> ## Documentation Index
> Fetch the complete documentation index at: https://sdk.qfapi.com/llms.txt
> Use this file to discover all available pages before exploring further.

# App Call App Android SDK

> Integrates the QFPay HaoJin Android SDK to enable App-to-App payments, refunds, queries, pre-authorisation, and card settlement.

## Latest Version

**version 2.3.4.jar**

The SDK supports configurable scan modes:

* `CollectionReq.SCAN_TYPE_SCAN` — Scan customer QR code
* `CollectionReq.SCAN_TYPE_QRCODE` — Display QR code for customer to scan

### Example

```java theme={null}
CollectionReq req = new CollectionReq(Long.parseLong(money));
req.setScan_type(scan_type);
```

<Note>
  To force QR code display mode (e.g. static QR for customer scanning), use `SCAN_TYPE_QRCODE`.

  The default camera used is the rear camera.
</Note>

***

## Introduction

HaoJin is a mobile application that provides integrated payment collection for merchants.

This SDK enables third-party apps to invoke HaoJin for payment operations.

Supported capabilities:

1. Payment, refund, transaction query, and transaction details
2. Transaction summary and channel configuration retrieval
3. Card transaction query, cancellation, and adjustment

<Frame>
  <img src="https://mintcdn.com/qfpay-8e347952/nhPCT07_mu66i7Fi/images/in-store/architecture__diagram.png?fit=max&auto=format&n=nhPCT07_mu66i7Fi&q=85&s=c5b7d615739f13da3b4b16f9dccd8f24" alt="Architecture Diagram" width="856" height="379" data-path="images/in-store/architecture__diagram.png" />
</Frame>

***

## Installation & Setup

### Required Permission

Add to **AndroidManifest.xml**:

```xml theme={null}
<uses-permission android:name="com.qfpay.haojin.permission.OPEN_API"/>
```

<Note>
  HaoJin App must be installed on the device.
</Note>

***

### Integrate JAR

Download and place the SDK in `/libs`, then import in `build.gradle`.

[Download Latest SDK](https://github.com/QFPay/docs/raw/refs/heads/docusaurus-developer-center/static/files/qfpay_haojin_api_2.3.6.zip)

***

### Set Target App ID

```java theme={null}
Config.setTargetAppId("in.haojin.nearbymerchant.oversea");
```

***

### Proguard Rules

Add to `proguard-rules.pro`:

```proguard theme={null}
-dontnote com.qfpay.haojin.model.**
-keep class com.qfpay.haojin.model.** {*;}
```

***

## API Usage

### Create Trade API Instance

```java theme={null}
ITradeAPI mTradeApi = TradeApiFactory.createTradeApi(XXXActivity, this);
```

***

## Collection (Payment)

```java theme={null}
CollectionReq collectionReq = new CollectionReq(100);

collectionReq.setScan_type(CollectionReq.SCAN_TYPE_SCAN);
collectionReq.setOut_trade_no("EXT202312345");
collectionReq.setWait_card_timeout(120);
collectionReq.setPay_method("card_payment");
collectionReq.setCamera_id(0);

int ret = mTradeApi.doTrade(collectionReq);
```

### Parse Result

```java theme={null}
CollectionResp collectionResp =
    (CollectionResp) mTradeApi.parseResponse(requestCode, resultCode, data);

if (collectionResp == null) return;

if (collectionResp.isSuccess()) {
    Transaction transaction = collectionResp.getPayResult();
} else {
    Log.e(TAG, collectionResp.getErrorMsg());
}
```

<Warning>
  The returned response may be `null`. Always perform a null check.
</Warning>

***

## Refund

```java theme={null}
RefundReq refundReq = new RefundReq(qfOrderId);
int ret = mTradeApi.doTrade(refundReq);
```

### Parse

```java theme={null}
RefundResp refundResp =
    (RefundResp) mTradeApi.parseResponse(requestCode, resultCode, data);

if (refundResp != null && refundResp.isSuccess()) {
    Transaction transaction = refundResp.getRefundResult();
}
```

***

## Query Transactions

### Multiple Transactions

```java theme={null}
GetTransListReq req = new GetTransListReq();
req.setChannels(selectedChannel);
req.setTypes(selectedType);
req.setMonth(month);
req.setStartTime(startTime);
req.setEndTime(endTime);
req.setPageSize(pageSize);
req.setPageNum(pageNum);

int ret = mTradeApi.doTrade(req);
```

<Note>
  • Supported types: payment, refund\
  • Time format: yyyy-MM-dd HH:mm:ss\
  • Month format: yyyyMM\
  • Page index starts from 1\
  • Time range overrides monthly query
</Note>

***

### Transaction Detail

```java theme={null}
GetTransReq req = new GetTransReq(qfOrderId);
req.setOut_trade_no("EXT20230123");
int ret = mTradeApi.doTrade(req);
```

***

## Transaction Summary

```java theme={null}
CheckTradeSumReq req = new CheckTradeSumReq();
int ret = mTradeApi.doTrade(req);
```

***

## User Configuration

```java theme={null}
GetUserConfigReq req = new GetUserConfigReq();
int ret = getTradeApi().doTrade(req);
```

<Warning>
  If user configuration cannot be retrieved, it may indicate an authorisation issue. Contact technical support.
</Warning>

***

## Pre-authorisation

<Note>
  Suitable for scenarios such as hotel check-ins or equipment rental where funds are reserved and later captured or cancelled.
</Note>

### Deduct

```java theme={null}
PreAuthTransDeductReq req = new PreAuthTransDeductReq(transId);
int ret = mTradeApi.doTrade(req);
```

### Cancel

```java theme={null}
PreAuthTransCancelReq req = new PreAuthTransCancelReq(transId);
int ret = mTradeApi.doTrade(req);
```

### List

```java theme={null}
PreAuthTransListReq req = new PreAuthTransListReq(10, 1);
int ret = mTradeApi.doTrade(req);
```

### Detail

```java theme={null}
PreAuthTransDetailReq req = new PreAuthTransDetailReq(transId);
int ret = mTradeApi.doTrade(req);
```

***

## Card Operations

### Card Refund

```java theme={null}
CardRefundReq req = new CardRefundReq(qfOrderId);
int ret = mTradeApi.doTrade(req);
```

### Card Settlement

```java theme={null}
CardSettleReq req = new CardSettleReq();
int ret = mTradeApi.doTrade(req);
```

***

## Version History

### v2.3.4

* Added scan type configuration

### v2.3.3

* Added `getOut_trade_no` and `getCardscheme` methods

### v2.3.2

* External order number support
* Configurable card swipe timeout

### v2.3.1

* Payment method selection support
* Camera selection support