在OkHttp中传递ip地址时，响应为null

问题描述

我正在研究一个结合了nodemcu和android的项目。我将nodemcu设置为服务器。我需要将其连接到android并根据说明获取数据。这是我的Android代码

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textView=findViewById(R.id.textView);
        button=findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                ConnectivityManager connectivityManager=(ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);
                assert connectivityManager!=null;
                NetworkInfo networkInfo=connectivityManager.getActiveNetworkInfo();
                if(networkInfo!=null&&networkInfo.isConnected()){
                    String url="http://192.168.8.100/";
                    new RequestServer().execute(url);
                }else {
                    Toast.makeText(MainActivity.this,"Error..",Toast.LENGTH_SHORT).show();
                }
            }
        });
    }
    private class RequestServer extends AsyncTask<String,Void,String> {
        @Override
        protected String doInBackground(String... url) {
            return ConnectionServer.getData(url[0]);
        }
        @Override
        protected void onPostExecute(String s) {
            if(s!=null){
                textView.setText(s);
            }else {
                Toast.makeText(MainActivity.this,"Error.",Toast.LENGTH_SHORT).show();
            }
        }
    }

这是ConnectionServer类的代码

public static String getData(String url){
        OkHttpClient.Builder builder=new OkHttpClient.Builder();
        builder.connectTimeout(5,TimeUnit.MINUTES)
                .writeTimeout(5,TimeUnit.MINUTES)
                .readTimeout(5,TimeUnit.MINUTES);
        OkHttpClient client=builder.build();
        Request request=new Request.Builder().url(url).build();
        try {
            Response response=client.newCall(request).execute();
            return Objects.requireNonNull(response.body()).string();
        } catch (IOException e) {
            e.printStackTrace();
            return null;
        }
    }

这是我的nodemcu代码

#include <Arduino.h>
#include<ESP8266WiFi.h>
#ifndef WIFI_SSID
  #define WIFI_SSID "****"
  #define WIFI_PASSWORD "****"
#endif
WiFiServer server(80);
void WiFiConnect();
void setup() {
  Serial.begin(9600);
  WiFiConnect();
  server.begin();
  Serial.println("Server Status:Ready");
}
void loop() {
  if(WiFi.status()!=WL_CONNECTED){
    WiFiConnect();
  }
  WiFiClient client=server.available();
  if(!client){
    return;
  }
  Serial.println("New Client Request");
  unsigned long timeout=millis()+3000;
  while(!client.available()&&millis()<timeout){
    delay(1);
  }
  if(millis()>timeout){
    Serial.println("Client Status:Timeout");
    client.flush();
    client.stop();
    return;
  }
  String request=client.readStringUntil('\r');
  Serial.println(request);
  client.flush();
  client.println("HTTP/1.1 200 OK\r\nContent-Type: text/html\r\n\r\n<!DOCTYPE HTML>\r\n<html><body>Request Received.</body></html>");
  Serial.println("Client Status:Request Recieved");
  client.flush();
  delay(1);
  Serial.println("Client Status:Disconnected");
}
void WiFiConnect(){
  WiFi.begin(WIFI_SSID,WIFI_PASSWORD);
  Serial.print("Connecting to ");
  Serial.print(WIFI_SSID);
  while(WiFi.status()!=WL_CONNECTED) {
    Serial.print(".");
    delay(500);
  }
  Serial.println();
  Serial.print("connected: ");
  Serial.println(WiFi.localIP());
  delay(10);
}

我的问题是我从未收到nodemcu的任何回复。在浏览器中输入ip地址时，我收到来自nodemcu的响应。而且在android中，我用链接（例如：www.google.com）替换ip地址时得到响应。我发现使用IP地址时OkHttp无法正常工作。请帮我。快乐编码：）

解决方法

将其添加到ConnectionServer.java

public static String getData(String url){
        OkHttpClient client=new OkHttpClient.Builder()
                .connectionSpecs(Arrays.asList(ConnectionSpec.MODERN_TLS,ConnectionSpec.COMPATIBLE_TLS,ConnectionSpec.CLEARTEXT))
                .build();
        Request request=new Request.Builder().url(url).build();
        try {
            Response response=client.newCall(request).execute();
            return Objects.requireNonNull(response.body()).string();
        } catch (IOException e) {
            e.printStackTrace();
            return null;
        }
    }

并将其添加到AndroidManifest.xml

<application>
  .
  .
  android:usesCleartextTraffic="true"
  .
  .
</application>

解决了我的问题。

android android arduino nodemcu okhttp

在OkHttp中传递ip地址时，响应为null

问题描述

解决方法

相关问答