[英]JSON data not being fetched from server in android app
因此,我才刚刚开始使用JSON和Volley。 我已经使用XAMMP创建了服务器,并添加了生成JSON数据所需的php脚本。 它在浏览器中正常显示。 但是,在模拟器上运行应用程序时。 永远不会检索数据,并且进度对话框会不断加载,因此应用程序绝不会崩溃。 我采用的代码如下。 我想念什么?
public class Config {
public static final String DATA_URL2= "http://10.0.2.2:8080/webservice/index.php";
public static final String KEY_ID = "ID";
public static final String KEY_NAME = "Name";
public static final String KEY_SURNAME = "Surname";
public static final String JSON_ARRAY = "result";}
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
private EditText editTextId;
private Button buttonGet;
private TextView textViewResult;
private ProgressDialog loading;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
editTextId = (EditText) findViewById(R.id.editTextId);
buttonGet = (Button) findViewById(R.id.buttonGet);
textViewResult = (TextView) findViewById(R.id.textViewResult);
buttonGet.setOnClickListener(this);
}
private void getData() {
loading = ProgressDialog.show(this,"Please wait...","Fetching...",false,false);
String url = Config.DATA_URL2.toString();
StringRequest stringRequest = new StringRequest(url, new Response.Listener<String>() {
@Override
public void onResponse(String response) {
loading.dismiss();
showJSON(response);
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
}
});
RequestQueue requestQueue = Volley.newRequestQueue(this);
requestQueue.add(stringRequest);
}
private void showJSON(String response){
String id="";
String name="";
String surname = "";
try {
JSONObject jsonObject = new JSONObject(response);
JSONArray result = jsonObject.getJSONArray(Config.JSON_ARRAY);
JSONObject collegeData = result.getJSONObject(0);
id = collegeData.getString(Config.KEY_ID);
name = collegeData.getString(Config.KEY_NAME);
surname = collegeData.getString(Config.KEY_SURNAME);
} catch (JSONException e) {
e.printStackTrace();
}
textViewResult.setText("ID:\t"+id+"\nName:\t" +name+ "\nSurname:\t"+ surname);
}
@Override
public void onClick(View v) {
getData();
}}
这是我的堆栈跟踪:
02-14 00:15:19.215 22098-22098/? I/art: Not late-enabling -Xcheck:jni (already on)
02-14 00:15:19.807 22098-22125/za.co.volleydemo D/OpenGLRenderer: Render dirty regions requested: true
02-14 00:15:19.839 22098-22098/za.co.volleydemo D/Atlas: Validating map...
02-14 00:15:19.902 22098-22106/za.co.volleydemo I/art: Background partial concurrent mark sweep GC freed 1945(127KB) AllocSpace objects, 0(0B) LOS objects, 52% free, 921KB/1945KB, paused 5.021ms total 25.227ms
02-14 00:15:19.958 22098-22125/za.co.volleydemo I/OpenGLRenderer: Initialized EGL, version 1.4
02-14 00:15:20.046 22098-22125/za.co.volleydemo D/OpenGLRenderer: Enabling debug mode 0
02-14 00:15:20.073 22098-22125/za.co.volleydemo W/EGL_emulation: eglSurfaceAttrib not implemented
02-14 00:15:20.073 22098-22125/za.co.volleydemo W/OpenGLRenderer: Failed to set EGL_SWAP_BEHAVIOR on surface 0xae2c5a40, error=EGL_SUCCESS
02-14 00:15:23.058 22098-22182/za.co.volleydemo E/Volley: [275] BasicNetwork.performRequest: Unexpected response code 401 for http://10.0.2.2:8080
02-14 00:15:23.076 22098-22125/za.co.volleydemo W/EGL_emulation: eglSurfaceAttrib not implemented
02-14 00:15:23.077 22098-22125/za.co.volleydemo W/OpenGLRenderer: Failed to set EGL_SWAP_BEHAVIOR on surface 0xa609f700, error=EGL_SUCCESS
02-14 00:15:23.220 22098-22182/za.co.volleydemo E/Volley: [275] BasicNetwork.performRequest: Unexpected response code 401 for http://10.0.2.2:8080
另外...这是我的PHP脚本
<?php
define('HOST','localhost');
define('USER','ruchen');
define('PASS','lollatjie');
define('DB','webservice1');
$con = mysqli_connect(HOST,USER,PASS,DB);
$sql = "select * from users where surname = 'Miller'";
$res = mysqli_query($con,$sql);
$result = array();
while($row = mysqli_fetch_array($res)){
array_push($result,
array('id'=>$row[0],
'name'=>$row[1],
'surname'=>$row[2]
));
}
echo json_encode(array("result"=>$result));
mysqli_close($con);
?>
最后,脚本通过我的互联网浏览器生成的JSON数据...
{"result":[{"id":"7","name":"Bob","surname":"Miller"}]}
401表示您无权使用此URL。
从此链接http代码
10.4.2 401未经授权
该请求需要用户认证。 响应必须包括一个WWW-Authenticate头域(第14.47节),该头域包含适用于所请求资源的质询。 客户可以用合适的授权头域(第14.8节)重复请求。 如果请求已包含授权凭证,则401响应指示已拒绝这些凭证的授权
我不确定为什么会收到错误代码401,但我注意到您的代码中有些奇怪的地方。 为什么要发出String请求而不是JsonObject请求?
毕竟,您是从php服务获取JSON数据?
将其更改为JsonObjectRequest,因为您的Json的开头是一个名为“结果”的对象,其中包含一个数组。
我在我的应用程序中做同样的事情,我的Volley下载看起来像这样:
theEvents = new ArrayList<Event>();
requestQueue = Volley.newRequestQueue(getActivity());
JsonObjectRequest jsonObjectRequest = new JsonObjectRequest
(Request.Method.GET, urlService, null, new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
try {
id = response.getString(Config.KEY_ID); // response is now the actual object called "result" from your JSON data.
// do something with the ID
}
.........etc
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