Question

我正在尝试将我的onilne数据库中的数据导入我的android应用程序中的listview。但是我收到错误。请帮助，这是我项目的一个重要部分。这是代码

MainActivity.java

public class MainActivity extends Activity {
     private String jsonResult;
     private String url = "http://pixography.netai.net/json.php";
     private ListView listView;
     private TextView textv1;

     @Override
     protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      listView = (ListView) findViewById(R.id.listView1);
      textv1=(TextView)findViewById(R.id.textView1);
      accessWebService();
     }

     @Override
     public boolean onCreateOptionsMenu(Menu menu) {
      // Inflate the menu; this adds items to the action bar if it is present.
      getMenuInflater().inflate(R.menu.main, menu);
      return true;
     }

     // Async Task to access the web
     private class JsonReadTask extends AsyncTask<String, Void, String> {
      @Override
      protected String doInBackground(String... params) {
       HttpClient httpclient = new DefaultHttpClient();
       HttpPost httppost = new HttpPost(params[0]);
       try {
        HttpResponse response = httpclient.execute(httppost);
        jsonResult = inputStreamToString(
          response.getEntity().getContent()).toString();
       }

       catch (ClientProtocolException e) {
        e.printStackTrace();
       } catch (IOException e) {
        e.printStackTrace();
       }
       return null;
      }

      private StringBuilder inputStreamToString(InputStream is) {
       String rLine = "";
       StringBuilder answer = new StringBuilder();
       BufferedReader rd = new BufferedReader(new InputStreamReader(is));

       try {
        while ((rLine = rd.readLine()) != null) {
         answer.append(rLine);
        }
       }

       catch (IOException e) {
        // e.printStackTrace();
        Toast.makeText(getApplicationContext(),
          "Error..." + e.toString(), Toast.LENGTH_LONG).show();
       }
       return answer;
      }

      @Override
      protected void onPostExecute(String result) {
       ListDrwaer();
      }
     }// end async task

     public void accessWebService() {
      JsonReadTask task = new JsonReadTask();
      // passes values for the urls string array
      task.execute(new String[] { url });
     }

     // build hash set for list view
     public void ListDrwaer() {
      List<Map<String, String>> dslrList = new ArrayList<Map<String, String>>();

      try {
       JSONObject jsonResponse = new JSONObject(jsonResult);
       JSONArray jsonMainNode = jsonResponse.optJSONArray("dslrstore");
       for (int i = 0; i < jsonMainNode.length(); i++) {
        JSONObject jsonChildNode = jsonMainNode.getJSONObject(i);
        String name = jsonChildNode.getString("Name");
        String location = jsonChildNode.getString("Location");
        String outPut = name + "-" + location;
        //textv1.setText(name);
        //textv1.setText(jsonResult);
        dslrList.add(createdslr("dslr", outPut));
       }
      } catch (JSONException e) {
       textv1.setText( "Error" + e.toString());

      }

      SimpleAdapter simpleAdapter = new SimpleAdapter(this, dslrList,
        android.R.layout.simple_list_item_1,
        new String[] { "dslr" }, new int[] { android.R.id.text1 });
      listView.setAdapter(simpleAdapter);
     }

     private HashMap<String, String> createdslr(String name, String location) {
      HashMap<String, String> dslrNamelocate = new HashMap<String, String>();
      dslrNamelocate.put(name,location);
      return dslrNamelocate;
     }
    }

main.xml中

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <TableRow
        android:id="@+id/tableRow1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" >

        <TextView
            android:id="@+id/textView1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="TextView" />

    </TableRow>


    <ListView
        android:id="@+id/listView1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
         >
    </ListView>

</LinearLayout>

JSON.php

<?php
$host = "mysql13.000webhost.com";
$user = "a2464928_rajat";
$password = "rajat123";
$db = "a2464928_minor";
$sql = "select * from dslrstore;";
$con= mysqli_connect($host,$user,$password,$db);
$result = mysqli_query($con,$sql);
$response = array();
while($row = mysqli_fetch_array($result))
{
    array_push($response,array("Name"=>$row[0],"Location"=>$row[1]));   
}
echo json_encode(array($response));
mysqli_close($con);
?>

错误是JSONArray无法转换为JSONObject。

Answer 1

首先，我不确定Android，但是当你返回JSON时，设置正确的标头是一种很好的方式。

到目前为止，您的php脚本（http://pixography.netai.net/json.php）将返回以下内容：

HTTP/1.1 200 OK
Date: Sun, 06 Dec 2015 20:37:02 GMT
Server: Apache
X-Powered-By: PHP/5.2.17
Content-Length: 238
Connection: close
Content-Type: text/html

尝试在脚本中的任何输出之前放置header('Content-type: application/json; charset=utf-8');，同时检查UTF-8 BOM问题，因为它会破坏php中正确的标头输出。

至少你会得到适当的JSON标题。

-

我在你的php代码中看到的另一件事 - 数组键是数字的，我不太确定，但我认为JSON对象键应该是字符串。那么也许你应该试试$response[$row[0]] = array("Name"=>$row[0],"Location"=>$row[1]);？

-

我还认为您应该在mysqli_close($con);之前加echo，以获得更好的效果。在为输出填满数据之后，没有理由保持mysql连接打开。

将数据提取到listview中

1 个答案: