页面浏览量颤动如何跳转到另一个页面

Question

您好，如果我按下第一个页面选项卡上的按钮，我试图跳转到我的第二个页面选项卡。目前我只知道我的第二页小部件的调用路线，但底部导航栏不存在......我不知道如何从我的第一页标签调用我的父小部件以跳转到第二页标签。

  class Parent  {

  int bottomSelectedIndex = 0;

  List<BottomNavigationBarItem> buildBottomNavBarItems() {
    return [
      BottomNavigationBarItem(
          icon: new Icon(Icons.home),
          title: new Text('First')
      ),
      BottomNavigationBarItem(
        icon: new Icon(Icons.search),
        title: new Text('Second'),
      ),

    ];
  }

  PageController pageController = PageController(
    initialPage: 0,
    keepPage: true,
  );

  Widget buildPageView() {
    return PageView(
      controller: pageController,
      onPageChanged: (index) {
        pageChanged(index);
      },
      children: <Widget>[
        First(),
        Second(),

      ],
    );
  }

  @override
  void initState() {
    super.initState();
  }

  void pageChanged(int index) {
    setState(() {
      bottomSelectedIndex = index;
    });
  }

  void bottomTapped(int index) {
    setState(() {
      bottomSelectedIndex = index;
      pageController.animateToPage(index, duration: Duration(milliseconds: 500), curve: Curves.ease);
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: buildPageView(),
      bottomNavigationBar: BottomNavigationBar(
        currentIndex: bottomSelectedIndex,
        onTap: (index) {
          bottomTapped(index);
        },
        items: buildBottomNavBarItems(),
      ),
    );
  }
  }

---

  class first {
        return Container(
    // here a pressbutton for jump to the second widget
        );

    }

----------------------------------------------------------


    class second
        return Container(

        );
    }

Answer 1

你可以用这个：

void onAddButtonTapped(int index) {

  // use this to animate to the page
  pageController.animateToPage(index);

  // or this to jump to it without animating
  pageController.jumpToPage(index);
}

将函数作为参数传递：

class first {
  final void Function(int) onAddButtonTapped;

        return Container(
// call it here onAddButtonTapped(2);
        );

    }

class Second {
  final void Function(int) onAddButtonTapped;

        return Container(
        );

    }

children: <Widget>[
        First(onAddButtonTapped),
        Second(onAddButtonTapped),
      ],

Answer 2

您可以将回调传递给您的第一个小部件，并在按下按钮时调用它，这样您就可以更改父小部件中的页面。 像这样的：

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Test',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: Parent(),
    );
  }
}

class Parent extends StatefulWidget {
  @override
  _ParentState createState() => _ParentState();
}

class _ParentState extends State<Parent> {
  int bottomSelectedIndex = 0;

  List<BottomNavigationBarItem> buildBottomNavBarItems() {
    return [
      BottomNavigationBarItem(
          icon: new Icon(Icons.home), title: new Text('First')),
      BottomNavigationBarItem(
        icon: new Icon(Icons.search),
        title: new Text('Second'),
      ),
    ];
  }

  PageController pageController = PageController(
    initialPage: 0,
    keepPage: true,
  );

  Widget buildPageView() {
    return PageView(
      controller: pageController,
      onPageChanged: (index) {
        pageChanged(index);
      },
      children: <Widget>[
        FirstWidget(
          onButtonPressed: () => pageController.animateToPage(
                1,
                duration: Duration(milliseconds: 300),
                curve: Curves.linear,
              ),
        ),
        SecondWidget(),
      ],
    );
  }

  @override
  void initState() {
    super.initState();
  }

  void pageChanged(int index) {
    setState(() {
      bottomSelectedIndex = index;
    });
  }

  void bottomTapped(int index) {
    setState(() {
      bottomSelectedIndex = index;
      pageController.animateToPage(index,
          duration: Duration(milliseconds: 500), curve: Curves.ease);
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Test'),
      ),
      body: buildPageView(),
      bottomNavigationBar: BottomNavigationBar(
        currentIndex: bottomSelectedIndex,
        onTap: (index) {
          bottomTapped(index);
        },
        items: buildBottomNavBarItems(),
      ),
    );
  }
}

class FirstWidget extends StatefulWidget {
  final VoidCallback onButtonPressed;

  FirstWidget({@required this.onButtonPressed});

  @override
  _FirstWidgetState createState() => _FirstWidgetState();
}

class _FirstWidgetState extends State<FirstWidget> {
  @override
  Widget build(BuildContext context) {
    return Container(
      color: Colors.red,
      child: Center(
        child: FlatButton(
          onPressed: widget.onButtonPressed,
          child: Text('Go to second page'),
        ),
      ),
    );
  }
}


class SecondWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Container(color: Colors.green);
  }
}