如何解决在OkHttp中传递ip地址时,响应为null
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。
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