编写安卓app接收esp8266的数据

要编写安卓app接收esp8266的数据，可以按照以下步骤进行：

1. 编写esp8266的代码，让它能够连接到WiFi并发送数据。可以使用Arduino IDE和ESP8266库来编写代码。以下是一个简单的示例：

#include <ESP8266WiFi.h>

const char* ssid = "YOUR_SSID"; //填写你的WiFi名称
const char* password = "YOUR_PASSWORD"; //填写你的WiFi密码
const char* host = "YOUR_HOST_ADDRESS"; //填写你的服务器地址

void setup() {
  Serial.begin(115200);
  delay(10);

  // 连接WiFi
  Serial.println();
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);
  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.println("");
  Serial.println("WiFi connected");

}

void loop() {
  // 发送数据
  Serial.print("connecting to ");
  Serial.println(host);

  WiFiClient client;
  const int httpPort = 80;
  if (!client.connect(host, httpPort)) {
    Serial.println("connection failed");
    return;
  }

  String url = "/data"; //填写你的数据接口路径
  Serial.print("Requesting URL: ");
  Serial.println(url);

  client.print(String("GET ") + url + " HTTP/1.1\r\n" +
               "Host: " + host + "\r\n" +
               "Connection: close\r\n\r\n");
  delay(500);

  // 读取服务器响应
  while (client.available()) {
    String line = client.readStringUntil('\r');
    Serial.print(line);
  }

  Serial.println();
  Serial.println("closing connection");
  delay(5000);
}

2. 在服务器上编写数据接口，用于接收esp8266发送的数据。可以使用PHP或其他服务器端语言来编写接口。以下是一个简单的PHP示例：

<?php
  header("Access-Control-Allow-Origin: *");
  header("Content-Type: application/json; charset=UTF-8");

  $data = file_get_contents('php://input');
  $json = json_decode($data);

  // 处理数据
  // ...

  // 返回响应
  $response = array('success' => true);
  echo json_encode($response);
?>

3. 在安卓app中使用HttpClient或其他网络库来连接服务器并接收数据。以下是一个简单的示例：

import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URI;
import java.net.URISyntaxException;

public class MainActivity extends AppCompatActivity {

    private static final String TAG = "MainActivity";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        new GetTask().execute();
    }

    private class GetTask extends AsyncTask<Void, Void, String> {

        @Override
        protected String doInBackground(Void... params) {
            String result = null;

            try {
                HttpClient httpClient = new DefaultHttpClient();
                HttpGet httpGet = new HttpGet();
                httpGet.setURI(new URI("http://YOUR_HOST_ADDRESS/data")); //填写你的数据接口地址
                HttpResponse httpResponse = httpClient.execute(httpGet);
                HttpEntity httpEntity = httpResponse.getEntity();
                result = EntityUtils.toString(httpEntity);
            } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
            } catch (URISyntaxException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }

            return result;
        }

        @Override
        protected void onPostExecute(String result) {
            Log.d(TAG, "result: " + result);
        }
    }
}

以上是一个简单的安卓app接收esp8266的数据的示例，你可以根据自己的需求进行修改和完善。