添加前后屏指令交互常量js文件；支付成功页添加指令传递&接收逻辑；

const/actioncmd.js

+//发送打印结果
+export const ACTION_PRINT_RESULT = "ACTION_PRINT_RESULT";
+
+//发送重打印指令
+export const ACTION_REPRINT = "ACTION_REPRINT";
\ No newline at end of file

pages/paysuccess/paysuccess.js

+import { ACTION_PRINT_RESULT } from '../../const/actioncmd'
+import { ACTION_REPRINT } from '../../const/actioncmd'
+
 Page({
   data: {
     orderPriceYuan: "--.--",
@@ -67,7 +70,7 @@ Page({
       //循环取出商品数据
       cmds.push(printer.setAlign(printer.ALIGN_LEFT));
       cmds.push(printer.printText(this.data.goodsList[i].name));
-      cmds.push(printer.printTwoText(this.data.goodsList[i].barcode,this.data.goodsList[i].quantity+""));
+      cmds.push(printer.printTwoText(this.data.goodsList[i].barcode, this.data.goodsList[i].quantity + ""));
     }
     cmds.push(printer.setAlign(printer.ALIGN_LEFT));
     cmds.push(printer.printDivide("-"));
@@ -87,9 +90,12 @@ Page({
   printCallback(res) {
     //通知后屏打印结果
     my.ix.sendBuddyMessage({
-      target: "****************",
       // 填入目标小程序的 AppID
-      data: res,
+      target: "****************",
+      data: {
+        action: ACTION_PRINT_RESULT,
+        data: res
+      },
       success: (res) => {
         console.info(`sendBuddyMessage success: ${JSON.stringify(res)}`);
       },
@@ -118,9 +124,9 @@ Page({
     my.ix.onBuddyMessage({
       success: (res) => {
         console.info(`onBuddyMessage success: ${JSON.stringify(res)}`);
-        if ("") {
+        if (res.action == ACTION_REPRINT) {
           //重新打印 
-
+          this.print();
         } else {
           //未知指令
         }