Prevent a crash when the fragment is detached

CHANGELOG.md

@@ -5,6 +5,9 @@
 * [FIXED] [4861](https://github.com/stripe/stripe-android/pull/4861) Remove font resource to save space and default to system default
 * [CHANGED] [4855](https://github.com/stripe/stripe-android/pull/4855) Remove force portrait mode in PaymentLauncher.
 
+### CardScan
+* [FIXED] [5075](https://github.com/stripe/stripe-android/pull/5075) Prevent a crash when the fragment is detached.
+
 ## 20.0.1 - 2022-04-11
 This release includes several PaymentSheet bug fixes.
 

stripecardscan/src/main/java/com/stripe/android/stripecardscan/cardscan/CardScanFragment.kt

@@ -124,7 +124,7 @@ class CardScanFragment : ScanFragment(), SimpleScanStateful<CardScanState> {
             ) {
                 launch(Dispatchers.Main) {
                     changeScanState(CardScanState.Correct)
-                    cameraAdapter.unbindFromLifecycle(requireActivity())
+                    activity?.let { cameraAdapter.unbindFromLifecycle(it) }
                     resultListener.cardScanComplete(ScannedCard(result.pan))
                 }.let { }
             }
@@ -203,13 +203,13 @@ class CardScanFragment : ScanFragment(), SimpleScanStateful<CardScanState> {
      * Set up viewFinderWindowView and viewFinderBorderView centered with predefined margins
      */
     private fun setupViewFinderConstraints() {
-
         val screenSize = Resources.getSystem().displayMetrics.let {
             Size(it.widthPixels, it.heightPixels)
         }
+
         val viewFinderMargin = (
             min(screenSize.width, screenSize.height) *
-                requireActivity().getFloatResource(R.dimen.stripeViewFinderMargin)
+                (context?.getFloatResource(R.dimen.stripeViewFinderMargin) ?: 0F)
             ).roundToInt()
 
         listOf(viewBinding.viewFinderWindow, viewBinding.viewFinderBorder).forEach { view ->
@@ -241,14 +241,16 @@ class CardScanFragment : ScanFragment(), SimpleScanStateful<CardScanState> {
      * Once the camera stream is available, start processing images.
      */
     override suspend fun onCameraStreamAvailable(cameraStream: Flow<CameraPreviewImage<Bitmap>>) {
-        scanFlow.startFlow(
-            context = requireActivity(),
-            imageStream = cameraStream,
-            viewFinder = viewBinding.viewFinderWindow.asRect(),
-            lifecycleOwner = this,
-            coroutineScope = this,
-            parameters = null
-        )
+        context?.let {
+            scanFlow.startFlow(
+                context = it,
+                imageStream = cameraStream,
+                viewFinder = viewBinding.viewFinderWindow.asRect(),
+                lifecycleOwner = this,
+                coroutineScope = this,
+                parameters = null
+            )
+        }
     }
 
     /**
@@ -267,20 +269,24 @@ class CardScanFragment : ScanFragment(), SimpleScanStateful<CardScanState> {
     override fun displayState(newState: CardScanState, previousState: CardScanState?) {
         when (newState) {
             is CardScanState.NotFound, CardScanState.Found -> {
-                viewBinding.viewFinderBackground
-                    .setBackgroundColor(
-                        requireActivity().getColorByRes(R.color.stripeNotFoundBackground)
-                    )
+                context?.let {
+                    viewBinding.viewFinderBackground
+                        .setBackgroundColor(
+                            it.getColorByRes(R.color.stripeNotFoundBackground)
+                        )
+                }
                 viewBinding.viewFinderWindow
                     .setBackgroundResource(R.drawable.stripe_card_background_not_found)
                 viewBinding.viewFinderBorder
                     .startAnimation(R.drawable.stripe_paymentsheet_card_border_not_found)
             }
             is CardScanState.Correct -> {
-                viewBinding.viewFinderBackground
-                    .setBackgroundColor(
-                        requireActivity().getColorByRes(R.color.stripeCorrectBackground)
-                    )
+                context?.let {
+                    viewBinding.viewFinderBackground
+                        .setBackgroundColor(
+                            it.getColorByRes(R.color.stripeCorrectBackground)
+                        )
+                }
                 viewBinding.viewFinderWindow
                     .setBackgroundResource(R.drawable.stripe_card_background_correct)
                 viewBinding.viewFinderBorder.startAnimation(R.drawable.stripe_card_border_correct)
@@ -293,8 +299,8 @@ class CardScanFragment : ScanFragment(), SimpleScanStateful<CardScanState> {
             stripePublishableKey = params.stripePublishableKey,
             instanceId = Stats.instanceId,
             scanId = Stats.scanId,
-            device = Device.fromContext(requireActivity()),
-            appDetails = AppDetails.fromContext(requireActivity()),
+            device = Device.fromContext(context),
+            appDetails = AppDetails.fromContext(context),
             scanStatistics = ScanStatistics.fromStats(),
             scanConfig = ScanConfig(0),
         )

stripecardscan/src/main/java/com/stripe/android/stripecardscan/framework/util/AppDetails.kt

@@ -14,7 +14,7 @@ internal data class AppDetails(
 ) {
     companion object {
         @JvmStatic
-        fun fromContext(context: Context) = AppDetails(
+        fun fromContext(context: Context?) = AppDetails(
             appPackageName = getAppPackageName(context),
             applicationId = getApplicationId(),
             libraryPackageName = getLibraryPackageName(),
@@ -26,7 +26,8 @@ internal data class AppDetails(
     }
 }
 
-internal fun getAppPackageName(context: Context): String? = context.applicationContext.packageName
+internal fun getAppPackageName(context: Context?): String? =
+    context?.applicationContext?.packageName
 
 private fun getApplicationId(): String = "" // no longer available in later versions of gradle.
 

stripecardscan/src/main/java/com/stripe/android/stripecardscan/framework/util/Device.kt

@@ -21,7 +21,7 @@ internal data class Device(
     val platform: String
 ) {
     companion object {
-        private val getDeviceDetails = cacheFirstResult { context: Context ->
+        private val getDeviceDetails = cacheFirstResult { context: Context? ->
             Device(
                 android_id = getAndroidId(),
                 name = getDeviceName(),
@@ -37,7 +37,7 @@ internal data class Device(
         }
 
         @JvmStatic
-        fun fromContext(context: Context) = getDeviceDetails(context.applicationContext)
+        fun fromContext(context: Context?) = getDeviceDetails(context?.applicationContext)
     }
 }
 
@@ -51,10 +51,12 @@ internal data class Device(
 @SuppressLint("HardwareIds")
 private fun getAndroidId() = "Redacted"
 
-private fun getDeviceBootCount(context: Context): Int =
+private fun getDeviceBootCount(context: Context?): Int =
     if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
         try {
-            Settings.Global.getInt(context.contentResolver, Settings.Global.BOOT_COUNT)
+            context?.let {
+                Settings.Global.getInt(it.contentResolver, Settings.Global.BOOT_COUNT)
+            } ?: -1
         } catch (t: Throwable) {
             -1
         }
@@ -65,27 +67,27 @@ private fun getDeviceBootCount(context: Context): Int =
 private fun getDeviceLocale(): String =
     "${Locale.getDefault().isO3Language}_${Locale.getDefault().isO3Country}"
 
-private fun getDeviceCarrier(context: Context) = try {
-    (context.getSystemService(Context.TELEPHONY_SERVICE) as TelephonyManager?)?.networkOperatorName
+private fun getDeviceCarrier(context: Context?) = try {
+    (context?.getSystemService(Context.TELEPHONY_SERVICE) as TelephonyManager?)?.networkOperatorName
 } catch (t: Throwable) {
     null
 }
 
-private fun getDevicePhoneType(context: Context) = try {
-    (context.getSystemService(Context.TELEPHONY_SERVICE) as TelephonyManager?)?.phoneType
+private fun getDevicePhoneType(context: Context?) = try {
+    (context?.getSystemService(Context.TELEPHONY_SERVICE) as TelephonyManager?)?.phoneType
 } catch (t: Throwable) {
     null
 }
 
-private fun getDevicePhoneCount(context: Context) =
+private fun getDevicePhoneCount(context: Context?) =
     if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
         try {
             if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
-                (context.getSystemService(Context.TELEPHONY_SERVICE) as TelephonyManager?)
+                (context?.getSystemService(Context.TELEPHONY_SERVICE) as TelephonyManager?)
                     ?.activeModemCount ?: -1
             } else {
                 @Suppress("deprecation")
-                (context.getSystemService(Context.TELEPHONY_SERVICE) as TelephonyManager?)
+                (context?.getSystemService(Context.TELEPHONY_SERVICE) as TelephonyManager?)
                     ?.phoneCount ?: -1
             }
         } catch (t: Throwable) {
@@ -95,8 +97,8 @@ private fun getDevicePhoneCount(context: Context) =
         -1
     }
 
-private fun getNetworkOperator(context: Context) =
-    (context.getSystemService(Context.TELEPHONY_SERVICE) as TelephonyManager?)?.networkOperator
+private fun getNetworkOperator(context: Context?) =
+    (context?.getSystemService(Context.TELEPHONY_SERVICE) as TelephonyManager?)?.networkOperator
 
 internal fun getOsVersion() = Build.VERSION.SDK_INT
 

stripecardscan/src/main/java/com/stripe/android/stripecardscan/scanui/ScanFragment.kt

@@ -73,8 +73,10 @@ abstract class ScanFragment : Fragment(), CoroutineScope {
         super.onStart()
         Stats.startScan()
 
-        if (!CameraAdapter.isCameraSupported(requireActivity())) {
-            showCameraNotSupported()
+        context?.let {
+            if (!CameraAdapter.isCameraSupported(it)) {
+                showCameraNotSupported()
+            }
         }
     }
 
@@ -94,7 +96,7 @@ abstract class ScanFragment : Fragment(), CoroutineScope {
 
     protected open fun hideSystemUi() {
         // Prevent screenshots and keep the screen on while scanning.
-        requireActivity().window.setFlags(
+        activity?.window?.setFlags(
             WindowManager.LayoutParams.FLAG_SECURE +
                 WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON,
             WindowManager.LayoutParams.FLAG_SECURE +