Flutter 局部路由实现详解

150 阅读 0 评论 99 点赞

我是靠谱客的博主醉熏鸡翅，这篇文章主要介绍Flutter 局部路由实现详解，现在分享给大家，希望可以做个参考。

Flutter是借鉴React的开发思想实现的，在子组件的插槽上，React有this.props.children，Vue有<slot></slot>。

当然Flutter也有类似的Widget，那就是Navigator，不过是以router的形式实现（像<router-view></router-view>？？？）。

Navigator的使用无非3个属性

initialRoute: 初始路由
onGenerateRoute: 匹配路由
onUnknownRoute: 404

在实现层面

首先：Navigator的高度为infinity。如果直接父级非最上级也是infinity会产生异常，例如，Scaffold -> Column -> Navigator。所以：Navigator需要附件限制高度，例如：Scaffold -> Column -> Container（height: 300） -> Navigator

然后：在onGenerateRoute属性中，使用第一个BuildContext参数，能够在MaterialApp未设置route的情况下使用Navigator.pushNamed(nContext, '/efg');跳到对应的子路由中。

最后：Navigator执行寻找路由顺序是 initialRoute -> onGenerateRoute -> onUnknownRoute，这个和React的Route是类似的。

最后附上源码

复制代码

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的高度为infinity'),
     Text('如果直接父级非最上级也是infinity会产生异常'),
     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(
           // 并没有在 MaterialApp 中设定 /efg 路由
           // 因为Navigator的特性 使用nContext 可以跳转 /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执行寻找路由顺序'),
     Text('initialRoute'),
     Text('onGenerateRoute'),
     Text('onUnknownRoute'),
    ],
   ),
  );
 }
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
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的高度为infinity'),
     Text('如果直接父级非最上级也是infinity会产生异常'),
     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(
           // 并没有在 MaterialApp 中设定 /efg 路由
           // 因为Navigator的特性 使用nContext 可以跳转 /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执行寻找路由顺序'),
     Text('initialRoute'),
     Text('onGenerateRoute'),
     Text('onUnknownRoute'),
    ],
   ),
  );
 }
}