Fixed a bug causing the onRefresh method not being triggered on the iOS

Author: Kamil Klyta

CHANGELOG.md

@@ -13,6 +13,7 @@
 - Trigger mode support added. Equivalent to trigger mode of the built-in **RefreshIndicator** widget.
 - The **PositionedIndicatorContainer** class is no longer exported from this package, however the source code is available in the example application. 
 - Now the *onRefresh* function will be triggered immediately when the indicator is released in the armed state. Previously, the *onRefresh* function was triggered when the indicator reached a target value in the loading state of `1.0`.
+- Fixed a bug causing the *onRefresh* method not being triggered on the iOS platform due to the use of bounce physics.
 - Multiple minor fixes, improvements and optimizations.
 ## 1.2.1
 - Flutter 3.0.0 migration backward compatibility fix ([#31](https://github.com/gonuit/flutter-custom-refresh-indicator/pull/31)) by [Jordan1122](https://github.com/Jordan1122)

lib/src/custom_refresh_indicator.dart

@@ -277,8 +277,25 @@ class CustomRefreshIndicatorState extends State<CustomRefreshIndicator>
   }
 
   bool _handleScrollUpdateNotification(ScrollUpdateNotification notification) {
-    /// hide when list starts to scroll
-    if (controller.isDragging || controller.isArmed) {
+    // Calculate the edge if not defined and possible.
+    // This may apply to two-way lists on the iOS platform with bouncing physics.
+    if (!controller.hasEdge) {
+      if (notification.metrics.extentBefore == 0 &&
+          notification.scrollDelta?.isNegative == true) {
+        controller.setIndicatorEdge(IndicatorEdge.start);
+      } else if (notification.metrics.extentAfter == 0 &&
+          notification.scrollDelta?.isNegative == false) {
+        controller.setIndicatorEdge(IndicatorEdge.end);
+      }
+    }
+
+    /// When the controller is armed, but the scroll update event is not triggered
+    /// by the user, the refresh action should be triggered
+    if (controller.isArmed && notification.dragDetails == null) {
+      _start();
+
+      /// Handle the indicator state depending on scrolling direction
+    } else if (controller.isDragging || controller.isArmed) {
       switch (controller.edge) {
         case IndicatorEdge.start:
           if (notification.metrics.extentBefore > 0.0) {
@@ -304,10 +321,6 @@ class CustomRefreshIndicatorState extends State<CustomRefreshIndicator>
           _hide();
           break;
       }
-
-      if (controller.isArmed && notification.dragDetails == null) {
-        _start();
-      }
     }
 
     return false;