chore: printer handling improvements + readme changes

Author: ignaciosantise

dapps/pos-app/README.md

@@ -62,4 +62,36 @@ android/
     └── wc_rn_upload.keystore  ← Place here
 ```
 
+**Build the release APK:**
+
+```bash
+npm run android:build
+```
+
+The release APK will be generated at `android/app/build/outputs/apk/release/app-release.apk`
+
+**Install on a device via USB:**
+
+> **Note**: Make sure USB debugging is enabled on your Android device. Go to Settings → About phone → Tap "Build number" 7 times → Developer options → Enable "USB debugging".
+
+1. Connect your device via USB and get its device ID:
+
+   ```bash
+   adb devices
+   ```
+   
+   Example output: `V510BAC07114B000171`
+
+2. Build the release APK:
+
+   ```bash
+   npm run android:build
+   ```
+
+3. Install the APK on your device (replace with your device ID):
+
+   ```bash
+   adb -s V510BAC07114B000171 install android/app/build/outputs/apk/release/app-release.apk
+   ```
+
 > **⚠️ Security Note**: Never commit `secrets.properties` or keystore files to version control.

dapps/pos-app/app/payment-success.tsx

@@ -50,8 +50,11 @@ export default function PaymentSuccessScreen() {
 
   const setPrinter = async () => {
     try {
-      const isConnected = await connectPrinter();
-      setIsPrinterConnected(isConnected);
+      const { connected, error } = await connectPrinter();
+      setIsPrinterConnected(connected);
+      if (!connected && error) {
+        console.error("Printer connection failed:", error);
+      }
     } catch (error) {
       console.error("Connection failed:", error);
       setIsPrinterConnected(false);

dapps/pos-app/app/scan.tsx

@@ -78,7 +78,6 @@ export default function QRModalScreen() {
           refId: uuidv4(),
           amount: Number(amount) * 100, // amount in cents i.e. $1 = 100
           currency: "USD",
-          chainId: 8453,
         };
 
         const data = await startPayment(paymentRequest);

dapps/pos-app/app/settings.tsx

@@ -28,9 +28,9 @@ export default function Settings() {
         showErrorToast("Failed to request Bluetooth permission");
         return;
       }
-      const isConnected = await connectPrinter();
-      if (!isConnected) {
-        showErrorToast("Failed to connect to printer");
+      const { connected, error } = await connectPrinter();
+      if (!connected) {
+        showErrorToast(error || "Failed to connect to printer");
         return;
       }
       await printWalletConnectReceipt(

dapps/pos-app/utils/printer.ts

@@ -10,20 +10,47 @@ export const requestBluetoothPermission = async () => {
   return result === RESULTS.GRANTED || result === RESULTS.LIMITED;
 };
 
-export const connectPrinter = async () => {
+export const connectPrinter = async (): Promise<{
+  connected: boolean;
+  error?: string;
+}> => {
   try {
     // Scan for devices
     const devices = await ReactNativePosPrinter.getDeviceList();
-    if (devices.length === 0) throw new Error("No printers found");
-
-    // Connect to first device (filter for your iMin, e.g., by name/vendor)
+    if (devices.length === 0) {
+      return {
+        connected: false,
+        error: "No printer detected on this device",
+      };
+    }
+
+    // Connect to first device
     const printer = devices[0].getDevice(); // { name, address, vendorId, productId, ... }
     await ReactNativePosPrinter.connectPrinter(printer.address); // e.g., 'USB' or mac address
     console.log("Connected to:", printer);
-    return true;
+    return { connected: true };
   } catch (error) {
     console.error("Connection failed:", error);
-    return false;
+
+    // Check for Bluetooth permission error
+    const errorMessage = error instanceof Error ? error.message : String(error);
+    if (
+      errorMessage.includes("BLUETOOTH_CONNECT") ||
+      errorMessage.includes("bluetooth") ||
+      errorMessage.includes("permission")
+    ) {
+      return {
+        connected: false,
+        error:
+          "Please enable Bluetooth on your device to connect to the printer",
+      };
+    }
+
+    // Generic error with details
+    return {
+      connected: false,
+      error: `Failed to connect: ${errorMessage}`,
+    };
   }
 };