Develop Reference

Display local date in textview (Kotlin)

I'm trying to display the local date (ie Tuesday, September 14, 2021) in a textview and I'm having a hard time finding a way to do it. Any tips or ideas?

You can use SimpleDateFormat class to format dates.
To acheive the format you specified in question, use this:
textView.text = SimpleDateFormat("EEEE, MMMM dd, yyyy").format(Date())
To understand the meaning of different date and time patterns, checkout this link.

java.time and a built-in localized format
Consider using java.time, the modern Java date and time API, for your date work. Please excuse my Java syntax. Declare a formatter:
private static final DateTimeFormatter DATE_FORMATTER
= DateTimeFormatter.ofLocalizedDate(FormatStyle.FULL).withLocale(Locale.US);
Use like this:
LocalDate today = LocalDate.now(ZoneId.systemDefault());
String text = today.format(DATE_FORMATTER);
System.out.println(text);
When running today, output was:
Wednesday, September 15, 2021
Now assign this text into your TextView as described in the other answers.
Not only will you want to avoid the troublesome SimpleDateFormat class, you will also want to avoid writing your own format pattern string since this is error-prone. And your wish goes nicely hand in hand with the wish of your users to see the date printed in an appropriate format for their locale. In the above code I used Local.US for demonstration. In real code you will want to leave out that bit. Then the formatter will take on the default locale of the device, and users in all locales will be happy. Simply like this:
private static final DateTimeFormatter DATE_FORMATTER
= DateTimeFormatter.ofLocalizedDate(FormatStyle.FULL);
Question: Doesn’t java.time require Android API level 26?
java.time works nicely on both older and newer Android devices. It just requires at least Java 6.
In Java 8 and later and on newer Android devices (from API level 26) the modern API comes built-in.
In non-Android Java 6 and 7 get the ThreeTen Backport, the backport of the modern classes (ThreeTen for JSR 310; see the links at the bottom).
On older Android either use desugaring or the Android edition of ThreeTen Backport. It’s called ThreeTenABP. In the latter case make sure you import the date and time classes from org.threeten.bp with subpackages.
Links
Similar question: Date formatting based on user locale on android.
Oracle tutorial: Date Time explaining how to use java.time.
Java Specification Request (JSR) 310, where java.time was first described.
ThreeTen Backport project, the backport of java.time to Java 6 and 7 (ThreeTen for JSR-310).
Java 8+ APIs available through desugaring
ThreeTenABP, Android edition of ThreeTen Backport
Question: How to use ThreeTenABP in Android Project, with a very thorough explanation.

Try this code
val sdf = SimpleDateFormat("EEE, MMMM dd, yyyy")
val current = sdf.format(Date())
textView.text = "$current"

Thank You everyone! Both of these solutions worked:
Solution 1:
val dateDisplay: TextView = findViewById(R.id.date)
dateDisplay.text = SimpleDateFormat("EEEE, MMMM dd, yyyy").format(Date())
Solution 2:
val sdf = SimpleDateFormat("EEE, MMMM dd, yyyy")
val current = sdf.format(Date())
val dateDisplay: TextView = findViewById(R.id.date)
dateDisplay.text = "$current"

How to get date time from UTC date time fromat?

I am getting date time from rest api as like this "2020-02-13T16:57:13.04 . How can i convert in java for android? So that i can use only date or time separately?
I have tried by this way
String dateStr = rowsArrayList.get(position).getDisplayDate();
SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'", Locale.ENGLISH);
df.setTimeZone(TimeZone.getTimeZone("UTC"));
Date date = null;
try {
date = df.parse(dateStr);
df.setTimeZone(TimeZone.getDefault());
String formattedDate = df.format(date);
Log.d("testDate",formattedDate);
} catch (ParseException e) {
e.printStackTrace();
Log.d("testDate",e.toString());
}
But getting the error
java.text.ParseException: Unparseable date: "2020-02-13T16:57:13.04"

Use yyyy-MM-dd'T'HH:mm:ss.SS as format instead of yyyy-MM-dd'T'HH:mm:ss'Z'
SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SS", Locale.ENGLISH);
java.time
You can also achieve this with java.time, the modern Java date and time API because the old classes (Date, Calendar and SimpleDateFormat) have lots of problems and design issues:
String sourceDateTime = "2020-02-13T16:57:13.04";
DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss.SS").withZone(DateTimeZone.UTC);
LocalDateTime localDateTime = LocalDateTime.parse(sourceDateTime, dateTimeFormatter);
LocalDate localDate = localDateTime.toLocalDate();
LocalTime localTime = localDateTime.toLocalTime();
System.out.println(localDate.toString() + " -> " + localTime.toString());
//Output should be: 2020-02-13 -> 16:57:13.040
Question: Can I use java.time on Android?
From Android 8.0 (API level 26) the modern API comes built-in.
For older android version, you can use ThreeTenABP, Android edition of ThreeTen Backport

SimpleDateFormat cannot parse your date-time string correctly.
SimpleDateFormat is notoriously troublesome and long outdated. Neither for this nor for any other purpose should you use it. Instead just use the LocalDateTime class from java.time, the modern Java date and time API. It parses your string wothout any explicit formatter.
You can’t with SimpleDateFormat
Your string has two decimals on the second of minute, .04, signifying 4 hundredths of a second. SimpleDateFormat only supports exactly three decimals on the seconds, not two or four or any other number. So there is no way that it can parse your string correctly.
java.time
It seems that you are assuming that the string you parse is in UTC and you want to convert it to the default time zone of your device. Your string is in ISO 8601 format, the format that the classes of java.time parse as their default, so we don’t need to specify any formatter.
String dateStr = "2020-02-13T16:57:13.04";
LocalDateTime dateTime = LocalDateTime.parse(dateStr);
ZonedDateTime inDefaultTimeZone = dateTime.atOffset(ZoneOffset.UTC)
.atZoneSameInstant(ZoneId.systemDefault());
System.out.println(inDefaultTimeZone);
On my computer in Europe/Copenhagen time zone the output from this snippet is:
2020-02-13T17:57:13.040+01:00[Europe/Copenhagen]
Question: Doesn’t java.time require Android API level 26?
java.time works nicely on both older and newer Android devices. It just requires at least Java 6.
In Java 8 and later and on newer Android devices (from API level 26) the modern API comes built-in.
In non-Android Java 6 and 7 get the ThreeTen Backport, the backport of the modern classes (ThreeTen for JSR 310; see the links at the bottom).
On (older) Android use the Android edition of ThreeTen Backport. It’s called ThreeTenABP. And make sure you import the date and time classes from org.threeten.bp with subpackages.
Links
Oracle tutorial: Date Time explaining how to use java.time.
Java Specification Request (JSR) 310, where java.time was first described.
ThreeTen Backport project, the backport of java.time to Java 6 and 7 (ThreeTen for JSR-310).
ThreeTenABP, Android edition of ThreeTen Backport
Question: How to use ThreeTenABP in Android Project, with a very thorough explanation.
Wikipedia article: ISO 8601

Take out the 'Z' on your format string
This should work:
SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss", Locale.ENGLISH);
Or if you want to keep the milliseconds then use SS:
SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SS", Locale.ENGLISH);

String dateStr = "Jul 16, 2013 12:08:59 AM";
SimpleDateFormat df = new SimpleDateFormat("MMM dd, yyyy HH:mm:ss a", Locale.ENGLISH);
df.setTimeZone(TimeZone.getTimeZone("UTC"));
Date date = df.parse(dateStr);
df.setTimeZone(TimeZone.getDefault());
String formattedDate = df.format(date);

Is Hour between an hour range?

The closest post I found on my question is How to compare current time with time range? But this doesn't work for me because i need to know if the current time on the users device is between a time range
so i got the current time like this...
DateFormat dateFormat = new SimpleDateFormat("yyyy-mm-dd hh:mm:ss a");
String horaString = dateFormat.format(hour);
Log.i("ALO","HORAAAAAASSSSTRRRRIIIINNNNGGG---->"+horaString);
first = horaString.charAt(11);
Log.i("ALOP","Char at 11 ---->"+first);
char second=horaString.charAt(12);
Log.i("ALOP","Char at 12 ---->"+second);
char third=horaString.charAt(13);
char fourth=horaString.charAt(14);
char fith=horaString.charAt(15);
StringBuilder sb = new StringBuilder();
sb.append(first);
sb.append(second);
sb.append(third);
sb.append(fourth);
sb.append(fith);
String currentTime = sb.toString();
now what is need to do is
6:00>=currentTime<=8:30 //Can i still do the comparison with AM/PM?
So this is what I need to do if currentTime = 8:29 a method that lets me know is True with a boolean.

java.time and ThreeTenABP
final LocalTime rangeBegin = LocalTime.of(6, 0);
final LocalTime rangeEnd = LocalTime.of(8, 30);
LocalTime currentTime = LocalTime.now(ZoneId.of("America/Bogota"));
boolean inClosedRange = ! (currentTime.isBefore(rangeBegin) || currentTime.isAfter(rangeEnd));
If you prefer to trust the device time zone setting rather than a hard-coded (or configured) time zone, use LocalTime.now(ZoneId.systemDefault()).
Since LocalTime hasn’t got an isBeforeOrEqual method nor an isEqualOrAfter, I am putting the condition negatively: if the current time is neither strictly before nor strictly after the range, it must be within it. Some will prefer the longer but also more direct:
boolean inClosedRange = currentTime.equals(rangeBegin)
|| (currentTime.isAfter(rangeBegin) && currentTime.isBefore(rangeEnd))
|| currentTime.equals(rangeEnd);
You will notice how much simpler it still is than your code using SimpleDateFormat and Date. I personally also find it clearer. I am using and recommending java.time, the modern Java date and time API.
Question: Can I use java.time on Android?
Yes, java.time works nicely on older and newer Android devices. It just requires at least Java 6.
In Java 8 and later and on newer Android devices (from API level 26) the modern API comes built-in.
In Java 6 and 7 get the ThreeTen Backport, the backport of the modern classes (ThreeTen for JSR 310; see the links at the bottom).
On (older) Android use the Android edition of ThreeTen Backport. It’s called ThreeTenABP. And make sure you import the date and time classes from org.threeten.bp with subpackages.
Links
Oracle tutorial: Date Time explaining how to use java.time.
Java Specification Request (JSR) 310, where java.time was first described.
ThreeTen Backport project, the backport of java.time to Java 6 and 7 (ThreeTen for JSR-310).
ThreeTenABP, Android edition of ThreeTen Backport
Question: How to use ThreeTenABP in Android Project, with a very thorough explanation.

There are two useful command: After, Before.
Here is an example how you can use them:
SimpleDateFormat dateFormat = new SimpleDateFormat("HH:mm");
Date fromTime = dateFormat.parse("6:00");
Date toTime = dateFormat.parse("8:30");
Date currentTime = dateFormat.parse(dateFormat.format(new Date()));
if(currentTime.after(fromTime) && currentTime.before(toTime)) {
// To do
}

Displaying date/time in devices timezone on Android using Kotlin

So my app fetches from information from a JSON file from a server, of which there are a few date/time values. The time and date are in UTC. I need to display these in my app, in the users local timezone.
Example of the data from JSON:
"start":"2018-10-20 03:00:00","finish":"2018-10-20 05:00:00"
My code so far, which display the date and time fine, in UTC..
val dateStringStart = radioScheduleDMList.get(position).start
val dateStringEnd = radioScheduleDMList.get(position).finish
val date = SimpleDateFormat("yyyy-MM-dd hh:mm:ss", Locale.getDefault()).parse(dateStringStart)
val dateEnd = SimpleDateFormat("yyyy-MM-dd hh:mm:ss", Locale.getDefault()).parse(dateStringEnd)
val day = SimpleDateFormat("d MMM").format(date)
val startDate = SimpleDateFormat("ha").format(date)
val endDate = SimpleDateFormat("ha").format(dateEnd)
How can I go about displaying this data using the devices timezone? I've been googling for hours.
Using the above example, my app shows "20 OCT" for the date, and "3AM-5AM" for the time. In my case, I live in Australia (GMT+10) so I would expect day "20 OCT" and "1PM-3PM". In short, I want to detect the user’s timezone offset from UTC and apply it for display.

java.time and ThreeTenABP
DateTimeFormatter jsonFormatter = DateTimeFormatter.ofPattern("uuuu-MM-dd HH:mm:ss");
DateTimeFormatter dateFormatter
= DateTimeFormatter.ofPattern("d MMM", Locale.forLanguageTag("en-AU"));
DateTimeFormatter hourFormatter
= DateTimeFormatter.ofPattern("ha", Locale.forLanguageTag("en-AU"));
ZoneId zone = ZoneId.systemDefault();
String dateStringStart = "2018-10-20 03:00:00";
OffsetDateTime startDateTime = LocalDateTime.parse(dateStringStart, jsonFormatter)
.atOffset(ZoneOffset.UTC);
ZonedDateTime userStartDateTime = startDateTime.atZoneSameInstant(zone);
String startDayString = userStartDateTime.format(dateFormatter);
String startTimeString = userStartDateTime.format(hourFormatter);
System.out.println("Start day: " + startDayString);
System.out.println("Start hour: " + startTimeString);
I’m sorry I don’t write Kotlin. Can you translate from Java on your own? When I run the above code on a JVM with default time zone Australia/Brisbane it outputs:
Start day: 20 Oct
Start hour: 1PM
Just do similarly for the end date and time.
Question: Can I use java.time on Android?
Yes, java.time works nicely on older and newer Android devices. It just requires at least Java 6.
In Java 8 and later and on newer Android devices (from API level 26) the modern API comes built-in.
In Java 6 and 7 get the ThreeTen Backport, the backport of the new classes (ThreeTen for JSR 310; see the links at the bottom).
On (older) Android use the Android edition of ThreeTen Backport. It’s called ThreeTenABP. And make sure you import the date and time classes from org.threeten.bp with subpackages.
Links
Oracle tutorial: Date Time explaining how to use java.time.
Java Specification Request (JSR) 310, where java.time was first described.
ThreeTen Backport project, the backport of java.time to Java 6 and 7 (ThreeTen for JSR-310).
ThreeTenABP, Android edition of ThreeTen Backport
Question: How to use ThreeTenABP in Android Project, with a very thorough explanation.

android timestamp parsing gone wrong(always in 1970)

im trying to convert a string(with unix timestamp) to an date with the format ( dd-MM-yyyy)
and this is working partly. The problem im having now is that my date is in 17-01-1970 (instead of march 16 2015)
im converting it like this:
SimpleDateFormat dateFormat = new SimpleDateFormat("dd-MM-yyyy");
Date d = null;
int dateMulti = Integer.parseInt(Date);
Calendar cal = Calendar.getInstance(Locale.ENGLISH);
cal.setTimeInMillis(dateMulti);
String date = DateFormat.format("dd-MM-yyyy", cal).toString();
Log.d("test",date);
try {
d = dateFormat.parse(date);
} catch (ParseException e) {
e.printStackTrace();
}
where Date = 1427101853
and the result = 17-01-1970
what am i doing wrong?

You are using the wrong format string in the first line:
SimpleDateFormat dateFormat = new SimpleDateFormat("dd-mm-yyyy");
mm is minutes. Use MM (months) instead.
edit A Unix timestamp is a number of seconds since 01-01-1970 00:00:00 GMT. Java measures time in milliseconds since 01-01-1970 00:00:00 GMT. You need to multiply the Unix timestamp by 1000:
cal.setTimeInMillis(dateMulti * 1000L);

Why you have "dd-mm-yyyy" in SimpleDateFormat and "dd-MM-yyyy" in DateFormat.format? Use this :
String date = DateFormat.format("dd-mm-yyyy", cal).toString();
If you want minutes, if you want months you have to put MM like #Jesper said :)

I should like to contribute the modern answer.
java.time
DateTimeFormatter dateFormatter = DateTimeFormatter
.ofLocalizedDate(FormatStyle.MEDIUM)
.withLocale(Locale.forLanguageTag("da"));
String unixTimeStampString = "1427101853";
int dateMulti = Integer.parseInt(unixTimeStampString);
ZonedDateTime dateTime = Instant.ofEpochSecond(dateMulti)
.atZone(ZoneId.of("Africa/Conakry"));
String formattedDate = dateTime.format(dateFormatter);
System.out.println(formattedDate);
The output from this snippet is:
23-03-2015
The output agrees with an online converter (link at the bottom). It tells me your timestamp equals “03/23/2015 # 9:10am (UTC)” (it also agrees with the date you asked the question). Please substitute your time zone if it didn’t happen to be Africa/Conakry.
The date-time classes that you were using — SimpleDateFormat, Date and Calendar — are long outdated and poorly designed, so I suggest you skip them and use java.time, the modern Java date and time API, instead. A minor one among the many advantages is it accepts seconds since the epoch directly, so you don’t need to convert to milliseconds. While this was no big deal, doing your own time conversions is a bad habit, you get clearer, more convincing and less error-prone code from leaving the conversions to the appropriate library methods.
Question: Can I use java.time on Android?
Yes, java.time works nicely on older and newer Android devices. It just requires at least Java 6.
In Java 8 and later and on newer Android devices (from API level 26, I’m told) the modern API comes built-in.
In Java 6 and 7 get the ThreeTen Backport, the backport of the new classes (ThreeTen for JSR 310; see the links at the bottom).
On (older) Android use the Android edition of ThreeTen Backport. It’s called ThreeTenABP. And make sure you import the date and time classes from org.threeten.bp with subpackages.
I wrote and ran the above snippet using the backport to make sure it would be compatible with ThreeTenABP.
Links
Timestamp Converter
Oracle tutorial: Date Time explaining how to use java.time.
Java Specification Request (JSR) 310, where java.time was first described.
ThreeTen Backport project, the backport of java.time to Java 6 and 7 (ThreeTen for JSR-310).
ThreeTenABP, Android edition of ThreeTen Backport
Question: How to use ThreeTenABP in Android Project, with a very thorough explanation.

I was also facing the same issue when I was using SimpleDateFormat Here is a method I have made, which is working fine for me.
private String getmDate(long time1) {
java.util.Date time = new java.util.Date((long) time1 * 1000);
String date = DateFormat.format("dd-MMM-yyyy' at 'HH:mm a", time).toString();
return date + "";
}
you can change the date format as you desire.