在运行使用AlarmManager广播接收器的IntentService [英] Running an IntentService in BroadcastReceiver using AlarmManager
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问题描述
我想在一个延伸我的接收类来调用服务 广播接收器，但服务没有启动，我得到这个错误：
致命异常：主要了java.lang.RuntimeException：无法
开始接收com.example.ahmed.service.AlarmReceiver：
显示java.lang.NullPointerException：试图调用虚拟
法java.lang.String中
android.content.Context.getPackageName（）在空
对象引用
在我MainActivity，我拨打了报警管理器：
为AlarmReceiver //日历设置
日历cur_cal =新的GregorianCalendar（）;
cur_cal.setTimeInMillis（System.currentTimeMillis的（））; //设置该日历的当前时间和日期
日历CAL =新的GregorianCalendar（）;
cal.add（Calendar.DAY_OF_YEAR，cur_cal.get（Calendar.DAY_OF_YEAR））;
cal.set（Calendar.HOUR_OF_DAY，8）;
cal.set（Calendar.MINUTE，07）;
cal.set（Calendar.SECOND，cur_cal.get（Calendar.SECOND））;
cal.set（Calendar.MILLISECOND，cur_cal.get（Calendar.MILLISECOND））;
cal.set（Calendar.DATE，cur_cal.get（Calendar.DATE））;
cal.set（的Calendar.MONTH，cur_cal.get（的Calendar.MONTH））; //检索将执行广播一的PendingIntent
alarmIntent =新意图（这一点，AlarmReceiver.class）;
的PendingIntent = PendingIntent.getBroadcast（在此，0，alarmIntent，0）; AlarmManager报警=（AlarmManager）getSystemService（Context.ALARM_SERVICE）;
alarm.setRepeating（AlarmManager.RTC_WAKEUP，cal.getTimeInMillis（），30 * 1000，的PendingIntent）;
//当您单击开始按钮，感应
公共无效onSensingButtonClickedToStart（最终查看视图）{
如果（！SensorEvent.isSensing）{
SensorEvent.isSensing = TRUE; 经理=（AlarmManager）getSystemService（Context.ALARM_SERVICE）;
INT间隔= 10000;
manager.setRepeating（AlarmManager.RTC_WAKEUP，System.currentTimeMillis的（），间隔的PendingIntent）;
Toast.makeText（这一点，感觉上，Toast.LENGTH_SHORT）.show（）;
}
} //当你点击停止按钮传感
公共无效onSensingButtonClickedToStop（最终查看视图）{
如果（SensorEvent.isSensing）{ 经理=（AlarmManager）getSystemService（Context.ALARM_SERVICE）;
manager.cancel（的PendingIntent）;
Toast.makeText（这一点，感觉关，Toast.LENGTH_SHORT）.show（）;
SensorEvent.isSensing = FALSE;
}
}
我的服务
公共类Sense8扩展IntentService { 公共静态加速度计加速度计;
公共静态陀螺陀螺仪;
公共静态光灯;
公共静态磁磁强计;
上下文语境; / **
*创建一个IntentService。你的子类的构造函数调用。
*
* /
公共Sense8（字符串名称）{
超（名）;
} 公共Sense8（）{
超级（Sense8）;
} @覆盖
保护无效onHandleIntent（意向意图）{ Log.d（accelerometer.isSensing，SensorEvent.isSensing +）;
如果（accelerometer.isSensing）{
加速度=新加速计（背景）;
陀螺仪=新的陀螺仪（背景）;
光=新灯（背景）;
磁力=新的磁力仪（背景）;
Toast.makeText（背景下，我跑，而不是一些传感器被俘虏，Toast.LENGTH_SHORT）.show（）;
Log.d（敬酒，我跑，而不是被拍摄的某些传感器）;
startSensing（）;
}
} 公共静态无效startSensing（）{
accelerometer.start（）;
gyroscope.start（）;
light.start（）;
magnetometer.start（）;
} 公共无效stopSensing（）{
accelerometer.stop（）;
gyroscope.stop（）;
light.stop（）;
magnetometer.stop（）; }
}
在我的接收器类中，我只叫 IntentService ：
@覆盖
公共无效的onReceive（上下文C，意图意图）{
意向书的服务=新意图（C，Sense8.class）;
c.startService（服务）;
}
但徒劳的，它甚至不启动，并直接与上述错误打我
我是什么做错了吗？有人能帮助我实现这个正确的方式。
修改
的家伙给了我第一个问题的解决方案，但现在我推传感按钮后，得到了同样的错误。
下面是SensorEvent：
公共类SensorEvent实现SensorEventListener { 公共静态布尔isSensing;
的SensorManager mSensorManager;
传感器mSensor;
DataWriter FileWriter的;
Constants.SensorType sensorType;
上下文语境;
私人SensorEvent（）
{} 私有静态SensorEvent INSTANCE = NULL; 公共静态SensorEvent的getInstance（）
{
如果（INSTANCE == NULL）
{INSTANCE =新SensorEvent（）;
}
返回实例;
} 公共静态SensorEvent的getInstance（上下文的背景下，Constants.SensorType sensorType）
{
如果（INSTANCE == NULL）
{INSTANCE =新SensorEvent（背景下，sensorType）;
}
返回实例;
}
公共SensorEvent（上下文的背景下，Constants.SensorType sensorType）{
this.sensorType = sensorType; this.context =背景;
this.mSensorManager =（的SensorManager）context.getSystemService（Context.SENSOR_SERVICE）;
this.mSensor = mSensorManager.getDefaultSensor（sensorType.getType（））;
// this.isSensing = TRUE;
}
公共无效的start（）{
isSensing = TRUE;
FileWriter的=新DataWriter（sensorType）;
mSensorManager.registerListener（这一点，mSensor，SensorManager.SENSOR_DELAY_NORMAL）;
} 公共无效停止（）{
尝试{
fileWriter.finish（）;
}赶上（IOException异常五）{
e.printStackTrace（）;
}
isSensing = FALSE;
}
@覆盖
公共无效onSensorChanged（android.hardware.SensorEvent事件）{ 尝试{
如果（isSensing）{
fileWriter.append（事件）; }其他{
fileWriter.finish（）;
mSensorManager.unregisterListener（本）;
}
}赶上（例外五）{
e.printStackTrace（）;
}
} @覆盖
公共无效onAccuracyChanged（传感器传感器，精度INT）{ }
}
解决方案
只是改变：
@覆盖
公共无效的onReceive（上下文C，意图意图）{
意向书的服务=新意图（背景下，Sense8.class）;
context.startService（服务）;
}
到
@覆盖
公共无效的onReceive（上下文C，意图意图）{
意向书的服务=新意图（C，Sense8.class）;
c.startService（服务）;
}
您还没有为您分配了背景来参数 C 。所以，你试图在空引用启动服务。
I want to call a Service in my Receiver class which extends BroadcastReceiver but the service didn't start and I got this error:
FATAL EXCEPTION: main java.lang.RuntimeException: Unable to
start receiver com.example.ahmed.service.AlarmReceiver:
java.lang.NullPointerException: Attempt to invoke virtual
method 'java.lang.String
android.content.Context.getPackageName()' on a null
object reference
In my MainActivity, I call the alarm manager:
// Calendar settings for AlarmReceiver
Calendar cur_cal = new GregorianCalendar();
cur_cal.setTimeInMillis(System.currentTimeMillis());//set the current time and date for this calendar
Calendar cal = new GregorianCalendar();
cal.add(Calendar.DAY_OF_YEAR, cur_cal.get(Calendar.DAY_OF_YEAR));
cal.set(Calendar.HOUR_OF_DAY, 8);
cal.set(Calendar.MINUTE, 07);
cal.set(Calendar.SECOND, cur_cal.get(Calendar.SECOND));
cal.set(Calendar.MILLISECOND, cur_cal.get(Calendar.MILLISECOND));
cal.set(Calendar.DATE, cur_cal.get(Calendar.DATE));
cal.set(Calendar.MONTH, cur_cal.get(Calendar.MONTH));
// Retrieve a PendingIntent that will perform a broadcast
alarmIntent = new Intent(this, AlarmReceiver.class);
pendingIntent = PendingIntent.getBroadcast(this, 0, alarmIntent, 0);
AlarmManager alarm = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
alarm.setRepeating(AlarmManager.RTC_WAKEUP, cal.getTimeInMillis(), 30 * 1000, pendingIntent);
// When you click Start sensing button
public void onSensingButtonClickedToStart(final View view) {
if (!SensorEvent.isSensing) {
SensorEvent.isSensing = true;
manager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
int interval = 10000;
manager.setRepeating(AlarmManager.RTC_WAKEUP, System.currentTimeMillis(), interval, pendingIntent);
Toast.makeText(this, "Sensing On", Toast.LENGTH_SHORT).show();
}
}
// when you click Stop sensing button
public void onSensingButtonClickedToStop(final View view) {
if (SensorEvent.isSensing) {
manager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
manager.cancel(pendingIntent);
Toast.makeText(this, "Sensing Off", Toast.LENGTH_SHORT).show();
SensorEvent.isSensing = false;
}
}
My Service
public class Sense8 extends IntentService {
public static Accelerometer accelerometer;
public static Gyroscope gyroscope;
public static Light light;
public static Magnetometer magnetometer;
Context context;
/**
* Creates an IntentService. Invoked by your subclass's constructor.
*
*/
public Sense8(String name) {
super(name);
}
public Sense8(){
super("Sense8");
}
@Override
protected void onHandleIntent(Intent intent) {
Log.d("accelerometer.isSensing", SensorEvent.isSensing + "");
if (accelerometer.isSensing) {
accelerometer = new Accelerometer(context);
gyroscope = new Gyroscope(context);
light = new Light(context);
magnetometer = new Magnetometer(context);
Toast.makeText(context, "I'm running instead of some sensors being captured", Toast.LENGTH_SHORT).show();
Log.d("toast", "I'm running instead of some sensors being captured");
startSensing();
}
}
public static void startSensing() {
accelerometer.start();
gyroscope.start();
light.start();
magnetometer.start();
}
public void stopSensing() {
accelerometer.stop();
gyroscope.stop();
light.stop();
magnetometer.stop();
}
}
In my Receiver class, I only call the IntentService:
@Override
public void onReceive(Context c, Intent intent) {
Intent service = new Intent(c, Sense8.class);
c.startService(service);
}
But in vain, it doesn't even start and hit me directly with the above error
What am I doing wrong? Can someone help me implement this the right way.
EDIT
the guys gave me the right solution for the first problem but now I get the same error after pushing the sensing button
Here is the SensorEvent:
public class SensorEvent implements SensorEventListener {
public static boolean isSensing;
SensorManager mSensorManager;
Sensor mSensor;
DataWriter fileWriter;
Constants.SensorType sensorType;
Context context;
private SensorEvent()
{}
private static SensorEvent INSTANCE = null;
public static SensorEvent getInstance()
{
if (INSTANCE == null)
{ INSTANCE = new SensorEvent();
}
return INSTANCE;
}
public static SensorEvent getInstance(Context context, Constants.SensorType sensorType)
{
if (INSTANCE == null)
{ INSTANCE = new SensorEvent(context, sensorType);
}
return INSTANCE;
}
public SensorEvent(Context context, Constants.SensorType sensorType) {
this.sensorType = sensorType;
this.context = context;
this.mSensorManager = (SensorManager) context.getSystemService(Context.SENSOR_SERVICE);
this.mSensor = mSensorManager.getDefaultSensor(sensorType.getType());
// this.isSensing = true;
}
public void start() {
isSensing = true;
fileWriter = new DataWriter(sensorType);
mSensorManager.registerListener(this, mSensor, SensorManager.SENSOR_DELAY_NORMAL);
}
public void stop() {
try {
fileWriter.finish();
} catch (IOException e) {
e.printStackTrace();
}
isSensing = false;
}
@Override
public void onSensorChanged(android.hardware.SensorEvent event) {
try {
if (isSensing) {
fileWriter.append(event);
} else {
fileWriter.finish();
mSensorManager.unregisterListener(this);
}
} catch (Exception e) {
e.printStackTrace();
}
}
@Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
}
}
解决方案
just change :
@Override
public void onReceive(Context c, Intent intent) {
Intent service = new Intent(context, Sense8.class);
context.startService(service);
}
to
@Override
public void onReceive(Context c, Intent intent) {
Intent service = new Intent(c, Sense8.class);
c.startService(service);
}
You haven't assigned you context to parameter c. So you are trying to start service on null reference.
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