基本Route跳转：
跳转：
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => second.Parent(),
settings: RouteSettings(name: '/Second', arguments: 'This is arguments')));
其中RouteSettings的name属性介绍
/// The name of the route (e.g., "/settings").
/// If null, the route is anonymous.
弹出：
Navigator.pop(context);
命名Route跳转：
定义routes信息：
MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
initialRoute: '/',
routes: {
'/': (context) => FirstPage(),
'/second': (context) => SecondPage()
},
);
跳转：
Navigator.pushNamed(context, '/Second',arguments: 'This is arguments');
//这里'/Second'是routeName，最终赋值给RouteSettings的name属性
弹出：
Navigator.pop(context);
检索route的顺序：
Generators for routes are searched for in the following order:
1. For the "/" route, the "home" property, if non-null, is used.
2. Otherwise, the "routes" table is used, if it has an entry for the route.
3. Otherwise, onGenerateRoute is called. It should return a non-null value for any valid route not handled by "home" and "routes".
4. Finally if all else fails onUnknownRoute is called.
MaterialApp中initialRoute属性:
官方介绍:
/// Defaults to [Window.defaultRouteName], which may be overridden by the code
/// that launched the application.
///
/// If the route contains slashes, then it is treated as a "deep link", and
/// before this route is pushed, the routes leading to this one are pushed
/// also. For example, if the route was `/a/b/c`, then the app would start
/// with the three routes `/a`, `/a/b`, and `/a/b/c` loaded, in that order.
///
/// If any part of this process fails to generate routes, then the
/// [initialRoute] is ignored and [Navigator.defaultRouteName] is used instead
/// (`/`). This can happen if the app is started with an intent that specifies
/// a non-existent route.
/// The [Navigator] is only built if routes are provided (either via [home],
/// [routes], [onGenerateRoute], or [onUnknownRoute]); if they are not,
/// [initialRoute] must be null and [builder] must not be null.
但经实际测试，对于initialRoute:'/a/b/c', 系统也会检测`/`,即
I/flutter (29676): * /
I/flutter (29676): * /a
I/flutter (29676): * /a/b
I/flutter (29676): * /a/b/c
这里我很纳闷，不知道是不是官方文档的问题，欢迎交流讨论。
运行后系统会逐个加载四个route name对应的widget页面，点返回键会依次返回。
一旦one or more of those objects was null, and therefore the initial route specified will be ignored and "/" will be used instead.
错误示例：
1. 如果赋值形如initialRoute:'/a'，会报异常但不会crash，会提示'/'和'/a'不能在route表中全被找到就会被默认置为'/'：
initialRoute: '/a',
routes: {
'/': (context) => FirstPage(),
'/b': (context) => SecondPage()
}
I/flutter (10022): ══╡ EXCEPTION CAUGHT BY FLUTTER FRAMEWORK ╞═════════════════════════════════════════════════════════
I/flutter (10022): The following message was thrown:
I/flutter (10022): Could not navigate to initial route.
I/flutter (10022): The requested route name was: "/a"
I/flutter (10022): The following routes were therefore attempted:
I/flutter (10022): * /
I/flutter (10022): * /a
I/flutter (10022): This resulted in the following objects:
I/flutter (10022): * MaterialPageRoute(RouteSettings("/", null), animation: null)
I/flutter (10022): * null
I/flutter (10022): One or more of those objects was null, and therefore the initial route specified will be ignored and
I/flutter (10022): "/" will be used instead.
2. 如果'/'不在routes中指定，且没有home属性，就会crash
initialRoute: '/a',
routes: {
'/a': (context) => FirstPage(),
'/b': (context) => SecondPage()
}
I/flutter (10022): ══╡ EXCEPTION CAUGHT BY FLUTTER FRAMEWORK ╞═════════════════════════════════════════════════════════
I/flutter (10022): The following message was thrown:
I/flutter (10022): Could not navigate to initial route.
I/flutter (10022): The requested route name was: "/a"
I/flutter (10022): The following routes were therefore attempted:
I/flutter (10022): * /
I/flutter (10022): * /a
I/flutter (10022): This resulted in the following objects:
I/flutter (10022): * null
I/flutter (10022): * MaterialPageRoute(RouteSettings("/a", null), animation: null)
I/flutter (10022): One or more of those objects was null, and therefore the initial route specified will be ignored and
I/flutter (10022): "/" will be used instead.
I/flutter (10022): ════════════════════════════════════════════════════════════════════════════════════════════════════
I/flutter (10022): Another exception was thrown: Could not find a generator for route RouteSettings("/", null) in the _WidgetsAppState.
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
3. 注意routes:属性里的'/'不能和home属性同时出现：
routes: {
'/': (context) => FirstPage(),
'/b': (context) => SecondPage()
}
home: FirstPage()
I/flutter (10022): ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
I/flutter (10022): The following assertion was thrown building MaterialApp(dirty, state: _MaterialAppState#0574c):
I/flutter (10022): If the home property is specified, the routes table cannot include an entry for "/", since it would
I/flutter (10022): be redundant.
I/flutter (10022): 'package:flutter/src/widgets/app.dart':
I/flutter (10022): Failed assertion: line 169 pos 10: 'home == null ||
I/flutter (10022): !routes.containsKey(Navigator.defaultRouteName)'
