feat(code): improve code legibility

lib/stacked_cards.dart

@@ -12,7 +12,7 @@ const List<Alignment> cardsAlign = [
   Alignment(0.0, 0.8),
   Alignment(0.0, 0.0)
 ];
-List<Size> cardsSize = List.filled(3, const Size(1, 1));
+final List<Size> cardsSize = List.filled(3, const Size(1, 1));
 
 class SwipeableCardsSection extends StatefulWidget {
   final SwipeableCardSectionController? cardController;
@@ -46,12 +46,18 @@ class SwipeableCardsSection extends StatefulWidget {
     this.enableSwipeUp = true,
     this.enableSwipeDown = true,
   }) : super(key: key) {
-    cardsSize[0] = Size(MediaQuery.of(context).size.width * cardWidthTopMul,
-        MediaQuery.of(context).size.height * cardHeightTopMul);
-    cardsSize[1] = Size(MediaQuery.of(context).size.width * cardWidthMiddleMul,
-        MediaQuery.of(context).size.height * cardHeightMiddleMul);
-    cardsSize[2] = Size(MediaQuery.of(context).size.width * cardWidthBottomMul,
-        MediaQuery.of(context).size.height * cardHeightBottomMul);
+    cardsSize[0] = Size(
+      MediaQuery.of(context).size.width * cardWidthTopMul,
+      MediaQuery.of(context).size.height * cardHeightTopMul,
+    );
+    cardsSize[1] = Size(
+      MediaQuery.of(context).size.width * cardWidthMiddleMul,
+      MediaQuery.of(context).size.height * cardHeightMiddleMul,
+    );
+    cardsSize[2] = Size(
+      MediaQuery.of(context).size.width * cardWidthBottomMul,
+      MediaQuery.of(context).size.height * cardHeightBottomMul,
+    );
   }
 
   @override
@@ -130,7 +136,9 @@ class _CardsSectionState extends State<SwipeableCardsSection>
 
     // Init the animation controller
     _controller = AnimationController(
-        duration: const Duration(milliseconds: 700), vsync: this);
+      duration: const Duration(milliseconds: 700),
+      vsync: this,
+    );
     _controller.addListener(() => setState(() {}));
     _controller.addStatusListener((AnimationStatus status) {
       if (status == AnimationStatus.completed) changeCardsOrder();
@@ -148,8 +156,8 @@ class _CardsSectionState extends State<SwipeableCardsSection>
             if (cards[1] != null) middleCard(),
             if (cards[0] != null) frontCard(),
             // Prevent swiping if the cards are animating
-          ((_controller.status != AnimationStatus.forward))
-              ? SizedBox.expand(
+            if (_controller.status != AnimationStatus.forward)
+              SizedBox.expand(
                 child: GestureDetector(
                   // While dragging the first card
                   onPanUpdate: (DragUpdateDetails details) {
@@ -163,7 +171,8 @@ class _CardsSectionState extends State<SwipeableCardsSection>
                         frontCardAlign.y +
                             20 *
                                 details.delta.dy /
-                                  MediaQuery.of(context).size.height);
+                                MediaQuery.of(context).size.height,
+                      );
 
                       frontCardRot = frontCardAlign.x; // * rotation speed;
                     });
@@ -202,11 +211,14 @@ class _CardsSectionState extends State<SwipeableCardsSection>
                       animateCards();
                     }
                   },
-                ))
-              : Container(),
+                ),
+              )
+            else
+              const SizedBox(),
           ],
         ),
-    ));
+      ),
+    );
   }
 
   Widget backCard() {
@@ -218,7 +230,8 @@ class _CardsSectionState extends State<SwipeableCardsSection>
         size: _controller.status == AnimationStatus.forward
             ? CardsAnimation.backCardSizeAnim(_controller).value
             : cardsSize[2],
-          child: cards[2]),
+        child: cards[2],
+      ),
     );
   }
 
@@ -231,7 +244,8 @@ class _CardsSectionState extends State<SwipeableCardsSection>
         size: _controller.status == AnimationStatus.forward
             ? CardsAnimation.middleCardSizeAnim(_controller).value
             : cardsSize[1],
-          child: cards[1]),
+        child: cards[1],
+      ),
     );
   }
 
@@ -239,13 +253,15 @@ class _CardsSectionState extends State<SwipeableCardsSection>
     return Align(
       alignment: _controller.status == AnimationStatus.forward
           ? CardsAnimation.frontCardDisappearAlignmentAnim(
-                    _controller, frontCardAlign)
-                .value
+              _controller,
+              frontCardAlign,
+            ).value
           : frontCardAlign,
       child: Transform.rotate(
         angle: (pi / 180.0) * frontCardRot,
         child: SizedBox.fromSize(size: cardsSize[0], child: cards[0]),
-        ));
+      ),
+    );
   }
 
   void changeCardsOrder() {
@@ -265,45 +281,58 @@ class _CardsSectionState extends State<SwipeableCardsSection>
   }
 
   void animateCards() {
-    _controller.stop();
-    _controller.value = 0.0;
-    _controller.forward();
+    _controller
+      ..stop()
+      ..value = 0.0
+      ..forward();
   }
 }
 
 class CardsAnimation {
   static Animation<Alignment> backCardAlignmentAnim(
-      AnimationController parent) {
+    AnimationController parent,
+  ) {
     return AlignmentTween(begin: cardsAlign[0], end: cardsAlign[1]).animate(
       CurvedAnimation(
         parent: parent,
-            curve: const Interval(0.4, 0.7, curve: Curves.easeIn)));
+        curve: const Interval(0.4, 0.7, curve: Curves.easeIn),
+      ),
+    );
   }
 
   static Animation<Size?> backCardSizeAnim(AnimationController parent) {
     return SizeTween(begin: cardsSize[2], end: cardsSize[1]).animate(
       CurvedAnimation(
         parent: parent,
-            curve: const Interval(0.4, 0.7, curve: Curves.easeIn)));
+        curve: const Interval(0.4, 0.7, curve: Curves.easeIn),
+      ),
+    );
   }
 
   static Animation<Alignment> middleCardAlignmentAnim(
-      AnimationController parent) {
+    AnimationController parent,
+  ) {
     return AlignmentTween(begin: cardsAlign[1], end: cardsAlign[2]).animate(
       CurvedAnimation(
         parent: parent,
-            curve: const Interval(0.2, 0.5, curve: Curves.easeIn)));
+        curve: const Interval(0.2, 0.5, curve: Curves.easeIn),
+      ),
+    );
   }
 
   static Animation<Size?> middleCardSizeAnim(AnimationController parent) {
     return SizeTween(begin: cardsSize[1], end: cardsSize[0]).animate(
       CurvedAnimation(
         parent: parent,
-            curve: const Interval(0.2, 0.5, curve: Curves.easeIn)));
+        curve: const Interval(0.2, 0.5, curve: Curves.easeIn),
+      ),
+    );
   }
 
   static Animation<Alignment> frontCardDisappearAlignmentAnim(
-      AnimationController parent, Alignment beginAlign) {
+    AnimationController parent,
+    Alignment beginAlign,
+  ) {
     if (beginAlign.x == -0.001 ||
         beginAlign.x == 0.001 ||
         beginAlign.x > 3.0 ||
@@ -312,23 +341,27 @@ class CardsAnimation {
         begin: beginAlign,
         end: Alignment(
           beginAlign.x > 0 ? beginAlign.x + 30.0 : beginAlign.x - 30.0,
-                  0.0) // Has swiped to the left or right?
-              )
-          .animate(CurvedAnimation(
+          0.0,
+        ), // Has swiped to the left or right?
+      ).animate(
+        CurvedAnimation(
           parent: parent,
-              curve: const Interval(0.0, 0.5, curve: Curves.easeIn)));
+          curve: const Interval(0.0, 0.5, curve: Curves.easeIn),
+        ),
+      );
     } else {
       return AlignmentTween(
         begin: beginAlign,
         end: Alignment(
           0.0,
-                  beginAlign.y > 0
-                      ? beginAlign.y + 30.0
-                      : beginAlign.y - 30.0) // Has swiped to the top or bottom?
-              )
-          .animate(CurvedAnimation(
+          beginAlign.y > 0 ? beginAlign.y + 30.0 : beginAlign.y - 30.0,
+        ), // Has swiped to the top or bottom?
+      ).animate(
+        CurvedAnimation(
           parent: parent,
-              curve: const Interval(0.0, 0.5, curve: Curves.easeIn)));
+          curve: const Interval(0.0, 0.5, curve: Curves.easeIn),
+        ),
+      );
     }
   }
 }