Android的API 14 - 網絡運營/的AsyncTask

Question

我最近提出基於使用POST數據HTTP請求（這裏找到：Android API 14 - POST Data to HTTP）一個問題，有人告訴我，我需要嘗試像的AsyncTask的東西，因爲我無法進行網絡主線程中的操作。

總之形式，我不知道如何做到這一點。任何幫助表示讚賞！這裏是我的代碼：

package me.babblebox.application; 

import java.io.IOException; 
import java.util.ArrayList; 
import java.util.List; 

import org.apache.http.HttpResponse; 
import org.apache.http.NameValuePair; 
import org.apache.http.client.ClientProtocolException; 
import org.apache.http.client.HttpClient; 
import org.apache.http.client.entity.UrlEncodedFormEntity; 
import org.apache.http.client.methods.HttpPost; 
import org.apache.http.impl.client.DefaultHttpClient; 
import org.apache.http.message.BasicNameValuePair; 

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

public class BabbleBoxActivity extends Activity { 
    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.main); 
    } 
    public void check_login() { 
     // Create a new HttpClient and Post Header 
     HttpClient httpclient = new DefaultHttpClient(); 
     HttpPost httppost = new HttpPost("http://babblebox.me/android/test.php"); 

     try { 
      // Add your data 
      List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2); 
      nameValuePairs.add(new BasicNameValuePair("id", "12345")); 
      nameValuePairs.add(new BasicNameValuePair("stringdata", "Hi")); 
      httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs)); 

      // Execute HTTP Post Request 
      HttpResponse response = httpclient.execute(httppost); 

     } catch (ClientProtocolException e) { 
      // TODO Auto-generated catch block 
     } catch (IOException e) { 
      // TODO Auto-generated catch block 
     } 
    } 
    public void check_login_button(View v) { 
      check_login(); 
    } 
} 

Answer 1

閱讀Processes and threads也AsyncTask。

以下是遠非完美，但你可以嘗試這樣的事情上手...

public class BabbleBoxActivity extends Activity { 

    // Leave onCreate() as it is 

    public void check_login_button(View v) { 
     PostTask postTask = new PostTask(); 
     postTask.execute(); 
    } 

    // EDITED THE LINE BELOW TO INCLUDE 'class' 
    private class PostTask extends AsyncTask<Void, Void, Void> { 

     // Move the code that was in check_login to the 
     // doInBackground method below 

     protected Void doInBackground(Void... params) { 

      HttpClient httpclient = new DefaultHttpClient(); 
      HttpPost httppost = new HttpPost("http://babblebox.me/android/test.php"); 

      try { 
       // Add your data 
       List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2); 
       nameValuePairs.add(new BasicNameValuePair("id", "12345")); 
       nameValuePairs.add(new BasicNameValuePair("stringdata", "Hi")); 
       httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs)); 

       // Execute HTTP Post Request 
       HttpResponse response = httpclient.execute(httppost); 

      } catch (ClientProtocolException e) { 
       // TODO Auto-generated catch block 
      } catch (IOException e) { 
       // TODO Auto-generated catch block 
      } 
      return null; 
     } 
    } 
} 

在現實中，你需要學習如何PARAMATERS傳遞到AsyncTask並得到它返回有效的結果。

編輯：

只是出於興趣，我整理了一下原來的代碼（沒有的AsyncTask，但在Android 2.2版，它允許在主線程網絡操作）。我添加了一些日誌代碼只是爲了檢查連接的工作...

HttpResponse response = httpclient.execute(httppost); 
Header[] headers = response.getAllHeaders(); 
Log.d("BabbleBox", "Header count: " + headers.length); 
for (int c = 0; c < headers.length; c++) 
    Log.d("Babblebox", "Header: name=" + headers[c].getName() + " value=" + headers[c].getValue()); 

...我得到了下面的響應頭。

Header count: 6 
Header: name=Date value=Sun, 11 Dec 2011 16:38:19 GMT 
Header: name=Server value=LiteSpeed 
Header: name=Connection value=close 
Header: name=X-Powered-By value=PHP/5.3.8 
Header: name=Content-Type value=text/html 
Header: name=Content-Length value=4 

從任何網絡「請求」（GET，POST，PUT）將取決於正在談話的遠程服務變化的響應。您需要計算出您的服務器將返回的內容，然後相應地處理響應。

Answer 2

如果你不想AsyncTask（不管是什麼原因）你，或許，可以這樣做

public void checkLoginAsync() { 

    Executors.newSingleThreadExecutor(new Runnable(){ 
      @Override 
      public void run() { 
        checkLogin(); 
    }); 
} 

你可能會做出checkLogin()接受聽衆的一些KND則因此報告了類似onLoginError和例如，你的活動實現了這個聽衆。或者，也許對您的應用程序，以便您可以終止該程序，無論當前顯示哪些活動。