Question

我知道这不是一个新的问题，我认为它与其他人稍有不同，在这里尝试从pendingIntent中取消当前警报，但在我的情况下，应用程序崩溃了。

在此应用中，我试图停止单击按钮时的警报。但是出现以下错误。

  java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.content.Context.getPackageName()' on a null object reference
        at android.content.ContextWrapper.getPackageName(ContextWrapper.java:132)
        at android.content.ComponentName.<init>(ComponentName.java:128)
        at android.content.Intent.<init>(Intent.java:4900)
        at com.aviz.www.reminder.Activity_Classes.AlarmActivity.stopAlarm(AlarmActivity.java:132)
        at com.aviz.www.reminder.Activity_Classes.WakeUpScreen$1.onClick(WakeUpScreen.java:44)
        at android.view.View.performClick(View.java:5637)
        at android.view.View$PerformClick.run(View.java:22429)
        at android.os.Handler.handleCallback(Handler.java:751)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:154)
        at android.app.ActivityThread.main(ActivityThread.java:6119)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)

AlarmActivity.java

 public void stopAlarm() {
        Intent intent = new Intent(AlarmActivity.this, AlarmReceiver.class);
        PendingIntent alarmIntent = PendingIntent.getBroadcast(AlarmActivity.this, mAlarmId, intent, 0);
        AlarmManager alarmManager = (AlarmManager) getSystemService(this.ALARM_SERVICE);
        alarmManager.cancel(alarmIntent);
    }

AlarmReceiver.java

public class AlarmReceiver extends BroadcastReceiver {
    public void onReceive(Context context, Intent intent) {
        Intent intent1 = new Intent(context,WakeUpScreen.class);
        context.startActivity(intent1);
        Uri alarmUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_ALARM);
        if (alarmUri == null) {
            alarmUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
        }
        Ringtone ringtone = RingtoneManager.getRingtone(context, alarmUri);
        ringtone.play();

    }
}

WakeUpScreen.java

mStop.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                alarmActivity.stopAlarm();
            }
        });

我尝试了一些与错误有关的解决方案，但我无法解决，有人可以帮助我解决此问题。

Answer 1

执行此操作以取消警报

 public static void cancelReminder(Context context,Class<?> cls)
    {
        // Disable a receiver

        ComponentName receiver = new ComponentName(context, cls);
        PackageManager pm = context.getPackageManager();

        pm.setComponentEnabledSetting(receiver,
                PackageManager.COMPONENT_ENABLED_STATE_DISABLED,
                PackageManager.DONT_KILL_APP);

        Intent intent1 = new Intent(context, cls);
        PendingIntent pendingIntent = PendingIntent.getBroadcast(context, DAILY_REMINDER_REQUEST_CODE_2, intent1, PendingIntent.FLAG_UPDATE_CURRENT);
        AlarmManager am = (AlarmManager) context.getSystemService(ALARM_SERVICE);
        am.cancel(pendingIntent);
        pendingIntent.cancel();
    }

如何安全地从PendingIntent中取消当前警报？

1 个答案: