微信小程序实现图片拖拽调换位置效果 -- 开箱即用

在编写类似发布朋友圈功能的功能时，需要实现图片的拖拽排序，删除图片等功能。

一、效果展示

**博主的小程序首页也采用了该示例代码，可以在威信中搜索：我的百宝工具箱

二、示例代码

1.1、在自己的小程序中创建组件

1.2、组件源码

wxml代码

bash 复制代码

<view class="drag-container">
  <view wx:for="{{dragImgList}}" wx:key="id"
  style="transform: translate({{index === currentIndex ? tranX : item.tranX}}px, {{index === currentIndex ? tranY : item.tranY}}px); z-index: {{index === currentIndex ? 10 : 1}}; width: {{previewSize}}px; height: {{previewSize}}px;" 
  class="drag-item drag-item-transition" 
  mark:index="{{index}}" mark:key="{{item.key}}" 
  catch:longpress="longPress" 
  catch:touchmove="touchMove" 
  catch:touchend="touchEnd">
    <image class="drag-item-img" src="{{item.src}}" mode="aspectFill"/>
    <view catch:tap="deleteImg" mark:key="{{item.key}}" class="drag-item-delete">
      <view class="drag-item-delete_default" style="{{deleteStyle}}">x</view>
    </view>
  </view>
  <view bindtap="uploadImage" class="drag-item drag-upload" hidden="{{dragImgList.length >= maxCount}}" style="transform: translate({{uploadPosition.tranX}}px, {{uploadPosition.tranY}}px); width: {{previewSize}}px; height: {{previewSize}}px;">
    <text>+</text>
  </view>
</view>

wxss代码

css 复制代码

.drag-container {
  position: relative;
  left: 30rpx;
  top: 20rpx;
}

.drag-item {
  position: absolute;
  top: 0;
  left: 0;
}

.drag-item-transition {
  transition: transform 0.1s
}

.drag-item-img {
  width: 100%;
  height: 100%;
}

.drag-item-delete {
  position: absolute;
  top: 0;
  right: 0;
}

.drag-item-delete_default {
  display: flex;
  width: 21px;
  height: 15px;
  line-height: 10px;
  justify-content: center;
  background-color: rgba(0, 0, 0, 0.7);
  border-radius: 0 0 0 12px;
  color: #FEFEFE;
}

.drag-upload {
  display: flex;
  justify-content: center;
  align-items: center;
  border: 2px dashed silver;
  width: 100%;
  height: 100%;
  box-sizing: border-box;
  font-size: 70px;
}
.drag-upload text{
  margin-top: -20%;
  color: silver;
}

js代码

js 复制代码

Component({
  properties: {
    // 每个格子的大小 100*100
    previewSize: {
      type: Number,
      value: 100
    },
    // 默认图片列表
    defaultImgList: {
      type: Array,
      value: [],
      observer(t) {
        if (t?.length && !this.data.dragImgList.length) {
          const e = this.getDragImgList(t);
          this.setUploaPosition(e.length), this.setData({
            dragImgList: e
          })
        }
      }
    },
    // 最大个数
    maxCount: {
      type: Number,
      value: 9
    },
    // 每行列数
    columns: {
      type: Number,
      value: 3
    },
    // 每个格子之间的间隔
    gap: {
      type: Number,
      value: 9
    },
    deleteStyle: {
      type: String,
      value: ""
    }
  },
  data: {
    dragImgList: [],
    containerRes: {
      top: 0,
      left: 0,
      width: 0,
      height: 0
    },
    currentKey: -1,
    currentIndex: -1,
    tranX: 0,
    tranY: 0,
    uploadPosition: {
      tranX: 0,
      tranY: 0
    }
  },
  lifetimes: {
    ready() {
      this.createSelectorQuery().select(".drag-container").boundingClientRect((({
        top: t,
        left: e
      }) => {
        this.setData({
          "containerRes.top": t,
          "containerRes.left": e
        })
      })).exec()
    }
  },
  methods: {
    longPress(t) {
      const e = t.mark.index,
        {
          pageX: a,
          pageY: i
        } = t.touches[0],
        {
          previewSize: s,
          containerRes: {
            top: n,
            left: r
          }
        } = this.data;
      this.setData({
        currentIndex: e,
        tranX: a - s / 2 - r,
        tranY: i - s / 2 - n
      })
    },
    touchMove(t) {
      if (this.data.currentIndex < 0) return;
      const {
        pageX: e,
        pageY: a
      } = t.touches[0], {
        previewSize: i,
        containerRes: {
          top: s,
          left: n
        }
      } = this.data, r = e - i / 2 - n, o = a - i / 2 - s;
      this.setData({
        tranX: r,
        tranY: o
      });
      const h = t.mark.key,
        g = this.getMoveKey(r, o);
      h !== g && this.data.currentKey !== h && (this.data.currentKey = h, this.replace(h, g))
    },
    getMoveKey(t, e) {
      const {
        dragImgList: a,
        previewSize: i,
        columns: s
      } = this.data, n = (t, e) => {
        const a = Math.round(t / i);
        return a >= e ? e - 1 : a < 0 ? 0 : a
      }, r = s * n(e, Math.ceil(a.length / s)) + n(t, s);
      return r >= a.length ? a.length - 1 : r
    },
    replace(t, e) {
      const a = this.data.dragImgList;
      a.forEach((a => {
        t < e ? a.key > t && a.key <= e ? a.key-- : a.key === t && (a.key = e) : t > e && (a.key >= e && a.key < t ? a.key++ : a.key === t && (a.key = e))
      })), this.getListPosition(a)
    },
    getListPosition(t) {
      const {
        previewSize: e,
        columns: a,
        gap: i
      } = this.data, s = t.map((t => (t.tranX = (e + i) * (t.key % a), t.tranY = Math.floor(t.key / a) * (e + i), t)));
      this.setData({
        dragImgList: s
      }), this.updateEvent(s)
    },
    touchEnd() {
      this.setData({
        tranX: 0,
        tranY: 0,
        currentIndex: -1
      }), this.data.currentKey = -1
    },
    updateEvent(t) {
      const e = [...t].sort(((t, e) => t.key - e.key)).map((t => t.src));
      this.triggerEvent("updateImageList", {
        list: e
      })
    },
    async uploadImage() {
      let {
        dragImgList: t,
        maxCount: e
      } = this.data;
      try {
        const a = await wx.chooseMedia({
            count: e - t.length,
            mediaType: ["image"]
          }),
          i = this.getDragImgList(a?.tempFiles?.map((({
            tempFilePath: t
          }) => t)) || [], !1);
        t = t.concat(i), this.setUploaPosition(t.length), this.setData({
          dragImgList: t
        }), this.updateEvent(t)
      } catch (t) {
        console.log(t)
      }
    },
    getContainerRect(t) {
      const {
        columns: e,
        previewSize: a,
        maxCount: i,
        gap: s
      } = this.data, n = t === i ? t : t + 1, r = Math.ceil(n / e);
      return {
        width: e * a + (e - 1) * s,
        height: r * a + s * (r - 1)
      }
    },
    getDragImgList(t, e = !0) {
      let {
        dragImgList: a,
        previewSize: i,
        columns: s,
        gap: n
      } = this.data;
      return t.map(((t, r) => {
        const o = (e ? 0 : a.length) + r;
        return {
          tranX: (i + n) * (o % s),
          tranY: Math.floor(o / s) * (i + n),
          src: t,
          id: o,
          key: o
        }
      }))
    },
    setUploaPosition(t) {
      const {
        previewSize: e,
        columns: a,
        gap: i
      } = this.data, s = {
        tranX: t % a * (e + i),
        tranY: Math.floor(t / a) * (e + i)
      }, {
        width: n,
        height: r
      } = this.getContainerRect(t);
      this.setData({
        uploadPosition: s,
        "containerRes.width": n,
        "containerRes.height": r
      })
    },
    deleteImg(t) {
      const e = t.mark.key,
        a = this.data.dragImgList.filter((t => t.key !== e));
      a.forEach((t => {
        t.key > e && t.key--
      })), this.getListPosition(a), this.setUploaPosition(a.length)
    }
  }
});

json代码

bash 复制代码

{
  "component": true,
  "usingComponents":{}
}

1.3、在自己的小程序中新建page

1.4、新建page的源码

wxml代码

bash 复制代码

<view>
	<wxDragImg
    	defaultImgList="{{imgList}}"
		previewSize="{{120}}"
		maxCount="{{9}}"
		columns="{{3}}"
		gap="{{10}}"
    	bind:updateImageList="updateImageList">
  </wxDragImg>
</view>

js代码

js 复制代码

Page({
  data: {
    imgList: []
  },
  onLoad() {},
  updateImageList(e) {
    console.log(e)
  }
})

json代码

bash 复制代码

{
  "usingComponents": {
    "wxDragImg": "../wx-drag-img"
  }
}