详解小程序设置缓存并且不覆盖原有数据

Page({ /**  * 页面的初始数据  */ data: { }, submit: function (event) {  var writecomment = event.detail.value.writecomment;  console.log(event);  var pages = getCurrentPages();  /***得到页面有两个，一个是总页面，一个是写的页面，我们需要的是总页面 */  var page = pages[2];  var commentlist = page.data.commentlist;//commentlist是另一个页面设置的数组，这里是取得那个页面定义的commentlist  /***获取总页面data里面的数组 */  if (event.detail.value.writecomment != '') {   commentlist.push(writecomment); /***把新的内容放入数组中去，然后更新 */   page.setData({    commentlist: commentlist,   })  }//这是缓存设置 wx.setStorage({  key: 'commentStorage',//key的值只是一个名称，可以自己设置  data: commentlist,//data指的是我们要放入缓存的数值，如果是固定的数据要用“”括起来，如果是变量就直接放变量的值 })  console.log(commentlist);//这是为了更好观察我自己设置的输出语句，可以不用管  wx.navigateBack({}) /***点击完成后跳转回到上一个页面 */ },   onLoad: function (options) { },})

<!--pages/comment/writecomment/writecomment.wxml--><view class='write-group'> <form bindsubmit='submit'>  <!-- 文本输入框 -->  <view class='textarea-position'>   <textarea name='writecomment' placeholder='请输入内容！' maxlength='-1' auto-height="true">   </textarea>  </view>  <!-- maxlength='-1'不限制输入字符长度，auto-height="true"输入框可以自动变化大小 -->    <view class='btn-position'>   <button type='primary' form-type='submit'>完成</button>  </view> </form></view>

//这是对应的样式文件/* pages/comment/writecomment/writecomment.wxss *//* 最外层样式 */.write-group{ width: 100%; height: 1254rpx;}/* 输入框层样式 */.textarea-group{ padding: 10rpx; width: 98%; height: 85%; overflow: scroll;}/* 提交表格样式 */.form{ width: 100%; height: 100%;}textarea {cursor:auto;width:95%;height:150px;display:block;position:relative;padding: 10rpx;} .chooseImg{ width:20%; height: 70rpx;}.image{ width: 170rpx; height: 50rpx;}.image-btn-group{ width: 200rpx; height: 50rpx; display: flex; justify-content: space-between;}.image-btn{ width: 100rpx; height: 100rpx; display: flex; justify-content: space-between;}.text{ font-size: 24rpx; height: 50rpx; width: 100rpx;}.textarea-position{ overflow: scroll; height: 1050rpx; width: 100%;}.btn-position{ display: fixed; margin-bottom: 5rpx;}.title { width: 100%; height: 96rpx; line-height: 96rpx; font-size: 28rpx; color: #989898;}.upload { width: 100%; margin-bottom: 30rpx;              }.uploadImgBox { width: 212rpx; height: 144rpx; margin-right: 33rpx; margin-bottom: 10rpx; position: relative; background: #fff;}.uploadImgBox:nth-child(3n) { margin-right: 0;}.uploadPhoto { width: 212rpx; height: 144rpx;}.closeImg { width: 30rpx; height: 30rpx; border-radius: 50%; position: absolute; right: 5rpx; top: 5rpx;} .service { width: 100%; height: 208rpx; border-top: 1rpx solid #ece9e9; border-bottom: 1rpx solid #ece9e9; line-height: 30rpx; font-size: 26rpx; padding-top: 20rpx;}.service textarea { width: 100%; height: 100%;}

// pages/comment/commentlist/commentlist.jsPage({ /**  * 页面的初始数据  */ data: {  commentlist: [],//设置缓存的那个数组在这里定义的 }, writecomment: function (event) {  wx.navigateTo({   url: '/pages/comment/writecomment/writecomment',//在页面函数的按钮  }) }, /**  * 生命周期函数--监听页面加载  */ onLoad: function (options) {  var that = this;  var commentlist = that.data.commentlist//取得commentlist //获取缓存数据  wx.getStorage({   key: 'commentStorage',//这个key值要与writecomment.js里面设置的key一致   success: function (res) {    for (let i in res.data) {     that.data.commentlist.push(res.data[i])//这里是把缓存数据放入到数组commentlist 里面    };    that.setData({     commentlist: commentlist//刷新commentlist     })   },  })  that.setData({   options: options,  }); }, /**  * 生命周期函数--监听页面初次渲染完成  */ onReady: function () { }, /**  * 生命周期函数--监听页面显示  */ onShow: function () { }, /**  * 生命周期函数--监听页面隐藏  */ onHide: function () { }, /**  * 生命周期函数--监听页面卸载  */ onUnload: function () { }, /**  * 页面相关事件处理函数--监听用户下拉动作  */ onPullDownRefresh: function () { }, /**  * 页面上拉触底事件的处理函数  */ onReachBottom: function () { }, /**  * 用户点击右上角分享  */ onShareAppMessage: function () { }})

<!--pages/comment/commentlist/commentlist.wxml--><view class='p-list-group'> <view class='p-list-group-more'>  <!-- 输出输入页面输入的内容 -->  <view class='p-list' wx:for='{{commentlist}}' wx:key="{{index}}">{{item}}</view> </view>  <!-- 写计划按钮与搜索按钮 --> <view class='cardclass'>  <button class='btn-search' open-type='' bindtap='search' style="background-image:url(/images/plan/icon-search-1.png);"> 搜索</button>  <!-- 写计划 --> <button class='btn-write' open-type='primary' bindtap='writecomment' style="background-image:url(/images/plan/icon-pen-1.png);">评论 </button> </view></view>

/* pages/comment/commentlist/commentlist.wxss */.p-list-group{ margin-right: 10rpx; margin-left: 10rpx; overflow: scroll; width:98%; right:1rpx;}.p-list-group-more{ right:1rpx; overflow: scroll; height:1000rpx; width:100%; margin-top: 10rpx;}.p-list{ text-overflow: ellipsis;/***文本太长显示省略号*/ overflow: scroll; width:99%; border: 1px solid #ccc; margin-right: 10rpx; margin-bottom: 20rpx; height: 100rpx;}.btn-search{ position: fixed; bottom: 5rpx; width: 30%; background-size: 45rpx 45rpx; background-repeat:no-repeat;}.btn-write{ position: fixed; bottom: 5rpx; width: 30%; background-size: 45rpx 45rpx; background-repeat:no-repeat; right:10rpx;}.cardclass{ display:flex; font-size:18rpx; justify-content: space-between; bottom: 5rpx; height:25rpx;}.image-list{ width:40rpx; height:30%;}