Flutter Stepper

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Flutter Stepper

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Stepper示例：针对Stepper样式实现自定义设计，Stepper的逻辑处理

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先上效果图：

import 'package:flutter/material.dart';

///
/// 1、Stepper的样式的自定义
/// 2、Stepper事件的逻辑处理
///
class SecondPage extends StatelessWidget {
  BuildContext mPreviousPageContext;
  SecondPage(BuildContext context) {
    this.mPreviousPageContext = context;
  }
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'SecondPage',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MainWidget(mPreviousPageContext),
    );
  }
}

class MainWidget extends StatefulWidget {
  BuildContext previousContext;
  MainWidget(BuildContext previousContext) {
    this.previousContext = previousContext;
  }
  @override
  MainState createState() {
    return MainState();
  }
}

class MainState extends State<MainWidget> {
  double mSlideValue = 4;
  int mCurrentStep = 0;

  static var mStepTitles = ['apple', 'banana', 'orange', 'watermelon'];
  static var mStepContents = [
    'this is the content of step!',
    'this is the content of step!',
    'this is the content of step!',
    'this is the content of step!'
  ];
  int mMaxStepValue = mStepTitles.length - 1;
  int mMinStepValue = 0;

  ///下一步操作
  _continue() {
    if (mCurrentStep >= mMaxStepValue) {
      //超过最大值，则不处理
      setState(() {
        mStepContents[mCurrentStep] = "this is last step!";
      });
      return;
    }
    setState(() {
      mCurrentStep++;
    });
  }

  ///上一步操作
  _cancel() {
    if (mCurrentStep <= mMinStepValue) {
      //超过最小值，则不处理
      setState(() {
        mStepContents[mCurrentStep] = "this is first step!";
      });
      return;
    }
    setState(() {
      mCurrentStep--;
    });
  }

  ///获取Step
  List<Step> _getSteps() {
    List<Step> steps = [];

    for (var index = 0; index < mStepTitles.length; index++) {
      steps.add(
        Step(
          title: Text('${mStepTitles[index]}'),
          content: Column(
            children: <Widget>[
              _buildCardWithListTile(mStepContents[index]),
            ],
          ),
          isActive: _getStepActive(index),
        ),
      );
    }

    return steps;
  }

  ///校验是否是正在活动
  bool _getStepActive(int stepIndex) {
    if (stepIndex == mCurrentStep) {
      return true;
    } else {
      return false;
    }
  }

  ///创建卡片布局
  _buildCardWithListTile(String content) {
    return Card(
      child: Column(
        children: <Widget>[
          //Layout
          ListTile(
            //标题
            title: Text('Title'),
            //次标题
            subtitle: Text('$content'),
            //头
            leading: CircleAvatar(
              child: Text('Air'),
            ),
            //尾
            trailing: Text('trailing'),
            isThreeLine: true,
            dense: false,
            selected: true,
            onTap: () {},
            onLongPress: () {},
          ),
        ],
      ),
      //外边距
      margin: EdgeInsets.all(0),
      //阴影
      elevation: 3,
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        // Here we take the value from the MyHomePage object that was created by
        // the App.build method, and use it to set our appbar title.
        title: Text('Hello'),
        leading: IconButton(
            icon: Icon(
              Icons.arrow_back,
              color: Colors.white,
            ),
            onPressed: () {
              _exitPage();
            }),
        automaticallyImplyLeading: false,
      ),
      body: Center(
        child: new Column(
          children: <Widget>[
            Slider(
                value: mSlideValue,
                min: 1,
                max: 10,
                label: 'label',
                activeColor: Colors.blue,
                inactiveColor: Colors.yellow,
                onChanged: (double value) {
                  print(value);
                  setState(() {
                    mSlideValue = value;
                  });
                }),
            createStepWidget(),
          ],
        ),
      ),
    );
  }

  ///创建Stepper
  createStepWidget() {
    return Stepper(
      controlsBuilder: (BuildContext context,
          {VoidCallback onStepContinue, VoidCallback onStepCancel}) {
        return Row(
          children: <Widget>[
            FlatButton(
              onPressed: _continue,
              child: Text('下一步'),
              color: Colors.blue,
              textColor: Colors.white,
              shape: RoundedRectangleBorder(
                borderRadius: BorderRadius.circular(10),
              ),
            ),
            FlatButton(
              onPressed: _cancel,
              child: Text('上一步'),
              textColor: Colors.black54,
            ),
          ],
        );
      },
      type: StepperType.vertical,
      currentStep: mCurrentStep,
      onStepContinue: _continue,
      onStepCancel: _cancel,
      steps: _getSteps(),
    );
  }

  ///关闭当前页面
  _exitPage() {
    Navigator.pop(widget.previousContext);
  }
}

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未完待续。。。