我得到这个日志猫：
08-14 11:42:55.923: W/System.err(1137): org.json.JSONException: Value {"error":0,"success":0,"tag":"helloworld"} of type org.json.JSONObject cannot be converted to JSONArray
如何解决此问题？
08-14 11:42:55.923: W/System.err(1137): at org.json.JSON.typeMismatch(JSON.java:111)
我使用的代码是：
public class MainActivity extends Activity {
TextView tv;
HttpClient client;
JSONObject json;
final static String URL = "http://192.168.1.9/sumit/hello.php";
//final static String URL = "http://json.org/example.html";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tv = (TextView) findViewById(R.id.tv1);
client = new DefaultHttpClient();
Log.e("my","check");
new Read().execute("tag");
// StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder()
// .detectAll().penaltyLog().build();
// StrictMode.setThreadPolicy(policy);
}
public JSONObject myData() throws ClientProtocolException, IOException,
JSONException {
StringBuilder url = new StringBuilder(URL);
HttpGet get = new HttpGet(url.toString());
HttpResponse r = client.execute(get);
int status = r.getStatusLine().getStatusCode();
if (status == 200) {
HttpEntity e = r.getEntity();
String data = EntityUtils.toString(e);
JSONArray datastream = new JSONArray(data);
JSONObject message = datastream.getJSONObject(0);
return message;
} else {
Toast.makeText(MainActivity.this, "error encountered",
Toast.LENGTH_SHORT).show();
return null;
}
}
class Read extends AsyncTask<String, Integer, String> {
@Override
protected String doInBackground(String... params) {
// TODO Auto-generated method stub
try {
json = myData();
return json.getString(params[0]);
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(String result) {
// TODO Auto-generated method stub
tv.setText(result);
}
}
}
生成的 JSON 代码：
{"tag":"hello","success":0,"error":0}
用于生成以下内容的代码：
<?php
// response Array
$response = array("tag" => helloworld, "success" => 0, "error" => 0);
echo json_encode($response);
?>
因为你得到的不是JSONArray - 它是JSONObject
JSONArray 在你的例子中看起来像这样：
[{"error":0,"success":0,"tag":"helloworld"}]
它是一个带有一个元素的数组（即 JSONObject ，其中包含字段）。
我不太了解 php（我也不知道json_encode是如何工作的），但试试这个：
<?
$response = array(array("tag" => helloworld, "success" => 0, "error" => 0));
echo json_encode($response);
?>