vue_todo案例超详细讲解(可跟做练手项目)（二）-阿里云开发者社区

🔥1.4_todo案例-底部统计

目的: 显示现在任务的总数

需求: 统计当前任务的条数

分析：

①: App.vue中 – 数组list – 传给TodoFooter.vue

②: 直接在标签上显示 / 定义计算属性用于显示都可以

③: 原数组只要改变, 所有用到此数组的地方都会更新

TodoFooter.vue - 接收list统计直接显示

<template>
  <footer class="footer">
    <span class="todo-count">剩余<strong>{{ count }}</strong></span>
    <ul class="filters">
      <li>
        <a class="selected" href="javascript:;">全部</a>
      </li>
      <li>
        <a href="javascript:;">未完成</a>
      </li>
      <li>
        <a href="javascript:;">已完成</a>
      </li>
    </ul>
    <button class="clear-completed">清除已完成</button>
  </footer>
</template>
<script>
export default {
  // 5.0 props定义
  props: ['farr'],
  // 5.1 计算属性 - 任务数量
  computed: {
    count(){
      return this.farr.length
    }
  },
}
</script>
<style>
</style>

App.vue - 传入数据

<TodoFooter :farr="showArr"></TodoFooter>

🔥1.5_todo案例-数据切换

目的: 点击底部切换数据

需求1: 点击底部切换 – 点谁谁有边框
需求2: 对应切换不同数据显示

分析：

①: TodoFooter.vue – 定义isSel – 值为all, yes, no其中一种

②: 多个class分别判断谁应该有类名selected

③: 点击修改isSel的值

④: 子传父, 把类型isSel传到App.vue

⑤: 定义计算属性showArr, 决定从list里显示哪些数据给TodoMain.vue和TodoFooter.vue

App.vue

<TodoFooter :farr="showArr" @changeType="typeFn"></TodoFooter>
<script>
    export default{
       data(){
            return {
              // ...其他省略
              getSel: "all" // 默认显示全部
            }
        },
        methods: {
            // ...其他省略
            typeFn(str){ // 'all' 'yes' 'no' // 修改类型
              this.getSel = str
            },
        },
        // 6.5 定义showArr数组 - 通过list配合条件筛选而来
          computed: {
            showArr(){
              if (this.getSel === 'yes') { // 显示已完成
                return this.list.filter(obj => obj.isDone === true)
              } else if (this.getSel === 'no') { // 显示未完成
                return this.list.filter(obj => obj.isDone === false)
              } else {
                return this.list // 全部显示
              }
            }
          },
    }
</script>

TodoFooter.vue

<template>
  <footer class="footer">
    <span class="todo-count">剩余<strong>{{ count }}</strong></span>
    <ul class="filters" @click="fn">
      <li>
        <!-- 6.1 判断谁应该有高亮样式: 动态class
            6.2 用户点击要切换isSel里保存的值
         -->
        <a :class="{selected: isSel === 'all'}" href="javascript:;" @click="isSel='all'">全部</a>
      </li>
      <li>
        <a :class="{selected: isSel === 'no'}" href="javascript:;" @click="isSel='no'">未完成</a>
      </li>
      <li>
        <a :class="{selected: isSel === 'yes'}" href="javascript:;" @click="isSel='yes'">已完成</a>
      </li>
    </ul>
    <!-- 7. 目标: 清除已完成 -->
    <!-- 7.0 点击事件 -->
    <button class="clear-completed" >清除已完成</button>
  </footer>
</template>
<script>
// 5. 目标: 数量统计
export default {
  // 5.0 props定义
  props: ['farr'],
  // 5.1 计算属性 - 任务数量
  computed: {
    count(){
      return this.farr.length
    }
  },
  // 6. 目标: 点谁谁亮
  // 6.0 变量isSel
  data(){
    return {
      isSel: 'all' // 全部:'all', 已完成'yes', 未完成'no'
    }
  },
  methods: {
    fn(){ // 切换筛选条件
      // 6.3 子 -> 父 把类型字符串传给App.vue 
      this.$emit("changeType", this.isSel)
    }
  }
}
</script>

🔥1.6_todo案例-清空已完成

目的: 点击右下角按钮- 把已经完成的任务清空了

需求: 点击右下角链接标签, 清除已完成任务

分析：

①: 清空标签 – 点击事件

②: 子传父 – App.vue – 一个清空方法

③: 过滤未完成的覆盖list数组 (不考虑恢复)

App.vue - 先传入一个自定义事件-因为得接收TodoFooter.vue里的点击事件

<TodoFooter :farr="showArr" @changeType="typeFn" @clear="clearFun"></TodoFooter>
<script>
    methods: {
        // ...省略其他
        clearFun(){ // 清除已完成
          this.list = this.list.filter(obj => obj.isDone == false)
        }
    }
</script>

TodoFooter.vue

<!-- 7. 目标: 清除已完成 -->
<!-- 7.0 点击事件 -->
<button class="clear-completed" @click="clearFn">清除已完成</button>
<script>
  methods: {
        clearFn(){ // 清空已完成任务
          // 7.1 触发App.vue里事件对应clearFun方法
          this.$emit('clear')
        }
    }
</script>

🔥1.7_todo案例-数据缓存

目的: 新增/修改状态/删除后, 马上把数据同步到浏览器本地存储

需求: 无论如何变化 – 都保证刷新后数据还在

分析：

①: App.vue – 侦听list数组改变 – 深度

②: 覆盖式存入到本地 – 注意本地只能存入JSON字符串

③: 刷新页面 – list应该默认从本地取值 – 要考虑无数据情况空数组

App.vue

<script>
    export default {
        data(){
            return {
                // 8.1 默认从本地取值
                list: JSON.parse(localStorage.getItem('todoList')) || [],
                // 6.4 先中转接收类型字符串
                getSel: "all" // 默认显示全部
            }
        },
        // 8. 目标: 数据缓存
        watch: {
            list: {
                deep: true,
                handler(){
                    // 8.0 只要list变化 - 覆盖式保存到localStorage里
                    localStorage.setItem('todoList', JSON.stringify(this.list))
                }
            }
        }
    };
</script>

🔥1.8_todo案例-全选功能

目标: 点击左上角v号, 可以设置一键完成, 再点一次取消全选

需求1: 点击全选 – 小选框受到影响
需求2: 小选框都选中(手选) – 全选自动选中状态

分析：

①: TodoHeader.vue – 计算属性 - isAll

②: App.vue – 传入数组list – 在isAll的set里影响小选框

③: isAll的get里统计小选框最后状态, 影响isAll – 影响全选状态

④: 考虑无数据情况空数组 – 全选不应该勾选

提示: 就是遍历所有的对象, 修改他们的完成状态属性的值

TodoHeader.vue

<!-- 9. 目标: 全选状态
9.0 v-model关联全选状态
页面变化(勾选true, 未勾选false) -> v-model -> isAll变量
-->
<input id="toggle-all" class="toggle-all" type="checkbox" v-model="isAll">
<script>
    export default {
        // ...其他省略
        // 9.1 定义计算属性
        computed: {
            isAll: {
                set(checked){ // 只有true / false
                    // 9.3 影响数组里每个小选框绑定的isDone属性
                    this.arr.forEach(obj => obj.isDone = checked)
                },
                get(){
                    // 9.4 小选框统计状态 -> 全选框
                    // 9.5 如果没有数据, 直接返回false-不要让全选勾选状态
                    return this.arr.length !== 0 && this.arr.every(obj => obj.isDone === true)
                }
            }
        },
    }
</script>

App.vue

<TodoHeader :arr="list" @create="createFn"></TodoHeader>

🔥base.css

hr {
  margin: 20px 0;
  border: 0;
  border-top: 1px dashed #c5c5c5;
  border-bottom: 1px dashed #f7f7f7;
}
.learn a {
  font-weight: normal;
  text-decoration: none;
  color: #b83f45;
}
.learn a:hover {
  text-decoration: underline;
  color: #787e7e;
}
.learn h3,
.learn h4,
.learn h5 {
  margin: 10px 0;
  font-weight: 500;
  line-height: 1.2;
  color: #000;
}
.learn h3 {
  font-size: 24px;
}
.learn h4 {
  font-size: 18px;
}
.learn h5 {
  margin-bottom: 0;
  font-size: 14px;
}
.learn ul {
  padding: 0;
  margin: 0 0 30px 25px;
}
.learn li {
  line-height: 20px;
}
.learn p {
  font-size: 15px;
  font-weight: 300;
  line-height: 1.3;
  margin-top: 0;
  margin-bottom: 0;
}
#issue-count {
  display: none;
}
.quote {
  border: none;
  margin: 20px 0 60px 0;
}
.quote p {
  font-style: italic;
}
.quote p:before {
  content: '“';
  font-size: 50px;
  opacity: .15;
  position: absolute;
  top: -20px;
  left: 3px;
}
.quote p:after {
  content: '”';
  font-size: 50px;
  opacity: .15;
  position: absolute;
  bottom: -42px;
  right: 3px;
}
.quote footer {
  position: absolute;
  bottom: -40px;
  right: 0;
}
.quote footer img {
  border-radius: 3px;
}
.quote footer a {
  margin-left: 5px;
  vertical-align: middle;
}
.speech-bubble {
  position: relative;
  padding: 10px;
  background: rgba(0, 0, 0, .04);
  border-radius: 5px;
}
.speech-bubble:after {
  content: '';
  position: absolute;
  top: 100%;
  right: 30px;
  border: 13px solid transparent;
  border-top-color: rgba(0, 0, 0, .04);
}
.learn-bar > .learn {
  position: absolute;
  width: 272px;
  top: 8px;
  left: -300px;
  padding: 10px;
  border-radius: 5px;
  background-color: rgba(255, 255, 255, .6);
  transition-property: left;
  transition-duration: 500ms;
}
@media (min-width: 899px) {
  .learn-bar {
    width: auto;
    padding-left: 300px;
  }
  .learn-bar > .learn {
    left: 8px;
  }
}

🔥index.css

html,
body {
  margin: 0;
  padding: 0;
}
button {
  margin: 0;
  padding: 0;
  border: 0;
  background: none;
  font-size: 100%;
  vertical-align: baseline;
  font-family: inherit;
  font-weight: inherit;
  color: inherit;
  -webkit-appearance: none;
  appearance: none;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
body {
  font: 14px 'Helvetica Neue', Helvetica, Arial, sans-serif;
  line-height: 1.4em;
  background: #f5f5f5;
  color: #4d4d4d;
  min-width: 230px;
  max-width: 550px;
  margin: 0 auto;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  font-weight: 300;
}
:focus {
  outline: 0;
}
.hidden {
  display: none;
}
.todoapp {
  background: #fff;
  margin: 130px 0 40px 0;
  position: relative;
  box-shadow: 0 2px 4px 0 rgba(0, 0, 0, 0.2),
              0 25px 50px 0 rgba(0, 0, 0, 0.1);
}
.todoapp input::-webkit-input-placeholder {
  font-style: italic;
  font-weight: 300;
  color: #e6e6e6;
}
.todoapp input::-moz-placeholder {
  font-style: italic;
  font-weight: 300;
  color: #e6e6e6;
}
.todoapp input::input-placeholder {
  font-style: italic;
  font-weight: 300;
  color: #e6e6e6;
}
.todoapp h1 {
  position: absolute;
  top: -155px;
  width: 100%;
  font-size: 100px;
  font-weight: 100;
  text-align: center;
  color: rgba(175, 47, 47, 0.15);
  -webkit-text-rendering: optimizeLegibility;
  -moz-text-rendering: optimizeLegibility;
  text-rendering: optimizeLegibility;
}
.new-todo,
.edit {
  position: relative;
  margin: 0;
  width: 100%;
  font-size: 24px;
  font-family: inherit;
  font-weight: inherit;
  line-height: 1.4em;
  border: 0;
  color: inherit;
  padding: 6px;
  border: 1px solid #999;
  box-shadow: inset 0 -1px 5px 0 rgba(0, 0, 0, 0.2);
  box-sizing: border-box;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
.new-todo {
  padding: 16px 16px 16px 60px;
  border: none;
  background: rgba(0, 0, 0, 0.003);
  box-shadow: inset 0 -2px 1px rgba(0,0,0,0.03);
}
.main {
  position: relative;
  z-index: 2;
  border-top: 1px solid #e6e6e6;
}
.toggle-all {
  text-align: center;
  border: none; /* Mobile Safari */
  opacity: 0;
  position: absolute;
}
.toggle-all + label {
  width: 60px;
  height: 34px;
  font-size: 0;
  position: absolute;
  top: -52px;
  left: -13px;
  -webkit-transform: rotate(90deg);
  transform: rotate(90deg);
}
.toggle-all + label:before {
  content: '❯';
  font-size: 22px;
  color: #e6e6e6;
  padding: 10px 27px 10px 27px;
}
.toggle-all:checked + label:before {
  color: #737373;
}
.todo-list {
  margin: 0;
  padding: 0;
  list-style: none;
}
.todo-list li {
  position: relative;
  font-size: 24px;
  border-bottom: 1px solid #ededed;
}
.todo-list li:last-child {
  border-bottom: none;
}
.todo-list li.editing {
  border-bottom: none;
  padding: 0;
}
.todo-list li.editing .edit {
  display: block;
  width: 506px;
  padding: 12px 16px;
  margin: 0 0 0 43px;
}
.todo-list li.editing .view {
  display: none;
}
.todo-list li .toggle {
  text-align: center;
  width: 40px;
  /* auto, since non-WebKit browsers doesn't support input styling */
  height: auto;
  position: absolute;
  top: 0;
  bottom: 0;
  margin: auto 0;
  border: none; /* Mobile Safari */
  -webkit-appearance: none;
  appearance: none;
}
.todo-list li .toggle {
  opacity: 0;
}
.todo-list li .toggle + label {
  /*
    Firefox requires `#` to be escaped - https://bugzilla.mozilla.org/show_bug.cgi?id=922433
    IE and Edge requires *everything* to be escaped to render, so we do that instead of just the `#` - https://developer.microsoft.com/en-us/microsoft-edge/platform/issues/7157459/
  */
  background-image: url('data:image/svg+xml;utf8,%3Csvg%20xmlns%3D%22http%3A//www.w3.org/2000/svg%22%20width%3D%2240%22%20height%3D%2240%22%20viewBox%3D%22-10%20-18%20100%20135%22%3E%3Ccircle%20cx%3D%2250%22%20cy%3D%2250%22%20r%3D%2250%22%20fill%3D%22none%22%20stroke%3D%22%23ededed%22%20stroke-width%3D%223%22/%3E%3C/svg%3E');
  background-repeat: no-repeat;
  background-position: center left;
}
.todo-list li .toggle:checked + label {
  background-image: url('data:image/svg+xml;utf8,%3Csvg%20xmlns%3D%22http%3A//www.w3.org/2000/svg%22%20width%3D%2240%22%20height%3D%2240%22%20viewBox%3D%22-10%20-18%20100%20135%22%3E%3Ccircle%20cx%3D%2250%22%20cy%3D%2250%22%20r%3D%2250%22%20fill%3D%22none%22%20stroke%3D%22%23bddad5%22%20stroke-width%3D%223%22/%3E%3Cpath%20fill%3D%22%235dc2af%22%20d%3D%22M72%2025L42%2071%2027%2056l-4%204%2020%2020%2034-52z%22/%3E%3C/svg%3E');
}
.todo-list li label {
  word-break: break-all;
  padding: 15px 15px 15px 60px;
  display: block;
  line-height: 1.2;
  transition: color 0.4s;
}
.todo-list li.completed label {
  color: #d9d9d9;
  text-decoration: line-through;
}
.todo-list li .destroy {
  display: none;
  position: absolute;
  top: 0;
  right: 10px;
  bottom: 0;
  width: 40px;
  height: 40px;
  margin: auto 0;
  font-size: 30px;
  color: #cc9a9a;
  margin-bottom: 11px;
  transition: color 0.2s ease-out;
}
.todo-list li .destroy:hover {
  color: #af5b5e;
}
.todo-list li .destroy:after {
  content: '×';
}
.todo-list li:hover .destroy {
  display: block;
}
.todo-list li .edit {
  display: none;
}
.todo-list li.editing:last-child {
  margin-bottom: -1px;
}
.footer {
  color: #777;
  padding: 10px 15px;
  height: 20px;
  text-align: center;
  border-top: 1px solid #e6e6e6;
}
.footer:before {
  content: '';
  position: absolute;
  right: 0;
  bottom: 0;
  left: 0;
  height: 50px;
  overflow: hidden;
  box-shadow: 0 1px 1px rgba(0, 0, 0, 0.2),
              0 8px 0 -3px #f6f6f6,
              0 9px 1px -3px rgba(0, 0, 0, 0.2),
              0 16px 0 -6px #f6f6f6,
              0 17px 2px -6px rgba(0, 0, 0, 0.2);
}
.todo-count {
  float: left;
  text-align: left;
}
.todo-count strong {
  font-weight: 300;
}
.filters {
  margin: 0;
  padding: 0;
  list-style: none;
  position: absolute;
  right: 0;
  left: 0;
}
.filters li {
  display: inline;
}
.filters li a {
  color: inherit;
  margin: 3px;
  padding: 3px 7px;
  text-decoration: none;
  border: 1px solid transparent;
  border-radius: 3px;
}
.filters li a:hover {
  border-color: rgba(175, 47, 47, 0.1);
}
.filters li a.selected {
  border-color: rgba(175, 47, 47, 0.2);
}
.clear-completed,
html .clear-completed:active {
  float: right;
  position: relative;
  line-height: 20px;
  text-decoration: none;
  cursor: pointer;
}
.clear-completed:hover {
  text-decoration: underline;
}
.info {
  margin: 65px auto 0;
  color: #bfbfbf;
  font-size: 10px;
  text-shadow: 0 1px 0 rgba(255, 255, 255, 0.5);
  text-align: center;
}
.info p {
  line-height: 1;
}
.info a {
  color: inherit;
  text-decoration: none;
  font-weight: 400;
}
.info a:hover {
  text-decoration: underline;
}
/*
  Hack to remove background from Mobile Safari.
  Can't use it globally since it destroys checkboxes in Firefox
*/
@media screen and (-webkit-min-device-pixel-ratio:0) {
  .toggle-all,
  .todo-list li .toggle {
    background: none;
  }
  .todo-list li .toggle {
    height: 40px;
  }
}
@media (max-width: 430px) {
  .footer {
    height: 50px;
  }
  .filters {
    bottom: 10px;
  }
}

vue_todo案例超详细讲解(可跟做练手项目)（二）

🔥1.4_todo案例-底部统计

🔥1.5_todo案例-数据切换

🔥1.6_todo案例-清空已完成

🔥1.7_todo案例-数据缓存

🔥1.8_todo案例-全选功能

🔥base.css

🔥index.css

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vue_todo案例超详细讲解(可跟做练手项目)（二）

🔥1.4_todo案例-底部统计

🔥1.5_todo案例-数据切换

🔥1.6_todo案例-清空已完成

🔥1.7_todo案例-数据缓存

🔥1.8_todo案例-全选功能

🔥base.css

🔥index.css

热门文章

最新文章

相关课程

相关电子书

相关实验场景