import 'package:flutter/material.dart';

class NavigatorPage extends StatefulWidget {
 @override
 _NavigatorPageState createState() => _NavigatorPageState();
}

class _NavigatorPageState extends State<NavigatorPage> {
 @override
 Widget build(BuildContext context) {
  return Scaffold(
   appBar: AppBar(
    title: Text('Navigator'),
   ),
   body: Column(
    children: <Widget>[
     Text('Navigator的高度為infinity'),
     Text('如果直接父級非最上級也是infinity會產(chǎn)生異常'),
     Container(
      height: 333,
      color: Colors.amber.withAlpha(111),
      child: Navigator( // Navigator
       initialRoute: '/abc',
       onGenerateRoute: (val) {
        RoutePageBuilder builder;
        switch (val.name) {
         case '/abc':
          builder = (BuildContext nContext, Animation<double> animation, Animation<double> secondaryAnimation) => Column(
           // 并沒有在 MaterialApp 中設(shè)定 /efg 路由
           // 因為Navigator的特性 使用nContext 可以跳轉(zhuǎn) /efg
           children: <Widget>[
            Text('呵呵呵'),
            RaisedButton(
             child: Text('去 /efg'),
             onPressed: () {
              Navigator.pushNamed(nContext, '/efg');
             },
            )
           ],
          );
         break;
         case '/efg':
          builder = (BuildContext nContext, Animation<double> animation, Animation<double> secondaryAnimation) => Row(
           children: <Widget>[
            RaisedButton(
             child: Text('去 /hhh'),
             onPressed: () {
              Navigator.pushNamed(nContext, '/hhh');
             },
            )
           ],
          );
         break;
         default:
          builder = (BuildContext nContext, Animation<double> animation, Animation<double> secondaryAnimation) => Center(
           child: RaisedButton(
            child: Text('去 /abc'),
            onPressed: () {
             Navigator.pushNamed(nContext, '/abc');
            },
           )
          );
        }
        return PageRouteBuilder(
         pageBuilder: builder,
         // transitionDuration: const Duration(milliseconds: 0),
        );
       },
       onUnknownRoute: (val) {
        print(val);
       },
       observers: <NavigatorObserver>[]
      ),
     ),
     Text('Navigator執(zhí)行尋找路由順序'),
     Text('initialRoute'),
     Text('onGenerateRoute'),
     Text('onUnknownRoute'),
    ],
   ),
  );
 }
}