android應用程序獲取互聯網數據

Question

這是當我運行此代碼時從互聯網bu提取數據的android代碼

public class data 
    {

    public String a()throws Exception

    {
        String data=null;

        BufferedReader b=null;

        try

        {

            HttpClient ob=new DefaultHttpClient();

            URI website=new URI("http://www.mybringback.com");

            HttpGet request=new HttpGet();

            request.setURI(website);

            HttpResponse response= ob.execute(request);

            b=new BufferedReader(new InputStreamReader(response.getEntity().getContent()));

            StringBuffer bu=new StringBuffer ();

            String i = null;

            while((i=b.readLine())!=null)
            {
                bu.append(i);
            }

            b.close();

            data=bu.toString();

            return data;
        }finally
        {
            if (b!=null)
            {
                try {
                    b.close();

                    return data;


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

我的主班

package com.example.hello;


import android.app.Activity;

import android.os.Bundle;

import android.widget.TextView;

import org.apache.http.HttpEntity;

import org.apache.http.HttpResponse;

import org.apache.http.client.HttpClient;

import org.apache.http.client.methods.HttpGet;

import org.apache.http.impl.client.DefaultHttpClient;

import java.io.*;

import java.net.URI;

public class MyActivity extends Activity
 {

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

    setContentView(R.layout.main);


    TextView m =(TextView)findViewById(R.id.de);

    data ob=new data();

    try {
        String v= ob.a();

        m.setText(v);

    } catch (Exception e) {

        e.printStackTrace();
    }
  }
 }

我的xml文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:orientation="vertical"
 android:layout_width="fill_parent"
 android:layout_height="fill_parent">
<ScrollView 
 android:layout_width="fill_parent" 
 android:layout_height="fill_parent">
 <TextView
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="Hello World, MyActivity"
    android:id="@+id/de">

 </TextView>
 </ScrollView>
</LinearLayout>

Answer 1

您正在ui線程上運行與網絡相關的操作。 可能正在獲取NetworkOnMainThreadException 。 使用Thread或Asynctask 。

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

如果網絡操作持續時間較短，請使用Asynctask 。

您可以Asynctask的內部類中更新UI onPostExecute 。

還要遵循Java命名約定並重命名變量和方法，這有助於提高可讀性

例：

public class MyActivity extends Activity
{
TextView m;  
@Override
public void onCreate(Bundle savedInstanceState)
{
   super.onCreate(savedInstanceState);
   setContentView(R.layout.main);
   m=(TextView)findViewById(R.id.de);
   new TheTask().execute()
}

class TheTask extends AsyncTask<Void,Void,String>
{
   String  _response=null;   
@Override
protected String doInBackground(Void... params) {
    // TODO Auto-generated method stub
     try
     {
       HttpClient ob=new DefaultHttpClient();
       URI website=new URI("http://www.mybringback.com");
       HttpGet request=new HttpGet();
       request.setURI(website);
       HttpResponse response= ob.execute(request);
       HttpEntity resEntity = response.getEntity();
       _response=EntityUtils.toString(resEntity); 
     }catch(Exception e)
     {
         e.printStackTrace();
     }
    return _response;
}
@Override
protected void onPostExecute(String result) {
    // TODO Auto-generated method stub
    super.onPostExecute(result);
            m.setText(result);
}
    }
}