什么是路由
- 對于普通的網(wǎng)站,所有的超鏈接都是URL地址,所有的URL地址都對應(yīng)服務(wù)器上對應(yīng)的資源;
- 對于單頁面應(yīng)用程序來說,主要通過URL中的hash(#號)來實現(xiàn)不同頁面之間的切換,同時,hash有一個特點:HTTP請求中不會包含hash相關(guān)的內(nèi)容;所以,單頁面程序中的頁面跳轉(zhuǎn)主要用hash實現(xiàn);
- 在單頁面應(yīng)用程序中,這種通過hash改變來切換頁面的方式,稱作前端路由(區(qū)別于后端路由);
在 vue 中使用 vue-router
1.導(dǎo)入 vue-router 組件類庫:
<!-- 1. 導(dǎo)入 vue-router 組件類庫 -->
<script src="./vue-router-2.7.0.js"></script>
2.使用 router-link 組件來導(dǎo)航
<!-- 2. 使用 router-link 組件來導(dǎo)航 -->
<router-link to="/login">登錄</router-link>
<router-link to="/register">注冊</router-link>
3.使用 router-view 組件來顯示匹配到的組件
<!-- 3. 使用 router-view 組件來顯示匹配到的組件 -->
<router-view></router-view>
4.注冊組件
// 4.1 使用 Vue.extend 來創(chuàng)建登錄組件
const login = {
template: '<h1>登錄組件</h1>'
}
// 4.2 使用 Vue.extend 來創(chuàng)建注冊組件
const register = {
template: '<h1>注冊組件</h1>'
}
5.指定路由規(guī)則
var router = new VueRouter({
routes: [
{ path: '/login', component : login },
{ path: '/register', component : register }
]
});
6.啟用路由規(guī)則
// 創(chuàng)建 Vue 實例,得到 ViewModel
var vm = new Vue({
el: '#app',
data: {},
methods: {},
router // 啟用路由,相當(dāng)于router : router
});
路由攜帶參數(shù)
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>目標(biāo):主要練習(xí)父子組件之間傳值</title>
</head>
<body>
<div id="app">
<router-link to="/login/1">登錄</router-link>
<router-link to="/register/2">注冊</router-link>
<router-view></router-view>
</div>
<script src="./js/vue.js"></script>
<script src="./js/vue-router.js"></script>
<script>
// 4.1 使用 Vue.extend 來創(chuàng)建登錄組件
const login = {
template: '<h1>登錄組件----{{this.$route.params.id}}</h1>'
}
// 4.2 使用 Vue.extend 來創(chuàng)建注冊組件
const register = {
template: '<h1>注冊組件----{{this.$route.params.id}}</h1>'
}
var router = new VueRouter({
routes: [
{ path: '/login/:id', component : login },
{ path: '/register/:id', component : register }
]
});
// 創(chuàng)建 Vue 實例,得到 ViewModel
var vm = new Vue({
el: '#app',
data: {},
methods: {},
router
});
</script>
</body>
</html>
路由的嵌套
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>路由嵌套</title>
</head>
<body>
<div id="app">
<router-link to="/account">Account</router-link>
<router-view></router-view>
</div>
<script src="./js/vue.js"></script>
<script src="./js/vue-router.js"></script>
<script>
const account = {
template : `<div>
這是account組件
<router-link to="/account/login">登錄</router-link>
<router-link to="/account/register">注冊</router-link>
<router-view></router-view>
</div>`
}
const login = {
template: '<h1>登錄組件</h1>'
}
const register = {
template: '<h1>注冊組件</h1>'
}
const router = new VueRouter({
routes: [
{
path : '/account',redirect : '/account/login'
},
{
path : '/account',
component : account,
children : [
{
path:'login',
component : login
},
{
path : 'register',
component : register
}
]
}
]
})
// Vue 實例
var vm = new Vue({
el: '#app',
data: {},
methods: {},
router,
components : {
account
}
});
</script>
</body>
</html>
命名視圖實現(xiàn)經(jīng)典布局
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>命名視圖實現(xiàn)經(jīng)典布局</title>
<style>
.header {
border: 1px solid red;
}
.content {
display: flex;
}
.sidebar {
flex: 2;
border: 1px solid green;
height: 500px;
}
.mainbox {
flex: 8;
border: 1px solid blue;
height: 500px;
}
</style>
</head>
<body>
<div id="app">
<router-view></router-view>
<div class="content">
<router-view name="a"></router-view>
<router-view name="b"></router-view>
</div>
</div>
<script src="./js/vue.js"></script>
<script src="./js/vue-router.js"></script>
<script>
var header = Vue.component('header', {
template: '<div class="header">header</div>'
});
var sidebar = Vue.component('sidebar', {
template: '<div class="sidebar">sidebar</div>'
});
var mainbox = Vue.component('mainbox', {
template: '<div class="mainbox">mainbox</div>'
});
// 創(chuàng)建路由對象
var router = new VueRouter({
routes: [{
path: '/',
components: {
default: header,
a: sidebar,
b: mainbox
}
}]
});
// 創(chuàng)建 Vue 實例,得到 ViewModel
var vm = new Vue({
el: '#app',
data: {},
methods: {},
router
});
</script>
</body>
</html>
watch屬性的使用
考慮一個問題:想要實現(xiàn) 名 和 姓 兩個文本框的內(nèi)容改變,則全名的文本框中的值也跟著改變;(用以前的知識如何實現(xiàn)???)
監(jiān)聽data中屬性的改變:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>watch</title>
</head>
<body>
<div id="app">
<input type="text" v-model="firstName"> +
<input type="text" v-model="lastName"> =
<span>{{fullName}}</span>
</div>
<script src="./js/vue.js"></script>
<script src="./js/vue-router.js"></script>
<script>
// 創(chuàng)建 Vue 實例,得到 ViewModel
var vm = new Vue({
el: '#app',
data: {
firstName: 'jack',
lastName: 'chen',
fullName: 'jack - chen'
},
methods: {},
watch: { // watch監(jiān)聽數(shù)據(jù)的改變
'firstName': function (newVal, oldVal) { // 第一個參數(shù)是新數(shù)據(jù),第二個參數(shù)是舊數(shù)據(jù)
this.fullName = newVal + ' - ' + this.lastName;
},
'lastName': function (newVal, oldVal) {
this.fullName = this.firstName + ' - ' + newVal;
}
}
});
</script>
</body>
</html>
監(jiān)聽對象的改變
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>watch</title>
</head>
<body>
<script src="./js/vue.js"></script>
<script src="./js/vue-router.js"></script>
<div id="app">
<router-link to="/login">登錄</router-link>
<router-link to="/register">注冊</router-link>
<router-view></router-view>
</div>
<script>
var login = {
template: '<h1>登錄組件</h1>'
};
var register = {
template: '<h1>注冊組件</h1>'
};
var router = new VueRouter({
routes: [
{
path: "/login",
component: login
},
{
path: "/register",
component: register
}
]
});
// 創(chuàng)建 Vue 實例,得到 ViewModel
var vm = new Vue({
el: '#app',
data: {},
methods: {},
router: router,
watch: {
'$route': function (newVal, oldVal) {
if (newVal.path === '/login') {
console.log('這是登錄組件');
}
}
}
});
</script>
</body>
</html>
computed計算屬性的使用
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>watch</title>
</head>
<body>
<script src="./js/vue.js"></script>
<script src="./js/vue-router.js"></script>
<div id="app">
<input type="text" v-model="firstName"> +
<input type="text" v-model="lastName"> =
<span>{{fullName}}</span>
</div>
<script>
// 創(chuàng)建 Vue 實例,得到 ViewModel
var vm = new Vue({
el: '#app',
data: {
firstName: 'jack',
lastName: 'chen'
},
methods: {},
computed: { // 計算屬性; 特點:當(dāng)計算屬性中所以來的任何一個 data 屬性改變之后,都會重新觸發(fā) 本計算屬性 的重新計算,從而更新 fullName 的值
fullName() { // 相當(dāng)于get方法,得到的是fullName屬性
return this.firstName + ' - ' + this.lastName;
}
}
});
</script>
</body>
</html>
有setter和getter的計算屬性
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>watch</title>
</head>
<body>
<script src="./js/vue.js"></script>
<script src="./js/vue-router.js"></script>
<div id="app">
<input type="text" v-model="firstName">
<input type="text" v-model="lastName">
<!-- 點擊按鈕重新為 計算屬性 fullName 賦值 -->
<input type="button" value="修改fullName" @click="changeName">
<span>{{fullName}}</span>
</div>
<script>
// 創(chuàng)建 Vue 實例,得到 ViewModel
var vm = new Vue({
el: '#app',
data: {
firstName: 'jack',
lastName: 'chen'
},
methods: {
changeName() {
this.fullName = 'TOM - chen2';
}
},
computed: {
fullName: {
get: function () {
return this.firstName + ' - ' + this.lastName;
},
set: function (newVal) {
var parts = newVal.split(' - ');
this.firstName = parts[0];
this.lastName = parts[1];
}
}
}
});
</script>
</body>
</html>
watch、computed和methods之間的對比
- computed屬性的結(jié)果會被緩存,除非依賴的響應(yīng)式屬性變化才會重新計算。主要當(dāng)作屬性來使用;
- methods方法表示一個具體的操作,主要書寫業(yè)務(wù)邏輯;
- watch一個對象,鍵是需要觀察的表達(dá)式,值是對應(yīng)回調(diào)函數(shù)。主要用來監(jiān)聽某些特定數(shù)據(jù)的變化,從而進(jìn)行某些具體的業(yè)務(wù)邏輯操作;可以看作是computed和methods的結(jié)合體;