Mysql的安卓Connectivty错误

Question

嗨，我想通过匹配一个列名即

"select column_name from day where date='$date'" 

从MySQL选定列取，但它给我严重的错误，我有检查，他们都很好，我想连接问题有在代码中的一些问题，请帮我

import java.io.BufferedReader; 
    import java.io.InputStream; 
    import java.io.InputStreamReader; 
    import java.util.ArrayList; 
    import java.util.Calendar; 
    import java.util.Date; 

    import org.apache.http.HttpEntity; 
    import org.apache.http.HttpResponse; 
    import org.apache.http.NameValuePair; 
    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 org.json.JSONObject; 

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

    public class Day extends Activity { 

     String dt=""; 
     String mc=""; 
     String bc=""; 
     ImageView dateimg; 
     String name; 
     String date; 
     InputStream is=null; 
     String result=null; 
     String line=null; 
     @Override 
     protected void onCreate(Bundle savedInstanceState) { 
      super.onCreate(savedInstanceState); 
      setContentView(R.layout.day_lay); 
      getCurrDate(); 
      select(); 
      dateimg = (ImageView) findViewById(R.id.img); 



      dateimg.setOnClickListener(new OnClickListener() 
      { 
        public void onClick(View v) 
        { 
         //getCurrDate(); 

         } 

      }); 



     } 


     public String getCurrDate() 
     { 

      Date cal = Calendar.getInstance().getTime(); 
      dt = cal.toLocaleString(); 

      mc = dt.substring(0, dt.length() - 17); 
      bc=mc.substring(4); 
      System.out.println("Date is"+bc); 
      date=bc; 
      return dt; 

     } 


     public void select() 
      { 
       ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(); 

      nameValuePairs.add(new BasicNameValuePair("date",date)); 

       try 
       { 
    HttpClient httpclient = new DefaultHttpClient()  
    HttpPost httppost = new HttpPost("http://192.168.1.1/wpcontent/themes/app/day.php"); 
        httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs)); 
        HttpResponse response = httpclient.execute(httppost); 
        HttpEntity entity = response.getEntity(); 
        is = entity.getContent(); 
        Log.e("pass 1", "connection success "); 
      } 
       catch(Exception e) 
      { 
        Log.e("Fail 1", e.toString()); 
        Toast.makeText(getApplicationContext(), "Invalid IP Address", 
        Toast.LENGTH_LONG).show(); 
      }  

       try 
       { 
        BufferedReader reader = new BufferedReader 
         (new InputStreamReader(is,"iso-8859-1"),8); 
         StringBuilder sb = new StringBuilder(); 
         while ((line = reader.readLine()) != null) 
       { 
         sb.append(line + "\n"); 
        } 
         is.close(); 
         result = sb.toString(); 
        Log.e("pass 2", "connection success "); 
      } 
       catch(Exception e) 
       { 
       Log.e("Fail 2", e.toString()); 
      }  

      try 
       { 
        JSONObject json_data = new JSONObject(result); 
        name=(json_data.getString("name")); 
       Toast.makeText(getBaseContext(), "Name : "+name, 
        Toast.LENGTH_SHORT).show(); 
       } 
       catch(Exception e) 
       { 
        Log.e("Fail 3", e.toString()); 
       } 

      System.out.println("Got Value"+name); 
      } 

    } 

//数据库选择

<?php 
    $host='127.0.0.1'; 
    $uname='root'; 
    $pwd='password'; 
    $db="android"; 

    $con = mysql_connect($host,$uname,$pwd) or die("connection failed"); 
    mysql_select_db($db,$con) or die("db selection failed"); 

    $date=$_REQUEST['date']; 

    $r=mysql_query("select mat from vicks where date='$date'",$con); 

    while($row=mysql_fetch_array($r)) 
    { 
     $flag[name]=$row[name]; 
    } 

    print(json_encode($flag)); 
    mysql_close($con); 
?> 

// Logcat

05-08 14:04:34.938: I/dalvikvm-heap(995): Grow heap (frag case) to 54.839MB for 2312016-byte allocation 
05-08 14:04:35.218: D/dalvikvm(995): GC_CONCURRENT freed 1K, 4% free 56085K/58055K, paused 11ms+23ms 
05-08 14:04:35.758: D/dalvikvm(995): GC_FOR_ALLOC freed 564K, 4% free 56086K/58055K, paused 172ms 
05-08 14:04:35.788: I/dalvikvm-heap(995): Grow heap (frag case) to 57.044MB for 2312016-byte allocation 
05-08 14:04:36.538: D/dalvikvm(995): GC_CONCURRENT freed <1K, 4% free 58344K/60359K, paused 11ms+98ms 
05-08 14:08:30.258: I/System.out(995): Date is8 
05-08 14:08:30.298: E/Fail 1(995): android.os.NetworkOnMainThreadException 
05-08 14:08:30.338: E/Fail 2(995): java.lang.NullPointerException 
05-08 14:08:30.338: E/Fail 3(995): java.lang.NullPointerException 
05-08 14:08:30.338: I/System.out(995): Got valuenull 

Answer 1

这不是关于连接性。这是关于处理主线程上的网络活动。

您可以禁用该警告（这是不好的做法），也可以在单独的线程中执行该任务。

一个常见的Android模式正在使用AsyncTask。 AsyncTask类在其构造函数中使用三个参数：params，progress，result。在你的情况下，如果你只需要在后台运行某些东西，它们全都可以为空。

private class DatabaseTask extends AsyncTask<void, void, void> 
    { 
     protected void doInBackground(Void... params) 
     { 
      // YOUR DB CODE 
     } 
    } 

，并执行这样的： 新DatabaseTask（）执行（）;

或者，如果要使用输入参数，则可以将第一个void更改为所需的任何类型。阅读更多here。