java – 在Fragments中使用JSON时,应用程序在Android开发中没有响应
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我在android中使用导航抽屉.我通过JSON从URL获取数据.当我在加载片段时运行应用程序时会出现错误
“Unfortunately the App has not responded ”
I’m getting the JSON Data from a PHP file and it is taken from the INTERNET for now it is in the localhost.
我的片段类是:
import java.util.ArrayList;
import java.util.HashMap;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class QMFragment extends Fragment {
public QMFragment(){}
// url to make request
private static String url = "http://localhost/app/qm_data.php";
// JSON Node names
private static final String TAG_QM = "qm";
private static final String TAG_ID = "id";
private static final String TAG_NAME = "name";
private static final String TAG_URL = "url";
// Hashmap for ListView
ArrayList<HashMap<String, String>> contactList = new ArrayList<HashMap<String, String>>();
// JSONArray
JSONArray qmArray = null;
// Creating JSON Parser instance
JSONParser jParser = new JSONParser();
// getting JSON string from URL
JSONObject json = jParser.getJSONFromUrl(url);
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_qm, container, false);
getData();
return rootView;
}
public void getData(){
try {
// Getting Array
qmArray = json.getJSONArray(TAG_QM);
// looping through All Data
for(int i = 0; i < qmArray.length(); i++){
JSONObject c = qmArray.getJSONObject(i);
// Storing each json item in variable
String id = c.getString(TAG_ID);
String name = c.getString(TAG_NAME);
String url = c.getString(TAG_URL);
// creating new HashMap
HashMap<String, String> map = new HashMap<String, String>();
// adding each child node to HashMap key => value
map.put(TAG_ID, id);
map.put(TAG_NAME, name);
map.put(TAG_URL, url);
// adding HashList to ArrayList
contactList.add(map);
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}
而我的JSONParser.java是:
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONException;
import org.json.JSONObject;
import android.util.Log;
public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
// constructor
public JSONParser() {
}
public JSONObject getJSONFromUrl(String url) {
// Making HTTP request
try {
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
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();
json = sb.toString();
} catch (Exception e) {
Log.e("Buffer Error", "Error Converting Result " + e.toString());
}
// try parse the string to a JSON object
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error Parsing Data " + e.toString());
}
// return JSON String
return jObj;
}
}
我的XML是:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/bg" >
<TextView
android:id="@+id/txtLabel"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginLeft="40dp"
android:layout_marginTop="5dp"
android:text="@string/head"
android:textColor="@color/text_color"
android:textSize="25sp" />
<TextView
android:layout_width="fill_parent"
android:layout_height="1px"
android:layout_alignParentLeft="true"
android:layout_below="@+id/txtLabel"
android:layout_marginTop="5dp"
android:background="#CCCCCC" />
<ScrollView
android:id="@+id/scrollView1"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_below="@+id/txtLabel"
android:layout_marginTop="10dp" >
<RelativeLayout
android:id="@+id/navigate_RLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
<TextView
android:id="@+id/txtqmhead"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/qm_heading"
android:textSize="25sp"
android:textColor="@color/text_color" />
<TextView
android:id="@+id/txtqmsub"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/qm_chn"
android:textSize="18sp"
android:textColor="@color/text_color"
android:layout_below="@+id/txtqmhead"
android:layout_marginLeft="28dp" />
<TableLayout
android:id="@+id/tbl"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentRight="true"
android:layout_below="@+id/txtqmsub"
android:layout_marginTop="20dp" >
</TableLayout>
</RelativeLayout>
</ScrollView>
</RelativeLayout>
和PHP文件是:
<?php
header('Content-type: application/json');
$server = "localhost";
$username = "root";
$password = "";
$db = "test";
$con = mysql_connect("localhost",$username,$password);
if (!$con)
{
die('Could not connect: ' . mysql_error());
}
mysql_select_db($db, $con);
$result = mysql_query("SELECT * FROM example ORDER BY date DESC");
while($row = mysql_fetch_assoc($result))
{
$output['qm'][]=$row;
}
print(json_encode($output));
mysql_close($con);
?>
LogCat:
12-24 10:19:54.322: E/AndroidRuntime(1700): FATAL EXCEPTION: main
12-24 10:19:54.322: E/AndroidRuntime(1700): android.os.NetworkOnMainThreadException
12-24 10:19:54.322: E/AndroidRuntime(1700): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1084)
12-24 10:19:54.322: E/AndroidRuntime(1700): at java.net.InetAddress.lookupHostByName(InetAddress.java:391)
12-24 10:19:54.322: E/AndroidRuntime(1700): at java.net.InetAddress.getAllByNameImpl(InetAddress.java:242)
12-24 10:19:54.322: E/AndroidRuntime(1700): at java.net.InetAddress.getAllByName(InetAddress.java:220)
12-24 10:19:54.322: E/AndroidRuntime(1700): at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:137)
12-24 10:19:54.322: E/AndroidRuntime(1700): at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
12-24 10:19:54.322: E/AndroidRuntime(1700): at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
12-24 10:19:54.322: E/AndroidRuntime(1700): at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)
12-24 10:19:54.322: E/AndroidRuntime(1700): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555)
12-24 10:19:54.322: E/AndroidRuntime(1700): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
12-24 10:19:54.322: E/AndroidRuntime(1700): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465)
12-24 10:19:54.322: E/AndroidRuntime(1700): at com.qrodsintegrated.JSONParser.getJSONFromUrl(JSONParser.java:38)
12-24 10:19:54.322: E/AndroidRuntime(1700): at com.qrodsintegrated.QMFragment.<init>(QMFragment.java:41)
12-24 10:19:54.322: E/AndroidRuntime(1700): at com.qrodsintegrated.MainActivity.displayView(MainActivity.java:175)
12-24 10:19:54.322: E/AndroidRuntime(1700): at com.qrodsintegrated.MainActivity.access$0(MainActivity.java:164)
12-24 10:19:54.322: E/AndroidRuntime(1700): at com.qrodsintegrated.MainActivity$SlideMenuClickListener.onItemClick(MainActivity.java:126)
12-24 10:19:54.322: E/AndroidRuntime(1700): at android.widget.AdapterView.performItemClick(AdapterView.java:292)
12-24 10:19:54.322: E/AndroidRuntime(1700): at android.widget.AbsListView.performItemClick(AbsListView.java:1058)
12-24 10:19:54.322: E/AndroidRuntime(1700): at android.widget.AbsListView$PerformClick.run(AbsListView.java:2514)
12-24 10:19:54.322: E/AndroidRuntime(1700): at android.widget.AbsListView$1.run(AbsListView.java:3168)
12-24 10:19:54.322: E/AndroidRuntime(1700): at android.os.Handler.handleCallback(Handler.java:605)
12-24 10:19:54.322: E/AndroidRuntime(1700): at android.os.Handler.dispatchMessage(Handler.java:92)
12-24 10:19:54.322: E/AndroidRuntime(1700): at android.os.Looper.loop(Looper.java:137)
12-24 10:19:54.322: E/AndroidRuntime(1700): at android.app.ActivityThread.main(ActivityThread.java:4340)
12-24 10:19:54.322: E/AndroidRuntime(1700): at java.lang.reflect.Method.invokeNative(Native Method)
12-24 10:19:54.322: E/AndroidRuntime(1700): at java.lang.reflect.Method.invoke(Method.java:511)
12-24 10:19:54.322: E/AndroidRuntime(1700): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
12-24 10:19:54.322: E/AndroidRuntime(1700): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
12-24 10:19:54.322: E/AndroidRuntime(1700): at dalvik.system.NativeStart.main(Native Method)
解决方法:
你有
JSONObject json = jParser.getJSONFromUrl(url);
在JSONParser中
HttpResponse httpResponse = httpClient.execute(httpPost);
在ui线程上运行NetworkRelated操作.
使用AsyncTask或Thread
http://developer.android.com/reference/android/os/AsyncTask.html
new TheTask().execute(params);
然后
class TheTask extends AsyncTask<Void,Void,Void>
{
protected void doInbackground(Void... params)
{
// your http request
return null;
}
}
你可以使asynctask成为片段的内部类,并在onPostExecute中更新ui
编辑:
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_qm, container, false);
new TheTask().execute(url);
return rootView;
}
然后
class TheTask extends AsyncTask<String,String,String>
{
@override
protected String doInbackground(String... params)
{
String _response =null;
try {
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(params[0]);
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
_response=EntityUtils.toString(httpEntity);
}catch(Exception e)
{
e.printStacktrace();
}
return _response;
}
@Override
protected void onPostExecute(String result) {
// TODO Auto-generated method stub
super.onPostExecute(result);
Log.i(".......",result);
}
}
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