Adding a calendar event in android

Tue Sep 5, 2017 by Bill Farmer. Categories: Hacking .

The android docs for the Calendar Provider are quite useful, but recommend the use of an AsyncQueryHandler for querying or adding events to calendars in an asynchronous thread. However the AsyncQueryHandler docs don’t include much guidance as to how to use it.

To add an entry to an android calendar you first have to find out the calendar id using an asynchronous query on the calendars table.

// QueryHandler
public class QueryHandler extends AsyncQueryHandler
{
    private static final String TAG = "QueryHandler";

    // Projection arrays
    private static final String[] CALENDAR_PROJECTION = new String[]
        {
            Calendars._ID
        };

    // The indices for the projection array above.
    private static final int CALENDAR_ID_INDEX = 0;

    private static final int CALENDAR = 0;
    private static final int EVENT    = 1;
    private static final int REMINDER = 2;

    private static QueryHandler queryHandler;

    // QueryHandler
    public QueryHandler(ContentResolver resolver)
    {
        super(resolver);
    }

    // insertEvent
    public static void insertEvent(Context context, long startTime,
                                   long endTime, String title)
    {
        ContentResolver resolver = context.getContentResolver();

        if (queryHandler == null)
            queryHandler = new QueryHandler(resolver);

        ContentValues values = new ContentValues();
        values.put(Events.DTSTART, startTime);
        values.put(Events.DTEND, endTime);
        values.put(Events.TITLE, title);

        if (BuildConfig.DEBUG)
            Log.d(TAG, "Calendar query start");

        queryHandler.startQuery(CALENDAR, values, Calendars.CONTENT_URI,
                                CALENDAR_PROJECTION, null, null, null);
    }

This method is called from an app activity.

        QueryHandler.insertEvent(this, startTime.getTimeInMillis(),
                                 endTime.getTimeInMillis(), title);

The insertEvent() method first creates a new QueryHandler which is subsequently reused. The start time, end time and title of the event are added to a ContentValues object and passed to the startQuery() method. This starts an asynchronous query on the Calendars table to find the first calendar id. A database cursor and the values are passed to the onQueryComplete() method.

    // onQueryComplete
    @Override
    public void onQueryComplete(int token, Object object, Cursor cursor)
    {
        // Use the cursor to move through the returned records
        cursor.moveToFirst();

        // Get the field values
        long calendarID = cursor.getLong(CALENDAR_ID_INDEX);

        if (BuildConfig.DEBUG)
            Log.d(TAG, "Calendar query complete " + calendarID);

        ContentValues values = (ContentValues) object;
        values.put(Events.CALENDAR_ID, calendarID);
        values.put(Events.EVENT_TIMEZONE,
                   TimeZone.getDefault().getDisplayName());

        startInsert(EVENT, null, Events.CONTENT_URI, values);
    }

This gets the calendar id from the cursor and adds it to the values along with the timezone. It’s probably not necessary to query the first calendar id because the value seems to be one, but there may be instances where it isn’t. The startInsert() method inserts the event asynchronously and the result is passed to the onInsertComplete() method.

    // onInsertComplete
    @Override
    public void onInsertComplete(int token, Object object, Uri uri)
    {
        if (uri != null)
        {
            if (BuildConfig.DEBUG)
                Log.d(TAG, "Insert complete " + uri.getLastPathSegment());

            switch (token)
            {
            case EVENT:
                long eventID = Long.parseLong(uri.getLastPathSegment());
                ContentValues values = new ContentValues();
                values.put(Reminders.MINUTES, 10);
                values.put(Reminders.EVENT_ID, eventID);
                values.put(Reminders.METHOD, Reminders.METHOD_ALERT);
                startInsert(REMINDER, null, Reminders.CONTENT_URI, values);
                break;
            }
        }
    }

This gets the event id and inserts a 10 minute reminder. All the AsyncQueryHandler asynchronous methods include an integer and an Object in the argument list which are passed to the onComplete() methods. This is useful for passing on parameters to be used later.

09-11 10:27:56.518  9808  9808 D QueryHandler: Calendar query start
09-11 10:27:56.687  9808  9808 D QueryHandler: Calendar query complete 1
09-11 10:27:56.801  9808  9808 D QueryHandler: Insert complete 112
09-11 10:27:56.944  9808  9808 D QueryHandler: Insert complete 1

Android takes a while to add the event as can be seen from the log.

Bill Farmer

Adding a calendar event in android

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