package com.ravi.seggerclient;如何在android编程中运行联网操作和循环操作
public class MainActivity extends Activity
{
EditText text,text2;
String selectedImagePath,ll=null;
Timer ravi;
static DatagramSocket clsoc;
static InetAddress ip;
static File ff;
byte[] arr = null;
static int len,totpac;
static RandomAccessFile raf;
static FileChannel chan;
static int buffsize;
static int i=0,id=0,numRead=0;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
text = (EditText)findViewById(R.id.editText1);
text2 = (EditText)findViewById(R.id.editText2);
final String state = Environment.getExternalStorageState();
((Button) findViewById(R.id.button1))
.setOnClickListener(new OnClickListener()
{
public void onClick(View arg0)
{
try
{
if (Environment.MEDIA_MOUNTED.equals(state))
{
String root = Environment.getExternalStorageDirectory().toString();
selectedImagePath = root +"/Nenjodu.mp4"; ff = new File(selectedImagePath);
text.setText(selectedImagePath+"File Is Found"+"File length"+ff.length());
}
}
catch(Exception e)
{
text.setText(""+e);
}
}
});
((Button) findViewById(R.id.button2))
.setOnClickListener(new View.OnClickListener()
{
public void onClick(View arg0)
{
try
{
Ravii rav = new Ravii();
ll="NOT SENT";
ll = rav.execute().get();
text2.setText(""+ll);
}
catch(Exception e)
{
Log.d("Error in Sending",""+e);
}
}
});
}
private class Ravii extends AsyncTask<String,Void,String>
{
@Override
protected String doInBackground(String... params)
{
// TODO Auto-generated method stub
try{
clsoc = new DatagramSocket();
ip = InetAddress.getByName("192.168.137.1");
len = (int)ff.length();
totpac = len/(30*1024)+1;
buffsize = 30;
String ss ="#"+totpac+"&";
Log.d("No of Packets",""+totpac);
byte[] fsize = new byte[1024];
fsize = ss.getBytes();
DatagramPacket dp = new DatagramPacket(fsize,fsize.length,ip,8000);
clsoc.send(dp);
raf = new RandomAccessFile(ff,"rw");
chan = raf.getChannel();
while(numRead>=0)
{
ByteBuffer buf = ByteBuffer.allocate(1024*buffsize);
if(i==id)
numRead = chan.read(buf);
if((numRead>0)&&(i==id))
{
arr = new byte[numRead];
System.arraycopy(buf.array(),0,arr,0,numRead);
DatagramPacket sp = new DatagramPacket(arr,arr.length,ip,8000);
clsoc.send(sp);
i++;
byte[] receiveData = new byte[1024];
DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);
clsoc.receive(receivePacket);
String mod = new String(receivePacket.getData());
System.out.println("\n" + mod);
id=Integer.parseInt(mod.substring(mod.indexOf("#") + 1, mod.indexOf("&")));
}
else if((numRead>0)&&(i!=id))
{
i--;
DatagramPacket sp = new DatagramPacket(arr,arr.length,ip,8000);
clsoc.send(sp);
text2.setText("ReSent "+i+" packet");
i++;
byte[] receiveData = new byte[1024];
DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);
clsoc.receive(receivePacket);
String mod = new String(receivePacket.getData());
id=Integer.parseInt(mod.substring(mod.indexOf("#") + 1, mod.indexOf("&")));
}
else
{
Toast.makeText(getApplicationContext(),"Nothing to Send" , Toast.LENGTH_SHORT).show();
}
}
return "SuccessFul";
}
catch(Exception e)
{
Log.d("Exception in the Client Sending",""+e);
}
}
}
}
嗨,我是新来的Android Programming.This是我的代码,客户端从一个移动发送大文件到其他使用UDP protocol.Although UDP上不优选这works.It是的一部分我的项目。在我开始使用Android的网络时,我开始知道使用AsyncTask在Android中使用后台线程完成网络,但是当我想要在后台线程中长时间运行循环时,循环包含网络(这就是Asynctask的原因首选),我面临错误 Android无法在未调用Looper.prepare()的线程内创建处理程序。 如何克服这一点以及如何在Android编程中一起运行网络和循环操作。欢迎任何建议。
java的导引头,按我的知识在Android的版本在3.0以上,联网操作都被阻挡在主UI线程没有任何权限。我选择了Asynctask for Networking,因为它是一个后台线程 – Ravi4U
是的,如果你在主UI线程中进行网络操作,它将阻止主UI。你已经使用了asynctask,但是asynctask不允许长时间阻塞操作。请参阅官方文档。 –