Android 使用asynk任务避免网络错误
我是android的初学者,我想知道如何用异步任务更新代码?? 这是密码 AndroidJSONParsingActivity.java 包com.androidhive.json解析Android 使用asynk任务避免网络错误,android,android-asynctask,Android,Android Asynctask,我是android的初学者,我想知道如何用异步任务更新代码?? 这是密码 AndroidJSONParsingActivity.java 包com.androidhive.json解析 import java.util.ArrayList; import java.util.HashMap; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; import android.
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);
}
});
}
import java.util.ArrayList;
导入java.util.HashMap;
导入org.json.JSONArray;
导入org.json.JSONException;
导入org.json.JSONObject;
导入android.app.ListActivity;
导入android.content.Intent;
导入android.os.Bundle;
导入android.util.Log;
导入android.view.view;
导入android.widget.AdapterView;
导入android.widget.AdapterView.OnItemClickListener;
导入android.widget.ListAdapter;
导入android.widget.ListView;
导入android.widget.simpledapter;
导入android.widget.TextView;
公共类AndroidJSONParsingActivity扩展了ListActivity{
//发出请求的url
专用静态字符串url=”http://api.androidhive.info/contacts/";
//JSON节点名称
专用静态最终字符串标记_CONTACTS=“CONTACTS”;
私有静态最终字符串标记\u ID=“ID”;
私有静态最终字符串标记_NAME=“NAME”;
私有静态最终字符串标记\u EMAIL=“EMAIL”;
私有静态最终字符串标记_ADDRESS=“ADDRESS”;
私有静态最终字符串标记_GENDER=“GENDER”;
专用静态最终字符串标记_PHONE=“PHONE”;
专用静态最终字符串标记\u PHONE\u MOBILE=“MOBILE”;
专用静态最终字符串标记\u PHONE\u HOME=“HOME”;
专用静态最终字符串标记\u PHONE\u OFFICE=“OFFICE”;
//联系JSONArray
JSONArray联系人=null;
@凌驾
创建时的公共void(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
//ListView的Hashmap
ArrayList contactList=新建ArrayList();
//创建JSON解析器实例
JSONParser jParser=新的JSONParser();
//从URL获取JSON字符串
JSONObject json=jParser.getJSONFromUrl(url);
试一试{
//获取联系人数组
contacts=json.getJSONArray(TAG_contacts);
//通过所有触点循环
对于(int i=0;ivalue
地图放置(标签标识,标识);
地图放置(标签名称、名称);
地图放置(标签、电子邮件、电子邮件);
地图放置(标签、手机、手机);
//将哈希列表添加到ArrayList
联系人列表。添加(地图);
}
}捕获(JSONException e){
e、 printStackTrace();
}
/**
*将解析的JSON数据更新到ListView中
* */
ListAdapter=新的SimpleAdapter(此,contactList,
R.layout.list_项目,
新字符串[]{TAG\u NAME,TAG\u EMAIL,TAG\u PHONE\u MOBILE},新int[]{
R.id.name、R.id.email、R.id.mobile});
setListAdapter(适配器);
//选择单个ListView项
ListView lv=getListView();
//在选择单个列表项时启动新屏幕
lv.setOnItemClickListener(新的OnItemClickListener(){
@凌驾
public void onItemClick(AdapterView父级、视图、,
内部位置,长id){
//从选定的ListItem获取值
字符串名称=((TextView)view.findviewbyd(R.id.name)).getText().toString();
字符串成本=((TextView)view.findViewById(R.id.email)).getText().toString();
字符串描述=((TextView)view.findviewbyd(R.id.mobile)).getText().toString();
//开始新的意图
Intent in=新的Intent(getApplicationContext(),SingleMenuItemActivity.class);
in.putExtra(标签名称、名称);
in.putExtra(标签、电子邮件、成本);
in.putExtra(标签、手机、说明);
星触觉(in);
}
});
}
这是本教程的链接
感谢您的帮助:)有什么问题吗?有任何logcat错误吗?请不要发表任何问题。他只是想有人为他编写代码。我有问题,我有很多错误。您需要提供有关错误的详细信息