance = CompactBlockProcessor.WalletBalance()
 
     private fun onStatus(status: Synchronizer.Status) {
         binding.textBalance.text = "Status: $status"
-        isSyncing = status != Synchronizer.Status.SYNCED
-        if (status == Synchronizer.Status.SCANNING) {
+        if (CompactBlockProcessor.WalletBalance().none()) {
             binding.textBalance.text = "Calculating balance..."
         } else {
-            if (!isSyncing) onBalance(balance)
+            onBalance(synchronizer.latestBalance)
         }
     }
+
+    /**
+     * Extension function which checks if the balance has been updated or its -1
+     */
+    private fun CompactBlockProcessor.WalletBalance.none(): Boolean{
+        if(synchronizer.latestBalance.totalZatoshi == -1L
+            && synchronizer.latestBalance.availableZatoshi == -1L) return true
+        return false
+    }
 }