php - 如何在android java中获取关联数组元素？

Question

我正在尝试从 php 中的 mysql 数据库获取数组的值，并在 android Activity 中显示这些值。

PHP 代码:

这里我的数组有两个值，比如 $j[] 有 1 和 2。

    for($y=0;$y<2;$y++){
    $val2 ="t".$y;

    $set = mysql_query("SELECT col3 FROM table WHERE col2 ='size' AND col1 ='".$j[$val2]."'",$con);     //col1 has two value hence given in for loop
    $res= mysql_fetch_array($set);   //it displays two size value for each col1
    $a1[]="size".$y;
    $r1[] = $res['col3']; 

    $set2 = mysql_query("SELECT col3 FROM table WHERE col2 ='price' AND col1 ='".$l[$val2]."'",$con);      // same like above
    $res2= mysql_fetch_array($set2);
    $a2[]="price".$y;
    $r2[] = $res2['meta_value']; 
         }
    $h=array();
    for($z=0;$z<$y;$z++){
    $h[]=array($a1[$z] => $r1[$z], $a2[$z] => $r2[$z]);  // storing values of size and price in associative array
    $check='1';
    }
    $r=$h[];
     if($check==NULL)
       {            
                  $r[$num_rows]="Record is not available";
                 print(json_encode($r));                 
         }
        else
         {
            $r[$num_rows]="success";
            print(json_encode($r));

          } 

以及运行此 php 页面时的输出，

    [[{"size0":"14","price0":"300"},{"size1":"18","price1":"350"}],"success"]

我的 Android Activity 是，

    String result = null;
             InputStream is = null;

                try{
                        HttpClient httpclient = new DefaultHttpClient();
                        HttpPost httppost = new HttpPost(link);
                        HttpResponse response = httpclient.execute(httppost); 
                        HttpEntity entity = response.getEntity();
                        is = entity.getContent();

                        Log.e("log_tag", "connection success ");
                }
                catch(Exception e)
                {
                        Log.e("log_tag", "Error in http connection "+e.toString());
                        Toast.makeText(getApplicationContext(), "Connection fail", Toast.LENGTH_SHORT).show();

                }
                //convert response to string
                try
                {
                        BufferedReader reader = new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8);
                        StringBuilder sb = new StringBuilder();
                        String line = null;
                        while ((line = reader.readLine()) != null) 
                        {
                                sb.append(line + "\n");
                        }
                        is.close();

                        result=sb.toString();
                     Log.e("log_tag", result);
                }
                catch(Exception e)
                {
                       Log.e("log_tag", "Error converting result "+e.toString());
                    Toast.makeText(getApplicationContext(), " Input reading fail", Toast.LENGTH_SHORT).show();

                }

                try
                {     
                JSONArray jArray = new JSONArray(result);       

                String re=jArray.getString(jArray.length()-1);      

               int flag=1;

                for(int i=0;i<jArray.length()-1;i++)

                        {                                                               
                                    JSONObject json_data = jArray.getJSONObject(i);

                                      Log.i("log_tag2","title: "+jArray['price0']);
                         }
                }
                catch(JSONException e)
                {
                        Log.e("log_tag", "Error parsing data "+e.toString());
                        Toast.makeText(getApplicationContext(), "JsonArray fail", Toast.LENGTH_SHORT).show();
                }

但是我收到错误，错误解析数据 org.json.JSONException:类型 org.json.JSONArray 的值无法转换为 JSONObject

我不知道如何获得值(value)？

Answer 1

for(int i=0;i<jArray.length();i++) { 
     JSONArray  jArrayInner = jArray.optJSONArray(i);
     if (jArrayInner != null) {
         for(int j=0;j<jArrayInner.length();j++) {
                JSONObject json_data = jArrayInner.getJSONObject(j);
                Log.i("log_tag2","title: "+json_data.optString("price0"));
                Log.i("log_tag2","title: "+json_data.optString("size0"));
          }
      }
     }                                                     

}

要从内部 json 对象检索数据(即从数组中正确检索数据)，必须使用 optString (opt*Type) 方法。此外，数组中的每个内部对象都应该具有相同的键(price 和 size)。