uni.app开发物联网小程序

1.当切换页面的时候&＃xff0c;容易与mqtt服务器断开连接&＃xff0c;并报错

原因&＃xff1a;在onLoad事件中&＃xff0c;获取参数的时候使用异步获取&＃xff0c;但是在事件里面还使用了这个参数&＃xff0c;导致mqtt发布的时候&＃xff0c;发了一个空主题&＃xff0c;导致连接被断开&＃xff0c;然后报异常&＃xff0c;错误代码如下

onLoad() {uni.getStorage({key: &＃39;opened_dev&＃39;,success:res&＃61;>{this.phone &＃61; res.data.phone;this.dev_id &＃61; res.data.dev_id;this.dev_name &＃61; res.data.name;this.dev_note &＃61; res.data.note;this.regist_time &＃61; res.data.regist_time;this.dev_type &＃61; res.data.type;this.img_src &＃61; res.data.dev_img;}});var globalData &＃61; getApp().globalData;globalData.on_mqtt_msg(this.msg_handler);//设置接收this.send_cmd(0,0);//获取全部信息this.timer_id &＃61; setInterval(this.get_dht11,3000);},


修改后&＃xff1a;

onLoad() {uni.getStorage({key: &＃39;opened_dev&＃39;,success:res&＃61;>{this.phone &＃61; res.data.phone;this.dev_id &＃61; res.data.dev_id;this.dev_name &＃61; res.data.name;this.dev_note &＃61; res.data.note;this.regist_time &＃61; res.data.regist_time;this.dev_type &＃61; res.data.type;this.img_src &＃61; res.data.dev_img;var globalData &＃61; getApp().globalData;globalData.on_mqtt_msg(this.msg_handler);//设置接收this.send_cmd(0,0);//获取全部信息this.timer_id &＃61; setInterval(this.get_dht11,3000);}});},


在pub的时候 加验证

mqtt_pub: function(topic, msg) { //发布消息if(topic &＃61;&＃61; null || topic &＃61;&＃61; "")return;//topic最容易出现空的问题 会导致Uncaught (in promise) thirdScriptError 小程序的现象是断开连接重连 然后闪一下if(msg &＃61;&＃61; null)return;if (client && is_connected){client.publish(topic, msg);}console.log("mqtt_pub," &＃43; "topic&＃61;" &＃43; topic &＃43; ",msg&＃61;"&＃43;msg);
},