我创建了一个BroadcastReceiver，在那里我启动了3个警报和3个通知，但我尝试了我的代码并且它没有工作，警报没有触发。 我还尝试将通知代码包含在if条件中，但是当通知应该启动应用程序崩溃时。 这是我的BroadcastReceiver代码：
@Override
public void onReceive(Context context, Intent intent)
{
if (intent.getAction().equals(Intent.ACTION_BOOT_COMPLETED)){
setAlarm(context);
}
String keyid = intent.getStringExtra("number");
String notif=PreferenceManager.getDefaultSharedPreferences(context).getString("notif", "abilitato");
if(notif.equals("abilitato")){
if(keyid.equals("0")){
Intent notificationIntent = new Intent(context, MainActivity.class);
notificationIntent.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);
PendingIntent contentIntent = PendingIntent.getActivity(context,
0, notificationIntent,
PendingIntent.FLAG_CANCEL_CURRENT);
Uri alarmSound = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
NotificationCompat.Builder mBuilder =
new NotificationCompat.Builder(context);
mBuilder.setContentIntent(contentIntent)
.setSmallIcon(R.drawable.ic_launcher)
.setContentTitle("E' ora di colazione!")
.setContentText("Cosa c'è per colazione?")
.setSound(alarmSound)
.setLights(Color.BLUE, 1000, 500)
.setVibrate(new long[] { 1000, 1000})
.setAutoCancel(true);
NotificationManager mNotificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
mNotificationManager.notify(1, mBuilder.build());
}
if(keyid.equals("1")){
Intent notificationIntent = new Intent(context, MainActivity.class);
notificationIntent.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);
PendingIntent contentIntent = PendingIntent.getActivity(context,
1, notificationIntent,
PendingIntent.FLAG_CANCEL_CURRENT);
Uri alarmSound = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
NotificationCompat.Builder mBuilder2 =
new NotificationCompat.Builder(context);
mBuilder2.setContentIntent(contentIntent)
.setSmallIcon(R.drawable.ic_launcher)
.setContentTitle("E' ora pranzo!")
.setContentText("Cosa c'è per pranzo?")
.setSound(alarmSound)
.setLights(Color.BLUE, 1000, 500)
.setVibrate(new long[] { 1000, 1000})
.setAutoCancel(true);
NotificationManager mNotificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
mNotificationManager.notify(1, mBuilder2.build());
}
if(keyid.equals("2")){
Intent notificationIntent = new Intent(context, MainActivity.class);
notificationIntent.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);
PendingIntent contentIntent = PendingIntent.getActivity(context,
2, notificationIntent,
PendingIntent.FLAG_CANCEL_CURRENT);
Uri alarmSound = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
NotificationCompat.Builder mBuilder3 =
new NotificationCompat.Builder(context);
mBuilder3.setContentIntent(contentIntent)
.setSmallIcon(R.drawable.ic_launcher)
.setContentTitle("E' ora cena!")
.setContentText("Cosa c'è per cena?")
.setSound(alarmSound)
.setLights(Color.BLUE, 1000, 500)
.setVibrate(new long[] { 1000, 1000})
.setAutoCancel(true);
NotificationManager mNotificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
mNotificationManager.notify(1, mBuilder3.build());
}
}
}
public void setAlarm(Context context){
String breakfast1=PreferenceManager.getDefaultSharedPreferences(context).getString("breakfast", "abilitato");
String lunch1=PreferenceManager.getDefaultSharedPreferences(context).getString("lunch", "abilitato");
String dinner1=PreferenceManager.getDefaultSharedPreferences(context).getString("dinner", "abilitato");
Database d;
AlarmManager alarmManager;
PendingIntent pendingIntent;
d=new Database(context);
String dataString=d.checkDataString();
String n;
//COLAZIONE
int duepunti = breakfast1.indexOf(":");
String hourColazione = breakfast1.substring(0,duepunti);
int intHourColazione=Integer.parseInt(hourColazione);
String minuteColazione = breakfast1.substring(duepunti + 1);
int intMinuteColazione=Integer.parseInt(minuteColazione);
int start = dataString.indexOf("/");
String dayString = dataString.substring(0,start);
String monthString = dataString.substring(start + 1,start+3);
String yearString = dataString.substring(start+4);
int day = Integer.parseInt(dayString);
int month = Integer.parseInt(monthString);
int year = Integer.parseInt(yearString);
Calendar calNow = Calendar.getInstance();
Calendar c = (Calendar) calNow.clone();
c.setTimeInMillis(System.currentTimeMillis());
c.set(Calendar.YEAR, year);
c.set(Calendar.MONTH, month-1);
c.set(Calendar.DAY_OF_MONTH, day);
c.set(Calendar.HOUR_OF_DAY, intHourColazione);
c.set(Calendar.MINUTE, intMinuteColazione);
c.set(Calendar.SECOND, 0);
c.set(Calendar.MILLISECOND, 0);
if(c.after(System.currentTimeMillis())){
c.add(Calendar.DAY_OF_MONTH, 1);
}
Intent myIntent = new Intent(context, MyReceiver.class);
n="0";
myIntent.putExtra("number", n);
if(PendingIntent.getBroadcast(context, 0,
myIntent,
PendingIntent.FLAG_NO_CREATE) == null){
pendingIntent = PendingIntent.getBroadcast(context, 0, myIntent,0);
alarmManager = (AlarmManager)context.getSystemService(Context.ALARM_SERVICE);
alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, c.getTimeInMillis(), AlarmManager.INTERVAL_DAY, pendingIntent);
}
//PRANZO
int duepunti2 = lunch1.indexOf(":");
String hourPranzo = lunch1.substring(0,duepunti2);
int intHourPranzo=Integer.parseInt(hourPranzo);
String minutePranzo = lunch1.substring(duepunti2 + 1);
int intMinutePranzo=Integer.parseInt(minutePranzo);
Calendar calNow2 = Calendar.getInstance();
Calendar c2 = (Calendar) calNow2.clone();
c2.setTimeInMillis(System.currentTimeMillis());
c2.set(Calendar.YEAR, year);
c2.set(Calendar.MONTH, month-1);
c2.set(Calendar.DAY_OF_MONTH, day);
c2.set(Calendar.HOUR_OF_DAY, intHourPranzo);
c2.set(Calendar.MINUTE, intMinutePranzo);
c2.set(Calendar.SECOND, 0);
c2.set(Calendar.MILLISECOND, 0);
if(c2.after(System.currentTimeMillis())){
c2.add(Calendar.DAY_OF_MONTH, 1);
}
Intent myIntent2 = new Intent(context, MyReceiver.class);
n="1";
myIntent2.putExtra("number", n);
if(PendingIntent.getBroadcast(context, 1,
myIntent2,
PendingIntent.FLAG_NO_CREATE) == null){
pendingIntent = PendingIntent.getBroadcast(context, 1, myIntent2 ,0);
alarmManager = (AlarmManager)context.getSystemService(Context.ALARM_SERVICE);
alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, c2.getTimeInMillis(), AlarmManager.INTERVAL_DAY, pendingIntent);
}
//CENA
int duepunti3 = dinner1.indexOf(":");
String hourCena = dinner1.substring(0,duepunti3);
int intHourCena=Integer.parseInt(hourCena);
String minuteCena = dinner1.substring(duepunti3 + 1);
int intMinuteCena=Integer.parseInt(minuteCena);
Calendar calNow3 = Calendar.getInstance();
Calendar c3 = (Calendar) calNow3.clone();
c3.setTimeInMillis(System.currentTimeMillis());
c3.set(Calendar.YEAR, year);
c3.set(Calendar.MONTH, month-1);
c3.set(Calendar.DAY_OF_MONTH, day);
c3.set(Calendar.HOUR_OF_DAY, intHourCena);
c3.set(Calendar.MINUTE, intMinuteCena);
c3.set(Calendar.SECOND, 0);
c3.set(Calendar.MILLISECOND, 0);
if(c.after(System.currentTimeMillis())){
c.add(Calendar.DAY_OF_MONTH, 1);
}
Intent myIntent3 = new Intent(context, MyReceiver.class);
n="2";
myIntent3.putExtra("number", n);
if(PendingIntent.getBroadcast(context, 2,
myIntent3,
PendingIntent.FLAG_NO_CREATE) == null){
pendingIntent = PendingIntent.getBroadcast(context, 2, myIntent3,0);
alarmManager = (AlarmManager)context.getSystemService(Context.ALARM_SERVICE);
alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, c3.getTimeInMillis(), AlarmManager.INTERVAL_DAY, pendingIntent);
}
}
}
在清单中：
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED"/>
...
<receiver android:name="com.lp.lemiediete.MyReceiver">
<intent-filter>
<action android:name="android.intent.action.BOOT_COMPLETED"/>
</intent-filter>
</receiver>
logcat的：
05-23 11:04:01.094: E/AndroidRuntime(5308): FATAL EXCEPTION: main
05-23 11:04:01.094: E/AndroidRuntime(5308): Process: com.lp.lemiediete, PID: 5308
05-23 11:04:01.094: E/AndroidRuntime(5308): java.lang.RuntimeException: Unable to start receiver com.lp.lemiediete.MyReceiver: java.lang.NullPointerException
05-23 11:04:01.094: E/AndroidRuntime(5308): at android.app.ActivityThread.handleReceiver(ActivityThread.java:2426)
05-23 11:04:01.094: E/AndroidRuntime(5308): at android.app.ActivityThread.access$1700(ActivityThread.java:135)
05-23 11:04:01.094: E/AndroidRuntime(5308): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1272)
05-23 11:04:01.094: E/AndroidRuntime(5308): at android.os.Handler.dispatchMessage(Handler.java:102)
05-23 11:04:01.094: E/AndroidRuntime(5308): at android.os.Looper.loop(Looper.java:136)
05-23 11:04:01.094: E/AndroidRuntime(5308): at android.app.ActivityThread.main(ActivityThread.java:5021)
05-23 11:04:01.094: E/AndroidRuntime(5308): at java.lang.reflect.Method.invokeNative(Native Method)
05-23 11:04:01.094: E/AndroidRuntime(5308): at java.lang.reflect.Method.invoke(Method.java:515)
05-23 11:04:01.094: E/AndroidRuntime(5308): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:827)
05-23 11:04:01.094: E/AndroidRuntime(5308): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:643)
05-23 11:04:01.094: E/AndroidRuntime(5308): at dalvik.system.NativeStart.main(Native Method)
05-23 11:04:01.094: E/AndroidRuntime(5308): Caused by: java.lang.NullPointerException
05-23 11:04:01.094: E/AndroidRuntime(5308): at com.lp.lemiediete.MyReceiver.onReceive(MyReceiver.java:25)
05-23 11:04:01.094: E/AndroidRuntime(5308): at android.app.ActivityThread.handleReceiver(ActivityThread.java:2419)
05-23 11:04:01.094: E/AndroidRuntime(5308): ... 10 more
答案 0 :(得分：0)
您正在getStringExtra("number")的{{1}}上致电Intent。那个onReceive()没有额外的kety“数字”，所以这将返回Intent。然后，您将在此处获得null：
NullPointerException也许您想在此代码中调用 if(keyid.equals("0")){
后添加return语句：
setAlarm()