【微信小程序项目实战】TodoList-项目主体搭设(2)

JS 部分

为便于分析各个组件的相互作用与原理，故先从 JS 入手，而后再完善 HTML 部分

以下所有代码（除了 import 导包语句）都写在 todo.js 的 Page({}) 对象内

数据 data

作为一款小而精的 todolist 小程序，我们仅需下方五个属性即可解决所有代码逻辑

1. inputValue 双向绑定输入框内容
2. todoList 当前的 todo 表
3. currentUndo 当前未完成的待办事项数
4. allComplete 事项是否全部完成
5. isFocus 用于搜索框自动获取焦点

data: {inputValue: '',todoList: [],currentUndo: 0,allComplete: false,isFocus:false},

onShow

由于我们没有在 app.json 中设置总标题，故在每个页面打开后，最好都在 onShow 钩子里面显式指定当前页面标题

// 进入此页面时，自动设置好标题onShow: function () {wx.setNavigationBarTitle({title: 'Todo待办事项'})},

输入框双向绑定

由于微信小程序 功能太少太烂 ，特别是仅仅提供了单向绑定，而不像 vue 还有 v-model 执行双向绑定；

所有这里需要开发者自行实现双向绑定功能，具体流程即：监听输入框内容，内容发生改变触发回调函数修改对应的值，而通过单向绑定，实现值的动态变化

// 输入框双向绑定处理inputChange(e) {this.setData({// e.detail.value可视为一种固定写法，可以从input类型的组件获取其值inputValue: e.detail.value})},

保存与读取

代码不难理解，即我们需要在每次对 todo 进行增删后，都自带保存数据到本地，这样子下次开启小程序就可直接读取数据了

onLoad 回调保证页面加载时自动从内存读取 todolist 数据

// 保存todos到本地内存saveTodos() {wx.setStorageSync('todo_list', this.data.todoList)},// 加载todos列表loadTodos() {let todos = wx.getStorageSync('todo_list')if (todos) {let undo = todos.filter((item) => {return !item.complete}).lengththis.setData({todoList: todos,currentUndo: undo})}console.log(todos);},// 页面加载钩子调用loadTodosonLoad() {this.loadTodos()},

添加新的待办事项

添加新待办事项的代码逻辑

// 将新的待办事项添加到栏内addTodo() {// 如果编辑框文本为空或者仅有空格的话，不予添加if (!this.data.inputValue || !this.data.inputValue.trim()) return// 每次都需要单独取出todolist然后push新的内容进去，最后setdata，你可以将其当做固定套路let todos = this.data.todoListtodos.push({title: this.data.inputValue,complete: false})this.setData({inputValue: "",todoList: todos,currentUndo: this.data.currentUndo + 1,   // 添加新待办，未完成数+1isFocus:true  // 添加完一个待办后，自动令编辑框获得焦点，省去客户重复点击过程})// 每次修改完毕都必须保存一下！this.saveTodos()},

完成待办事项

请注意此处 complete 状态的设置：点击一次完成事项，再点击一次取消完成变为待办，此时就需要对 complete 做出判断，以动态增减 currentUndo 的数值量

// 点击完成单个事项toggleTodo(e) {let index = e.currentTarget.dataset.indexlet todos = this.data.todoListtodos[index].complete = !todos[index].completethis.setData({todoList: todos,currentUndo: this.data.currentUndo + (todos[index].complete ? -1 : 1),})this.saveTodos()},// 选中全部的待办事项toggleAllTodos() {this.data.allComplete = !this.data.allCompletelet todos = this.data.todoListtodos.forEach(i => {i.complete = this.data.allComplete})this.setData({todoList: todos,currentUndo: this.data.allComplete ? 0 : todos.length})this.saveTodos()},

删除待办事项

删除单个待办事项的方法为通过索引找到该 todo，并使用 splice 删去，之后更新数据即可

删除多个待办事项时需要配合 foreach 方法

// 删除单个待办事项removeTodo(e) {let index = e.currentTarget.dataset.indexlet todos = this.data.todoListlet remove = todos.splice(index, 1)[0]this.setData({todoList: todos,currentUndo: this.data.currentUndo - (remove.complete ? 0 : 1)})this.saveTodos()},// 删除选中项removeTodos(e) {let todos = this.data.todoListlet remain = []todos.forEach(i => {if (!i.complete) remain.push(i)})this.setData({todoList: remain})this.saveTodos()// wx自带的手机振动接口，vibrateShort表示振动15mswx.vibrateShort()},

WXML

顶部输入框

这里涉及到的 t-input 配置项可以自行前往官网查询 API，这里不做过多解释
bind:change、bind:blur、bind:enter 分别表示 内容改变、是否获取焦点、按下回车键 后的回调函数

对于 t-button，如果他在 t-input 内部，则需使用 slot="suffix" 指定插槽来安放该 button

<!-- 顶部添加栏 -->
<view class="todo-input"><t-inputvalue="{{inputValue}}"style="border-radius: 12rpx;"clearableplaceholder="请输入事项名称"confirm-type="done"bind:change="inputChange"bind:blur="isFocus=!isFocus"bind:enter="addTodo"focus="{{isFocus}}"><t-buttonwx:if="{{inputValue}}"slot="suffix"theme="light"size="small"bindtap="addTodo">添加</t-button></t-input>
</view>

主体

block 配以 wx:if，实现状态页显示：当待办事项列表为空时，动态判断并显示 404 页面

<!-- 当todo列表存在数据时，渲染该页面 -->
<block wx:if="{{todoList.length}}"><view class="todo-control"><image bindtap="toggleAllTodos" src="../../image/pages/all.png"></image><text wx:if="{{currentUndo}}">待完成任务 {{currentUndo}}</text><imagebindtap="removeTodos"src="../../image/pages/delete.png"wx:if="{{todoList.length>currentUndo}}"></image></view><view class="todo-itembox"><viewclass="todo-items {{item.complete?'comp':''}}"wx:for="{{todoList}}"wx:key="index"data-index="{{index}}"bindtap="toggleTodo"><iconclass="checkbox"type="{{ item.complete ? 'success' : 'circle' }}"></icon><text class="title">{{ item.title }}</text><iconclass="remove"type="clear"size="16"catchtap="removeTodo"data-index=" {{index}} "/></view></view>
</block><!-- 当todo列表为空时，渲染该页面 -->
<block wx:else><view class="todo-empty"><image src="../../image/state/no-data.png"></image><view style="color: gray;">当前还没有待办事项哦~</view></view>
</block>

回到顶部按钮

<!-- 回到顶部悬浮按钮 -->
<!-- 判断当且仅当列表项多于6个时,才会显示该悬浮按钮 -->
<t-fab wx:if="{{todoList.length>6}}" icon="arrow-up" bind:click="fabBack2Top" />

CSS 部分由于不方便表述，故留到文末以源码的形式展现给大家

完整代码

JS

import Message from "tdesign-miniprogram/message/index";// pages/todo/todo.js
Page({data: {inputValue: "",todoList: [],currentUndo: 0,allComplete: false,isFocus: false,},// 进入此页面时，自动设置好标题onShow: function () {wx.setNavigationBarTitle({title: "Todo待办事项",});},// 输入框双向绑定处理inputChange(e) {this.setData({inputValue: e.detail.value,});},// 保存todos到本地内存saveTodos() {wx.setStorageSync("todo_list", this.data.todoList);},// 加载todos列表loadTodos() {let todos = wx.getStorageSync("todo_list");if (todos) {let undo = todos.filter((item) => {return !item.complete;}).length;this.setData({todoList: todos,currentUndo: undo,});}console.log(todos);},// 页面加载钩子调用loadTodosonLoad() {this.loadTodos();},// 将新的待办事项添加到栏内addTodo() {if (!this.data.inputValue || !this.data.inputValue.trim()) return;let todos = this.data.todoList;todos.push({title: this.data.inputValue,complete: false,});this.setData({inputValue: "",todoList: todos,currentUndo: this.data.currentUndo + 1,isFocus: true,});this.saveTodos();},// 悬浮按钮回到顶部fabBack2Top() {wx.pageScrollTo({duration: 500,scrollTop: 0,});},// 点击完成单个事项toggleTodo(e) {let index = e.currentTarget.dataset.index;let todos = this.data.todoList;todos[index].complete = !todos[index].complete;this.setData({todoList: todos,currentUndo: this.data.currentUndo + (todos[index].complete ? -1 : 1),});this.saveTodos();},// 选中全部的待办事项toggleAllTodos() {this.data.allComplete = !this.data.allComplete;let todos = this.data.todoList;todos.forEach((i) => {i.complete = this.data.allComplete;});this.setData({todoList: todos,currentUndo: this.data.allComplete ? 0 : todos.length,});this.saveTodos();},// 删除单个待办事项removeTodo(e) {let index = e.currentTarget.dataset.index;let todos = this.data.todoList;let remove = todos.splice(index, 1)[0];this.setData({todoList: todos,currentUndo: this.data.currentUndo - (remove.complete ? 0 : 1),});this.saveTodos();},// 删除选中项removeTodos(e) {let todos = this.data.todoList;let remain = [];todos.forEach((i) => {if (!i.complete) remain.push(i);});this.setData({todoList: remain,});if (this.data.currentUndo === 0) {Message.success({context: this,content: "完成所有任务，休息一下吧！",duration: 2000,offset: [20, 32],closeBtn: true,});}this.saveTodos();wx.vibrateShort();},
});

WXML

<view class="todo-container"><!-- 顶部添加栏 --><view class="todo-input"><t-inputvalue="{{inputValue}}"style="border-radius: 12rpx;"clearableplaceholder="请输入事项名称"confirm-type="done"bind:change="inputChange"bind:blur="isFocus=!isFocus"bind:enter="addTodo"focus="{{isFocus}}"><t-buttonwx:if="{{inputValue}}"slot="suffix"theme="light"size="small"bindtap="addTodo">添加</t-button></t-input></view><!-- 当todo列表存在数据时，渲染该页面 --><block wx:if="{{todoList.length}}"><view class="todo-control"><image bindtap="toggleAllTodos" src="../../image/pages/all.png"></image><text wx:if="{{currentUndo}}">待完成任务 {{currentUndo}}</text><imagebindtap="removeTodos"src="../../image/pages/delete.png"wx:if="{{todoList.length>currentUndo}}"></image></view><view class="todo-itembox"><viewclass="todo-items {{item.complete?'comp':''}}"wx:for="{{todoList}}"wx:key="index"data-index="{{index}}"bindtap="toggleTodo"><iconclass="checkbox"type="{{ item.complete ? 'success' : 'circle' }}"></icon><text class="title">{{ item.title }}</text><iconclass="remove"type="clear"size="16"catchtap="removeTodo"data-index=" {{index}} "/></view></view></block><!-- 当todo列表为空时，渲染该页面 --><block wx:else><view class="todo-empty"><image src="../../image/state/no-data.png"></image><view style="color: gray;">当前还没有待办事项哦~</view></view></block><!-- 回到顶部悬浮按钮 --><!-- 判断当且仅当列表项多于6个时,才会显示该悬浮按钮 --><t-fabwx:if="{{todoList.length>6}}"icon="arrow-up"bind:click="fabBack2Top"/>
</view>

WXSS

.todo-container {margin: 0;padding: 0;width: 100vw;min-height: 100vh;background-color: #ededed;display: flex;flex-direction: column;position: relative;
}.todo-input {margin: 12rpx 32rpx;display: flex;flex-direction: row;justify-content: space-between;
}.todo-empty {display: flex;flex-direction: column;justify-content: center;align-items: center;height: 100%;
}
.todo-empty image {width: 450rpx;height: 450rpx;
}/* 悬浮按钮 */
.fab {position: absolute;right: 0;bottom: 0;
}/* 多选操纵栏 */
.todo-control {display: flex;flex-direction: row;justify-content: space-between;align-items: center;height: 80rpx;margin: 12rpx 32rpx;
}
.todo-control image {height: 70rpx;width: 70rpx;
}/* todo项目展示 */
.todo-items {border-radius: 8rpx;height: 120rpx;background-color: white;margin: 10rpx 32rpx;display: flex;flex-direction: row;justify-content: space-between;align-items: center;
}
.comp {background-color: lightgray;
}
.todo-items .checkbox {margin-left: 24rpx;
}
.todo-items .title {min-width: 70%;max-width: 70%;text-overflow: ellipsis;overflow: hidden;white-space: nowrap;
}
.todo-items .remove {margin-right: 24rpx;
}