ExpandView Animation In Flutter

ExpandView Animation In Flutter :

expandview animation.dart

import 'package:flutter/material.dart';
class FilterView extends StatefulWidget {
  final bool expanded;
  final double expandedHeight;

  FilterView({
    this.expanded = false,
    this.expandedHeight = 200.0,
  });

  @override
  State<StatefulWidget> createState() => FilterViewState();
}

class FilterViewState extends State<FilterView> with SingleTickerProviderStateMixin {
  AnimationController _controller;
  Animation<double> _animation;
  bool _expanded;

  @override
  void initState() {
    super.initState();
    _controller = AnimationController(vsync: this, duration: const Duration(milliseconds: 200));
    final CurvedAnimation curve = CurvedAnimation(parent: this._controller, curve: Curves.easeInCubic);
    _animation = Tween(begin: 34.0, end: this.widget.expandedHeight).animate(curve)
      ..addListener(() {
        setState(() {});
      });
    this._expanded = this.widget.expanded;
    if (this._expanded) {
      this._controller.forward();
    }
  }

  @override
  void dispose() {
    super.dispose();
    this._controller.dispose();
  }

  @override
  Widget build(BuildContext context) {
    Widget _filterForm = Padding(
      padding: EdgeInsets.only(bottom: 46),
      child: ListView(
        children: <Widget>[
          Wrap(
            children: <Widget>[],
          ),
        ],
      ),
    );
    Widget _expandButton = Card(
      color: Theme.of(context).primaryColor,
      shape: RoundedRectangleBorder(borderRadius: BorderRadius.vertical(top: Radius.zero, bottom: Radius.circular(2))),
      margin: EdgeInsets.all(0),
      child: InkWell(
        child: Container(
          padding: EdgeInsets.only(bottom: 6, top: 3),
          child: Row(
            mainAxisAlignment: MainAxisAlignment.center,
            crossAxisAlignment: CrossAxisAlignment.center,
            children: <Widget>[
              Text(
                '筛选',
                style: TextStyle(fontSize: 16, color: Colors.white),
              ),
              SizedBox(width: 10),
              Icon(
                this._expanded ? Icons.expand_less : Icons.menu,
                color: Colors.white,
                size: 25,
              ),
            ],
          ),
        ),
        onTap: () {
          this._expanded ? this._controller.reverse(from: this._animation.value) : this._controller.forward();
          this.setState(() => this._expanded = !this._expanded);
        },
      ),
    );
    Widget _filterFormButton = Positioned(
      child: Row(
        mainAxisAlignment: MainAxisAlignment.end,
        children: <Widget>[
          RaisedButton.icon(
            onPressed: () {},
            color: Theme.of(context).backgroundColor,
            textTheme: ButtonTextTheme.primary,
            label: Text('重置'),
            icon: Icon(Icons.replay),
          ),
          SizedBox(width: 10),
          RaisedButton.icon(
            onPressed: () {},
            color: Theme.of(context).primaryColor,
            textTheme: ButtonTextTheme.primary,
            label: const Text('查询'),
            icon: Icon(Icons.search),
          )
        ],
      ),
      bottom: 0,
      right: 10,
    );
    return SizedBox(
      width: MediaQuery.of(context).size.width,
      height: this._animation.value,
      child: Column(
        mainAxisAlignment: MainAxisAlignment.end,
        children: <Widget>[
          Expanded(
            child: Container(
              child: Stack(
                children: <Widget>[
                  _filterForm,
                  _filterFormButton,
                ],
              ),
              decoration: BoxDecoration(
                border: Border.all(color: Theme.of(context).primaryColor, width: 3),
              ),
            ),
          ),
          _expandButton,
        ],
      ),
    );
  }
}

The flutter tutorial  is a website that bring you the latest and amazing resources of code. All the languages codes are included in this website. The languages like flutter, android, java,kotlin etc.with the help of this languages any user can develop the beautiful application

For more information about Flutter. visit www.fluttertutorial.in