我正在开发一个应用程序，当没有移动信号的覆盖区域时，将数据保存到数据库中。当服务返回时，它将从数据库中获取所有数据并上传到服务器。
现在我有两个问题。
- 当第一次将数据插入数据库时，IntentService 停止。（当网络服务返回时，它还会在服务器上上传数据，为了检查网络连接，我使用了计时器。）我不想停止服务。
- 当我第二次启动它再次创建的服务并给出 Nullpointerexception 时。因为数据库中没有数据，所以它也给出了一些关于数据检索的其他错误。
我的代码有什么问题？我只希望当用户启动服务时它会一直运行到数据库中的最后一个数据，然后它会停止。我在 intentservice 中使用了线程，因为之前我的应用程序崩溃了。
LogCat 错误
10-14 20:44:02.135: E/Service(10042): Service Created..
10-14 20:44:02.505: E/Service Started(10042): Successful
10-14 20:44:03.585: E/Service Network(10042): Network is offline
10-14 20:44:08.656: E/Service Network(10042): Network is offline
10-14 20:44:13.616: E/Service Network(10042): Network is offline
10-14 20:44:18.646: E/Service Network(10042): Network is offline
10-14 20:44:23.595: E/Service Network(10042): Network is offline
10-14 20:44:29.526: E/Service Network(10042): Network is online
10-14 20:44:31.256: E/Data Sent(10042): Response 200
10-14 20:44:33.599: E/Service Network(10042): Network is online
10-14 20:44:34.446: E/Data Sent(10042): Response 200
10-14 20:44:38.646: E/Service Network(10042): Network is online
10-14 20:44:40.616: E/Data Sent(10042): Response 200
10-14 20:44:43.625: E/Service Network(10042): Network is offline
10-14 20:44:48.595: E/Service Network(10042): Network is offline
10-14 20:44:53.586: E/Service Network(10042): Network is offline
10-14 20:45:20.486: E/Service(10042): Service Created..
10-14 20:45:20.587: E/Service Started(10042): Successful
10-14 20:45:20.627: E/Insertion(10042): java.lang.NullPointerException
10-14 20:45:21.666: E/Service Network(10042): Network is offline
10-14 20:45:23.616: E/Service Network(10042): Network is offline
10-14 20:45:36.645: E/Service Network(10042): Network is offline
10-14 20:45:38.585: E/Service Network(10042): Network is offline
10-14 20:45:41.786: E/Service Network(10042): Network is online
10-14 20:45:42.026: E/AndroidRuntime(10042): FATAL EXCEPTION: Timer-1
10-14 20:45:42.026: E/AndroidRuntime(10042): java.lang.NullPointerException
10-14 20:45:42.026: E/AndroidRuntime(10042): at com.remote.synchronizer.haris.SQLiteAdapter.getAllContacts(SQLiteAdapter.java:93)
10-14 20:45:42.026: E/AndroidRuntime(10042): at com.remote.synchronizer.haris.OfflineDataService$1$1.run(OfflineDataService.java:80)
10-14 20:45:42.026: E/AndroidRuntime(10042): at java.util.Timer$TimerImpl.run(Timer.java:284)
10-14 20:45:43.646: E/Service Network(10042): Network is online
10-14 20:45:44.266: E/Data Sent(10042): Response 200
SQLiteAdapter.java
package com.remote.synchronizer.haris;
import java.util.ArrayList;
import java.util.List;
import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
public class SQLiteAdapter extends SQLiteOpenHelper {
public static final String DATABASE_NAME = "Product";
public static final String TABLE_NAME = "Orders";
public static final int DATABASE_VERSION = 1;
public static final String KEY_ID = " _id"; //
public static final String KEY_NAME = "name";
public static final String KEY_SHOP = "shop";
private static final String KEY_CITY = "city";
private static final String KEY_DATE = "datee";
private static final String KEY_ORDER = "orderr";
private SQLiteDatabase sqLiteDatabase;
private SQLiteAdapter sqLiteHelper=this;
private static final String CREATE_TABLE =
"CREATE TABLE " + TABLE_NAME + " ("
+ KEY_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
+ KEY_NAME + " VARCHAR,"
+ KEY_SHOP + " VARCHAR," + KEY_CITY + " VARCHAR, " + KEY_DATE + " VARCHAR, " + KEY_ORDER + " VARCHAR" +");";
public SQLiteAdapter(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(CREATE_TABLE);
sqLiteDatabase=db;
}
/*public void close(){
sqLiteHelper.close();
}
*/
public void insert(String name, String shop, String city, String datee, String orderr){
try
{
ContentValues contentValues = new ContentValues();
contentValues.put(KEY_NAME, name);
contentValues.put(KEY_SHOP, shop);
contentValues.put(KEY_CITY, city);
contentValues.put(KEY_DATE, datee);
contentValues.put(KEY_ORDER, orderr);
sqLiteDatabase.insertOrThrow(TABLE_NAME, KEY_ID, contentValues);
//sqLiteDatabase.close();
}
catch(Exception e)
{
e.printStackTrace();
Log.e("Insertion", e.toString());
}
}
public void deleteAll(){
sqLiteDatabase.delete(TABLE_NAME, null, null);
}
public void delete_byID(int id){
sqLiteDatabase.delete(TABLE_NAME, KEY_ID+"="+id, null);
}
/*public Cursor queueAll(){
String[] columns = new String[]{KEY_ID, KEY_NAME, KEY_SHOP, KEY_CITY, KEY_DATE, KEY_ORDER};
Cursor cursor = sqLiteDatabase.query(TABLE_NAME, columns,
null, null, null, null, null);
return cursor;
}*/
public List<NameValuePair> getAllContacts() {
List<NameValuePair> postParameters = new ArrayList<NameValuePair>();
String selectQuery = "SELECT * FROM " + TABLE_NAME;
sqLiteHelper.getReadableDatabase();
Cursor cursor = sqLiteDatabase.rawQuery(selectQuery, null);
if(cursor.moveToFirst()){
while(!cursor.isAfterLast())
{
postParameters.add(new BasicNameValuePair("User", cursor.getString(cursor.getColumnIndex(KEY_NAME))));
postParameters.add(new BasicNameValuePair("ShopName", cursor.getString(cursor.getColumnIndex(KEY_SHOP))));
postParameters.add(new BasicNameValuePair("city", cursor.getString(cursor.getColumnIndex(KEY_CITY))));
postParameters.add(new BasicNameValuePair("OrderDate", cursor.getString(cursor.getColumnIndex(KEY_DATE))));
postParameters.add(new BasicNameValuePair("OrderDetail", cursor.getString(cursor.getColumnIndex(KEY_ORDER))));
cursor.moveToNext();
}
}
//cursor.close();
return postParameters;
};
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Log.w(SQLiteAdapter.class.getName(),
"Upgrading database from version " + oldVersion + " to "
+ newVersion + ", which will destroy all old data");
db.execSQL("DROP TABLE IF EXISTS " + CREATE_TABLE);
onCreate(db);
}
}
离线数据服务.java
package com.remote.synchronizer.haris;
import java.util.ArrayList;
import java.util.List;
import java.util.Timer;
import java.util.TimerTask;
import org.apache.http.NameValuePair;
import android.app.IntentService;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.os.Handler;
import android.os.HandlerThread;
import android.util.Log;
public class OfflineDataService extends IntentService {
boolean wifi,edge;
private Timer timer= new Timer();
SQLiteDatabase db;
String un,shop,city,date,order;
private SQLiteAdapter mySQLiteAdapter;
Cursor cursor;
public OfflineDataService() {
super("OfflineDataService");
}
@Override
public void onCreate() {
super.onCreate();
Log.e("Service", "Service Created.. ");
mySQLiteAdapter = new SQLiteAdapter(this);
mySQLiteAdapter.getWritableDatabase();
}
@Override
protected void onHandleIntent(final Intent intent) {
final Handler threadHandler;
threadHandler = new Handler();
new Thread(new Runnable(){
@Override
public void run() {
Bundle bundle=intent.getExtras();
un=bundle.getString("un");
shop=bundle.getString("shop");
city=bundle.getString("city");
date=bundle.getString("date");
order=bundle.getString("order");
Log.e("Service Started", "Successful");
//Inserting New Record
mySQLiteAdapter.insert(un,shop,city,date,order);
timer.scheduleAtFixedRate(new TimerTask(){
@Override
public void run() {
//Checking network connectivity
wifi=NetworkInfo.Wifi(OfflineDataService.this);
edge=NetworkInfo.EDGE(OfflineDataService.this);
if(wifi==true||edge==true)
{
Log.e("Service Network", "Network is online");
List<NameValuePair> contacts=new ArrayList<NameValuePair>();
contacts=mySQLiteAdapter.getAllContacts();
String url="http://10.0.2.2:3325/Product/Create?";
int response = 0;
try
{
response = CustomHttpClient.executeHttpPost(url, contacts);
if(response==200)
{
Log.e("Data Sent", "Response 200");
}
else{
Log.e("Service Data", "Faield to upload data" );
}
}
catch (Exception e)
{
Log.e("Data Sending", e.toString());
e.printStackTrace();
}
}
else
{
Log.e("Service Network", "Network is offline");
}
}
}, 1000, 5000);
}
}).start();
}
/*@Override
public void onDestroy() {
super.onDestroy();
// mySQLiteAdapter.deleteAll();
Log.e("Service Destroy", "Successful");
}*/
}
我需要使用 onStartCommand 而不是 onHandleIntent 还是需要使用 service 而不是 IntentService 来控制它们？