feat：兼容直播间封面为空

pages/shareRoom/shareRoom.js

@@ -74,7 +74,7 @@ Page({
     }
 
     this.setData({
-      shared_img: data.appListPicUrl,
+      shared_img: data.appListPicUrl|| 'https://plaza.4dkankan.com/statics/img/pic_bg@2x.png',
       layoutHeight: wx.getSystemInfoSync().windowHeight - 170
     })
 

pages/shared/shared.js

@@ -34,7 +34,7 @@ Page({
     this.shareCodeImg = data.shareWxQrCode
 
     this.setData({
-      shared_img: data.appListPicUrl,
+      shared_img: data.appListPicUrl || 'https://plaza.4dkankan.com/statics/img/pic_bg@2x.png',
       layoutHeight: wx.getSystemInfoSync().windowHeight - 170
     })
     const query = wx.createSelectorQuery()
@@ -94,7 +94,7 @@ Page({
   },
   savePhoto () {
     wx.saveImageToPhotosAlbum({
-      filePath: this.data.img_url,
+      filePath: this.data.img_url ,
       success(res) {
         wx.showModal({
           title: '图片保存成功',