如何在广播接收器内设置闹钟

Question

在我的应用程序中，用户可以选择让他的事件重复，并且该重复事件的每次重复都会有一个通知(警报(，提醒用户他的事件即将开始。

因此，当第一个警报被调用时，它会打开 BroadcastReceiver，创建通知，并应为下一次重复出现设置警报：

@Override
public void onReceive(Context context, Intent intent) {
// When onReceive gets called the event notification is triggered
DatabaseHelper myDatabaseHelper = new DatabaseHelper(context);
// Create notification
int id = intent.getIntExtra("id", 0);
String name = intent.getStringExtra("name");
long notificationTime = intent.getLongExtra("notificationTime", 0);
String recurrenceType = intent.getStringExtra("recurrenceType");
String message = intent.getStringExtra("message");
if (recurrenceType.equals("Every week")) {
// repeatInterval = unix timestamp so * 1000 to get in Millis for notificationTime
long repeatInterval = 604800 * 1000;
notificationTime += repeatInterval;
myDatabaseHelper.updateNotificationTime(notificationTime);
setAlarm(context, intent, id, name, notificationTime, recurrenceType, message);
} else {
myDatabaseHelper.updateNotificationTime(0);
}
createNotification(context, message, name, id);
}
}

现在，这对于事件的第一个警报工作正常。通知已创建。现在，当第二个警报被调用时，意图为空，因此在第一个警报之后，所有其他意图都是空的，并且创建了一个空通知，然后应用程序崩溃并显示 NullPointerException。注意：我正在保持我的应用和设备处于打开状态。setAlarm(...( 方法位于 BroadcastReceiver 类中。

如何设置闹钟：

public void setAlarm(Context context, Intent intent, int id, String name, long notificationTime, String recurrenceType, String message){
AlarmManager alarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
Intent intentAlarm = new Intent(context, AlarmReceiver.class);
intent.putExtra("id", id);
intent.putExtra("name", name);
intent.putExtra("notificationTime", notificationTime);
intent.putExtra("recurrenceType", recurrenceType);
intent.putExtra("message", message);
// A PendingIntent specifies an action to take in the future [context, request code, intent, flag]
PendingIntent pendingIntent = PendingIntent.getBroadcast(context, id, intentAlarm, PendingIntent.FLAG_UPDATE_CURRENT);
// RTC_WAKEUP will wake up the device when it goes off
alarmManager.set(AlarmManager.RTC_WAKEUP, notificationTime, pendingIntent);
}

堆栈跟踪：

08-25 12:12:35.917 19323-19323/com.madgusto.when2game E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.madgusto.when2game, PID: 19323
java.lang.RuntimeException: Unable to start receiver com.madgusto.when2game.alarm.AlarmReceiver: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean java.lang.String.equals(java.lang.Object)' on a null object reference
  at android.app.ActivityThread.handleReceiver(ActivityThread.java:3018)
  at android.app.ActivityThread.-wrap18(ActivityThread.java)
  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1544)
  at android.os.Handler.dispatchMessage(Handler.java:102)
  at android.os.Looper.loop(Looper.java:154)
  at android.app.ActivityThread.main(ActivityThread.java:6077)
  at java.lang.reflect.Method.invoke(Native Method)
  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866)
  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean java.lang.String.equals(java.lang.Object)' on a null object reference
  at com.madgusto.when2game.alarm.AlarmReceiver.onReceive(AlarmReceiver.java:48)
  at android.app.ActivityThread.handleReceiver(ActivityThread.java:3011)
  at android.app.ActivityThread.-wrap18(ActivityThread.java) 
  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1544) 
  at android.os.Handler.dispatchMessage(Handler.java:102) 
  at android.os.Looper.loop(Looper.java:154) 
  at android.app.ActivityThread.main(ActivityThread.java:6077) 
  at java.lang.reflect.Method.invoke(Native Method) 
  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866) 
  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756) 

所以空指针在：

if (recurrenceType.equals("Every week")) {

现在，我如何以正确的方式在广播接收器内设置闹钟？谢谢！

Answer 1

很明显发生了什么。看看这个代码：

Intent intentAlarm = new Intent(context, AlarmReceiver.class);
intent.putExtra("id", id);
intent.putExtra("name", name);
intent.putExtra("notificationTime", notificationTime);
intent.putExtra("recurrenceType", recurrenceType);
intent.putExtra("message", message);
PendingIntent pendingIntent = PendingIntent.getBroadcast(context, id, intentAlarm, PendingIntent.FLAG_UPDATE_CURRENT);

你在变量intentAlarm中创建了一个Intent，但你使用变量intent将所有"额外"放入Intent中。然后你intentAlarm作为参数传递给PendingIntent.getBroadcast().当然，intentAlarm没有任何"额外功能"。

尝试将所有"额外内容"放在intentAlarm中。