App Payment means that the Trusty Pay user selects goods and places orders in the merchant's App, and selects Trusty Pay at the payment stage. Then the Trusty Pay client will be pulled up from the merchant's App, and the system will automatically redirect back to the merchant's App after the user completes the payment in the Trusty Pay client.

App Payment is a payment product more inclined to online scenarios, and often used for online retailers, catering takeout, etc

Procedure: Submit a pre-order request for APP payment through this interface, obtain the tradeNo to call payment.

1. Merchant backend

JAVA :

@Test
public class callTrustyPayApi {

    //Trusty Pay App ID
    String appId = "gxIRTg7qHCSCAU15" ;
    //Merchant ID
    String mchntId = "1006";
    // Merchant Key
    String key = "Mc1GG7C3o5SEvdTUYgUuagXhgh1WfszR";
    // MD5 or HMACSHA256
    String signType = "MD5";


    // Get the random string
    String nonceStr = "20260101011232321231322";

    Map< String, String> unifiedOrderParams = new HashMap();
    unifiedOrderParams.put("app_id", appId);
    unifiedOrderParams.put("mchnt_id", mchntId);
    unifiedOrderParams.put("nonce_str", nonceStr);
    unifiedOrderParams.put("sign_type", signType);
    unifiedOrderParams.put("body", "Ipadmini16G white");
    unifiedOrderParams.put("detail", "");
    // Trusty Pay result notification URL. Check [Notification API]
    // The merchant notification URL must be accessible by external networks.
    unifiedOrderParams.put("notifyUrl", "https://www.merchant.backend.com/callback");
    // Return to the merchant APP payment order result page
    unifiedOrderParams.put("frontendUrl", "merchant-app://merchantxxx/pay-result.");
    unifiedOrderParams.put("tradeNo", "OD202601010000000001");
    unifiedOrderParams.put("timeExpire", "30");
    unifiedOrderParams.put("totalAmount", "10000");
    unifiedOrderParams.put("trnCcy", "MMK");
    unifiedOrderParams.put("tradeType", "APP");

    // 1. Sort parameter names in ascending alphabetical order based on their ASCII encoded names
    Set< String> keySet = unifiedOrderParams.keySet();
    String[] keyArray = keySet.toArray(new String[keySet.size()]);
    Arrays.sort(keyArray);

    // 2. Sort ASCII code of parameter names by lexicographical sequence based on the format of "key=value"
    StringBuilder sb = new StringBuilder();
    for (String k : keyArray) {
        // Empty parameter values are excluded in the signature;
        if (unifiedOrderParams.get(k).trim().length() > 0)
        {
            sb.append(k).append("=").append(unifiedOrderParams.get(k).trim()).append("&");
        }
    }
    // 3. Join API Key
    sb.append("key=").append(key);

    // System.out.println(sb.toString());
    //above: app_id=gxIRTg7qHCSCAU15&body=Ipadmini16G white&frontendUrl=your_app_scheme://your_app_host&mchnt_id=1006
       &nonce_str=20260101011232321231322
       ¬ifyUrl=https://www.merchant.backend.com/callback&sign_type=MD5&timeExpire=30&totalAmount=10000&
       &tradeNo=OD202601010000000001&tradeType=APP&trnCcy=MMK&key=Mc1GG7C3o5SEvdTUYgUuagXhgh1WfszR


    // 4. Signature with MD5 or HMACSHA256 ,and convert all result chars to upper case
    String sign = signature(sb.toString(), signType);

    // System.out.println(sign);
    // MD5 signature above: 31423A9CA4D6FD7DB467EC76521A3FE6

    // 5. Add signature to the request
    unifiedOrderParams.put("sign", sign);

    // 6. Send request
    String url = "http://xxxxx/openapi/v1/trusty/unifiedorder";
    HttpHeaders headers = new HttpHeaders();
    headers.setContentType(MediaType.APPLICATION_JSON);
    HttpEntity< Map< String, String>> httpEntity = new HttpEntity< >(unifiedOrderParams,headers);
    ResponseEntity< Map> responseEntity = restTemplate.exchange(url, HttpMethod.POST, httpEntity, Map.class);

    // 7. Process the response
    // ....
   // 8. return appUrl to open trusty pay app
}
            

val intent = Intent(Intent.ACTION_VIEW, Uri.parse(trustyapp_url))
intent.flags = Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK

if (intent.resolveActivity(context.packageManager) != null) {
    context.startActivity(intent)
} else {
    // No trusty app found
}

Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(trustyapp_url));
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
if (intent.resolveActivity(context.getPackageManager()) != null) {
    context.startActivity(intent);
} else {
    // No trusty app found
}

<key>LSApplicationQueriesSchemes</key>
<array>
    <!-- for production environment -->
    <string>jl-app</string>
    <!-- for UAT environment -->
    <string>jl-app-uat</string>
</array>

UIApplication.shared.open(trustyapp_url, options: [:]) { success in
    if !success {
        // Failed to launch the trusty app
    }
}

[[UIApplication sharedApplication] openURL:trustyapp_url options:@{} completionHandler:^(BOOL success) {
    if (!success) {
      // Failed to launch the trusty app
    }
}];