我在android应用程序中做JSON解析。我想解析位于WAMP服务器上的JSON文件。我正在传递JSON文件的url。我在安卓代码中没有任何错误，但我不知道…每当我运行android应用程序时，它就会被强制关闭。
This My JSONParse类通过传递url解析JSON
package com.example.notificationjson;
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;
}
}
这个JSON文件url: localhost:8080/BestVoyage_PHP/webservices/notification.json这是我的JSON文件输出:{"posts":[{"notification":"Opening shortly in Surat and Jamnagar"},{"notification":"Our New destinations are brazil, argentina, beijing, shanghai, and Scandianvian Countries"}]}
这是我的活动类，我在listview中显示JSON数据
package com.example.notificationjson;
import java.util.ArrayList;
import java.util.HashMap;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.os.Bundle;
import android.app.ListActivity;
import android.content.Intent;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;
import android.widget.AdapterView.OnItemClickListener;
public class MainActivity extends ListActivity {
private static String url = "http://10.0.2.2:8080/BestVoyage_PHP/webservices/notification.json";
// JSON Node names
private static final String TAG_POSTS = "posts";
private static final String TAG_NOTIFICATION = "notification";
// contacts JSONArray
JSONArray posts = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Log.d(url, "urlurl");
// Hashmap for ListView
ArrayList<HashMap<String, String>> contactList = new ArrayList<HashMap<String, String>>();
// Creating JSON Parser instance
JSONParser jParser = new JSONParser();
// getting JSON string from URL
JSONObject json = jParser.getJSONFromUrl(url);
try {
// Getting Array of Contacts
posts = json.getJSONArray(TAG_POSTS);
// looping through All Contacts
for(int i = 0; i < posts.length(); i++){
JSONObject c = posts.getJSONObject(i);
// Storing each json item in variable
String notification = c.getString(TAG_NOTIFICATION);
// creating new HashMap
HashMap<String, String> map = new HashMap<String, String>();
// adding each child node to HashMap key => value
map.put(TAG_NOTIFICATION, notification);
// adding HashList to ArrayList
contactList.add(map);
}
} catch (JSONException e) {
e.printStackTrace();
}
/**
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(this, contactList,
R.layout.list_item,
new String[] {TAG_NOTIFICATION}, new int[] {R.id.notification});
setListAdapter(adapter);
// selecting single ListView item
ListView lv = getListView();
// Launching new screen on Selecting Single ListItem
lv.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// getting values from selected ListItem
String noti = ((TextView) view.findViewById(R.id.notification)).getText().toString();
// Starting new intent
Intent in = new Intent(getApplicationContext(), SingleMenuItemActivity.class);
in.putExtra(TAG_NOTIFICATION, noti);
startActivity(in);
}
});
}
}
这是logcat:
01-01 23:10:37.105: D/AndroidRuntime(730): Shutting down VM
01-01 23:10:37.105: W/dalvikvm(730): threadid=1: thread exiting with uncaught exception (group=0x40015560)
01-01 23:10:37.125: E/AndroidRuntime(730): FATAL EXCEPTION: main
01-01 23:10:37.125: E/AndroidRuntime(730): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.notificationjson/com.example.notificationjson.MainActivity}: java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list'
01-01 23:10:37.125: E/AndroidRuntime(730): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647)
01-01 23:10:37.125: E/AndroidRuntime(730): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
01-01 23:10:37.125: E/AndroidRuntime(730): at android.app.ActivityThread.access$1500(ActivityThread.java:117)
01-01 23:10:37.125: E/AndroidRuntime(730): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
01-01 23:10:37.125: E/AndroidRuntime(730): at android.os.Handler.dispatchMessage(Handler.java:99)
01-01 23:10:37.125: E/AndroidRuntime(730): at android.os.Looper.loop(Looper.java:123)
01-01 23:10:37.125: E/AndroidRuntime(730): at android.app.ActivityThread.main(ActivityThread.java:3683)
01-01 23:10:37.125: E/AndroidRuntime(730): at java.lang.reflect.Method.invokeNative(Native Method)
01-01 23:10:37.125: E/AndroidRuntime(730): at java.lang.reflect.Method.invoke(Method.java:507)
01-01 23:10:37.125: E/AndroidRuntime(730): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
01-01 23:10:37.125: E/AndroidRuntime(730): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
01-01 23:10:37.125: E/AndroidRuntime(730): at dalvik.system.NativeStart.main(Native Method)
01-01 23:10:37.125: E/AndroidRuntime(730): Caused by: java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list'
01-01 23:10:37.125: E/AndroidRuntime(730): at android.app.ListActivity.onContentChanged(ListActivity.java:243)
01-01 23:10:37.125: E/AndroidRuntime(730): at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:210)
01-01 23:10:37.125: E/AndroidRuntime(730): at android.app.Activity.setContentView(Activity.java:1657)
01-01 23:10:37.125: E/AndroidRuntime(730): at com.example.notificationjson.MainActivity.onCreate(MainActivity.java:40)
01-01 23:10:37.125: E/AndroidRuntime(730): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
01-01 23:10:37.125: E/AndroidRuntime(730): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
01-01 23:10:37.125: E/AndroidRuntime(730): ... 11 more
当您的活动启动时，问题已经发生了(尚未涉及JSON解析)。扩展了ListActivity类。这个类要求你在你的布局中定义一个id为android.R.id.list的ListView。
您可以从日志目录中的这一行看到:
Caused by: java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list'
它来自你的接口XML，你的ListView必须被称为list如果你要扩展ListActivity