Merge pull request #2104 from AlphaWallet/allow-zero-value-tx-on-eth

allow zero value native transactions so data can be attached

AlphaWallet/Transfer/ViewControllers/SendViewController.swift

@@ -283,8 +283,15 @@ class SendViewController: UIViewController, CanScanQRCode {
         let input = targetAddressTextField.value.trimmed
         targetAddressTextField.errorState = .none
         amountTextField.errorState = .none
-
-        guard let value = viewModel.validatedAmount(value: amountTextField.ethCost) else {
+        let checkIfGreaterThanZero: Bool
+        // allow users to input zero on native transactions as they may want to send custom data
+        switch transferType {
+        case .nativeCryptocurrency, .dapp:
+            checkIfGreaterThanZero = false
+        case .ERC20Token, .ERC875Token, .ERC875TokenOrder, .ERC721Token, .ERC721ForTicketToken:
+            checkIfGreaterThanZero = true
+        }
+        guard let value = viewModel.validatedAmount(value: amountTextField.ethCost, checkIfGreaterThanZero: checkIfGreaterThanZero) else {
             amountTextField.errorState = .error
             return
         }
@@ -454,7 +461,7 @@ extension SendViewController: AmountTextFieldDelegate {
         textField.statusLabel.text = viewModel.availableLabelText
         textField.availableTextHidden = viewModel.availableTextHidden
 
-        guard viewModel.validatedAmount(value: textField.ethCost, checkIfGreaterThenZero: false) != nil else {
+        guard viewModel.validatedAmount(value: textField.ethCost, checkIfGreaterThanZero: false) != nil else {
             textField.errorState = .error
             return
         }

AlphaWallet/Transfer/ViewModels/SendViewModel.swift

@@ -117,7 +117,7 @@ struct SendViewModel {
         return true
     }
 
-    func validatedAmount(value amountString: String, checkIfGreaterThenZero: Bool = true) -> BigInt? {
+    func validatedAmount(value amountString: String, checkIfGreaterThanZero: Bool = true) -> BigInt? {
         let parsedValue: BigInt? = {
             switch transferType {
             case .nativeCryptocurrency, .dapp:
@@ -135,7 +135,7 @@ struct SendViewModel {
             }
         }()
 
-        guard let value = parsedValue, checkIfGreaterThenZero ? value > 0 : true else {
+        guard let value = parsedValue, checkIfGreaterThanZero ? value > 0 : true else {
             return nil
         }