How can I set date on Alarmmanger?

Question

I have tried this code to alarm at March first. But It doesn't work. How can I solve this problem?

Content of APP

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When we press the button(click1), if it was on March first, Alarmmanger calls intent. so this application prints new Activity.

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ERROR

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When we press the button(click1), then anytime Alarmmanger calls intent.

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HOW CAN I SOLVE IT??

-SORRY FOR MY NOT GOOD ENGLISH.. ㅠㅠ

public class MainActivity extends Activity {

private AlarmManager alarm;

private NotificationManager notification;
Calendar calendar = Calendar.getInstance();

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);}
    public void click1(View v) {
    notification = (NotificationManager)getSystemService(NOTIFICATION_SERVICE);
    alarm = (AlarmManager)getSystemService(Context.ALARM_SERVICE);
    Calendar cal = new GregorianCalendar();
    cal.setTimeInMillis(System.currentTimeMillis());


    calendar.clear();
    calendar.set(cal.YEAR,3,1);


    setAlarm();
    }



private void setAlarm(){

alarm.set(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), pendingIntent());


}
private PendingIntent pendingIntent() {
    // TODO Auto-generated method stub
    Intent i = new Intent(getApplicationContext(), MainActivity.class);
    PendingIntent p = PendingIntent.getActivity(this, 0, i, 0);
    return p;

}

Answer 1

You don´t need create another Calendar only to obtain the actual year.
When you ask for a new instance of Calendar it will be initialized with the actual date and time Try this:

Calendar calendar = Calendar.getInstance();
int year = calendar.get(Calendar.YEAR);
calendar.set(year,Calendar.MARCH,1);

One other thing, if you set the alarm to a past time, the alarm always will go off.

Answer 2

tl;dr

LocalDate.of( 2016 , Month.MARCH , 1 ).atStartOfDay( ZoneId.of( "America/Montreal" ) ).toInstant().toEpochMilli()

Avoid old date-time classes

You are using troublesome old legacy date-time classes. Now supplanted by the java.time classes.

LocalDate

The LocalDate class represents a date-only value without time-of-day and without time zone.

LocalDate ld = LocalDate.of( 2016 , Month.MARCH , 1 );

You can pass a number instead of a Month enum object, numbered sanely 1-12 for January-December.

Time zone

For an alarm we need a time-of-day. You can get the first moment of the day. This is usually the time 00:00:00 , but not always due to to Daylight Saving Time (DST) or other anomalies. Let java.time determine the time.

A time zone is crucial in determining a date. For any given moment, the date varies around the globe by zone. For example, a few minutes after midnight in Paris France is a new day while still “yesterday” in Montréal Québec.

ZonedDateTime

Apply a ZoneId to get a ZonedDateTime .

ZoneId z = ZoneId.of( "America/Montreal" ) ;
ZonedDateTime zdt = ld.atStartOfDay( z ) ;

If your alarm library requires this moment be represented as a count of milliseconds since the epoch of start of 1970 UTC, interrogate for a long integer from an extracted Instant object.

long millisecondsSinceEpoch = zdt.toInstant().toEpochMilli() ;

About java.time

The java.time framework is built into Java 8 and later. These classes supplant the old troublesome date-time classes such as java.util.Date , .Calendar , & java.text.SimpleDateFormat .

The Joda-Time project, now in maintenance mode , advises migration to java.time.

To learn more, see the Oracle Tutorial . And search Stack Overflow for many examples and explanations.

Much of the java.time functionality is back-ported to Java 6 & 7 in ThreeTen-Backport and further adapted to Android in ThreeTenABP (see How to use… ).

The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval , YearWeek , YearQuarter , and more.