Correctly handle the scenario when the user scans a QR that requests an asset that he does not own, when that happens just parse the To and Memo fields and show a snackbar with a proper message, do not fill the amount field.

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

@@ -17,9 +17,11 @@ import androidx.navigation.fragment.findNavController
 import androidx.navigation.fragment.navArgs
 import com.afollestad.materialdialogs.MaterialDialog
 import com.afollestad.materialdialogs.customview.customView
+import com.google.android.material.snackbar.Snackbar
 import com.google.common.primitives.UnsignedLong
 import com.google.zxing.BarcodeFormat
 import com.google.zxing.Result
+import com.jakewharton.rxbinding3.material.dismisses
 import com.jakewharton.rxbinding3.widget.textChanges
 import cy.agorise.bitsybitshareswallet.R
 import cy.agorise.bitsybitshareswallet.adapters.BalancesDetailsAdapter
@@ -372,6 +374,12 @@ class SendTransactionFragment : ConnectedFragment(), ZXingScannerView.ResultHand
 
             tietTo.setText(invoice.to)
 
+            if (invoice.memo != null) {
+                tietMemo.setText(invoice.memo)
+                if (invoice.memo.startsWith("PP"))
+                    tietMemo.isEnabled = false
+            }
+
             var balanceDetail: BalanceDetail? = null
 
             // Try to select the invoice's Asset in the Assets spinner
@@ -386,18 +394,20 @@ class SendTransactionFragment : ConnectedFragment(), ZXingScannerView.ResultHand
                 }
             }
 
-            if (invoice.memo != null) {
-                tietMemo.setText(invoice.memo)
-                if (invoice.memo.startsWith("PP"))
-                    tietMemo.isEnabled = false
+            // If the user does not own any of the requested asset then show a SnackBar to explain the issue and
+            // return early to avoid filling the asset field
+            if (balanceDetail == null) {
+                Snackbar.make(rootView, getString(R.string.error__you_dont_own_asset, invoice.currency.toUpperCase()),
+                    Snackbar.LENGTH_INDEFINITE).setAction(android.R.string.ok) {  }.show()
+                return
             }
 
             var amount = 0.0
             for (nextItem in invoice.lineItems) {
                 amount += nextItem.quantity * nextItem.price
             }
-            // TODO Improve pattern to account for different asset precisions
-            val df = DecimalFormat("####." + "#".repeat(balanceDetail?.precision ?: 5))
+
+            val df = DecimalFormat("####." + "#".repeat(balanceDetail.precision))
             df.roundingMode = RoundingMode.CEILING
             df.decimalFormatSymbols = DecimalFormatSymbols(Locale.getDefault())
             tietAmount.setText(df.format(amount))

app/src/main/res/layout/fragment_send_transaction.xml

@@ -8,6 +8,7 @@
     tools:context=".fragments.SendTransactionFragment">
 
     <androidx.constraintlayout.widget.ConstraintLayout
+        android:id="@+id/rootView"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:paddingTop="@dimen/activity_vertical_margin"

app/src/main/res/values-es/strings.xml

@@ -98,6 +98,7 @@
     <string name="msg__camera_permission_necessary">El permiso de cámara es necesario para leer códigos QR.</string>
     <string name="text__transaction_sent">¡Transacción enviada!</string>
     <string name="msg__transaction_not_sent">No se pudo enviar la transacción</string>
+    <string name="error__you_dont_own_asset">No tienes nada de %1$s</string>
 
     <!-- Send Transaction info dialog -->
     <string name="msg__to_explanation">Escribe la cuenta BitShares de la persona a la que le deseas enviar fondos.\nPor ejemplo: agorise-faucet</string>

app/src/main/res/values/strings.xml

@@ -99,6 +99,7 @@
     <string name="msg__camera_permission_necessary">Camera permission is necessary to read QR codes.</string>
     <string name="text__transaction_sent">Transaction sent!</string>
     <string name="msg__transaction_not_sent">Unable to send transaction</string>
+    <string name="error__you_dont_own_asset">You don\'t own any %1$s</string>
 
     <!-- Send Transaction info dialog -->
     <string name="msg__to_explanation">Type in the Bitshares account name of the person you want to send funds to.\nFor example: agorise-faucet</string>