android - 错误 android.os.networkonmainthreadexception asynctask getResponseCode

Question

当在同一个类上运行我的代码时，应用程序运行良好。但是当我在两个不同的类上运行此代码时，我的应用程序出现错误 android.os.networkonmainthreadexception。调试时，我在 responseHttp = httpConnection.getResponseCode(); 检测到错误应用程序运行到 responseHttp = httpConnection.getResponseCode(); 行，它会捕获{}，取消“If..else”。并记录错误 android.os.networkonmainthreadexception。你能帮帮我吗!!

我的代码类Asynctask

package com.example.finishdemo;

import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
import android.os.AsyncTask;

public class TestConnectionNew extends AsyncTask<String, Void, String> {
private int responseHttp = 0;
private String flag="false";

@Override
protected String doInBackground(String... urltest) {
    // TODO Auto-generated method stub
    try {
        URL url = new URL(urltest[0]);
        URLConnection connection = url.openConnection();
        connection.setConnectTimeout(2000);
        HttpURLConnection httpConnection = (HttpURLConnection) connection;
        **responseHttp = httpConnection.getResponseCode();**
        if (responseHttp == HttpURLConnection.HTTP_OK) {
            flag = "true";
        } else {
            flag = "false";
        }
    } catch (Exception e) {
        e.printStackTrace();
        System.out.println("Thong bao loi: "+e.toString());
    }
    return flag;
}
}

主要代码类:

package com.example.finishdemo;
public class Hoadon extends Activity {
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.hoadon);
    TestConnectionNew t=new TestConnectionNew();
    String recieve=t.doInBackground("http://longvansolution.tk/monthlytarget.php");
    if(recieve.equalsIgnoreCase("true"))
    {
        doTimerTask();
    }else
        if(recieve.equalsIgnoreCase("false"))
    {
        showAlert("Không kết nối được đến server hoặc thiết bị chưa có kết nối internet!");
    }

Answer 1

使用asynctask.execute用于执行 AsyncTask 而不是手动调用 doInBackground:

 TestConnectionNew t = new TestConnectionNew();
 t.execute("http://longvansolution.tk/monthlytarget.php");

将您的 TestConnectionNew 更改为

public class TestConnectionNew extends AsyncTask<String, Void, String> {
private int responseHttp = 0;
private String flag="false";

@Override
protected String doInBackground(String... urltest) {
    // TODO Auto-generated method stub
    try {
        URL url = new URL(urltest[0]);
        URLConnection connection = url.openConnection();
        connection.setConnectTimeout(2000);
        HttpURLConnection httpConnection = (HttpURLConnection) connection;
        **responseHttp = httpConnection.getResponseCode();**
        if (responseHttp == HttpURLConnection.HTTP_OK) {
            flag = "true";
        } else {
            flag = "false";
        }
    } catch (Exception e) {
        e.printStackTrace();
        System.out.println("Thong bao loi: "+e.toString());
    }
    return flag;
}

@Override
     protected void onPostExecute(String recieve) {
           if(recieve.equalsIgnoreCase("true"))
            {
               doTimerTask();
           }else
           if(recieve.equalsIgnoreCase("false"))
             {
              showAlert("Không kết nối được đến server hoặc thiết bị chưa có kết nối internet!");
             }
      }
}

有关我们如何使用 AsyncTask 的更多帮助，请参阅:

http://developer.android.com/reference/android/os/AsyncTask.html