[#1315] Provide Locale to MonetarySeparators API

Closes #1315

CHANGELOG.md

@@ -8,6 +8,8 @@ and this library adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 - `TransactionOverview.txIdString()` to provide a readable transaction ID to SDK-consuming apps
+- `MonetarySeparators.current(locale: Locale? = null)` now accepts `Locale` on input to force separators locale. If 
+  no value is provided, the default one is used. 
 
 ### Removed
 - `LightWalletEndpointExt` and its functions and variables were removed from the SDK's public APIs entirely. It's 

demo-app/src/main/java/cash/z/ecc/android/sdk/demoapp/ui/screen/send/view/SendView.kt

@@ -49,6 +49,7 @@ import cash.z.ecc.android.sdk.model.ZecSendExt
 import cash.z.ecc.android.sdk.model.ZecString
 import cash.z.ecc.android.sdk.model.ZecStringExt
 import cash.z.ecc.android.sdk.model.toZecString
+import java.util.Locale
 
 @Preview(name = "Send")
 @Composable
@@ -112,7 +113,7 @@ private fun SendMainContent(
     onSend: (ZecSend) -> Unit
 ) {
     val context = LocalContext.current
-    val monetarySeparators = MonetarySeparators.current()
+    val monetarySeparators = MonetarySeparators.current(locale = Locale.US)
     val allowedCharacters = ZecString.allowedCharacters(monetarySeparators)
 
     var amountZecString by rememberSaveable {

sdk-incubator-lib/src/main/java/cash/z/ecc/android/sdk/model/ZecString.kt

@@ -35,11 +35,17 @@ data class MonetarySeparators(val grouping: Char, val decimal: Char) {
 
     companion object {
         /**
+         * @param locale Preferred Locale for the returned monetary separators. If Locale is not provided, the
+         * default one will be used.
+         *
          * @return The current localized monetary separators.  Do not cache this value, as it
          * can change if the system Locale changes.
          */
-        fun current(): MonetarySeparators {
-            val decimalFormatSymbols = DecimalFormatSymbols.getInstance()
+        fun current(locale: Locale? = null): MonetarySeparators {
+            val decimalFormatSymbols =
+                locale?.let {
+                    DecimalFormatSymbols.getInstance(locale)
+                } ?: DecimalFormatSymbols.getInstance()
 
             return MonetarySeparators(
                 decimalFormatSymbols.groupingSeparator,
@@ -83,7 +89,6 @@ fun Zatoshi.Companion.fromZecString(
         }
     val localizedPattern = "#${monetarySeparators.grouping}##0${monetarySeparators.decimal}0#"
 
-    // TODO [#321]: https://github.com/zcash/secant-android-wallet/issues/321
     val decimalFormat =
         DecimalFormat(localizedPattern, symbols).apply {
             isParseBigDecimal = true