Develop Reference

How to get current hour in android?

Time class is no longer possible to use.
I want to ask you, how to detect in app 3-4am?
I need that to set up for example night mode in my app.
Can you give me some example how to do it?

Instead of using Time (because Time class was deprecated in API level 22.) you can use Calendar for getting current hour
val rightNow = Calendar.getInstance()
val currentHourIn24Format: Int =rightNow.get(Calendar.HOUR_OF_DAY) // return the hour in 24 hrs format (ranging from 0-23)
val currentHourIn12Format: Int = rightNow.get(Calendar.HOUR) // return the hour in 12 hrs format (ranging from 0-11)

We can use the Calendar class to get a format like "HH:mm:ss"
Calendar calendar = Calendar.getInstance();
int hour24hrs = calendar.get(Calendar.HOUR_OF_DAY);
int hour12hrs = calendar.get(Calendar.HOUR);
int minutes = calendar.get(Calendar.MINUTE);
int seconds = calendar.get(Calendar.SECOND);
System.out.println("Current hour 24hrs format: " + hour24hrs + ":" + minutes +":"+ seconds);
System.out.println("Current hour 12hrs format: " + hour12hrs + ":" + minutes +":"+ seconds);
Other option using the Date class and applying the format "HH:mm:ss":
DateFormat dateFormat = new SimpleDateFormat("HH:mm:ss");
Date date = new Date();
String dateformatted = dateFormat.format(date);
System.out.println(dateformatted);

You can use following methods:
SimpleDateFormat format = new SimpleDateFormat("HH", Locale.US);
String hour = format.format(new Date());
Calendar calendar = Calendar.getInstance();
int hourOfDay = calendar.get(Calendar.HOUR_OF_DAY);

How to set alarm manager using date and time from Textview

I am converting a timestamp into date and time and setting the result on a textview.
For example 1443884578 is Sat 3 October 2015 18:02
I would like to set the above date and time into an alarm manager.After research i found a code that uses a date time picker.
public void onDateSelectedButtonClick(View v) {
// Get the date from our datepicker
int day = picker.getDayOfMonth();
int month = picker.getMonth();
int year = picker.getYear();
// Create a new calendar set to the date chosen
// we set the time to midnight (i.e. the first minute of that day)
Calendar c = Calendar.getInstance();
c.set(year, month, day);
c.set(Calendar.HOUR_OF_DAY, 0);
c.set(Calendar.MINUTE, 0);
c.set(Calendar.SECOND, 0);
// Ask our service to set an alarm for that date, this activity talks to the client that talks to the service
scheduleClient.setAlarmForNotification(c);
// Notify the user what they just did
Toast.makeText(this, "Notification set for: " + day + "/" + (month + 1) + "/" + year, Toast.LENGTH_SHORT).show();
}
However its getting only the date and fires the alarm the minute the date occurs.
PROBLEM: I would like to get the date and time from my textview and skip this date time picker in the format i have. Is this possible?

String input = "Sat October 3 2015 18:02"; // Instead of String input = "Mon Feb 06 2015";
Calendar cal = Calendar.getInstance();
Date date = new Date();
// Changed the format to represent time of day
SimpleDateFormat sdf = new SimpleDateFormat("EEE MMM dd yyyy HH:mm:ss", Locale.ENGLISH);
try {
date = sdf.parse(input);
} catch (ParseException e) {
e.printStackTrace();
}
cal.setTime(date);
//We haven't parsed the seconds from the original date so this will result
//in 18:02:00 - 10seconds.
//For a correct calculation, you could parse the seconds as well
//See SimpleDateFormat above, but you would have to provide the original date
//with seconds as well
cal.add(Calendar.SECOND, -10);
scheduleClient.setAlarmForNotification(cal);

Issue in convert calendar object to date android

I want to convert calendar object to date as follow.
int year,month,day;
mCalendarEnd = Calendar.getInstance();
year = mCalendarEnd.get(Calendar.YEAR);
month = mCalendarEnd.get(Calendar.MONTH)+1;
day = mCalendarEnd.get(Calendar.DAY_OF_MONTH);
Now convert it to date object
Date d1 = new Date(day,month,year);
when I print date object:
System.out.println("Date : "+d1.getDay()+"/"+d1.getMonth()+"/"+d1.getYear());
it should print current date but in above code it prints the wrong date. Any idea how can I solve this problem? your all suggestion are appreciable.

You need to do it like this
//Set calendar
Calendar calendar = Calendar.getInstance();
Date date1 = calendar.getTime(); // gives a date object
//To get day difference, Just an example
calendar.add(Calendar.DAY_OF_MONTH, -7);
Date date2 = calendar.getTime(); // gives a date object
long differenceInMillis = Date1.getTime() - Date2.getTime();
long differenceInDays = TimeUnit.DAYS.convert(differenceInMillis, TimeUnit.MILLISECONDS);
Or No need of date objects
Calendar calendar = Calendar.getInstance();
long date1InMillis = calendar.getTimeInMillis();
calendar.add(Calendar.DAY_OF_MONTH, -7);
long date2InMillis = calendar.getTimeInMillis();
long differenceInMillis = date1InMillis - date2InMillis;
long differenceInDays = TimeUnit.DAYS.convert(differenceInMillis, TimeUnit.MILLISECONDS);
calendar.getTimeInMillis()

calendar.getTime() returns Date object.
but if you just need today date new Date() returns today date as Date object, too.
Calendar example:
Calendar calendar = Calendar.getInstance()
Log.i("My Tag", "calendar getTime -----> " + calendar.getTime());
Output:
My Tag: calendar getTime -----> Wed Dec 05 13:03:43 GMT+03:30 2018
Date Example:
Log.i("My Tag", "new Date -----> " + new Date());
Output:
My Tag: new Date -----> Wed Dec 05 13:05:38 GMT+03:30 2018
as you see both of them have the same output.

Why you don't use just the calendar?
System.out.println("Date : " + day + "/" + month + "/" + year);
result 1/1/1900
or you want other format? but dont increment the month with 1
System.out.println("Date : " + day + "/" + new DateFormatSymbols().getMonths()[month] + "/" + year);
result 1/January/1900

Put this in your code:
Date d1 = new Date(year, month, day);
System.out.println("Date : " + d1.getDate() + "/" +d1.getMonth() + "/" + d1.getYear());
you will get the correct date.

d1=new Date(year, month, day);
System.out.println("Dt:"+d1.getDate()+"/"+d1.getMonth()+"/"+d1.getYear());

Get Date of past 7days from current in android

I am trying to fetch the date 7days prior to today's date.
I am using SimpleDateFormat to fetch today's date.
SimpleDateFormat sdf1 = new SimpleDateFormat("dd/MM/yyyy");
Please guide me through this
Updated answer which I found most useful
SimpleDateFormat sdf=new SimpleDateFormat("dd/MM/yyyy");
String currentDateandTime = sdf.format(new Date());
Date cdate=sdf.parse(currentDateandTime);
Calendar now2= Calendar.getInstance();
now2.add(Calendar.DATE, -7);
String beforedate=now2.get(Calendar.DATE)+"/"+(now2.get(Calendar.MONTH) + 1)+"/"+now2.get(Calendar.YEAR);
Date BeforeDate1=sdf.parse(beforedate);
cdate.compareTo(BeforeDate1);
Thank you for you reply

Use java.util.Calendar, set it to today's date and then subtract 7 days.
Calendar cal = GregorianCalendar.getInstance();
cal.setTime(new Date());
cal.add(Calendar.DAY_OF_YEAR, -7);
Date 7daysBeforeDate = cal.getTime();
Edit: In Java 8 it can be done much easier by using classes from java.time package:
final LocalDate date = LocalDate.now();
final LocalDate dateMinus7Days = date.minusDays(7);
//Format and display date
final String formattedDate = dateMinus7Days.format(DateTimeFormatter.ISO_LOCAL_DATE);
System.out.println(formattedDate);

You can try out this,
import java.util.Calendar;
public class AddDaysToCurrentDate {
public static void main(String[] args) {
//create Calendar instance
Calendar now = Calendar.getInstance();
System.out.println("Current date : " + (now.get(Calendar.MONTH) + 1)
+ "-"
+ now.get(Calendar.DATE)
+ "-"
+ now.get(Calendar.YEAR));
//add days to current date using Calendar.add method
now.add(Calendar.DATE,1);
System.out.println("date after one day : " + (now.get(Calendar.MONTH) + 1)
+ "-"
+ now.get(Calendar.DATE)
+ "-"
+ now.get(Calendar.YEAR));
//substract days from current date using Calendar.add method
now = Calendar.getInstance();
now.add(Calendar.DATE, -10);
System.out.println("date before 10 days : " + (now.get(Calendar.MONTH) + 1)
+ "-"
+ now.get(Calendar.DATE)
+ "-"
+ now.get(Calendar.YEAR));
}
}
/*
Typical output would be
Current date : 12-25-2007
date after one day : 12-26-2007
date before 10 days : 12-15-2007
*/

Android get date before 7 days (one week)
Date myDate = dateFormat.parse(dateString);
And then either figure out how many milliseconds you need to subtract:
Date newDate = new Date(myDate.getTime() - 604800000L); // 7 * 24 * 60 * 60 * 1000
Or use the API provided by the java.util.Calendar class:
Calendar calendar = Calendar.getInstance();
calendar.setTime(myDate);
calendar.add(Calendar.DAY_OF_YEAR, -7);
Date newDate = calendar.getTime();
Then, if you need to, convert it back to a String:
and finally
String date = dateFormat.format(newDate);

you can use this kotlin function to get any date before the current date.
/**
* get specific date before current date
* [day] number of day
* [month] number of month
* [year] number of year
* [count] number of day, month, year
*
* return date
*/
fun getBeforeDate(day: Boolean = false, month: Boolean = false, year: Boolean = false, count: Int = 0): String{
val currentCalendar = Calendar.getInstance()
val myFormat = "dd/MM/yyyy" // you can use your own date format
val sdf = SimpleDateFormat(myFormat, Locale.getDefault())
if (day){
currentCalendar.add(Calendar.DAY_OF_YEAR, -count)
}else if(month){
currentCalendar.add(Calendar.MONTH, -count)
}else if(year){
currentCalendar.add(Calendar.YEAR, -count)
}else{
// if user not provide any value then give current date
currentCalendar.add(Calendar.DAY_OF_YEAR, 0)
// or you can throw Exception
//throw Exception("Please provide at least one value")
}
return sdf.format(currentCalendar.time)
}

fun getBeforeDate(day: Boolean = false, month: Boolean = false, year: Boolean = false, count: Int = 0): String{
val currentCalendar = Calendar.getInstance()
val myFormat = "dd/MM/yyyy" // you can use your own date format
val sdf = SimpleDateFormat(myFormat, Locale.getDefault())
if (day){
currentCalendar.add(Calendar.DAY_OF_YEAR, -count)
}else if(month){
currentCalendar.add(Calendar.MONTH, -count)
}else if(year){
currentCalendar.add(Calendar.YEAR, -count)
}else{
// if user not provide any value then give current date
currentCalendar.add(Calendar.DAY_OF_YEAR, 0)
// or you can throw Exception
//throw Exception("Please provide at least one value")
}
return sdf.format(currentCalendar.time)
}

setting particular date to Date object

I've been trying this from a long time.
I'm having today's date and I want to compare it with specific date.
But when I set particular date like this, it gives me wrong output:
Calendar cal;
SimpleDateFormat dateformatter;
String currentdate;
cal = Calendar.getInstance();
dateformatter = new SimpleDateFormat("yyyy-MM-dd");
//Getting today's date
currentdate = dateformatter.format(cal.getTime());
Log.i(Class_Tag, "current = " + currentdate);
//Setting specific date
Date start = cal.getTime();
cal.set(2012, 06, 20);
Date end = cal.getTime();
Log.i(Class_Tag, "end = " + dateformatter.format(end));
long diff = end.getDate() - start.getDate();
Log.i(Class_Tag, "diff : " + diff);
long diff1 = end.getMonth() - start.getMonth();
Log.i(Class_Tag, "diff mnth : " + diff1);
long diff2 = end.getYear() - start.getYear();
Log.i(Class_Tag, "diff yr : " + diff2);
if (start.compareTo(end) == 0) {
Log.i(Class_Tag, "EQUAL");
} else if (start.compareTo(end) < 0) {
Log.i(Class_Tag, "end b4 start, delete");
} else {
Log.i(Class_Tag, "start b4 end, do nothing");
OUTPUT:
current = 2012-06-20
end = 2012-07-20 ////WHY it is showing month as '7' when I've set it to '6'?
diff : 0
diff mnth : 1 //Because of the wrong month in end date, this comes 1 instead of 0
diff yr : 0
end b4 start, delete //this also is not correct
I've tried several solutions, but no gains.
My only objective is to get whether that particular date has passed today's date or not.
Any help appreciated.
Edit
in the following code snippet,
//Setting specific date
Date start = cal.getTime();
cal.set(2012, 06, 20);
Date end = cal.getTime();
If I set cal.set(2012, 06, 20); to cal.set(2012, 05, 20);, the month diff. comes out to 0.
This implies that month in particular date is getting incremented by '1', but WHY?

Try this;
Calendar cal = Calendar.getInstance();
long dateNowMillis = cal.getTimeInMillis();
cal.set(2013, 1, 23);
long specDate = cal.getTimeInMillis();
if(dateNowMillis > specDate)
{
System.out.println("Passed");
}
else if(dateNowMillis == specDate)
{
System.out.println("Now");
}
else
{
System.out.println("Not passed");
}

FYI,
A month is represented by an integer from 0 to 11; 0 is January, 1 is February, and so forth; thus 11 is December.
You can check read more about Date here and more about SimpleDateFormat.
Update:
One more thing about getMonth() => Its deprecated, instead Calendar.get(Calendar.MONTH), check here.