Fix title display.

pages/category/category.js

@@ -2,13 +2,14 @@ const product = require('../../utils/product.js')
 
 Page({
   data: {
+    title: '',
     items: []
   },
 
   onLoad: function(params) {
     var that = this
-    wx.setNavigationBarTitle({
-      title: params.type
+    this.setData({
+      title: '巴爷供销社 - ' + params.type
     })
     product.getCategories(params.type, function(result) {
       var data = getApp().store.sync(result.data)
@@ -24,6 +25,10 @@ Page({
     })
   },
 
+  onReady() {
+    wx.setNavigationBarTitle({ title: this.data.title })
+  },
+
   bindTapProduct: function(e) {
     var that = this
     var cartItems = wx.getStorageSync('cartItems') || []