Android4.0 之后不允许在主线程进行网络连接

Android4.0 以后不允许在主线程进行网络连接

Android4.0 以后不允许在主线程进行网络连接，否则会出现 android.os.NetworkOnMainThreadException。因此，必须另起一个线程进行网络连接方面的操作。

package com.lujinhong.irmcdc.dao;import java.io.IOException;import java.net.Socket;import java.net.UnknownHostException;import java.util.Scanner;public class ResourceDao {	String returnLine = "hi";	public String getAllContentByName() {		Runnable r = new NetWorkHandler();		Thread thread = new Thread(r);		thread.start();		try {			Thread.sleep(15000);		} catch (InterruptedException e) {			e.printStackTrace();		}		return returnLine;	}	private class NetWorkHandler implements Runnable {		String line = "line";		Socket socket = null;		Scanner scanner = null;		@Override		public void run() {			try {				socket = new Socket("time-A.timefreq.bldrdoc.gov", 13);				scanner = new Scanner(socket.getInputStream());				while (scanner.hasNextLine()) {					line = scanner.nextLine();					returnLine += line;				}			} catch (UnknownHostException e) {				e.printStackTrace();			} catch (IOException e) {				e.printStackTrace();			} finally {				scanner.close();				try {					socket.close();				} catch (IOException e) {					e.printStackTrace();				}			}		}	}}

1、由于网络连接需要一定时间，为了在主界面上进行网络信息的展现，暂时用sleep()方法简单实现，使主线程等待网络信息读取完成。

Thread.sleep(5000);