feat(callback): add currentIndex and previoudIndex to `onSwipe` (#7)

CHANGELOG.md

@@ -1,3 +1,8 @@
+## NEXT
+
+- **BREAKING CHANGES**:
+  - Add currentIndex and previousIndex to the onSwipe callback
+
 ## [2.1.0]
 
 - Add option to display more cards at a time. Useful if the widgets you want in your cards take time to build (for example a network image or video): displaying more cards builds them in advance and makes a fast serie of swipes more fluid.

example/lib/main.dart

@@ -75,7 +75,13 @@ class _ExamplePageState extends State<Example> {
     );
   }
 
-  void _swipe(int index, CardSwiperDirection direction) {
+  void _swipe(
-    debugPrint('the card $index was swiped to the: ${direction.name}');
+    int previousIndex,
+    int currentIndex,
+    CardSwiperDirection direction,
+  ) {
+    debugPrint(
+      'the card $previousIndex was swiped to the ${direction.name}. Now the card $currentIndex is on top',
+    );
   }
 }

lib/src/card_swiper.dart

@@ -316,8 +316,15 @@ class _CardSwiperState<T extends Widget> extends State<CardSwiper<T>>
     if (status == AnimationStatus.completed) {
       setState(() {
         if (_swipeType == SwipeType.swipe) {
-          widget.onSwipe?.call(_currentIndex, detectedDirection);
+          final previousIndex = _currentIndex;
           _stack.removeAt(_currentIndex);
+          widget.onSwipe?.call(
+            previousIndex,
+            widget.isLoop && _stack.isEmpty
+                ? widget.cards.length - 1
+                : _currentIndex,
+            detectedDirection,
+          );
 
           if (_stack.isEmpty) {
             widget.onEnd?.call();

lib/src/typedefs.dart

@@ -1,7 +1,8 @@
 import 'package:flutter_card_swiper/src/enums.dart';
 
 typedef CardSwiperOnSwipe = void Function(
-  int index,
+  int previousIndex,
+  int currentIndex,
   CardSwiperDirection direction,
 );