1 onShow: function() {
 2 
 3    4 
 5     let _this = this;
 6     wx.request({
 7       url: \'https://api.weixin.qq.com/cgi-bin/token\',
 8       data: {
 9         grant_type: \'client_credential\',
10         appid: \'填写appid\', //不能缺少
11         secret: \'填写app秘钥\' //不能缺少
12       },
13       success: function(res) {
14 
15         wx.request({
16           url: \'https://api.weixin.qq.com/wxa/getwxacodeunlimit?access_token=\' + res.data.access_token,
17           data: {
18             // "path": "pages/index/index", 默认跳转到主页:pages/index/index，可指定
19             "width": 430,
20             "scene": wx.getStorageSync(\'uid\')
21           },
22           responseType: \'arraybuffer\', // 这行很重要,转为二进制数组
23           header: {
24             \'content-type\': \'application/json;charset=utf-8\'
25           },
26           method: \'POST\',
27           success(res) {
28             //转为base64
29             let bin64 = wx.arrayBufferToBase64(res.data);
30 
31             _this.setData({
32 　　　　　　　　　　//base 64设置到页面上
33               img: "data:image/png;base64," + bin64
34             });
35           }
36         })
37       }
38     })
39   },