diff --git a/app/src/main/java/net/mynero/wallet/service/UTXOService.java b/app/src/main/java/net/mynero/wallet/service/UTXOService.java index c608686..00a52bf 100644 --- a/app/src/main/java/net/mynero/wallet/service/UTXOService.java +++ b/app/src/main/java/net/mynero/wallet/service/UTXOService.java @@ -1,9 +1,12 @@ package net.mynero.wallet.service; +import android.util.Pair; + import androidx.lifecycle.LiveData; import androidx.lifecycle.MutableLiveData; import net.mynero.wallet.model.CoinsInfo; +import net.mynero.wallet.model.PendingTransaction; import net.mynero.wallet.model.TransactionInfo; import net.mynero.wallet.model.Wallet; import net.mynero.wallet.model.WalletManager; @@ -34,6 +37,8 @@ public class UTXOService extends ServiceBase { } public ArrayList selectUtxos(long amount, boolean sendAll) throws Exception { + final long basicFeeEstimate = calculateBasicFee(amount); + final long amountWithBasicFee = amount + basicFeeEstimate; ArrayList selectedUtxos = new ArrayList<>(); ArrayList seenTxs = new ArrayList<>(); List utxos = getUtxos(); @@ -48,7 +53,7 @@ public class UTXOService extends ServiceBase { amountSelected = Wallet.SWEEP_ALL; } else { //if amount selected is still less than amount needed, and the utxos tx hash hasn't already been seen, add utxo - if (amountSelected <= amount && !seenTxs.contains(coinsInfo.getHash())) { + if (amountSelected <= amountWithBasicFee && !seenTxs.contains(coinsInfo.getHash())) { selectedUtxos.add(coinsInfo.getKeyImage()); // we don't want to spend multiple utxos from the same transaction, so we prevent that from happening here. seenTxs.add(coinsInfo.getHash()); @@ -58,10 +63,18 @@ public class UTXOService extends ServiceBase { } } - if (amountSelected <= amount && !sendAll) { + if (amountSelected < amountWithBasicFee && !sendAll) { throw new Exception("insufficient wallet balance"); } return selectedUtxos; } + + private long calculateBasicFee(long amount) { + ArrayList> destinations = new ArrayList<>(); + destinations.add(new Pair<>("87MRtZPrWUCVUgcFHdsVb5MoZUcLtqfD3FvQVGwftFb8eSdMnE39JhAJcbuSW8X2vRaRsB9RQfuCpFciybJFHaz3QYPhCLw", amount)); + // destination string doesn't actually matter here, so i'm using the donation address. amount also technically doesn't matter + // priority also isn't accounted for in the Monero C++ code. maybe this is a bug by the core Monero team, or i'm using an outdated method. + return WalletManager.getInstance().getWallet().estimateTransactionFee(destinations, PendingTransaction.Priority.Priority_Low); + } }