• flutter PageView实现左右滑动切换视图


     

     更新时间:2019年07月17日 11:24:40   转载 作者:早起的年轻人   
     
    这篇文章主要为大家详细介绍了flutter PageView实现左右滑动切换视图,具有一定的参考价值,感兴趣的小伙伴们可以参考一下

    本文实例为大家分享了flutter PageView左右滑动切换视图的具体代码,供大家参考,具体内容如下

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    import 'dart:math';
     
    import 'package:cached_network_image/cached_network_image.dart';
    import 'package:flutter/cupertino.dart';
    import 'package:flutter/material.dart';
    import 'package:flutter_x/base/base_appbar_page.dart';
     
    class LeftPageViewPage extends StatefulWidget {
     @override
     State<StatefulWidget> createState() {
      return new LeftPageViewPageState();
     }
    }
     
    class LeftPageViewPageState extends BaseAppBarPageState<LeftPageViewPage> {
     @override
     String buildInitState() {
      buildBackBar("pageView", backIcon: Icons.arrow_back_ios);
      return null;
     }
     
     final _controller = new PageController();
     static const _kDuration = const Duration(milliseconds: 300);
     static const _kCurve = Curves.ease;
     final List<Widget> _pages = <Widget>[
      new ConstrainedBox(
       constraints: const BoxConstraints.expand(),
       child: new CachedNetworkImage(
         double.infinity,
        height: double.infinity,
        fit: BoxFit.fill,
        imageUrl:
        placeholder: (context, url) => new SizedBox(
          24.0,
         height: 24.0,
         child: new CircularProgressIndicator(
          strokeWidth: 2.0,
         ),
        ),
        errorWidget: (context, url, error) => new Icon(Icons.error),
       ),
      ),
      new ConstrainedBox(
       constraints: const BoxConstraints.expand(),
       child: new CachedNetworkImage(
         double.infinity,
        height: double.infinity,
        fit: BoxFit.fill,
        imageUrl:
        placeholder: (context, url) => new SizedBox(
          24.0,
         height: 24.0,
         child: new CircularProgressIndicator(
          strokeWidth: 2.0,
         ),
        ),
        errorWidget: (context, url, error) => new Icon(Icons.error),
       ),
      ),
      new ConstrainedBox(
        constraints: const BoxConstraints.expand(),
        child: new Stack(
         //Stack即层叠布局控件,能够将子控件层叠排列
         //alignment:此参数决定如何去对齐没有定位(没有使用Positioned)或部分定位的子widget。所谓部分定位,在这里特指没有在某一个轴上定位:left、right为横轴,top、bottom为纵轴,只要包含某个轴上的一个定位属性就算在该轴上有定位。
         alignment: AlignmentDirectional.topStart,
         children: <Widget>[
          new CachedNetworkImage(
            double.infinity,
           height: double.infinity,
           fit: BoxFit.fill,
           placeholder: (context, url) => SizedBox( 24,height: 25,child: CircularProgressIndicator(strokeWidth: 2.0,),),
           errorWidget: (context, url, error) => new Icon(Icons.error),
          ),
          new Align(
           alignment: Alignment.bottomCenter,
           child: new Container(
            margin: EdgeInsets.only(bottom: 80.0),
            child: FlatButton(onPressed: (){}, child: Text("立即体验")) ,
           ),
          ),
         ],
        )),
     ];
     
     @override
     Widget buildWidget(BuildContext context) {
      // TODO: implement buildWidget
      return new Stack(
       children: <Widget>[
        //pageViw
        PageView.builder(
         physics: new AlwaysScrollableScrollPhysics(),
         controller: _controller,
         itemBuilder: (BuildContext context, int index) {
          return _pages[index];
         },
         //条目个数
         itemCount: _pages.length,
        ),
        //圆点指示器
        new Positioned(
         bottom: 0.0,
         left: 0.0,
         right: 0.0,
         child: new Container(
          color: Colors.white,
          padding: const EdgeInsets.all(20.0),
          child: new Center(
           child: new DotsIndicator(
             controller: _controller,
             itemCount: _pages.length,
             onPageSelected: (int page) {
              _controller.animateToPage(
               page,
               duration: _kDuration,
               curve: _kCurve,
              );
             }),
          ),
         ),
        ),
       ],
      );
     }
    }
     
    class DotsIndicator extends AnimatedWidget {
     DotsIndicator({
      this.controller,
      this.itemCount,
      this.onPageSelected,
      this.color: Colors.red,
     }) : super(listenable: controller);
     
     /// The PageController that this DotsIndicator is representing.
     final PageController controller;
     
     /// The number of items managed by the PageController
     final int itemCount;
     
     /// Called when a dot is tapped
     final ValueChanged<int> onPageSelected;
     
     /// The color of the dots.
     ///
     /// Defaults to `Colors.white`.
     final Color color;
     
     // The base size of the dots
     static const double _kDotSize = 8.0;
     
     // The increase in the size of the selected dot
     static const double _kMaxZoom = 2.0;
     
     // The distance between the center of each dot
     static const double _kDotSpacing = 25.0;
     
     Widget _buildDot(int index) {
      double selectedness = Curves.easeOut.transform(
       max(
        0.0,
        1.0 - ((controller.page ?? controller.initialPage) - index).abs(),
       ),
      );
      double zoom = 1.0 + (_kMaxZoom - 1.0) * selectedness;
      return new Container(
        _kDotSpacing,
       child: new Center(
        child: new Material(
         color: color,
         type: MaterialType.circle,
         child: new Container(
           _kDotSize * zoom,
          height: _kDotSize * zoom,
          child: new InkWell(
           onTap: () => onPageSelected(index),
          ),
         ),
        ),
       ),
      );
     }
     
     Widget build(BuildContext context) {
      return new Row(
       mainAxisAlignment: MainAxisAlignment.center,
       children: new List<Widget>.generate(itemCount, _buildDot),
      );
     }
    }

    以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持脚本之家。

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  • 原文地址:https://www.cnblogs.com/sundaysandroid/p/13490871.html
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