当我第一次安装Android应用程序时，我试图将数据从服务存储到设备上的本地sqlite数据库中。但调试中的应用程序在logcat中的异步任务中给出致命异常，应用程序突然关闭。任何有解释的帮助都可以，我还在学习android开发。以下是我的代码＆amp;服务参考，谢谢。请进一步帮助我如何将这些数据存储在本地sqlite数据库中。
来自服务的JSON响应：
{"GetData":[{"Email":"hans@gmail.com",
"FirstName":"Hansel",
"GroupName":"FB",
"HomeAddress":"E-8\/9, UGF, Second Suite, NY",
"ID":"hans@gmail.com",
"LastName":"Gretel",
"MobileNumbers":["+128990068","+12399884"],
"Name":"Hansel Gretel",
"OfficeAddress":"D-82, Second Floor, London Boulevard, NJ",
"TelephoneNumbers":["01312300534","+128790084"]},
{"Email":"ishyk@gmail.com",
"FirstName":"Airina",
"GroupName":"FB",
"HomeAddress":"E-8\/9, UGF, Second Suite, NY",
"ID":"ishyk@gmail.com",
"LastName":"Shyk",
"MobileNumbers":["+1 (287) 304-5115","+1 (285) 304-5115"],
"Name":"Airina Shyk",
"OfficeAddress":"D-82, Third Floor, London Boulevard, NJ",
"TelephoneNumbers":["+1 (125) 367-6085","+1 (125) 367-6087"]}]}
我的MainActivity类：
package com.fb.jsondata;
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.app.ProgressDialog;
import android.content.Intent;
import android.os.AsyncTask;
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 MainActivity extends ListActivity {
private ProgressDialog pDialog;
// URL to get contacts JSON
private static String url = "http://fb.mysite.com/CDService/CDService.svc/GetMyData///johndow@gmail.com";
// JSON Node names
private static final String TAG_CONTACTS = "GetData";
private static final String TAG_ID = "ID";
private static final String TAG_FIRST_NAME = "FirstName";
private static final String TAG_LAST_NAME = "LastName";
private static final String TAG_NAME = "Name";
private static final String TAG_EMAIL = "Email";
private static final String TAG_HOME_ADDRESS = "HomeAddress";
private static final String TAG_OFFICE_ADDRESS = "OfficeAddress";
private static final String TAG_GROUP_NAME = "GroupName";
private static final String TAG_PHONE = "TelephoneNumbers";
private static final String TAG_PHONE_MOBILE = "MobileNumbers";
// contacts JSONArray
JSONArray contacts = null;
// mobile JSONArray
JSONArray mobiles = null;
// telephone JSONArray
JSONArray telephones = null;
// Hashmap for ListView
ArrayList<HashMap<String, String>> contactList;
ArrayList<String> myMob;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
contactList = new ArrayList<HashMap<String, String>>();
ListView lv = getListView();
// Listview on item click listener
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 single contact activity
Intent in = new Intent(getApplicationContext(),
SingleContactActivity.class);
in.putExtra(TAG_NAME, name);
in.putExtra(TAG_EMAIL, cost);
in.putExtra(TAG_PHONE_MOBILE, description);
startActivity(in);
}
});
// Calling async task to get json
new GetContacts().execute();
}
/**
* Async task class to get json by making HTTP call
* */
private class GetContacts extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
pDialog = new ProgressDialog(MainActivity.this);
pDialog.setMessage("Please wait...");
pDialog.setCancelable(false);
pDialog.show();
}
@Override
protected Void doInBackground(Void... arg0) {
// Creating service handler class instance
ServiceHandler sh = new ServiceHandler();
// Making a request to url and getting response
String jsonStr = sh.makeServiceCall(url, ServiceHandler.GET);
Log.d("Response: ", "> " + jsonStr);
if (jsonStr != null) {
try {
JSONObject jsonObj = new JSONObject(jsonStr);
// Getting JSON Array node
contacts = jsonObj.getJSONArray(TAG_CONTACTS);
// looping through All Contacts
for (int i = 0; i < contacts.length(); i++) {
JSONObject c = contacts.getJSONObject(i);
String id = c.getString(TAG_ID);
String name = c.getString(TAG_NAME);
String email = c.getString(TAG_EMAIL);
String address = c.getString(TAG_HOME_ADDRESS);
String address1 = c.getString(TAG_OFFICE_ADDRESS);
String gender = c.getString(TAG_GROUP_NAME);
// Phone node is JSON Object
mobiles = c.getJSONArray(TAG_PHONE_MOBILE);
for(int n=0;n<mobiles.length();n++)
{
String mobile = (String) mobiles.get(n);
myMob.add(mobile);
}
// tmp hashmap for single contact
HashMap<String, String> contact = new HashMap<String, String>();
// adding each child node to HashMap key => value
contact.put(TAG_ID, id);
contact.put(TAG_NAME, name);
contact.put(TAG_EMAIL, email);
contact.put(TAG_PHONE_MOBILE, myMob.toString());
// adding contact to contact list
contactList.add(contact);
}
} catch (JSONException e) {
e.printStackTrace();
}
} else {
Log.e("ServiceHandler", "Couldn't get any data from the url");
}
return null;
}
@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
// Dismiss the progress dialog
if (pDialog.isShowing())
pDialog.dismiss();
/**
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(
MainActivity.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);
}
}
}
服务处理程序类：
package com.fb.jsondata;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.List;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.utils.URLEncodedUtils;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;
public class ServiceHandler {
static String response = null;
public final static int GET = 1;
public final static int POST = 2;
public ServiceHandler() {
}
/**
* Making service call
* @url - url to make request
* @method - http request method
* */
public String makeServiceCall(String url, int method) {
return this.makeServiceCall(url, method, null);
}
/**
* Making service call
* @url - url to make request
* @method - http request method
* @params - http request params
* */
public String makeServiceCall(String url, int method,
List<NameValuePair> params) {
try {
// http client
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpEntity httpEntity = null;
HttpResponse httpResponse = null;
// Checking http request method type
if (method == POST) {
HttpPost httpPost = new HttpPost(url);
// adding post params
if (params != null) {
httpPost.setEntity(new UrlEncodedFormEntity(params));
}
httpResponse = httpClient.execute(httpPost);
} else if (method == GET) {
// appending params to url
if (params != null) {
String paramString = URLEncodedUtils
.format(params, "utf-8");
url += "?" + paramString;
}
HttpGet httpGet = new HttpGet(url);
httpResponse = httpClient.execute(httpGet);
}
httpEntity = httpResponse.getEntity();
response = EntityUtils.toString(httpEntity);
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return response;
}
}
Logcat响应：
08-06 17:41:27.980: E/AndroidRuntime(362): FATAL EXCEPTION: AsyncTask #1
08-06 17:41:27.980: E/AndroidRuntime(362): java.lang.RuntimeException: An error occured while executing doInBackground()
08-06 17:41:27.980: E/AndroidRuntime(362): at android.os.AsyncTask$3.done(AsyncTask.java:200)
08-06 17:41:27.980: E/AndroidRuntime(362): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
08-06 17:41:27.980: E/AndroidRuntime(362): at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
08-06 17:41:27.980: E/AndroidRuntime(362): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
08-06 17:41:27.980: E/AndroidRuntime(362): at java.util.concurrent.FutureTask.run(FutureTask.java:137)
08-06 17:41:27.980: E/AndroidRuntime(362): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1068)
08-06 17:41:27.980: E/AndroidRuntime(362): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:561)
08-06 17:41:27.980: E/AndroidRuntime(362): at java.lang.Thread.run(Thread.java:1096)
08-06 17:41:27.980: E/AndroidRuntime(362): Caused by: java.lang.ClassCastException: java.lang.String
08-06 17:41:27.980: E/AndroidRuntime(362): at com.bnk.jsondata.MainActivity$GetContacts.doInBackground(MainActivity.java:160)
08-06 17:41:27.980: E/AndroidRuntime(362): at com.bnk.jsondata.MainActivity$GetContacts.doInBackground(MainActivity.java:1)
08-06 17:41:27.980: E/AndroidRuntime(362): at android.os.AsyncTask$2.call(AsyncTask.java:185)
08-06 17:41:27.980: E/AndroidRuntime(362): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
08-06 17:41:27.980: E/AndroidRuntime(362): ... 4 more
08-06 17:41:30.931: E/WindowManager(362): Activity com.bnk.jsondata.MainActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@45f61928 that was originally added here
08-06 17:41:30.931: E/WindowManager(362): android.view.WindowLeaked: Activity com.bnk.jsondata.MainActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@45f61928 that was originally added here
08-06 17:41:30.931: E/WindowManager(362): at android.view.ViewRoot.<init>(ViewRoot.java:247)
08-06 17:41:30.931: E/WindowManager(362): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:148)
08-06 17:41:30.931: E/WindowManager(362): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91)
08-06 17:41:30.931: E/WindowManager(362): at android.view.Window$LocalWindowManager.addView(Window.java:424)
08-06 17:41:30.931: E/WindowManager(362): at android.app.Dialog.show(Dialog.java:241)
08-06 17:41:30.931: E/WindowManager(362): at com.bnk.jsondata.MainActivity$GetContacts.onPreExecute(MainActivity.java:109)
08-06 17:41:30.931: E/WindowManager(362): at android.os.AsyncTask.execute(AsyncTask.java:391)
08-06 17:41:30.931: E/WindowManager(362): at com.bnk.jsondata.MainActivity.onCreate(MainActivity.java:94)
08-06 17:41:30.931: E/WindowManager(362): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
08-06 17:41:30.931: E/WindowManager(362): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
08-06 17:41:30.931: E/WindowManager(362): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
08-06 17:41:30.931: E/WindowManager(362): at android.app.ActivityThread.access$2300(ActivityThread.java:125)
08-06 17:41:30.931: E/WindowManager(362): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
08-06 17:41:30.931: E/WindowManager(362): at android.os.Handler.dispatchMessage(Handler.java:99)
08-06 17:41:30.931: E/WindowManager(362): at android.os.Looper.loop(Looper.java:123)
08-06 17:41:30.931: E/WindowManager(362): at android.app.ActivityThread.main(ActivityThread.java:4627)
08-06 17:41:30.931: E/WindowManager(362): at java.lang.reflect.Method.invokeNative(Native Method)
08-06 17:41:30.931: E/WindowManager(362): at java.lang.reflect.Method.invoke(Method.java:521)
08-06 17:41:30.931: E/WindowManager(362): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
08-06 17:41:30.931: E/WindowManager(362): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
08-06 17:41:30.931: E/WindowManager(362): at dalvik.system.NativeStart.main(Native Method)
我已经添加了logcat，看看。
答案 0 :(得分：0)
我可以在
的日志中看到 ClassCastExceptionfor(int n=0;n<mobiles.length();n++)
{
String mobile = (String) mobiles.get(n);
myMob.add(mobile);
}
请改用mobiles.getString(n)。希望这会对你有所帮助。
答案 1 :(得分：0)
我很惊讶你没有获得nullpointerexception ...因为你没有初始化myMob ArrayList .... 我建议你首先初始化ArrayList myMob ...然后查看结果..