Android的后台服务崩溃，它刷出来 [英] Android background Service crash while It swipe out
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问题描述
当我删除我的应用程序从任务manager.0流程和1个服务离开了。应用程序也再次崩溃又一次我应该怎么做才能解决这个问题？这是我的服务类。我想问一件事的OnStart（）方法和OnStartCommand（）方法？的区别
包com.example.vaccinationsystem;
进口java.text.SimpleDateFormat的;
进口的java.util.ArrayList;
进口的java.util.Calendar;
进口org.ksoap2.SoapEnvelope;
进口org.ksoap2.serialization.PropertyInfo;
进口org.ksoap2.serialization.SoapObject;
进口org.ksoap2.serialization.SoapPrimitive;
进口org.ksoap2.serialization.SoapSerializationEnvelope;
进口org.ksoap2.transport.HttpTransportSE;
进口android.annotation.Sup pressLint;
进口android.app.AlarmManager;
进口android.app.Notification;
进口android.app.NotificationManager;
进口android.app.PendingIntent;
进口android.app.Service;
进口android.content.Intent;
进口android.os.IBinder;
进口android.os.SystemClock;
进口android.util.Log;
进口android.widget.TabHost.OnTabChangeListener;
@燮pressLint（覆盖）
公共类BackgroundServices延伸服务{
字符串userid;
SoapObject请求;
的PropertyInfo p_userId;
SoapSerializationEnvelope信封;
HttpTransportSE httpTransport;
SoapPrimitive响应;
ArrayList的＆LT;字符串＆GT; listRec;
字符串s;
INT totalDifference;
INT countNotification = 0;
私有静态最后弦乐METHOD_NAME =警报;
私有静态最后弦乐NAMESPACE =http://org.fyp.ws;
私有静态最后弦乐SOAP_ACTION =http://org.fyp.ws/Alerts;
私有静态最后字符串URL = StaticIP.ipAddress
+GeneralUserServices WSDL？;
@覆盖
公众的IBinder onBind（意向为arg0）{
返回null;
}
// @覆盖
//公共无效的onCreate（）{
//
// Toast.makeText（这一点，恭喜！为MyService创建，
// Toast.LENGTH_LONG）.show（）;
// // Log.d（TAG的onCreate）;
//}
@覆盖
公共无效ONSTART（意向意图，诠释startId）{
用户id = intent.getExtras（）的getString（USER_ID）。
listRec =新的ArrayList＆LT;字符串＆GT;（）;
要求=新SoapObject（命名空间METHOD_NAME）;
p_userId =新的PropertyInfo（）;
信封=新SoapSerializationEnvelope（SoapEnvelope.VER11）;
httpTransport =新HttpTransportSE（URL）;
p_userId.setName（用户id）; //定义了网络变量名
p_userId.setValue（用户id）; //定义值FNAME变量
p_userId.setType（为String.class）; //定义变量的类型
request.addProperty（p_userId）; //通行证属性到可变
envelope.setOutputSoapObject（要求）;
尝试 {
httpTransport.call（SOAP_ACTION，包）;
响应=（SoapPrimitive）envelope.getResponse（）;
// Toast.makeText（getApplicationContext（），response.toString（），
// Toast.LENGTH_LONG）.show（）;
的String []行= response.toString（）分裂（`）。
的for（int i = 0; I＆LT; row.length;我++）{
的String []纪录=行[I] .split（〜）;
// totalDifference = 0;
日历C = Calendar.getInstance（）;
SimpleDateFormat的DF =新的SimpleDateFormat（YYYY-MM-DD）;
串CURDATE = df.format（c.getTime（））的toString（）。
字符串visitDate =记录[1];
java.util.Date CD = df.parse（CURDATE）;
java.util.Date VD = df.parse（visitDate）;
日历cCurDate = Calendar.getInstance（）;
cCurDate.setTime（CD）;
cCurDate.add（Calendar.DAY_OF_YEAR，0）;
java.util.Date newCurDate = cCurDate.getTime（）;
日历cNotificationStartVisitDate = Calendar.getInstance（）;
cNotificationStartVisitDate.setTime（VD）;
cNotificationStartVisitDate.add（Calendar.DAY_OF_YEAR，-15）;
java.util.Date notificationStartDate = cNotificationStartVisitDate
.getTime（）;
日历cOrignalVisitDate = Calendar.getInstance（）;
cOrignalVisitDate.setTime（VD）;
cOrignalVisitDate.add（Calendar.DAY_OF_YEAR，0）;
java.util.Date newOriDateVisitDate = cOrignalVisitDate
.getTime（）;
totalDifference = 0;
如果（notificationStartDate.before（newCurDate））{
而（newOriDateVisitDate.after（newCurDate））{
cOrignalVisitDate.add（Calendar.DAY_OF_YEAR，-1）;
newOriDateVisitDate = cOrignalVisitDate.getTime（）;
totalDifference ++;
S =左;
}
而（newOriDateVisitDate.before（newCurDate））{
cOrignalVisitDate.add（Calendar.DAY_OF_YEAR，+ 1）;
newOriDateVisitDate = cOrignalVisitDate.getTime（）;
totalDifference ++;
S =前;
}
countNotification ++;
listRec.add（记录[2] +疫苗因：+将String.valueOf（totalDifference）
+天+ S）;
}
}
对于（INT J = 0; J＆LT; countNotification; J ++）{
NotificationManager纳米=（NotificationManager）getApplicationContext（）
.getSystemService（getApplicationContext（）NOTIFICATION_SERVICE。）;
通知注=新的通知（R.drawable.nav_down，
接种警报！，System.currentTimeMillis的（））;
意图inNotification =新的意图（这一点，GenUserFunction.class）;
inNotification.putExtra（user_ID的，用户id）;
PendingIntent I = PendingIntent.getActivity（getBaseContext（），0，inNotification，0）;
note.setLatestEventInfo（getApplicationContext（），疫苗由于，
listRec.get（J），I）;
nm.notify（J，注意）;
}
// Toast.makeText（getApplicationContext（），
//将String.valueOf（listRec.size（）），Toast.LENGTH_SHORT）.show（）;
}赶上（例外五）{
// TODO：处理异常
的System.out.println（e.getMessage（））;
}
// Toast.makeText（这一点，我的服务启动，Toast.LENGTH_LONG）.show（）;
//注意：您可以开始一个新的线程，并用它进行长时间的后台
//从这里处理。
}
@覆盖
公共无效的onDestroy（）{
在这里输入code
super.onDestroy（）;
// Toast.makeText（这一点，为MyService停止，Toast.LENGTH_LONG）.show（）;
// Log.d（TAG的onDestroy）;
}
}
解决方案
-
无效ONSTART（意向意图，诠释startId）是德precated，你需要使用INT onStartCommand（意向意图，诠释标志，INT startId）代替。 -
ONSTART（...）从被称为onStartCommand（...）向后兼容，以及在onStartCommand（...）返回START_STICKY值的默认实现。于是，杀后，你的服务将被系统重新启动。当服务被系统重新启动时，ONSTART（...）方法可以带一个空的意图对象，intent.getExtras（） .getString（USER_ID）投NullPointerException异常和服务将崩溃，以及系统重新启动......
作为结论：你需要检查意图为空 befor使用它的对象
When i remove my app from task manager.0 process and 1 service left. App do crash again and again what should i do to resolve it? This is my service class. I want to ask one more thing the difference between OnStart() method and OnStartCommand() method?
package com.example.vaccinationsystem;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Calendar;
import org.ksoap2.SoapEnvelope;
import org.ksoap2.serialization.PropertyInfo;
import org.ksoap2.serialization.SoapObject;
import org.ksoap2.serialization.SoapPrimitive;
import org.ksoap2.serialization.SoapSerializationEnvelope;
import org.ksoap2.transport.HttpTransportSE;
import android.annotation.SuppressLint;
import android.app.AlarmManager;
import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.os.SystemClock;
import android.util.Log;
import android.widget.TabHost.OnTabChangeListener;
@SuppressLint("Override")
public class BackgroundServices extends Service {
String userId;
SoapObject request;
PropertyInfo p_userId;
SoapSerializationEnvelope envelope;
HttpTransportSE httpTransport;
SoapPrimitive response;
ArrayList<String> listRec;
String s;
int totalDifference;
int countNotification = 0;
private static final String METHOD_NAME = "Alerts";
private static final String NAMESPACE = "http://org.fyp.ws";
private static final String SOAP_ACTION = "http://org.fyp.ws/Alerts";
private static final String URL = StaticIP.ipAddress
+ "GeneralUserServices?wsdl";
@Override
public IBinder onBind(Intent arg0) {
return null;
}
// @Override
// public void onCreate() {
//
// Toast.makeText(this, "Congrats! MyService Created",
// Toast.LENGTH_LONG).show();
// // Log.d(TAG, "onCreate");
// }
@Override
public void onStart(Intent intent, int startId) {
userId = intent.getExtras().getString("user_Id");
listRec = new ArrayList<String>();
request = new SoapObject(NAMESPACE, METHOD_NAME);
p_userId = new PropertyInfo();
envelope = new SoapSerializationEnvelope(SoapEnvelope.VER11);
httpTransport = new HttpTransportSE(URL);
p_userId.setName("userId");// Define the variable name in the web
p_userId.setValue(userId);// Define value for fname variable
p_userId.setType(String.class);// Define the type of the variable
request.addProperty(p_userId);// Pass properties to the variable
envelope.setOutputSoapObject(request);
try {
httpTransport.call(SOAP_ACTION, envelope);
response = (SoapPrimitive) envelope.getResponse();
// Toast.makeText(getApplicationContext(), response.toString(),
// Toast.LENGTH_LONG).show();
String[] row = response.toString().split("`");
for (int i = 0; i < row.length; i++) {
String[] record = row[i].split("~");
// totalDifference = 0;
Calendar c = Calendar.getInstance();
SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd");
String curDate = df.format(c.getTime()).toString();
String visitDate = record[1];
java.util.Date cD = df.parse(curDate);
java.util.Date vD = df.parse(visitDate);
Calendar cCurDate = Calendar.getInstance();
cCurDate.setTime(cD);
cCurDate.add(Calendar.DAY_OF_YEAR, 0);
java.util.Date newCurDate = cCurDate.getTime();
Calendar cNotificationStartVisitDate = Calendar.getInstance();
cNotificationStartVisitDate.setTime(vD);
cNotificationStartVisitDate.add(Calendar.DAY_OF_YEAR, -15);
java.util.Date notificationStartDate = cNotificationStartVisitDate
.getTime();
Calendar cOrignalVisitDate = Calendar.getInstance();
cOrignalVisitDate.setTime(vD);
cOrignalVisitDate.add(Calendar.DAY_OF_YEAR, 0);
java.util.Date newOriDateVisitDate = cOrignalVisitDate
.getTime();
totalDifference = 0;
if (notificationStartDate.before(newCurDate)) {
while (newOriDateVisitDate.after(newCurDate)) {
cOrignalVisitDate.add(Calendar.DAY_OF_YEAR, -1);
newOriDateVisitDate = cOrignalVisitDate.getTime();
totalDifference++;
s = "left";
}
while (newOriDateVisitDate.before(newCurDate)) {
cOrignalVisitDate.add(Calendar.DAY_OF_YEAR, +1);
newOriDateVisitDate = cOrignalVisitDate.getTime();
totalDifference++;
s = "ago";
}
countNotification++;
listRec.add(record[2] + " Vaccine due: " + String.valueOf(totalDifference)
+ " days " + s);
}
}
for (int j = 0; j < countNotification; j++) {
NotificationManager nm = (NotificationManager) getApplicationContext()
.getSystemService(getApplicationContext().NOTIFICATION_SERVICE);
Notification note = new Notification(R.drawable.nav_down,
"Vaccination ALerts!", System.currentTimeMillis());
Intent inNotification = new Intent(this,GenUserFunction.class);
inNotification.putExtra("user_id", userId);
PendingIntent i = PendingIntent.getActivity(getBaseContext(), 0,inNotification, 0);
note.setLatestEventInfo(getApplicationContext(), "Vaccine Due",
listRec.get(j), i);
nm.notify(j, note);
}
// Toast.makeText(getApplicationContext(),
// String.valueOf(listRec.size()), Toast.LENGTH_SHORT).show();
} catch (Exception e) {
// TODO: handle exception
System.out.println(e.getMessage());
}
// Toast.makeText(this, "My Service Started", Toast.LENGTH_LONG).show();
// Note: You can start a new thread and use it for long background
// processing from here.
}
@Override
public void onDestroy() {
enter code here
super.onDestroy();
// Toast.makeText(this, "MyService Stopped", Toast.LENGTH_LONG).show();
// Log.d(TAG, "onDestroy");
}
}
解决方案
void onStart(Intent intent, int startId)is deprecated, you need to useint onStartCommand(Intent intent, int flags, int startId)instead.onStart(...)is called from theonStartCommand(...)for backwards compatibility, and default implementation of theonStartCommand(...)returns the START_STICKY value. So, after the killing, yours service will be restarted by the system. When the service is restarted by the system,onStart(...)method can be called with a null intent object, andintent.getExtras().getString("user_Id")throws theNullPointerException, and service will be crashed, and restarted by the system...
As conclusion: you need to check the intent object for null befor using it.
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