thai_promptpay_flutter

Flutter widgets สำหรับสร้าง QR พร้อมเพย์ (Thai PromptPay / EMVCo) จากเบอร์มือถือ / เลขบัตรประชาชน-เลขที่ผู้เสียภาษี / e-Wallet พร้อมจำนวนเงิน

Flutter widgets that render a Thai PromptPay (EMVCo) QR code from a mobile number, National ID / Tax ID or e-Wallet, with an optional amount.

▶ Live demo — every widget plus an interactive "build your QR" playground and a decode demo, running in your browser.

This is the Flutter rendering layer on top of the pure-Dart thai_promptpay codec (kept pure-Dart so it still runs back-end / CLI). This package adds the widgets — it depends on flutter + qr_flutter + thai_promptpay

• thainum (for the baht text), and re-exports the codec, so importing this package alone gives you encodePromptPay / decodePromptPay / PromptPayTarget etc. too.

flutter pub add thai_promptpay_flutter

PromptPayQr — the QR widget

import 'package:thai_promptpay_flutter/thai_promptpay_flutter.dart';

// Convenience constructors (accept 0812345678, 081-234-5678, +66…):
PromptPayQr.mobile('0812345678', amountSatang: 10000); // 100.00 baht
PromptPayQr.nationalId('1101700230708');
PromptPayQr.eWallet('004999000000001', size: 180);

// Or pass a target directly:
PromptPayQr(
  target: const PromptPayTarget(PromptPayType.mobile, '0812345678'),
  amountSatang: 5000,
  size: 240,
);

Money is in integer satang (1 baht = 100 satang) — exact, no double. If the number/ID is invalid the widget shows errorBuilder (a default placeholder when null) instead of throwing:

PromptPayQr.mobile(
  userInput,
  errorBuilder: (context, error) => const Text('Invalid PromptPay number'),
);

PromptPayQrCard — a drop-in card

A Material card with the QR, a title, the recipient, and the amount shown as Thai baht text (via thainum):

PromptPayQrCard(
  target: const PromptPayTarget(PromptPayType.mobile, '0812345678'),
  amountSatang: 10000,            // shows '฿100.00' + 'หนึ่งร้อยบาทถ้วน'
  title: 'พร้อมเพย์ / PromptPay',
  recipientLabel: 'ร้านกาแฟ',
);

PromptPayAmountField — enter an amount (v0.2.0+)

A text field for entering a baht amount that reports integer satang (exact, no double). Restricts input to digits + at most two decimals and shows a ฿ prefix. Wire it to a PromptPayQr for a live "enter an amount" screen:

int? satang;

Column(children: [
  PromptPayAmountField(onChanged: (s) => setState(() => satang = s)),
  PromptPayQr.mobile('0812345678', amountSatang: satang),
]);

The exact baht↔satang helpers behind it are exported for reuse: satangFromBahtString('100.50') → 10050, bahtStringFromSatang(10050) → '100.50', and BahtAmountInputFormatter() for your own TextFields.

PromptPayBillQr / PromptPayBillQrCard — Bill Payment (v0.3.0+)

Render a PromptPay Bill Payment (EMVCo tag 30) QR — the one on invoices / utilities / tax forms — from a Biller ID + Ref1 (optional Ref2 + amount):

// The bare QR widget:
PromptPayBillQr(
  billerId: '010553609264101',   // 13- or 15-digit Tax ID [+ suffix]
  ref1: '000002201649894',
  ref2: 'INV0001',               // optional
  amountSatang: 25075,           // optional → 250.75 baht
);

// A drop-in card: QR + title + Biller/Ref rows + amount as Thai baht text:
PromptPayBillQrCard(
  billerId: '010553609264101',
  ref1: '000002201649894',
  ref2: 'INV0001',
  amountSatang: 25075,
  billerLabel: 'การไฟฟ้านครหลวง',
);

Like PromptPayQr, invalid input shows an errorBuilder (or a default placeholder) instead of throwing, and a payload getter exposes the exact EMVCo string the widget renders. The bill-payment payload is verified byte-for-byte by the underlying thai_promptpay codec.

Scanning / decoding (v0.4.0+)

Decode a Thai QR — personal PromptPay, Bill Payment, or a Slip Verify Mini-QR — from the camera, a still image, or a raw payload string.

Pure decode (no UI, never throws — null when unrecognized):

final ThaiQrResult? result = decodeThaiQr(payload);
switch (result) {
  case PromptPayResult(:final payload):     // personal PromptPay (tag 29)
  case BillPaymentResult(:final payload):   // bill payment (tag 30)
  case SlipResult(:final slip):             // slip verify mini-QR
  case null:                                // not a recognized Thai QR
}

Camera scanner — PromptPayScanner wraps mobile_scanner and reports the first recognized Thai QR via onResult:

PromptPayScanner(
  onResult: (result) {
    switch (result) {
      case PromptPayResult(:final payload): /* ... */
      case BillPaymentResult(:final payload): /* ... */
      case SlipResult(:final slip): /* ... */
    }
  },
  onUnrecognized: (rawValue) { /* a QR, but not a Thai one */ },
)

Pair a decoded ThaiQrResult with ThaiQrResultCard for a ready-made display widget:

ThaiQrResultCard(result);             // from a ThaiQrResult
ThaiQrResultCard.fromPayload(payload); // decode + display in one step

Still image — decode a Thai QR from a photo/file path:

final ThaiQrResult? result = await decodeThaiQrFromImage('/path/to/photo.jpg');

Camera permission / platform setup

PromptPayScanner (and decodeThaiQrFromImage) need the camera setup that mobile_scanner requires. From the mobile_scanner README:

• iOS — add a camera-usage description to ios/Runner/Info.plist:

  <key>NSCameraUsageDescription</key>
  <string>This app needs camera access to scan QR codes.</string>
  

  mobile_scanner 7.x targets an iOS deployment target of 12.0 or higher.

• Android — mobile_scanner 7.x requires a minSdkVersion of 23 or higher (set in android/app/build.gradle). The <uses-permission android:name="android.permission.CAMERA" /> and <uses-feature> entries are contributed by the plugin's manifest, so you do not normally add them yourself.

• macOS — enable the camera entitlement and add NSCameraUsageDescription (see the mobile_scanner README for details).

Image analysis (decodeThaiQrFromImage) is supported on Android, physical iOS devices, and macOS (not the iOS Simulator or web); the helper returns null rather than throwing where it is unsupported.

Notes

• Output is verified through the codec — thai_promptpay is checked byte-for-byte against the canonical PromptPay references.
• Scope: personal PromptPay (mobile / National ID / e-Wallet) and Bill Payment (tag 30). The tag-62 additional-data block (Ref3) is tolerated on decode but not generated.

License

MIT © 2026 MaIII (ultramcu)