由于小程序一次只能上传一张图片，循环上传多张图片
核心代码如下：

<view class="pic">
        <view class="one" bindtap="upload" data-img="img1">
            <image class="upload_img1" src="/img/phone_upload.png"></image>
            <view>点击上传手持身份证</view>
            <image class="myimg" src="{{img1}}"></image>
        </view>
        <view class="one"></view>
        <view class="one" bindtap="upload" data-img="img2">
            <image class="upload_img1" src="/img/phone_upload.png"></image>
            <view>点击上传带头像一面</view>
            <image class="myimg" src="{{img2}}"></image>
        </view>
        <view class="one" bindtap="upload"  data-img="img3">
            <image class="upload_img1" src="/img/phone_upload.png"></image>
            <view>点击上传带国徽一面</view>
            <image class="myimg" src="{{img3}}"></image>
        </view>
    </view>

//上传图片
    upload: function (e) {
        var that = this;
        var img = e.currentTarget.dataset.img;
        wx.chooseImage({
            count: 1, // 默认9
            sizeType: ['original', 'compressed'], // 可以指定是原图还是压缩图，默认二者都有
            sourceType: ['album', 'camera'], // 可以指定来源是相册还是相机，默认二者都有
            success: res => {
                wx.showToast({
                    title: '正在上传...',
                    icon: 'loading',
                    mask: true,
                    duration: 1000
                })
                // 返回选定照片的本地文件路径列表，tempFilePath可以作为img标签的src属性显示图片
                let tempFilePaths = res.tempFilePaths[0];
                if (img == "img1") {
                    that.setData({ img1: tempFilePaths })
                    that.my_img(0, tempFilePaths);
                } else if (img == "img2") {
                    that.setData({ img2: tempFilePaths })
                    that.my_img(1, tempFilePaths);
                } else if (img == "img3") {
                    that.setData({ img3: tempFilePaths })
                    that.my_img(2, tempFilePaths);
                } else if (img == "img4") {
                    that.setData({ img4: tempFilePaths })
                    that.my_img(3, tempFilePaths);
                } else if (img == "img5") {
                    that.setData({ img5: tempFilePaths })
                    that.my_img(4, tempFilePaths);
                }
                console.log(tempFilePaths)
            }
        })
    },
    my_img: function (i, content) {
        var new_img = this.data.imgArr;
        new_img[i] = content;
        this.setData({
            imgArr: new_img
        })
    }

uploadAll: function (userId) {
        var uploadImgCount = 0;
        var uploadArr = this.data.imgArr;
        var url = app.globalData.api + 'wechat/uploadFile';
        for (var i = 6; i >=0; i--) {
            var j = i+1;
            if (uploadArr[i]) {
                wx.uploadFile({
                    url: url,
                    filePath: uploadArr[i],
                    name: 'file',
                    formData: {
                        userId:userId,
                        type:j
                    },
                    header: {"Content-Type": "multipart/form-data"},
                    success: function (res) {
                        uploadImgCount++;
                        //如果是最后一张,则隐藏等待中
                        if (uploadImgCount == 7) {
                            console.log("success")
                            wx.hideToast();
                            //上传所有图片
                            app.jump("/pages/d_home/d_home");
                        }
                    },
                    fail: function (res) {
                        wx.hideToast();
                        wx.showModal({
                            title: '错误提示',
                            content: '上传图片失败',
                            showCancel: false,
                            success: function (res) { }
                        })
                    }
                });
            } else {
                uploadImgCount++;
            }
        }
        
    },