实战：手机控制esp8266

0.配置

arduino下位机

#include <ESP8266WiFi.h>#include <PubSubClient.h>WiFiClient espClient;PubSubClient client(espClient);const char* wifissid = \"CMCC-wenzheng\"; //改成自己家wificonst char* password = \"wenzhengspace666\"; //改成自己家wificonst char* mqtt_server = \"106.13.150.28\";const char* mqtt_id = \"565402462_ESP\";   //改成自己的QQ号+_ESPconst char* Mqtt_sub_topic = \"565402462_ESP\";   //改成自己的QQ号+_ESPconst char* Mqtt_pub_topic = \"565402462\";  //  上报消息给  手机APP的TOPIC  //改成自己的QQ号long lastMsg = 0; //定时用的

app上位机

private String host = \"tcp://106.13.150.28:1883\";private String userName = \"android\";private String passWord = \"android\";private String mqtt_id = \"565402462\"; //定义成自己的QQ号  切记！不然会掉线！！！private String mqtt_sub_topic = \"565402462\"; //为了保证你不受到别人的消息  哈哈private String mqtt_pub_topic = \"565402462_ESP\"; //为了保证你不受到别人的消息  哈哈  自己QQ好后面加 _PCprivate int led_flag =1;

1.手机控制esp8266小灯亮灭

app上位机

image_1 =findViewById(R.id.image_1);image_1.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {if(led_flag == 0){publishmessageplus(mqtt_pub_topic,\"{\\\"set_led\\\":1}\");led_flag =1;}else{publishmessageplus(mqtt_pub_topic,\"{\\\"set_led\\\":0}\");led_flag =0;}}

arduino下位机

arduino下位机void callback(char* topic, byte* payload, unsigned int length) {String msg=\"\";String LED_set = \"\";Serial.print(\"Message arrived [\");Serial.print(topic);Serial.print(\"] \");for (int i = 0; i < length; i++){msg+= (char)payload[i];}Serial.println(msg);if(msg.indexOf(\"led\"))  //判断是否是要设置LED灯{//取出LED_set数据 并执行LED_set = msg.substring(msg.indexOf(\"led\\\":\")+5,msg.indexOf(\"}\")); //起点，终点digitalWrite(2,!LED_set.toInt());}}

2.esp8266上报adc模拟量

app上位机处理数据

case 3:  //MQTT 收到消息回传   UTF8Buffer msg=new UTF8Buffer(object.toString());String T_val = msg.obj.toString().substring(msg.obj.toString().indexOf(\"temperature\\\":\")+13,msg.obj.toString().indexOf(\"}\"));String text_val = \"温度：\"+T_val;text_test.setText(text_val);break;

arduino下位机

void loop() {if (!client.connected()) {reconnect();}client.loop();long now = millis();if (now - lastMsg > 2000){lastMsg = now;String json = \"{\\\"temperature\\\":\"+String(analogRead(A0))+\"}\";//温度上报使用ADC模拟随机数client.publish(Mqtt_pub_topic,json.c_str());}}

注意：

• String json = “{“temperature”:”+String(analogRead(A0))+\”}\”;
  之所以用很多转义符“\\”是因为：
  转义字符\”\”的使用技巧（谢谢这个博主的回答）