Question

我在androidStudio中具有以下代码，每当我单击按钮时，都会出现错误：“ NetworkOnMainThreadException”。

我也使用AsyncTask。我也添加了清单...如果您告诉我如何解决我的问题，我将很高兴。并告诉我我的代码中是否有任何问题不起作用或不正确。

package stach;

import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import java.net.HttpURLConnection;
import java.net.InetSocketAddress;
import java.net.URL;
import java.io.*;
import java.net.UnknownHostException;
import java.nio.charset.Charset;
import java.net.InetAddress;
import java.net.Socket;
import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import javax.net.ssl.HttpsURLConnection;

public class UserPassCon extends AppCompatActivity {

    public static String ServerKind;
    public static Button b;
    public static TextView t;
    public static EditText U;
    public static EditText P;
    TextView editText;
    String PassCode;
    String Username;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_user_pass_con);
        b = (Button) findViewById(R.id.Connect);
        t = (TextView) findViewById(R.id.textView2);
        U = (EditText) findViewById(R.id.UserName);
        P = (EditText) findViewById(R.id.PassWord);

        editText = (TextView) findViewById(R.id.textView2);
        editText.setText(ServerKind);
        new GetI().execute();

    }
}




class GetI extends AsyncTask<URL, Void, String> {

    protected void sendPost() throws Exception {

        String url = "https://www..google.com/";
        URL obj = new URL(url);
        HttpsURLConnection con = (HttpsURLConnection) obj.openConnection();

        //add reuqest header
        con.setRequestMethod("POST");
        con.setRequestProperty("ServerKind", UserPassCon.ServerKind);
        con.setRequestProperty("Password", UserPassCon.P.getText().toString());
        con.setRequestProperty("Username", UserPassCon.U.getText().toString());
        con.setRequestProperty("Accept-Language", "en-US,en;q=0.5");

        String urlParameters = "sn=C02G8416DRJM&cn=&locale=&caller=&num=12345";

        // Send post request
        con.setDoOutput(true);
        DataOutputStream wr = new DataOutputStream(con.getOutputStream());
        wr.writeBytes(urlParameters);
        wr.flush();
        wr.close();

        BufferedReader in = new BufferedReader(
                new InputStreamReader(con.getInputStream()));
        String inputLine;
        StringBuffer response = new StringBuffer();

        while ((inputLine = in.readLine()) != null) {
            response.append(inputLine);
        }
        in.close();

        String[] Res = response.toString().split("=");

        if (Res[0] == "error") {
           UserPassCon.t.setText("error");
        }
        if (Res[0] == "ok") {
            Socket s = new Socket();
            try {
                s.connect(new InetSocketAddress(Res[1], 510));
            }
            //Host not found
            catch (UnknownHostException e) {

                UserPassCon.t.setText("host not found !");

            }
            UserPassCon.b.setText("Connected");
        }
    }
    @Override
    protected void onPostExecute(String s) {
        super.onPostExecute(s);
        UserPassCon.b.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                try {
                    sendPost();
                } catch (Exception e) {
     UserPassCon.t.setText(e.toString());//the Exception will be caught here .
                }
            }
        });
    }

    @Override
    protected String doInBackground(URL... params) {

        return null;
    }

}

正如我所说的，我已经尝试过AsyncTask ...我应该在GetI类中单击按钮时运行http请求...如果您知道其他方法，请在此处留下您的答案... 预先感谢！

Answer 1

在您的代码中发现了问题。您在onPostExecute方法而不是在 doInBackground 中调用 sendPost（）。您必须在 doInBackground 中调用 sendPost（），否则将收到 NetworkOnMainThreadException 。发生这种情况是因为在主线程上调用了 onPostExecute（）。任何与网络相关的任务均不允许在主线程上执行。您确实在使用AsynTask。但这没有用，因为要在不同线程或单独线程上执行任务，需要使用 doInBackground（）。希望这对您有帮助

android studio和java问题

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