From 3da1f0a1f731e0725c42d528d95cee60640c1480 Mon Sep 17 00:00:00 2001
From: Romain Rastel <rromain35@gmail.com>
Date: Sun, 10 Jul 2022 15:21:50 +0200
Subject: [PATCH] fixes #289

---
 CHANGELOG.md                          |  4 ++++
 example/pubspec.lock                  |  2 +-
 lib/src/flex_entrance_transition.dart | 29 +++++++++++++++------------
 pubspec.yaml                          |  2 +-
 4 files changed, 22 insertions(+), 15 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index a98bf7de..5d60d4ae 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 1.3.1
+### Fixed
+* Rare LateInitializationError with DrawerMotion (https://github.com/letsar/flutter_slidable/issues/289).
+
 ## 1.3.0
 ### Added
 * Padding and BorderRadius to SlidableAction.
diff --git a/example/pubspec.lock b/example/pubspec.lock
index 05d2639d..7712ce54 100644
--- a/example/pubspec.lock
+++ b/example/pubspec.lock
@@ -68,7 +68,7 @@ packages:
       path: ".."
       relative: true
     source: path
-    version: "1.3.0"
+    version: "1.3.1"
   flutter_test:
     dependency: "direct dev"
     description: flutter
diff --git a/lib/src/flex_entrance_transition.dart b/lib/src/flex_entrance_transition.dart
index fc913ddf..35bcc29d 100644
--- a/lib/src/flex_entrance_transition.dart
+++ b/lib/src/flex_entrance_transition.dart
@@ -1,5 +1,5 @@
-import 'package:flutter/widgets.dart';
 import 'package:flutter/rendering.dart';
+import 'package:flutter/widgets.dart';
 
 // INTERNAL USE
 // ignore_for_file: public_member_api_docs
@@ -42,7 +42,7 @@ class FlexEntranceTransition extends MultiChildRenderObjectWidget {
 }
 
 class _FlexEntranceTransitionParentData extends FlexParentData {
-  late Tween<double> mainAxisPosition;
+  Tween<double>? mainAxisPosition;
 }
 
 class _RenderFlexEntranceTransition extends RenderBox
@@ -123,17 +123,20 @@ class _RenderFlexEntranceTransition extends RenderBox
   }
 
   void updateChildOffsets(RenderObject child) {
-    final parentData = child.parentData as _FlexEntranceTransitionParentData?;
-    final mainAxisPosition = parentData!.mainAxisPosition.evaluate(
-      _mainAxisPosition,
-    );
-    switch (_direction) {
-      case Axis.horizontal:
-        parentData.offset = Offset(mainAxisPosition, 0);
-        break;
-      case Axis.vertical:
-        parentData.offset = Offset(0, mainAxisPosition);
-        break;
+    final parentData = child.parentData;
+    if (parentData is _FlexEntranceTransitionParentData) {
+      final mainAxisPosition = parentData.mainAxisPosition?.evaluate(
+            _mainAxisPosition,
+          ) ??
+          0;
+      switch (_direction) {
+        case Axis.horizontal:
+          parentData.offset = Offset(mainAxisPosition, 0);
+          break;
+        case Axis.vertical:
+          parentData.offset = Offset(0, mainAxisPosition);
+          break;
+      }
     }
   }
 
diff --git a/pubspec.yaml b/pubspec.yaml
index f27e3b65..3154c832 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,6 +1,6 @@
 name: flutter_slidable
 description: A Flutter implementation of slidable list item with directional slide actions that can be dismissed.
-version: 1.3.0
+version: 1.3.1
 homepage: https://github.com/letsar/flutter_slidable
 
 environment: