Ich möchte das Kalenderereignis der letzten sieben Tage auf Android-Geräten erhalten. ich bin anfänger also sag mir schritt für schritt lösung dafür ..! nur kalender holen und lesen nicht updaten und löschen. Hilft mir jemand? Ich habe Code unten verwendet!

<code>public class Example {

    public static void readCalendar(Context context) {

        ContentResolver contentResolver = context.getContentResolver();

        // Fetch a list of all calendars synced with the device, their display names and whether the
        // user has them selected for display.

        final Cursor cursor = contentResolver.query(Uri.parse("content://calendar/calendars"),
                (new String[] { "_id", "displayName", "selected" }), null, null, null);
        // For a full list of available columns see http://tinyurl.com/yfbg76w

        HashSet<String> calendarIds = new HashSet<String>();

        while (cursor.moveToNext()) {

            final String _id = cursor.getString(0);
            final String displayName = cursor.getString(1);
            final Boolean selected = !cursor.getString(2).equals("0");

            Log.v("anim","Id: " + _id + " Display Name: " + displayName + " Selected: " + selected);
            calendarIds.add(_id);
        }

        // For each calendar, display all the events from the previous week to the end of next week.        
        for (String id : calendarIds) {
            Uri.Builder builder = Uri.parse("content://calendar/instances/when").buildUpon();
            long now = new Date().getTime();
            ContentUris.appendId(builder, now - DateUtils.WEEK_IN_MILLIS);
            ContentUris.appendId(builder, now + DateUtils.WEEK_IN_MILLIS);

            Cursor eventCursor = contentResolver.query(builder.build(),
                    new String[] { "title", "begin", "end", "allDay"}, "Calendars._id=" + id,
                    null, "startDay ASC, startMinute ASC"); 
            // For a full list of available columns see http://tinyurl.com/yfbg76w

            while (eventCursor.moveToNext()) {
                final String title = eventCursor.getString(0);
                final Date begin = new Date(eventCursor.getLong(1));
                final Date end = new Date(eventCursor.getLong(2));
                final Boolean allDay = !eventCursor.getString(3).equals("0");

                Log.v("anim","Title: " + title + " Begin: " + begin + " End: " + end +
                        " All Day: " + allDay);
            }
        }
    }


}
</code>

Ich habe null-pointerException.