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const _kDuration = const Duration(milliseconds: 2000);
const _kAnimInterval03 = const Interval(.00, .90);
...  
Widget _buildAnimation(BuildContext context, Widget child) {
    return Container(
      child: Container(
        width: _kActionSize * 4,
        height: 256.0,
        color: Colors.black87,
        child: Center(

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const _kAnimInterval01 = const Interval(.00, .30);
const _kAnimInterval02 = const Interval(.00, .30);
const _kAnimInterval03 = const Interval(.30, .60);
const _kAnimInterval04 = const Interval(.60, .90);
const _kAnimInterval05 = const Interval(.60, .90);

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Tween<Offset>(
  begin: Offset(-1.0, 0.0),
  end: Offset(0.0, 0.0),
).animate(
  CurvedAnimation(
    parent: controller,
    curve: Interval(.30, .60),
  ),
),

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class SlidableDrawerDelegateDemo extends StatefulWidget {
  @override
  _SlidableDrawerDelegateDemoState createState() =>
      new _SlidableDrawerDelegateDemoState();
}

class _SlidableDrawerDelegateDemoState extends State<SlidableDrawerDelegateDemo>
    with TickerProviderStateMixin {
  AnimationController _controller;

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@override
Widget build(BuildContext context) {
  return AnimatedBuilder(
    builder: _buildAnimation,
    animation: controller,
  );
}

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  Widget _buildAnimation(BuildContext context, Widget child) {
    return Container(
      child: SkewTransition(
        skew: skewTransform1,
        child: SkewTransition(
          skew: skewTransform2,
          child: Container(
            width: _kActionSize * 4,
            height: 256.0,
            color: Colors.black87,

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SlidableDrawerDelegateAnimation({
    Key key,
    this.controller,
  })  : dxPositions = <Animation<Offset>>[
          Tween<Offset>(
            begin: Offset(-1.0, 0.0),
            end: Offset(1.0, 0.0),
          ).animate(
            CurvedAnimation(
              parent: controller,

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/// Animates the skew of transformed widget.
class SkewTransition extends AnimatedWidget {
  /// Creates a skew transition.
  ///
  /// The [skew] argument must not be null.
  const SkewTransition({
    Key key,
    @required Animation<double> skew,
    this.child,
  }) : super(key: key, listenable: skew);

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const _kDuration = const Duration(milliseconds: 4000);
const _kActionSize = 64.0;
const _kCount = 3;

const _kAnimInterval01 = const Interval(.00, .30);
const _kAnimInterval02 = const Interval(.00, .30);

const _kAnimInterval03 = const Interval(.30, .60);

const _kAnimInterval04 = const Interval(.60, .90);

letsar

import 'dart:async';

import 'package:flutter/material.dart';

const _kDuration = const Duration(milliseconds: 4000);
const _kActionSize = 64.0;
const _kCount = 3;

const _kAnimInterval01 = const Interval(.00, .30);
const _kAnimInterval02 = const Interval(.00, .30);