Fix issue #20.

Author: chenenyu

CHANGELOG.md

@@ -1,3 +1,7 @@
+## [0.4.4] - 2022/04/20.
+
+* issue #20. Fix error `Concurrent modification during iteration`.
+
 ## [0.4.3] - 2022/02/17.
 
 * issue #19.

lib/src/lifecycle_observer.dart

@@ -22,10 +22,11 @@ class LifecycleObserver extends NavigatorObserver with WidgetsBindingObserver {
   @protected
   factory LifecycleObserver.internalGet(BuildContext context) {
     NavigatorState navigator = Navigator.of(context);
-    for (LifecycleObserver observer in _cache) {
+    for (int i = _cache.length - 1; i >= 0; i--) {
+      LifecycleObserver observer = _cache[i];
       if (observer.navigator == null) {
         WidgetsBinding.instance?.removeObserver(observer);
-        _cache.remove(observer);
+        _cache.removeAt(i);
       } else if (observer.navigator == navigator) {
         return observer;
       }

pubspec.yaml

@@ -1,6 +1,6 @@
 name: lifecycle
 description: Lifecycle support for Flutter widgets.
-version: 0.4.3
+version: 0.4.4
 homepage: https://github.com/chenenyu/lifecycle
 
 environment: