Kalenderdaten unter Android 

Addieren von vier Wochen zu einem Datum

package com.example;
public class Main extends android.app.Activity
{
  android.widget.DatePicker picker;
  android.widget.DatePicker picker1;
  android.widget.LinearLayout layout;
  public void onCreate( final android.os.Bundle bundle )
  { super.onCreate( bundle );
    picker = new android.widget.DatePicker( this );
    picker1 = new android.widget.DatePicker( this );
    final android.widget.DatePicker.OnDateChangedListener listener
    = new android.widget.DatePicker.OnDateChangedListener()
    { public void onDateChanged
      ( final android.widget.DatePicker picker,
        final int year, final int month, final int day )
      { final java.util.GregorianCalendar calendar = new java.util.GregorianCalendar( year, month, day );
        calendar.add( java.util.Calendar.DATE, 28 );
        final int y  = calendar.get( java.util.Calendar.YEAR );
        final int m = calendar.get( java.util.Calendar.MONTH );
        final int d  = calendar.get( java.util.Calendar.DAY_OF_MONTH );
        picker1.updateDate( y, m, d ); }};
    final android.widget.DatePicker.OnDateChangedListener listener1
    = new android.widget.DatePicker.OnDateChangedListener()
    { public void onDateChanged
      ( final android.widget.DatePicker picker,
        final int year, final int month, final int day ) {} };
    final java.util.Calendar calendar
    = java.util.Calendar.getInstance( java.util.TimeZone.getDefault() );
    final int year  = calendar.get( java.util.Calendar.YEAR );
    final int month = calendar.get( java.util.Calendar.MONTH );
    final int day   = calendar.get( java.util.Calendar.DAY_OF_MONTH );
    picker.init( year, month, day, listener );
    picker1.init( year, month, day, listener1 );
    Main.this.layout = new android.widget.LinearLayout( this );
    Main.this.layout.setOrientation( android.widget.LinearLayout.VERTICAL );
    Main.this.layout.addView( Main.this.picker );
    Main.this.layout.addView( Main.this.picker1 );
    setContentView( Main.this.layout ); }}

Hinzufügen eines Termins zum Kalender (ungetestet)

Die Kalender-API wurde mehrfach überarbeitet. Das Hinzufügen eines Termins zum Kalender verlangt anscheinend ein Exchange - oder Google -Konto. Daher konnte dies nicht getestet werden. Daher enthält der folgende Code möglicherweise noch Fehler. An Stelle des Android-Kalenders kann möglicherweise auch eine Datenbank oder Tabellenkalkulation verwendet werden, um die Termine aufzunehmen, wenn kein Google-Konto erwünscht ist.

void add
( final java.util.GregorianCalendar calendar,
  final android.app.Activity activity )
{ final long date = calendar.getTimeInMillis();
  calendar.add( java.util.Calendar.DATE, 1 );
  final long date1 = calendar.getTimeInMillis();
  final java.lang.String caluri = caluri( activity );
  if( caluri != null )
  { android.content.ContentResolver cr1 = getContentResolver();
    android.content.ContentValues values = new android.content.ContentValues();
    values.put( "calendar_id", 1 );
    values.put( "title", "Text" );
    values.put( "allDay", 0 );
    values.put( "dtstart", date );
    values.put( "dtend", date1 );
    values.put( "description", "Volkshochschule" );
    values.put( "hasAlarm", 1 );
    values.put( "eventTimezone", android.text.format.Time.getCurrentTimezone() );
    final android.net.Uri events = android.net.Uri.parse( caluri + "events" );
    android.net.Uri event = cr1.insert( events, values ); }}
@java.lang.SuppressWarnings( "deprecation" )
java.lang.String caluri( final android.app.Activity activity )
{ String result = null;
  android.net.Uri cals = android.net.Uri.parse( "content://calendar/calendars" );
  android.database.Cursor cursor = null;
  try
  { cursor = activity.managedQuery( cals, null, null, null, null ); }
  catch( final java.lang.Exception exception ) {}
  java.lang.System.out.println( "-5" );
  if( cursor != null )result = "content://calendar/";
  else
  { cals = android.net.Uri.parse( "content://com.android.calendar/calendars" );
    try
    { cursor = activity.managedQuery( cals, null, null, null, null ); }
    catch( final java.lang.Exception e ) {}
    if( cursor != null )
    result = "content://com.android.calendar/"; }
  return result; }

Zu AndroidManifest.xml hinzuzufügen

<uses-permission android:name="android.permission.READ_CALENDAR"/>
<uses-permission android:name="android.permission.WRITE_CALENDAR"/>