From 7df108e288b94376c9d056ee85ba5c80b14ed531 Mon Sep 17 00:00:00 2001
From: Adam Wushensky <awush@stripe.com>
Date: Mon, 28 Mar 2022 10:42:05 -0700
Subject: [PATCH 1/2] Update the interface so reference to the callback is not
 lost on activity killed

---
 .../getbouncer/cardscan/ui/CardScanSheet.kt   | 37 ++++++++++++-------
 1 file changed, 23 insertions(+), 14 deletions(-)

diff --git a/cardscan-ui/src/main/java/com/getbouncer/cardscan/ui/CardScanSheet.kt b/cardscan-ui/src/main/java/com/getbouncer/cardscan/ui/CardScanSheet.kt
index 7c3cbb87..f02517ae 100644
--- a/cardscan-ui/src/main/java/com/getbouncer/cardscan/ui/CardScanSheet.kt
+++ b/cardscan-ui/src/main/java/com/getbouncer/cardscan/ui/CardScanSheet.kt
@@ -40,10 +40,15 @@ sealed interface CardScanSheetResult : Parcelable {
 
 class CardScanSheet private constructor(private val apiKey: String) {
 
-    private var onFinished:
-        ((cardScanSheetResult: CardScanSheetResult) -> Unit)? = null
     private lateinit var launcher: ActivityResultLauncher<CardScanSheetParams>
 
+    /**
+     * Callback to notify when scanning finishes and a result is available.
+     */
+    fun interface CardScanResultCallback {
+        fun onCardScanSheetResult(cardScanSheetResult: CardScanSheetResult)
+    }
+
     companion object {
         /**
          * Create a [CardScanSheet] instance with [ComponentActivity].
@@ -57,9 +62,14 @@ class CardScanSheet private constructor(private val apiKey: String) {
         fun create(
             from: ComponentActivity,
             apiKey: String,
+            cardScanResultCallback: CardScanResultCallback,
             registry: ActivityResultRegistry = from.activityResultRegistry,
         ) = CardScanSheet(apiKey).apply {
-            launcher = from.registerForActivityResult(activityResultContract, registry, ::onResult)
+            launcher = from.registerForActivityResult(
+                activityResultContract,
+                registry,
+                cardScanResultCallback::onCardScanSheetResult,
+            )
         }
 
         @JvmStatic
@@ -67,12 +77,20 @@ class CardScanSheet private constructor(private val apiKey: String) {
         fun create(
             from: Fragment,
             apiKey: String,
+            cardScanResultCallback: CardScanResultCallback,
             registry: ActivityResultRegistry? = null,
         ) = CardScanSheet(apiKey).apply {
             launcher = if (registry != null) {
-                from.registerForActivityResult(activityResultContract, registry, ::onResult)
+                from.registerForActivityResult(
+                    activityResultContract,
+                    registry,
+                    cardScanResultCallback::onCardScanSheetResult,
+                )
             } else {
-                from.registerForActivityResult(activityResultContract, ::onResult)
+                from.registerForActivityResult(
+                    activityResultContract,
+                    cardScanResultCallback::onCardScanSheetResult,
+                )
             }
         }
 
@@ -138,9 +156,7 @@ class CardScanSheet private constructor(private val apiKey: String) {
         enableEnterManually: Boolean,
         enableNameExtraction: Boolean,
         enableExpiryExtraction: Boolean,
-        onFinished: (cardScanSheetResult: CardScanSheetResult) -> Unit
     ) {
-        this.onFinished = onFinished
         launcher.launch(
             CardScanSheetParams(
                 apiKey = apiKey,
@@ -150,11 +166,4 @@ class CardScanSheet private constructor(private val apiKey: String) {
             )
         )
     }
-
-    /**
-     * When a result is available from the activity, call [onFinished] if it's available.
-     */
-    private fun onResult(cardScanSheetResult: CardScanSheetResult) {
-        onFinished?.let { it(cardScanSheetResult) }
-    }
 }

From 7f66760d8d9af5ebf5108bcb4ef8de7e4a1e3466 Mon Sep 17 00:00:00 2001
From: Adam Wushensky <awush@stripe.com>
Date: Mon, 28 Mar 2022 10:46:03 -0700
Subject: [PATCH 2/2] Fix the demo

---
 .../java/com/getbouncer/cardscan/demo/LaunchActivity.java    | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/cardscan-demo/src/main/java/com/getbouncer/cardscan/demo/LaunchActivity.java b/cardscan-demo/src/main/java/com/getbouncer/cardscan/demo/LaunchActivity.java
index f43a6bea..79381cce 100644
--- a/cardscan-demo/src/main/java/com/getbouncer/cardscan/demo/LaunchActivity.java
+++ b/cardscan-demo/src/main/java/com/getbouncer/cardscan/demo/LaunchActivity.java
@@ -30,7 +30,7 @@ protected void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_launch);
 
-        final CardScanSheet sheet = CardScanSheet.create(this, API_KEY);
+        final CardScanSheet sheet = CardScanSheet.create(this, API_KEY, this::handleScanResult);
 
         // Because this activity displays card numbers, disallow screenshots.
         getWindow().setFlags(
@@ -52,8 +52,7 @@ protected void onCreate(@Nullable Bundle savedInstanceState) {
             sheet.present(
                 /* enableEnterCardManually */ enableEnterCardManually,
                 /* enableExpiryExtraction */ enableExpiryExtraction,
-                /* enableNameExtraction */ enableNameExtraction,
-                this::handleScanResult
+                /* enableNameExtraction */ enableNameExtraction
             );
         });