基本的 android http 获取

Question

我是编程方面的 android 菜鸟，但在一些程序的帮助下，我可以学习基础知识。我想对 arduino ethernetshield 做一个基本的 http get 请求。

为此，我找到了一些代码，但我无法让它工作。 我总是卡在 getResponse 部分，我尝试了几页的代码。

我发现以下页面提供了可读代码： How to work with an image using url in android?

现在我创建了以下内容： 按下一个按钮并访问一个网址：

---

package adhttpget.test;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URI;
import java.net.URL;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Toast;

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;



public class AdhttpgetActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
    }


public void pushbutton1(View view) {
    Toast.makeText(getBaseContext(), "button press", Toast.LENGTH_SHORT).show();
            Log.e("button", "pressed");

             URL connectURL = new URL("http://192.168.0.48/?out=13&status=2");
             HttpURLConnection conn = (HttpURLConnection)connectURL.openConnection(); 

             // do some setup
             conn.setDoInput(true); 
             conn.setDoOutput(true); 
             conn.setUseCaches(false); 
             conn.setRequestMethod("GET"); 

             // connect and flush the request out
             conn.connect();
             conn.getOutputStream().flush();

             // now fetch the results
             String response = getResponse(conn);    // <-- THIS IS MY PROBLEM



}
private String getResponseOrig(HttpURLConnection conn)
{
    InputStream is = null;
    try 
    {
        is = conn.getInputStream(); 
        // scoop up the reply from the server
        int ch; 
        StringBuffer sb = new StringBuffer(); 
        while( ( ch = is.read() ) != -1 ) { 
            sb.append( (char)ch ); 
        } 
        return sb.toString(); 
    }
    catch(Exception e)
    {
       Log.e("http", "biffed it getting HTTPResponse");
    }
    finally 
    {
        try {
        if (is != null)
            is.close();
        } catch (Exception e) {}
    }

    return "";
}

}

---

我在哪里可以找到有关如何正确编写代码的信息？ 还是你碰巧有某种暗示的答案，所以我可以从中学习？

Answer 1

你必须创建一个BufferedReader传递InputStream，然后你才能读取字符串

private static String convertStreamToString(InputStream is) {
    BufferedReader reader = new BufferedReader(new InputStreamReader(is));
    StringBuilder sb = new StringBuilder();

    String line = null;
    try {
        while ((line = reader.readLine()) != null) {
            sb.append(line + "\n");
        }
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        try {
            is.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    return sb.toString();
}

然后我建议您使用与 Thread UI 分离的线程（使用 Thread、AsyncTask、Handler 等）建立连接（或读/写文件），因为这将改善您的应用程序。

http://developer.android.com/intl/es/guide/components/processes-and-threads.html