Changed position to position + 1 to fix logic

.gitignore

@@ -70,3 +70,6 @@ build/
 !**/ios/**/default.pbxuser
 !**/ios/**/default.perspectivev3
 !/packages/flutter_tools/test/data/dart_dependencies_test/**/.packages
+example/ios/Flutter/flutter_export_environment.sh
+example/pubspec.lock
+pubspec.lock

CHANGELOG.md

@@ -1,6 +1,15 @@
 # Changelog
 All notable changes to this project will be documented in this file.
 
+## [0.1.4] - 2019-05-02
+### Added
+- [#10](https://github.com/mobiten/flutter_staggered_animations/issues/10) Takes a lot of time to animate...
+- Added property resetDelayEvery to reset the delay every N rows (optional)
+
+## [0.1.3] - 2019-05-01
+### Fixed
+- Fixed position 0 and 1 loading at the same time
+
 ## [0.1.2] - 2019-09-11
 ### Fixed
 - [#1](https://github.com/mobiten/flutter_staggered_animations/issues/1) Do not forward animation after dispose 

lib/src/animation_configuration.dart

@@ -26,6 +26,12 @@ class AnimationConfiguration extends InheritedWidget {
   /// The column count of the grid
   final int columnCount;
 
+  /// How many rows on the `mainAxis` until the delay is reset to 0. 
+  /// Use on very long `ListView` or `GridView` to avoid a very high [delay].
+  /// Keep the number similar to the expected number of rows in screen.
+  /// An alternative to `AnimationLimiter`.
+  final int resetDelayEvery;
+
   /// Configure the children's animation to be synchronized (all the children's animation start at the same time).
   ///
   /// Default value for [duration] is 225ms.
@@ -38,6 +44,7 @@ class AnimationConfiguration extends InheritedWidget {
   })  : position = 0,
         delay = Duration.zero,
         columnCount = 1,
+        resetDelayEvery = 1,
         assert(duration != null),
         assert(child != null),
         super(key: key, child: child);
@@ -66,6 +73,7 @@ class AnimationConfiguration extends InheritedWidget {
     @required this.position,
     this.duration = const Duration(milliseconds: 225),
     this.delay,
+    this.resetDelayEvery,
     @required Widget child,
   })  : columnCount = 1,
         assert(duration != null),
@@ -98,6 +106,7 @@ class AnimationConfiguration extends InheritedWidget {
     @required this.position,
     this.duration = const Duration(milliseconds: 225),
     this.delay,
+    this.resetDelayEvery,
     @required this.columnCount,
     @required Widget child,
   })  : assert(duration != null),

lib/src/animation_configurator.dart

@@ -34,30 +34,40 @@ class AnimationConfigurator extends StatelessWidget {
       );
     }
 
-    final _position = animationConfiguration.position ?? 0;
+    final _position = animationConfiguration.position ?? 0 + 1;
     final _duration = duration ?? animationConfiguration.duration;
     final _delay = delay ?? animationConfiguration.delay;
     final _columnCount = animationConfiguration.columnCount;
+    final _resetDelayEvery = animationConfiguration.resetDelayEvery;
 
     return AnimationExecutor(
       duration: _duration,
-      delay: stagger(_position, _duration, _delay, _columnCount),
+      delay:
+          stagger(_position, _duration, _delay, _columnCount, _resetDelayEvery),
       builder: (context, animationController) =>
           animatedChildBuilder(animationController),
     );
   }
 
-  Duration stagger(
-      int position, Duration duration, Duration delay, int columnCount) {
-    var delayInMilliseconds =
-        (delay == null ? duration.inMilliseconds ~/ 6 : delay.inMilliseconds);
+  Duration stagger(int position, Duration duration, Duration delay,
+      int columnCount, int resetDelayEvery) {
+    final delayInMilliseconds =
+        (delay?.inMilliseconds ?? duration.inMilliseconds ~/ 6);
 
     int _computeStaggeredGridDuration() {
-      return (position ~/ columnCount + position % columnCount) *
-          delayInMilliseconds;
+      var row = position ~/ columnCount;
+      if (resetDelayEvery != null) {
+        row = row % resetDelayEvery;
+      }
+      var calculatedPosition = row + position % columnCount;
+      return calculatedPosition * delayInMilliseconds;
     }
 
     int _computeStaggeredListDuration() {
+      if (resetDelayEvery != null) {
+        return (position ~/ resetDelayEvery) * delayInMilliseconds;
+      }
+
       return position * delayInMilliseconds;
     }
 

pubspec.yaml

@@ -1,6 +1,6 @@
 name: flutter_staggered_animations
 description: Easily add staggered animations to your ListView, GridView, Column and Row children as shown in Material Design guidelines
-version: 0.1.2
+version: 0.1.4
 authors:
   - Aurélien Lepage <aurelien@mobiten.com>
   - Charles-Henri Dumalin <charles-henri@mobiten.com>