所以，我试图运行我的应用程序，它应该在第一次运行后显示通知。但是，它给了我这样的错误：
java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.pm.ApplicationInfo android.content.Context.getApplicationInfo()' on a null object reference
12-10 12:01:03.512 3132-3132/apps.skripsi.petvac E/AndroidRuntime: at android.app.Notification$Builder.<init>(Notification.java:1951)
12-10 12:01:03.512 3132-3132/apps.skripsi.petvac E/AndroidRuntime: at android.support.v4.app.NotificationCompatApi21$Builder.<init>(NotificationCompatApi21.java:68)
12-10 12:01:03.512 3132-3132/apps.skripsi.petvac E/AndroidRuntime: at android.support.v4.app.NotificationCompat$NotificationCompatImplApi21.build(NotificationCompat.java:759)
12-10 12:01:03.512 3132-3132/apps.skripsi.petvac E/AndroidRuntime: at android.support.v4.app.NotificationCompat$Builder.build(NotificationCompat.java:1559)
12-10 12:01:03.512 3132-3132/apps.skripsi.petvac E/AndroidRuntime: at apps.skripsi.petvac.navigationmenu.MainMenu.createButtonNotification(MainMenu.java:383)
12-10 12:01:03.512 3132-3132/apps.skripsi.petvac E/AndroidRuntime: at apps.skripsi.petvac.navigationmenu.MainMenu$DataBinatangOperation.onPostExecute(MainMenu.java:235)
12-10 12:01:03.512 3132-3132/apps.skripsi.petvac E/AndroidRuntime: at apps.skripsi.petvac.navigationmenu.MainMenu$DataBinatangOperation.onPostExecute(MainMenu.java:145)
12-10 12:01:03.512 3132-3132/apps.skripsi.petvac E/AndroidRuntime: at android.os.AsyncTask.finish(AsyncTask.java:632)
12-10 12:01:03.512 3132-3132/apps.skripsi.petvac E/AndroidRuntime: at android.os.AsyncTask.access$600(AsyncTask.java:177)
12-10 12:01:03.512 3132-3132/apps.skripsi.petvac E/AndroidRuntime: at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:645)
12-10 12:01:03.512 3132-3132/apps.skripsi.petvac E/AndroidRuntime: at android.os.Handler.dispatchMessage(Handler.java:102) …android ×1