Fix issue #86: eliminate forced unwrapping crashes

app/src/main/java/com/electricdreams/numo/BalanceCheckActivity.kt

@@ -149,17 +149,23 @@ class BalanceCheckActivity : AppCompatActivity() {
             try {
                 Log.d(TAG, "1. Creating Satocash client...")
                 satocashClient = SatocashNfcClient(tag)
+                val client = satocashClient
+                if (client == null) {
+                    Log.e(TAG, "❌ Failed to create Satocash client")
+                    handleBalanceCheckError(getString(R.string.balance_check_error_invalid_nfc_tag))
+                    return@Thread
+                }
 
                 Log.d(TAG, "2. Connecting to NFC card...")
-                satocashClient!!.connect()
+                client.connect()
                 Log.d(TAG, "✅ Successfully connected to NFC card")
 
                 Log.d(TAG, "3. Selecting Satocash applet...")
-                satocashClient!!.selectApplet(SatocashNfcClient.SATOCASH_AID)
+                client.selectApplet(SatocashNfcClient.SATOCASH_AID)
                 Log.d(TAG, "✅ Satocash Applet found and selected!")
 
                 Log.d(TAG, "4. Initializing secure channel...")
-                satocashClient!!.initSecureChannel()
+                client.initSecureChannel()
                 Log.d(TAG, "✅ Secure Channel Initialized!")
 
                 Log.d(TAG, "5. Getting accurate card balance (no PIN authentication)...")
@@ -191,8 +197,15 @@ class BalanceCheckActivity : AppCompatActivity() {
     private val cardBalance: Long
         get() {
             Log.d(TAG, "Getting card balance using getProofInfo (no PIN required)...")
+            val client = satocashClient
+            if (client == null) {
+                Log.e(TAG, "Satocash client is null when reading balance")
+                updateCardInfoDisplay(getString(R.string.balance_check_info_no_state_data))
+                return 0
+            }
+
             return try {
-                val status = satocashClient!!.status
+                val status = client.status
                 Log.d(TAG, "Card status: $status")
 
                 val nbProofsUnspent = status.getOrDefault("nb_proofs_unspent", 0) as Int
@@ -207,7 +220,7 @@ class BalanceCheckActivity : AppCompatActivity() {
 
                 Log.d(TAG, "Total proofs in card: $totalProofs ($nbProofsUnspent unspent, $nbProofsSpent spent)")
 
-                val proofStates = satocashClient!!.getProofInfo(
+                val proofStates = client.getProofInfo(
                     SatocashNfcClient.Unit.SAT,
                     SatocashNfcClient.ProofInfoType.METADATA_STATE,
                     0,
@@ -222,7 +235,7 @@ class BalanceCheckActivity : AppCompatActivity() {
                     return 0
                 }
 
-                val amounts = satocashClient!!.getProofInfo(
+                val amounts = client.getProofInfo(
                     SatocashNfcClient.Unit.SAT,
                     SatocashNfcClient.ProofInfoType.METADATA_AMOUNT_EXPONENT,
                     0,

app/src/main/java/com/electricdreams/numo/PaymentReceivedActivity.kt

@@ -78,8 +78,9 @@ class PaymentReceivedActivity : AppCompatActivity() {
         amount = intent.getLongExtra(EXTRA_AMOUNT, 0)
 
         // Parse token to extract amount and unit if not provided
-        if (amount == 0L && tokenString != null) {
-            parseToken(tokenString!!)
+        val token = tokenString
+        if (amount == 0L && token != null) {
+            parseToken(token)
         }
 
         // Set up UI
@@ -196,13 +197,14 @@ class PaymentReceivedActivity : AppCompatActivity() {
     }
 
     private fun shareToken() {
-        if (tokenString.isNullOrEmpty()) {
+        val token = tokenString
+        if (token.isNullOrEmpty()) {
             Toast.makeText(this, R.string.payment_received_error_no_token, Toast.LENGTH_SHORT).show()
             return
         }
 
         // Create intent to share/export the token
-        val cashuUri = "cashu:$tokenString"
+        val cashuUri = "cashu:$token"
 
         // Create intent for viewing the URI
         val uriIntent = Intent(Intent.ACTION_VIEW, android.net.Uri.parse(cashuUri)).apply {

app/src/main/java/com/electricdreams/numo/PaymentRequestActivity.kt

@@ -471,9 +471,12 @@ class PaymentRequestActivity : AppCompatActivity() {
             }
         }
 
-        if (isResumingPayment && resumeNostrSecretHex != null && resumeNostrNprofile != null) {
+        val secretHex = resumeNostrSecretHex
+        val nprofile = resumeNostrNprofile
+
+        if (isResumingPayment && secretHex != null && nprofile != null) {
             // Resume with stored keys
-            handler.resume(paymentAmount, resumeNostrSecretHex!!, resumeNostrNprofile!!, callback)
+            handler.resume(paymentAmount, secretHex, nprofile, callback)
         } else {
             // Start fresh
             handler.start(paymentAmount, pendingPaymentId, callback)
@@ -484,13 +487,17 @@ class PaymentRequestActivity : AppCompatActivity() {
         lightningStarted = true
 
         // Check if we're resuming with existing Lightning quote
-        if (resumeLightningQuoteId != null && resumeLightningMintUrl != null && resumeLightningInvoice != null) {
-            Log.d(TAG, "Resuming Lightning quote: id=$resumeLightningQuoteId")
+        val quoteId = resumeLightningQuoteId
+        val mintUrl = resumeLightningMintUrl
+        val invoice = resumeLightningInvoice
+
+        if (quoteId != null && mintUrl != null && invoice != null) {
+            Log.d(TAG, "Resuming Lightning quote: id=$quoteId")
 
             lightningHandler?.resume(
-                quoteId = resumeLightningQuoteId!!,
-                mintUrlStr = resumeLightningMintUrl!!,
-                invoice = resumeLightningInvoice!!,
+                quoteId = quoteId,
+                mintUrlStr = mintUrl,
+                invoice = invoice,
                 callback = createLightningCallback()
             )
         } else {

app/src/main/java/com/electricdreams/numo/TopUpActivity.kt

@@ -352,16 +352,35 @@ class TopUpActivity : AppCompatActivity() {
                 Log.d(TAG, "Connected to NFC card")
 
                 satocashClient = tempClient
-                satocashWallet = SatocashWallet(satocashClient!!)
+                val client = satocashClient
+                if (client == null) {
+                    Log.e(TAG, "Satocash client is null after connection")
+                    showStatusMessage(
+                        getString(R.string.top_up_status_nfc_error, "Client init failed"),
+                        success = false
+                    )
+                    return@Thread
+                }
+
+                satocashWallet = SatocashWallet(client)
 
-                satocashClient!!.selectApplet(SatocashNfcClient.SATOCASH_AID)
+                client.selectApplet(SatocashNfcClient.SATOCASH_AID)
                 Log.d(TAG, "Satocash Applet found and selected!")
 
-                satocashClient!!.initSecureChannel()
+                client.initSecureChannel()
                 Log.d(TAG, "Secure Channel Initialized!")
 
                 try {
-                    val importedCount = satocashWallet!!.importProofsFromToken(token).join()
+                    val wallet = satocashWallet
+                    if (wallet == null) {
+                        showStatusMessage(
+                            getString(R.string.top_up_status_generic_error, "Wallet not initialized"),
+                            success = false
+                        )
+                        return@Thread
+                    }
+
+                    val importedCount = wallet.importProofsFromToken(token).join()
                     showStatusMessage(
                         getString(R.string.top_up_status_success_imported, importedCount),
                         success = true
@@ -383,8 +402,8 @@ class TopUpActivity : AppCompatActivity() {
                             Log.d(TAG, "PIN authentication needed")
 
                             try {
-                                satocashClient?.let { client ->
-                                    client.close()
+                                satocashClient?.let { clientToClose ->
+                                    clientToClose.close()
                                     Log.d(TAG, "NFC connection closed before PIN entry")
                                     satocashClient = null
                                 }
@@ -478,22 +497,41 @@ class TopUpActivity : AppCompatActivity() {
                 Log.d(TAG, "Connected to NFC card for PIN import")
 
                 satocashClient = tempClient
-                satocashWallet = SatocashWallet(satocashClient!!)
+                val client = satocashClient
+                if (client == null) {
+                    Log.e(TAG, "Satocash client is null for PIN import")
+                    showStatusMessage(
+                        getString(R.string.top_up_status_nfc_error, "Client init failed"),
+                        success = false
+                    )
+                    return@Thread
+                }
 
-                satocashClient!!.selectApplet(SatocashNfcClient.SATOCASH_AID)
+                satocashWallet = SatocashWallet(client)
+
+                client.selectApplet(SatocashNfcClient.SATOCASH_AID)
                 Log.d(TAG, "Satocash Applet found and selected!")
 
-                satocashClient!!.initSecureChannel()
+                client.initSecureChannel()
                 Log.d(TAG, "Secure Channel Initialized!")
 
                 Log.d(TAG, "Authenticating with saved PIN...")
-                val authenticated = satocashWallet!!.authenticatePIN(pin).join()
+                val wallet = satocashWallet
+                if (wallet == null) {
+                    showStatusMessage(
+                        getString(R.string.top_up_status_generic_error, "Wallet not initialized"),
+                        success = false
+                    )
+                    return@Thread
+                }
+
+                val authenticated = wallet.authenticatePIN(pin).join()
 
                 if (authenticated) {
                     Log.d(TAG, "PIN Verified! Card Ready.")
 
                     val token = pendingProofToken ?: ""
-                    val importedCount = satocashWallet!!.importProofsFromToken(token).join()
+                    val importedCount = wallet.importProofsFromToken(token).join()
 
                     waitingForRescan = false
                     savedPin = null
@@ -540,8 +578,8 @@ class TopUpActivity : AppCompatActivity() {
                 showStatusMessage(message, success = false)
             } finally {
                 try {
-                    satocashClient?.let { client ->
-                        client.close()
+                    satocashClient?.let { clientToClose ->
+                        clientToClose.close()
                         Log.d(TAG, "NFC connection closed.")
                         satocashClient = null
                     }

app/src/main/java/com/electricdreams/numo/core/worker/BitcoinPriceWorker.kt

@@ -122,7 +122,8 @@ class BitcoinPriceWorker private constructor(context: Context) {
     }
 
     fun start() {
-        if (scheduler != null && !scheduler!!.isShutdown) return
+        val currentScheduler = scheduler
+        if (currentScheduler != null && !currentScheduler.isShutdown) return
 
         scheduler = Executors.newSingleThreadScheduledExecutor().also { exec ->
             exec.scheduleAtFixedRate(
@@ -210,7 +211,9 @@ class BitcoinPriceWorker private constructor(context: Context) {
                     reader = BufferedReader(InputStreamReader(connection.inputStream))
                     val response = buildString {
                         var line: String?
-                        while (reader!!.readLine().also { line = it } != null) {
+                        while (true) {
+                            line = reader?.readLine()
+                            if (line == null) break
                             append(line)
                         }
                     }

app/src/main/java/com/electricdreams/numo/feature/history/TransactionDetailActivity.kt

@@ -368,11 +368,9 @@ class TransactionDetailActivity : AppCompatActivity() {
 
     private fun openBasketReceipt() {
         // Use saved basket data if available, otherwise fall back to checkoutBasketJson
-        val basketJsonToUse = if (savedBasket != null) {
-            convertSavedBasketToCheckoutBasket(savedBasket!!).toJson()
-        } else {
-            checkoutBasketJson
-        }
+        val basketJsonToUse = savedBasket?.let { basket ->
+            convertSavedBasketToCheckoutBasket(basket).toJson()
+        } ?: checkoutBasketJson
 
         val intent = Intent(this, BasketReceiptActivity::class.java).apply {
             putExtra(BasketReceiptActivity.EXTRA_CHECKOUT_BASKET_JSON, basketJsonToUse)

app/src/main/java/com/electricdreams/numo/feature/items/CheckoutScannerActivity.kt

@@ -194,11 +194,16 @@ class CheckoutScannerActivity : AppCompatActivity() {
 
     private fun updateBasketForCurrentItem() {
         val item = currentItem ?: return
+        val itemId = item.id
+        if (itemId == null) {
+            Toast.makeText(this, "Item ID missing", Toast.LENGTH_SHORT).show()
+            return
+        }
 
         if (currentQuantity <= 0) {
-            basketManager.removeItem(item.id!!)
+            basketManager.removeItem(itemId)
         } else {
-            val updated = basketManager.updateItemQuantity(item.id!!, currentQuantity)
+            val updated = basketManager.updateItemQuantity(itemId, currentQuantity)
             if (!updated) {
                 basketManager.addItem(item, currentQuantity)
             }
@@ -380,8 +385,9 @@ class CheckoutScannerActivity : AppCompatActivity() {
         updateQuantityDisplay()
 
         // Load image
-        if (!item.imagePath.isNullOrEmpty()) {
-            val imageFile = File(item.imagePath!!)
+        val path = item.imagePath
+        if (!path.isNullOrEmpty()) {
+            val imageFile = File(path)
             if (imageFile.exists()) {
                 val bitmap: Bitmap? = BitmapFactory.decodeFile(imageFile.absolutePath)
                 if (bitmap != null) {

app/src/main/java/com/electricdreams/numo/feature/items/ItemEntryActivity.kt

@@ -298,12 +298,16 @@ class ItemEntryActivity : AppCompatActivity() {
             dialog.dismiss() 
         }
         dialogView.findViewById<Button>(R.id.dialog_confirm_button).setOnClickListener {
-            currentItem?.let { item ->
-                itemManager.removeItem(item.id!!)
+            val item = currentItem
+            val itemId = item?.id
+            if (item != null && itemId != null) {
+                itemManager.removeItem(itemId)
                 setResult(RESULT_OK)
-                dialog.dismiss()
-                finish()
+            } else {
+                Toast.makeText(this, "Unable to delete item: missing ID", Toast.LENGTH_SHORT).show()
             }
+            dialog.dismiss()
+            finish()
         }
         dialog.show()
     }

app/src/main/java/com/electricdreams/numo/feature/items/adapters/SelectionBasketAdapter.kt

@@ -78,8 +78,10 @@ class SelectionBasketAdapter(
             }
 
             removeButton.setOnClickListener {
-                val itemId = item.id!!
-                onItemRemoved(itemId)
+                val itemId = item.id
+                if (itemId != null) {
+                    onItemRemoved(itemId)
+                }
             }
         }
     }