React-navigation导航系统(5)-Router

tags: React-Native

Routers

Router定义一个组件的navigation state,允许开发者定义路径和可以操作的actions.

内建的Routers

• StackRouter
• TabRouter

使用Routers

为了手动定制一个navigator,在组件里可以放一个静态的router.(使用内建的组件快速的定制一个navigator,使用Navigator Factory更容易实现).

 class MyNavigator extends React.Component {    static router = StackRouter(routes, config);    ...}

现在你可以把这个组件作为另一个navigator的screen对待,MyNavigator的导航逻辑在StackRouter中定义.

定制化Router

看看[定制Router API 部分](https://reactnavigation.org/docs/routers/api)学习StackRouter和TabRouter的API.
只要你愿意也可以重写router的函数.

定制Navigation的Actions

为了重写navigation的行为,你可以在getStateForAction中重写navigation state的逻辑,从而手动处理routes和index.

 const MyApp = StackNavigator({  Home: { screen: HomeScreen },  Profile: { screen: ProfileScreen },}, {  initialRouteName: 'Home',})MyApp.router = {  ...MyApp.router,  getStateForAction(action, state) {    if (state && action.type === 'PushTwoProfiles') {      const routes = [        ...state.routes,        {key: 'A', routeName: 'Profile', params: { name: action.name1 }},        {key: 'B', routeName: 'Profile', params: { name: action.name2 }},      ];      return {        ...state,        routes,        index: routes.length - 1,      };    }    return MyApp.router.getStateForAction(action, state);  },};

阻止某些Navigation的Actions

有时候根据你的route,需要阻止某些navigation的活动

 const MyStackRouter = StackRouter({  Home: { screen: HomeScreen },  Profile: { screen: ProfileScreen },}, {  initialRouteName: 'Home',})const MyAppRouter = {  ...MyStackRouter,  getStateForAction(action, state) {    if (      state &&      action.type === NavigationActions.BACK &&      state.routes[state.index].params.isEditing    ) {      // Returning null from getStateForAction means that the action      // has been handled/blocked, but there is not a new state      return null;    }    return MyStackRouter.getStateForAction(action, state);  },};

操作定制URIs

或许你的app有一个独特的URI,内建的routers处理不了.你可以通过getActionForPathAndParams来扩展router.

 import { NavigationActions } from 'react-navigation'const MyApp = StackNavigator({  Home: { screen: HomeScreen },  Profile: { screen: ProfileScreen },}, {  initialRouteName: 'Home',})const previousGetActionForPathAndParams = MyApp.router.getActionForPathAndParamsObject.assign(MyApp.router, {  getActionForPathAndParams(path, params) {    if (      path === 'my/custom/path' &&      params.magic === 'yes'    ) {      // returns a profile navigate action for /my/custom/path?magic=yes      return NavigationActions.navigate({        routeName: 'Profile',        action: NavigationActions.navigate({          // This child action will get passed to the child router          // ProfileScreen.router.getStateForAction to get the child          // navigation state.          routeName: 'Friends',        }),      });    }    return previousGetActionForPathAndParams(path, params);  },};

定制Router API

你可以童工下面的函数来构建自己的router对象,

 const MyRouter = {  getStateForAction: (action, state) => ({}),  getActionForPathAndParams: (path, params) => null,  getPathAndParamsForState: (state) => null,  getComponentForState: (state) => MyScreen,  getComponentForRouteName: (routeName) => MyScreen,};// Now, you can make a navigator by putting the router on it:class MyNavigator extends React.Component {  static router = MyRouter;  render() {    ...  }}

getStateForAction(action,state)

根据给定的action来定义返回的navigation sate.当一个action通过props.navigation.dispatch()传递,或者任何其他的助手函数被调用,例如navigation.navitate()的时候,这个函数将会运行.

通常这个函数将会以下面的形式返回navitaion state.

 {  index: 1, // identifies which route in the routes array is active  routes: [    {      // Each route needs a name to identify the type.      routeName: 'MyRouteName',      // A unique identifier for this route in the routes array:      key: 'myroute-123',      // (used to specify the re-ordering of routes)      // Routes can have any data, as long as key and routeName are correct      ...randomRouteData,    },    ...moreRoutes,  ]}

如果router已经在外部处理了acion,或者想不改变任何的navigation state就消化它,这个函数就返回null.

getComponentForRouterName(routeName)

为给定的route name返回子组件或者navigator.
像这样声明一个routergetStateForAction输出的state.

 {  index: 1,  routes: [    { key: 'A', routeName: 'Foo' },    { key: 'B', routeName: 'Bar' },  ],}

基于state中的额routeName,router将会调用router.getComponentForRouteName('Foo')或router.getComponentForRouteName('Bar')来返回对应的有效组件.

 getComponentForState(state)

从深度嵌套navigation state返回激活的组件

 getActionForPathAndParams

返回一个可选配置的navigation action,在用户导航到这个路径并且有可选的查询参数的时候使用这个action.

 getPathAndParamsForState

用户在app中返回同一个URL链接的点时,这个函数返回路径和参数.
从这个函数返回的路径和参数应该是从一个action获得的,这个action是重传进入router的getActionForPathAndParams的.这个action一旦通过getStateForAction传递,会给你返回形似的state.

 getScreenConfig

这个函数从一个route获取navigation的可选项.必须要提供screen的当前navigation prop和被返回的选项的名字.

• navigation-这是screen将会使用的navigation prop,对应在screen的route和state.Dispatch将会根据screen的上下文来触发actions.
• optionName-被获取的选项的名字,例如’title’

在实例的视图内,或许你需要远程获取配置的标题

 // First, prepare a navigation prop for your child, or re-use one if already available.const childNavigation = addNavigationHelpers({  // In this case we use navigation.state.index because we want the title for the active route.  state: navigation.state.routes[navigation.state.index],  dispatch: navigation.dispatch,})const screenTitle = this.props.router.getScreenConfig(childNavigation, 'title');

StackRouter

管理navigation堆栈的逻辑,包括入栈,出栈,操作路径解析创建深层次的堆栈.

让我们看看简单的stack router

 const MyApp = StackRouter({  Home: { screen: HomeScreen },  Profile: { screen: ProfileScreen },}, {  initialRouteName: 'Home',})

RouteConfig

最简单的stack router期待的参数是一个config对象,这里是示例配置

 const MyApp = StackRouter({ // This is the RouteConfig:  Home: {    screen: HomeScreen,    path: '',  },  Profile: {    screen: ProfileScreen,    path: 'profile/:name',  },  Settings {    // This can be handy to lazily require a screen:    getScreen: () => require('Settings').default,    // Note: Child navigators cannot be configured using getScreen because    // the router will not be accessible. Navigators must be configured    // using `screen: MyNavigator`    path: 'settings',  },});

每一个在config中的条目有如下内容

• path-设定条目的路径和参数可以在stack中被解析
• screen-设定screen组件或者子navigator
• getScreen-为screen组件设定惰性加载的设定

StackConfig

配置的选项也被传递进入stack router.

• initalRouteName-stack首次加载的默认路由的routeName
• initialRouteParams-初始化route的默认参数
• paths-提供routeName到path配置的映射,将会重写routeConfigs里的path设置

Supported Actions

stack router可以对下面的导航actions作为响应.如果有可能,router将会代理到子代router的action操作.

• Navigate-如果routeName和router的routerConfigs其中之一匹配,将会push一个新的route到堆栈.
• Back-返回(props)
• Reset-清除堆栈,提供一个新的actions创建新的navigation state
• SetParams-screen dispatch一个action去改变当前route的参数

TabRouter

管理应用中的一套tabs,处理tabs之间的跳转,处理back键的操作返回到初始化的tab.
看看简单的tabs router

 const MyApp = TabRouter({  Home: { screen: HomeScreen },  Settings: { screen: SettingsScreen },}, {  initialRouteName: 'Home',})

RouteConfig

tabs router有为每一个tab的routeConfig

 const MyApp = TabRouter({ // This is the RouteConfig:  Home: {    screen: HomeScreen,    path: 'main',  },  Settings: {    // This can be handy to lazily require a tab:    getScreen: () => require('./SettingsScreen').default,    // Note: Child navigators cannot be configured using getScreen because    // the router will not be accessible. Navigators must be configured    // using `screen: MyNavigator`    path: 'settings',  },});

config中的每一个config可能有

• config-每一个tab的path
• screen-定制screen组件或者子代navigator
• getScreen-为一个screen组件设定惰性加载的设置(navigator没有这样的配置)

Tab Router Config

被传递到router的可配置选项

• initialRouteName-首次加载的tab的routeName
• order-tabs的顺序
• path-提供routeName到path config的映射,映射重写routeConfig中的path设定
• backBehavior-点击back按钮应该返回到初始化的tab吗？如果是的话,设置initialRoute,否则就是none,默认到initialRoute的行为.

Support Actions

tabs router会对下面的navigation actions做出响应.如果有可能,router将代理到子代router的action.

• Navigate-如果和tab的routeName匹配,就会跳转到对应的tab
• Back-如果不是第一个默认的tab,就跳转到第一个tab
• SetParams-screen dispatch一个Action来改变当前route的state