Question

我想在android studio中建立一个基本的登录系统。我正在使用xampp服务器。当我在手机上运行应用程序时，文本框上出现错误（android.os.NetworkOnMainThreadException）。以下代码是我的login.java文件

package com.kmsoft.mam.deneme;

import java.util.ArrayList;
import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class login2 extends Activity {
    EditText un,pw;
    TextView error;
    Button ok;
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        un=(EditText)findViewById(R.id.et_un);
        pw=(EditText)findViewById(R.id.et_pw);
        ok=(Button)findViewById(R.id.btn_login);
        error=(TextView)findViewById(R.id.tv_error);

        ok.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub

                ArrayList<NameValuePair> postParameters = new ArrayList<NameValuePair>();
                postParameters.add(new BasicNameValuePair("username", un.getText().toString()));
                postParameters.add(new BasicNameValuePair("password", pw.getText().toString()));
                //String valid = "1";
                String response = null;
                try {
                    response = CustomHttpClient.executeHttpPost("http://localhost:1337/projects/Deneme/check.php", postParameters);
                    String res=response.toString();
                    // res = res.trim();
                    res= res.replaceAll("\\s+","");
                    //error.setText(res);

                    if(res.equals("1"))
                        error.setText("Correct Username or Password");
                    else
                        error.setText("Sorry!! Incorrect Username or Password");
                } catch (Exception e) {
                    un.setText(e.toString());
                }

            }
        });
    }
}

以下代码是我的CustommHttpClient.java文件

package com.kmsoft.mam.deneme;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URI;
import java.util.ArrayList;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.conn.params.ConnManagerParams;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.params.HttpConnectionParams;
import org.apache.http.params.HttpParams;

public class CustomHttpClient {
    /** The time it takes for our client to timeout */
    public static final int HTTP_TIMEOUT = 30 * 1000; // milliseconds

    /** Single instance of our HttpClient */
    private static HttpClient mHttpClient;

    /**
     * Get our single instance of our HttpClient object.
     *
     * @return an HttpClient object with connection parameters set
     */
    private static HttpClient getHttpClient() {
        if (mHttpClient == null) {
            mHttpClient = new DefaultHttpClient();
            final HttpParams params = mHttpClient.getParams();
            HttpConnectionParams.setConnectionTimeout(params, HTTP_TIMEOUT);
            HttpConnectionParams.setSoTimeout(params, HTTP_TIMEOUT);
            ConnManagerParams.setTimeout(params, HTTP_TIMEOUT);
        }
        return mHttpClient;
    }

    /**
     * Performs an HTTP Post request to the specified url with the
     * specified parameters.
     *
     * @param url The web address to post the request to
     * @param postParameters The parameters to send via the request
     * @return The result of the request
     * @throws Exception
     */
    public static String executeHttpPost(String url, ArrayList<NameValuePair> postParameters) throws Exception {
        BufferedReader in = null;
        try {
            HttpClient client = getHttpClient();
            HttpPost request = new HttpPost(url);
            UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(postParameters);
            request.setEntity(formEntity);
            HttpResponse response = client.execute(request);
            in = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));

            StringBuffer sb = new StringBuffer("");
            String line = "";
            String NL = System.getProperty("line.separator");
            while ((line = in.readLine()) != null) {
                sb.append(line + NL);
            }
            in.close();

            String result = sb.toString();
            return result;
        } finally {
            if (in != null) {
                try {
                    in.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    /**
     * Performs an HTTP GET request to the specified url.
     *
     * @param url The web address to post the request to
     * @return The result of the request
     * @throws Exception
     */
    public static String executeHttpGet(String url) throws Exception {
        BufferedReader in = null;
        try {
            HttpClient client = getHttpClient();
            HttpGet request = new HttpGet();
            request.setURI(new URI(url));
            HttpResponse response = client.execute(request);
            in = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));

            StringBuffer sb = new StringBuffer("");
            String line = "";
            String NL = System.getProperty("line.separator");
            while ((line = in.readLine()) != null) {
                sb.append(line + NL);
            }
            in.close();

            String result = sb.toString();
            return result;
        } finally {
            if (in != null) {
                try {
                    in.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

Answer 1

Http必须在Android的后台线程中完成，就像在大多数平台上一样。 AsyncTask是实现此目的的默认方式。

Answer 2

您正在尝试在主线程上运行netowrk操作，这就是您获得此异常的原因。

您应该使用异步任务，而不是在后台运行，并且根本不阻止UI线程。

Answer 3

使用AsyncTask执行网络操作并在AsyncTask的onPostExecute（）方法中更新UI ..

For your Reference

用户名文本框上的“android.os.NetworkOnMainThreadException”

3 个答案: