feat: support hbar transfer

CHANGELOG.md

@@ -12,7 +12,6 @@ This changelog is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.
 - Unified the inactivity-unassign bot into a single script with `DRY_RUN` support, and fixed handling of cross-repo PR references for stale detection.
 - Added unit tests for `SubscriptionHandle` class covering cancellation state, thread management, and join operations.
 - Refactored `account_create_transaction_create_with_alias.py` example by splitting monolithic function into modular functions: `generate_main_and_alias_keys()`, `create_account_with_ecdsa_alias()`, `fetch_account_info()`, `print_account_summary()` (#1016)
-- 
 - Modularized `transfer_transaction_fungible` example by introducing `account_balance_query()` & `transfer_transaction()`.Renamed `transfer_tokens()` → `main()`
 - Phase 2 of the inactivity-unassign bot: Automatically detects stale open pull requests (no commit activity for 21+ days), comments with a helpful InactivityBot message, closes the stale PR, and unassigns the contributor from the linked issue.
 - Added `__str__()` to CustomFixedFee and updated examples and tests accordingly.
@@ -31,8 +30,9 @@ This changelog is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.
 - Support selecting specific node account ID(s) for queries and transactions and added `Network._get_node()` with updated execution flow (#362)
 - Add TLS support with two-stage control (`set_transport_security()` and `set_verify_certificates()`) for encrypted connections to Hedera networks. TLS is enabled by default for hosted networks (mainnet, testnet, previewnet) and disabled for local networks (solo, localhost) (#855)
 - Add PR inactivity reminder bot for stale pull requests `.github/workflows/pr-inactivity-reminder-bot.yml`
-- Add comprehensive training documentation for _Executable class `docs/sdk_developers/training/executable.md`
+- Add comprehensive training documentation for \_Executable class `docs/sdk_developers/training/executable.md`
 - Added empty `docs/maintainers/good_first_issues.md` file for maintainers to write Good First Issue guidelines (#1034)
+- Added `add_hbar_transfer`, `add_approved_hbar_transfer`, and internal `_add_hbar_transfer` to accept `Hbar` objects in addition to raw tinybar integers, with internal normalization to tinybars. Added tests validating the new behavior.
 
 ### Changed
 
@@ -64,7 +64,7 @@ This changelog is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.
 - Added `.github/workflows/merge-conflict-bot.yml` to automatically detect and notify users of merge conflicts in Pull Requests.
 - Added `.github/workflows/bot-office-hours.yml` to automate the Weekly Office Hour Reminder.
 - feat: Implement account creation with EVM-style alias transaction example.
-- Added validation logic in `.github/workflows/pr-checks.yml` to detect when no new chnagelog entries are added under [Unreleased].
+- Added validation logic in `.github/workflows/pr-checks.yml` to detect when no new changelog entries are added under [Unreleased].
 - Support for message chunking in `TopicSubmitMessageTransaction`.
 
 ### Changed
@@ -79,6 +79,10 @@ This changelog is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.
 
 - fixed workflow: changelog check with improved sensitivity to deletions, additions, new releases
 
+### Breaking Changes
+
+- Changed error message in `TransferTransaction._add_hbar_transfer()` and `AbstractTokenTransferTransaction._add_token_transfer()` when amount is zero from "Amount must be a non-zero integer" to "Amount must be a non-zero value." for clarity and consistency.
+
 ## [0.1.9] - 2025-11-26
 
 ### Added

src/hiero_sdk_python/tokens/abstract_token_transfer_transaction.py

@@ -149,7 +149,9 @@ def _add_token_transfer(
         if not isinstance(account_id, AccountId):
             raise TypeError("account_id must be an AccountId instance.")
         if not isinstance(amount, int) or amount == 0:
-            raise ValueError("Amount must be a non-zero integer.")
+            raise ValueError("Amount must be a integer.")
+        if amount == 0:
+            raise ValueError("amount must be a non-zero value.")
         if expected_decimals is not None and not isinstance(expected_decimals, int):
             raise TypeError("expected_decimals must be an integer.")
         if not isinstance(is_approved, bool):

src/hiero_sdk_python/transaction/transfer_transaction.py

@@ -2,11 +2,12 @@
 Defines TransferTransaction for transferring HBAR or tokens between accounts.
 """
 
-from typing import Dict, List, Optional, Tuple
+from typing import Dict, List, Optional, Tuple, Union
 
 from hiero_sdk_python.account.account_id import AccountId
 from hiero_sdk_python.channels import _Channel
 from hiero_sdk_python.executable import _Method
+from hiero_sdk_python.hbar import Hbar
 from hiero_sdk_python.hapi.services import basic_types_pb2, crypto_transfer_pb2, transaction_pb2
 from hiero_sdk_python.hapi.services.schedulable_transaction_body_pb2 import (
     SchedulableTransactionBody,
@@ -29,7 +30,8 @@ def __init__(
         self,
         hbar_transfers: Optional[Dict[AccountId, int]] = None,
         token_transfers: Optional[Dict[TokenId, Dict[AccountId, int]]] = None,
-        nft_transfers: Optional[Dict[TokenId, List[Tuple[AccountId, AccountId, int, bool]]]] = None,
+        nft_transfers: Optional[Dict[TokenId,
+                                     List[Tuple[AccountId, AccountId, int, bool]]]] = None,
     ) -> None:
         """
         Initializes a new TransferTransaction instance.
@@ -59,24 +61,35 @@ def _init_hbar_transfers(self, hbar_transfers: Dict[AccountId, int]) -> None:
             self.add_hbar_transfer(account_id, amount)
 
     def _add_hbar_transfer(
-        self, account_id: AccountId, amount: int, is_approved: bool = False
+        self, account_id: AccountId, amount: Union[int, Hbar], is_approved: bool = False
     ) -> "TransferTransaction":
         """
         Internal method to add a HBAR transfer to the transaction.
 
         Args:
             account_id (AccountId): The account ID of the sender or receiver.
-            amount (int): The amount of the HBAR to transfer.
+            amount (Union[int, Hbar]): The amount of the HBAR to transfer (in tinybars if int, or Hbar object).
             is_approved (bool, optional): Whether the transfer is approved. Defaults to False.
 
         Returns:
             TransferTransaction: The current instance of the transaction for chaining.
         """
         self._require_not_frozen()
+
         if not isinstance(account_id, AccountId):
             raise TypeError("account_id must be an AccountId instance.")
-        if not isinstance(amount, int) or amount == 0:
-            raise ValueError("Amount must be a non-zero integer.")
+
+        if amount is None:
+            raise TypeError("amount cannot be None.")
+
+        if isinstance(amount, Hbar):
+            amount = amount.to_tinybars()
+        elif not isinstance(amount, int):
+            raise TypeError("amount must be an integer or Hbar object.")
+
+        if amount == 0:
+            raise ValueError("Amount must be a non-zero value.")
+
         if not isinstance(is_approved, bool):
             raise TypeError("is_approved must be a boolean.")
 
@@ -85,16 +98,17 @@ def _add_hbar_transfer(
                 transfer.amount += amount
                 return self
 
-        self.hbar_transfers.append(HbarTransfer(account_id, amount, is_approved))
+        self.hbar_transfers.append(
+            HbarTransfer(account_id, amount, is_approved))
         return self
 
-    def add_hbar_transfer(self, account_id: AccountId, amount: int) -> "TransferTransaction":
+    def add_hbar_transfer(self, account_id: AccountId, amount: Union[int, Hbar]) -> "TransferTransaction":
         """
         Adds a HBAR transfer to the transaction.
 
         Args:
             account_id (AccountId): The account ID of the sender or receiver.
-            amount (int): The amount of the HBAR to transfer.
+            amount (Union[int, Hbar]): The amount of the HBAR to transfer (in tinybars if int, or Hbar object).
 
         Returns:
             TransferTransaction: The current instance of the transaction for chaining.
@@ -103,14 +117,14 @@ def add_hbar_transfer(self, account_id: AccountId, amount: int) -> "TransferTran
         return self
 
     def add_approved_hbar_transfer(
-        self, account_id: AccountId, amount: int
+        self, account_id: AccountId, amount: Union[int, Hbar]
     ) -> "TransferTransaction":
         """
         Adds a HBAR transfer with approval to the transaction.
 
         Args:
             account_id (AccountId): The account ID of the sender or receiver.
-            amount (int): The amount of the HBAR to transfer.
+            amount (Union[int, Hbar]): The amount of the HBAR to transfer (in tinybars if int, or Hbar object).
 
         Returns:
             TransferTransaction: The current instance of the transaction for chaining.
@@ -190,7 +204,8 @@ def _from_protobuf(cls, transaction_body, body_bytes: bytes, sig_map):
 
             if crypto_transfer.HasField("transfers"):
                 for account_amount in crypto_transfer.transfers.accountAmounts:
-                    account_id = AccountId._from_proto(account_amount.accountID)
+                    account_id = AccountId._from_proto(
+                        account_amount.accountID)
                     amount = account_amount.amount
                     is_approved = account_amount.is_approval
                     transaction.hbar_transfers.append(
@@ -210,17 +225,21 @@ def _from_protobuf(cls, transaction_body, body_bytes: bytes, sig_map):
                         expected_decimals = token_transfer_list.expected_decimals.value
 
                     transaction.token_transfers[token_id].append(
-                        TokenTransfer(token_id, account_id, amount, expected_decimals, is_approved)
+                        TokenTransfer(token_id, account_id, amount,
+                                      expected_decimals, is_approved)
                     )
 
                 for nft_transfer in token_transfer_list.nftTransfers:
-                    sender_id = AccountId._from_proto(nft_transfer.senderAccountID)
-                    receiver_id = AccountId._from_proto(nft_transfer.receiverAccountID)
+                    sender_id = AccountId._from_proto(
+                        nft_transfer.senderAccountID)
+                    receiver_id = AccountId._from_proto(
+                        nft_transfer.receiverAccountID)
                     serial_number = nft_transfer.serialNumber
                     is_approved = nft_transfer.is_approval
 
                     transaction.nft_transfers[token_id].append(
-                        TokenNftTransfer(token_id, sender_id, receiver_id, serial_number, is_approved)
+                        TokenNftTransfer(
+                            token_id, sender_id, receiver_id, serial_number, is_approved)
                     )
 
         return transaction

tests/integration/transfer_transaction_e2e_test.py

@@ -7,6 +7,7 @@
 from hiero_sdk_python.crypto.private_key import PrivateKey
 from hiero_sdk_python.exceptions import PrecheckError
 from hiero_sdk_python.hbar import Hbar
+from hiero_sdk_python.hbar_unit import HbarUnit
 from hiero_sdk_python.query.account_balance_query import CryptoGetAccountBalanceQuery
 from hiero_sdk_python.response_code import ResponseCode
 from hiero_sdk_python.tokens.nft_id import NftId
@@ -448,3 +449,47 @@ def test_integration_transfer_transaction_approved_token_transfer():
 
     finally:
         env.close()
+
+
+@pytest.mark.integration
+def test_integration_transfer_transaction_with_hbar_units():
+    env = IntegrationTestEnv()
+
+    try:
+        new_account_private_key = PrivateKey.generate()
+        new_account_public_key = new_account_private_key.public_key()
+
+        initial_balance = Hbar(1)
+
+        account_transaction = AccountCreateTransaction(
+            key=new_account_public_key, initial_balance=initial_balance, memo="Recipient Account"
+        )
+
+        receipt = account_transaction.execute(env.client)
+
+        assert (
+            receipt.status == ResponseCode.SUCCESS
+        ), f"Account creation failed with status: {ResponseCode(receipt.status).name}"
+
+        account_id = receipt.account_id
+        assert account_id is not None
+
+        transfer_transaction = TransferTransaction()
+        transfer_transaction.add_hbar_transfer(env.operator_id, Hbar(-1.5, HbarUnit.HBAR))
+        transfer_transaction.add_hbar_transfer(account_id, Hbar(1.5, HbarUnit.HBAR))
+
+        receipt = transfer_transaction.execute(env.client)
+
+        assert (
+            receipt.status == ResponseCode.SUCCESS
+        ), f"Transfer failed with status: {ResponseCode(receipt.status).name}"
+
+        query_transaction = CryptoGetAccountBalanceQuery(account_id)
+        balance = query_transaction.execute(env.client)
+
+        expected_balance_tinybars = Hbar(1).to_tinybars() + Hbar(1.5, HbarUnit.HBAR).to_tinybars()
+        assert (
+            balance and balance.hbars.to_tinybars() == expected_balance_tinybars
+        ), f"Expected balance: {expected_balance_tinybars}, actual balance: {balance.hbars.to_tinybars()}"
+    finally:
+        env.close()

tests/unit/test_transfer_transaction.py

@@ -284,11 +284,11 @@ def test_zero_amount_validation(mock_account_ids):
     transfer_tx = TransferTransaction()
 
     # Test zero HBAR amount should raise ValueError
-    with pytest.raises(ValueError, match="Amount must be a non-zero integer"):
+    with pytest.raises(ValueError, match="Amount must be a non-zero value"):
         transfer_tx.add_hbar_transfer(account_id_1, 0)
 
     # Test zero token amount should raise ValueError
-    with pytest.raises(ValueError, match="Amount must be a non-zero integer"):
+    with pytest.raises(ValueError, match="Amount must be a non-zero value"):
         transfer_tx.add_token_transfer(token_id_1, account_id_1, 0)