我正在使用Androidhive教程从 JSON 文件中获取数据并将其作为列表或网格查看。但是当运行这个应用程序时，应用程序崩溃并退出。我在代码上找不到任何错误。您可以从上面的教程链接下载源代码。但是我在这里提供了类文件。请有人帮助我尽快解决问题。先谢谢了。
AndroidJSONParsingActivity.java
package com.example.samplejsonparsing;
import java.util.ArrayList;
import java.util.HashMap;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.ListActivity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;
public class AndroidJSONParsingActivity extends ListActivity {
// url to make request
private static String url = "http://api.androidhive.info/contacts/";
// JSON Node names
private static final String TAG_CONTACTS = "contacts";
private static final String TAG_ID = "id";
private static final String TAG_NAME = "name";
private static final String TAG_EMAIL = "email";
private static final String TAG_ADDRESS = "address";
private static final String TAG_GENDER = "gender";
private static final String TAG_PHONE = "phone";
private static final String TAG_PHONE_MOBILE = "mobile";
private static final String TAG_PHONE_HOME = "home";
private static final String TAG_PHONE_OFFICE = "office";
// contacts JSONArray
JSONArray contacts = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// 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
contacts = json.getJSONArray(TAG_CONTACTS);
// looping through All Contacts
for(int i = 0; i < contacts.length(); i++){
JSONObject c = contacts.getJSONObject(i);
// Storing each json item in variable
String id = c.getString(TAG_ID);
String name = c.getString(TAG_NAME);
String email = c.getString(TAG_EMAIL);
String address = c.getString(TAG_ADDRESS);
String gender = c.getString(TAG_GENDER);
// Phone number is agin JSON Object
JSONObject phone = c.getJSONObject(TAG_PHONE);
String mobile = phone.getString(TAG_PHONE_MOBILE);
String home = phone.getString(TAG_PHONE_HOME);
String office = phone.getString(TAG_PHONE_OFFICE);
// 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_EMAIL, email);
map.put(TAG_PHONE_MOBILE, mobile);
// 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_NAME, TAG_EMAIL, TAG_PHONE_MOBILE }, new int[] {
R.id.name, R.id.email, R.id.mobile });
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 name = ((TextView) view.findViewById(R.id.name)).getText().toString();
String cost = ((TextView) view.findViewById(R.id.email)).getText().toString();
String description = ((TextView) view.findViewById(R.id.mobile)).getText().toString();
// Starting new intent
Intent in = new Intent(getApplicationContext(), SingleMenuItemActivity.class);
in.putExtra(TAG_NAME, name);
in.putExtra(TAG_EMAIL, cost);
in.putExtra(TAG_PHONE_MOBILE, description);
startActivity(in);
}
});
}
}
JSONParser.java
package com.example.samplejsonparsing;
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;
}
}
SingleMenuItemActivity.java
package com.example.samplejsonparsing;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.widget.TextView;
public class SingleMenuItemActivity extends Activity {
// JSON node keys
private static final String TAG_NAME = "name";
private static final String TAG_EMAIL = "email";
private static final String TAG_PHONE_MOBILE = "mobile";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.single_list_item);
// getting intent data
Intent in = getIntent();
// Get JSON values from previous intent
String name = in.getStringExtra(TAG_NAME);
String cost = in.getStringExtra(TAG_EMAIL);
String description = in.getStringExtra(TAG_PHONE_MOBILE);
// Displaying all values on the screen
TextView lblName = (TextView) findViewById(R.id.name_label);
TextView lblCost = (TextView) findViewById(R.id.email_label);
TextView lblDesc = (TextView) findViewById(R.id.mobile_label);
lblName.setText(name);
lblCost.setText(cost);
lblDesc.setText(description);
}
}
也许这可能是一个愚蠢的问题，但请不要忽视这一点。
08-08 10:18:50.240: D/AbsListView(14239): Get MotionRecognitionManager
08-08 10:18:50.285: D/AndroidRuntime(14239): Shutting down VM
08-08 10:18:50.285: W/dalvikvm(14239): threadid=1: thread exiting with uncaught exception (group=0x40ee32a0)
08-08 10:18:50.295: E/AndroidRuntime(14239): FATAL EXCEPTION: main
08-08 10:18:50.295: E/AndroidRuntime(14239): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.samplejsonparsing/com.example.samplejsonparsing.AndroidJSONParsingActivity}: android.os.NetworkOnMainThreadException
08-08 10:18:50.295: E/AndroidRuntime(14239): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2100)
08-08 10:18:50.295: E/AndroidRuntime(14239): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2125)
08-08 10:18:50.295: E/AndroidRuntime(14239): at android.app.ActivityThread.access$600(ActivityThread.java:140)
08-08 10:18:50.295: E/AndroidRuntime(14239): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1227)
08-08 10:18:50.295: E/AndroidRuntime(14239): at android.os.Handler.dispatchMessage(Handler.java:99)
08-08 10:18:50.295: E/AndroidRuntime(14239): at android.os.Looper.loop(Looper.java:137)
08-08 10:18:50.295: E/AndroidRuntime(14239): at android.app.ActivityThread.main(ActivityThread.java:4898)
08-08 10:18:50.295: E/AndroidRuntime(14239): at java.lang.reflect.Method.invokeNative(Native Method)
08-08 10:18:50.295: E/AndroidRuntime(14239): at java.lang.reflect.Method.invoke(Method.java:511)
08-08 10:18:50.295: E/AndroidRuntime(14239): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1006)
08-08 10:18:50.295: E/AndroidRuntime(14239): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:773)
08-08 10:18:50.295: E/AndroidRuntime(14239): at dalvik.system.NativeStart.main(Native Method)
08-08 10:18:50.295: E/AndroidRuntime(14239): Caused by: android.os.NetworkOnMainThreadException
08-08 10:18:50.295: E/AndroidRuntime(14239): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1118)
08-08 10:18:50.295: E/AndroidRuntime(14239): at java.net.InetAddress.lookupHostByName(InetAddress.java:385)
08-08 10:18:50.295: E/AndroidRuntime(14239): at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236)
08-08 10:18:50.295: E/AndroidRuntime(14239): at java.net.InetAddress.getAllByName(InetAddress.java:214)
08-08 10:18:50.295: E/AndroidRuntime(14239): at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:137)
08-08 10:18:50.295: E/AndroidRuntime(14239): at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
08-08 10:18:50.295: E/AndroidRuntime(14239): at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
08-08 10:18:50.295: E/AndroidRuntime(14239): at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)
08-08 10:18:50.295: E/AndroidRuntime(14239): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:670)
08-08 10:18:50.295: E/AndroidRuntime(14239): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:509)
08-08 10:18:50.295: E/AndroidRuntime(14239): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
08-08 10:18:50.295: E/AndroidRuntime(14239): at com.example.samplejsonparsing.JSONParser.getJSONFromUrl(JSONParser.java:38)
08-08 10:18:50.295: E/AndroidRuntime(14239): at com.example.samplejsonparsing.AndroidJSONParsingActivity.onCreate(AndroidJSONParsingActivity.java:54)
08-08 10:18:50.295: E/AndroidRuntime(14239): at android.app.Activity.performCreate(Activity.java:5206)
08-08 10:18:50.295: E/AndroidRuntime(14239): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1083)
08-08 10:18:50.295: E/AndroidRuntime(14239): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2064)
08-08 10:18:50.295: E/AndroidRuntime(14239): ... 11 more
08-08 10:19:39.280: I/Process(14239): Sending signal. PID: 14239 SIG: 9
AndroidManifest
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.samplejsonparsing"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="17" />
<uses-permission android:name="android.permission.INTERNET"/>
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.example.samplejsonparsing.AndroidJSONParsingActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:label="@string/app_name"
android:name="com.example.samplejsonparsing.SingleMenuItemActivity" >
</activity>
</application>
</manifest>