java 使用 AsyncTask 进行安卓网络连接

Using AsyncTask for android network connection

提问by Chris James Hancocks

I am having some trouble using AsyncTaskas I have never come across it before and have no clue what I am doing with it.

我在使用时遇到了一些麻烦，AsyncTask因为我以前从未遇到过它，也不知道我在用它做什么。

Basically I am getting a force close because I am trying to run the connection on a main class. Could someone possibly help me with adding AsyncTaskinto the code:

基本上，我正在强制关闭，因为我试图在主类上运行连接。有人可以帮我添加AsyncTask代码：

package com.smarte.smartipcontrol;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;

public class IPControl extends Activity {

  private Socket socket;
  private String serverIpAddress;
  private static final int REDIRECTED_SERVERPORT = 32;
  public PrintWriter out;
  public BufferedReader in ;

    @Override
      public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // Get the message from the intent
        Intent intent = getIntent();
        serverIpAddress = intent.getStringExtra(IPEntry.ACTUALSMARTIP);
        createConnection();

      }

  public void getModel(View view) {
    try {
      out.println("[m\r\n");
      //System.out.print("root\r\n");
      while (! in .ready());
      String textStatus = readBuffer();

    } catch (IOException e) {}
  }

  public void createConnection() {
    try {
      InetAddress serverAddr = InetAddress.getByName(serverIpAddress);
      socket = new Socket(serverAddr, REDIRECTED_SERVERPORT);
    } catch (UnknownHostException e1) {
      e1.printStackTrace();
    } catch (IOException e1) {
      e1.printStackTrace();
    }
    try {
      out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket.getOutputStream())), true); in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
      while (! in .ready());
      readBuffer();
      out.println("root\r\n");
      //System.out.print("root\r\n");
      while (! in .ready());
      readBuffer();
      out.println("root\r\n");
      //System.out.print("root\r\n");
      while (! in .ready());
      readBuffer();
    } catch (IOException e) {}


    //R.id.textStatus
  }

  private String readBuffer() throws IOException {
    String msg = "";

    while ( in .ready()) {
      msg = msg + (char) in .read();
    }
    //System.out.print(msg);
    if (msg.indexOf("SNX_COM> ") != -1) return msg.substring(0, msg.indexOf("SNX_COM> "));
    else return msg;
  }

}

采纳答案by slezadav

Just one quick example of how it migtht look like:

只是它的外观的一个简单示例：

public class IPControl extends Activity {
    private ProgressDialog pd = null;
    private String data = null;
    private Socket socket;
    private String serverIpAddress;
    private static final int REDIRECTED_SERVERPORT = 32;
    public PrintWriter out;
    public BufferedReader in ;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.main);

        try{   
            this.pd = ProgressDialog.show(this, "Loading..", "Please Wait...", true, false);
            new AsyncAction().execute();

        }catch (Exception e) {
            e.printStackTrace();
        }
    }

    private class AsyncAction extends AsyncTask<String, Void, String> {
        protected Void doInBackground(String... args) { 
            try {
                InetAddress serverAddr = InetAddress.getByName(serverIpAddress);
                socket = new Socket(serverAddr, REDIRECTED_SERVERPORT);
            } catch (UnknownHostException e1) {
                e1.printStackTrace();
            } catch (IOException e1) {
                e1.printStackTrace();
            }
            try {
                out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket.getOutputStream())), true);
                in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
                while (! in.ready());
                readBuffer();
                out.println("root\r\n");
                //System.out.print("root\r\n");
                while (! in .ready());
                readBuffer();
                out.println("root\r\n");
                //System.out.print("root\r\n");
                while (! in .ready());
                String msg = "";

                while (in.ready()) {
                    msg = msg + (char) in .read();
                }
            } catch (IOException e) {}

        return null;//returns what you want to pass to the onPostExecute()
    }

    protected void onPostExecute(String result) {
        //resultis the data returned from doInbackground
        IPControl.this.data = result;

        if (IPControl.this.pd != null) {
            IPControl.this.pd.dismiss();
        }
    } 
}

回答by Anup Cowkur

Go through this simple tutorial to get a good grounding on what an AsyncTask is and how to use it:

通过这个简单的教程，可以很好地了解 AsyncTask 是什么以及如何使用它：

https://androidresearch.wordpress.com/2012/03/17/understanding-asynctask-once-and-forever/

https://androidresearch.wordpress.com/2012/03/17/understanding-asynctask-once-and-forever/

Then try modifying your code to use async tasks. If you get problems, Just come back here :-)

然后尝试修改您的代码以使用异步任务。如果您遇到问题，请回到这里:-)

回答by Nermeen

By checking the documentaion here..

通过检查此处的文档..

You need to put the create connection part in the doInBackground.. then in the onPostExecutedo whatever you want to update the ui.

您需要将创建连接部分放在doInBackground.. 然后在onPostExecute执行任何您想要更新 ui 的操作。