I have an app on the PlayStore and I am building a feature where the user will not see ads more than a specific number in one day.
I am thinking about comparing the current date and time to the previously saved one but haven't find a proper way to do that.
How can I compare date and time to know if 24 hours have passed or not?
Some posts that I found but not helpful:
medium.com
stackoverflow
stackoverflow
tl;dr
[This Answer uses Java syntax. You’ll have to translate to Kotlin syntax.]
if
(
Duration // Represents elapsed time on the scale of hours-minutes-seconds.
.between( // Calculates elapsed time between two points in time.
Instant.parse( "2021-03-23T15:30:57.013678Z" ) , // Last moment when an ad was show.
Instant.now() // Current moment.
) // Returns a `Duration` object.
.toHours() // Extract total number of whole hours from the `Duration` object.
>= 24L // Test if equals-to or greater-than 24 hours.
)
{ show ad }
java.time
You asked:
… know if 24 hours have passed or not?
Use the modern java.time classes defined in JSR 310. The java.time classes are built into Android 26 and later. Most of the functionality is available in earlier Android using the latest tooling’s “API desugaring“.
Instant adShown = Instant.parse( "2021-03-23T15:30:57.013678Z" ) ;
Instant now = Instant.now() ;
Duration d = Duration.between( adShown , now ) ;
long hoursSinceAdShown = d.toHours() ;
if( hoursSinceAdShown >= 24L ) { … show ad }
Record your next ad-showing as text in standard ISO 8601 format.
String output = Instant.now().toString() ;
2021-03-23T15:30:57.013678Z
Your Question asked for two different things:
Once per day
Every 24 hours
The first involves a calendar, dates, and a time zone. The second does not. I showed you code for the second.
You can use a scheduled executor service to trigger from a background thread the next showing of an ad at a specific moment. Search Stack Overflow to learn more as this has been covered many times already.
Use this code to check the current date, Yesterday or Particulardate. Pass Epoch time to this method
// input format (we get a value as Epoch)
private val inputFormat = SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'")
private val outputFormat = SimpleDateFormat("MMM dd")
// have to pass the time value as Epoch time.
private fun calculateDateMonth(time: String): String {
var returnValue = ""
val dateTime = DateTime((time.toLong()) * 1000L)
val inputTime = inputFormat.parse(dateTime.toString())
val convertDateMonth = outputFormat.format(inputTime!!)
val timeInMilliseconds = outputFormat.parse(convertDateMonth)!!
val mTime: Calendar = Calendar.getInstance()
mTime.setTimeInMillis(timeInMilliseconds.time)
val now = Calendar.getInstance()
returnValue = when {
now[Calendar.DATE] == mTime[Calendar.DATE] // check isToday
now[Calendar.DATE] - mTime[Calendar.DATE] == 1 // check Yesterday
else -> convertDateMonth // Month and Date
}
return returnValue
}
Related
Hello everyone I'm trying to make a small timer that will display how many minutes and seconds are left until a certain time. I want to do this using the difference between the present time and the time to which the countdown is running, but I can't figure out how to do it.
It is necessary to output the time in the format "hh:mm". That is, if now, for example, "13:27:28", and the desired time is "14:00:00", then the final result should be "32:32". And is it possible to compare time somehow? Check whether the present time is greater or less than the specified one.
import java.time.LocalTime
import java.time.format.DateTimeFormatter
fun main(args: Array<String>) {
println(calculateTime("13:27:28", "14:00:00"))
}
private fun calculateTime(from: String, to: String): String {
val formatter = DateTimeFormatter.ofPattern("hh:mm:ss")
val time1 = LocalTime.parse(from, formatter)
val time2 = LocalTime.parse(to, formatter)
return time1.toString() + time2.toString()
}
Try Stopwatch from Apache Commons
val stopWatch = StopWatch().apply { start() }
...
stopWatch.stop()
println("Completed after $stopWatch")
and you get something like this: "Completed after 00:00:18.832"
let say i will like to automatically change my textview text at 02:00pm everyday how do I implement this functionality.
val df = DateFormat.getTimeInstance(DateFormat.SHORT, Locale.JAPAN).parse("2:00pm")
val systemDat = Calendar.getInstance(Locale.JAPAN).after(df)
if (systemDat) {
binding.includeTokyoSession.text_one.text = "successful"
} else {
binding.includeTokyoSession.text_one.text = "failure"
}
I suppose you want to change the text of your TextView after a particular time, but it seems that you're not aware of the date when comparing and you have a couple of mistakes in your code.
First, this line of code:
DateFormat.getTimeInstance(DateFormat.SHORT, Locale.JAPAN).parse("2:00pm")
will return a Date instance with this date and time in your local timezone 01-01-1970 02:00:00. However, you need to get a Date instance with today's date and the time 14:00:00.
Second, this line of code:
Calendar.getInstance(Locale.JAPAN).after(df)
this is a wrong usage of the Calendar::after() function, and that's because you can only pass a Calendar object to the function in order to get the right comparison result, otherwise it will always return false.
In your case you're passing a Date object.
Following is the implementation of the Calendar::after() function.
public boolean after(Object when) {
return when instanceof Calendar
&& compareTo((Calendar)when) > 0;
}
If you want to proper compare the current time today with 14:00 (comparing only the time today), here is a modification to your code:
val calendarToCompare = Calendar.getInstance(Locale.JAPAN).apply {
set(Calendar.HOUR_OF_DAY, 14)
set(Calendar.MINUTE, 0)
set(Calendar.SECOND, 0)
set(Calendar.MILLISECOND, 0)
}
val systemDat = Calendar.getInstance().after(calendarToCompare)
if (systemDat) {
textview.text = "successful"
} else {
textview.text = "failure"
}
If you want to perform a lifecycle-aware view update (ex. to set the text of your textview), you can check this gist.
I'm implementing count down timer for the android app using JodaTime.
Depending of devices the output is different.
DateTime openingDateTime = new DateTime(2018, DateTimeConstants.JUNE, 14, 21, 0, 0, DateTimeZone.forID("Europe/Moscow"));
DateTime nowDateTime = DateTime.now(DateTimeZone.forID("Europe/Moscow"));
long difference = openingDateTime.getMillis() - nowDateTime.getMillis();
(...)
onTick(difference);
(...)
PeriodFormatter periodFormatter = new PeriodFormatterBuilder()
.printZeroAlways()
.appendDays().appendSuffix(" day", " days")
.appendSeparator(" ")
.appendHours()
.appendSeparator(":")
.appendMinutes()
.appendSeparator(":")
.appendSeconds()
.toFormatter();
(...)
#Override
public void onTick(long millisUntilFinished) {
Duration duration = new Duration(millisUntilFinished);
Period period = duration.toPeriod(PeriodType.dayTime());
tvCounter.setText(periodFormatter.print(period));
}
On the one device output is correct: 491 days 4:39:18
on the other is wrong: 0 days 11788:49:11.
What am I doing wrong?
Thanks to your comments, I can now reproduce your problem. Just add following static initializer to your test class (at first place) to simulate the device where you observe your expected output:
static {
TimeZone.setDefault(TimeZone.getTimeZone("GMT"));
}
According to the spec (see also the accepted answer on this SO-post), the conversion duration.toPeriod(periodType) should only use so-called precise duration fields, that is hours, minutes, seconds and milliseconds but not days.
My analysis of source code of Joda-Time (v2.9.6):
The internal class org.joda.time.chrono.BasicChronology contains following constant:
private static final DurationField cDaysField = new PreciseDurationField(DurationFieldType.days(), 86400000L);
So we see that here this duration field is marked as "precise", but: The subclass ZonedChronology wraps it and override the behaviour of method isPrecise():
public boolean isPrecise() {
return iTimeField ? iField.isPrecise() : iField.isPrecise() && this.iZone.isFixed();
}
This shows an extra zone dependency of the precision property of the days()-duration-field, namely precise for fixed zones like UTC and else imprecise.
I don't know if the analyzed and observed behaviour is a feature or a bug. Let's say, it is dangerous to expect the creation of Period-objects by duration.toPeriod(...) to be zone-independent. And it is not documented there to have a precise days-component if the system zone is fixed.
Unfortunately, the implicit dependency on the default time zone is deeply coded into Joda-Time via its chronology-design. As workaround, you can use:
Period p = new Period(nowDateTime, openingDateTime, PeriodType.dayTime());
I retrieve following values from the media store
MediaStore.Images.Media.DATE_TAKEN
MediaStore.Images.Media.DATE_MODIFIED
And read the dates from the result like following:
int dateTakenColumn = cursor.getColumnIndex(MediaStore.Images.Media.DATE_TAKEN);
int dateModifiedColumn = cursor.getColumnIndex(MediaStore.Images.Media.DATE_MODIFIED);
String dateToken = cursor.getString(dateTakenColumn);
String dateModified = cursor.getString(dateModifiedColumn);
long lDateToken = dateToken != null ? Long.parseLong(dateToken) : 0;
long lDateModified = dateModified != null ? Long.parseLong(dateModified) : 0;
And can see following behaviour (example values):
lDateToken looks like following: 1450696995000 <= CORRECT
lDateModified looks like following: 1450696995 <= WRONG
It seems like the modification dates are all cut off. I checked the real files last modified date with a file explorer, and the values should be fine, but I always get such short numbers from my media files.
Any ideas on why this happens?
PS: checked this http://developer.android.com/reference/android/provider/MediaStore.Images.ImageColumns.html, but the modified field is not listed there...
DATE_TAKEN is in milliseconds since 1970.
See the docs
DATE_MODIFIED is in seconds since 1970, so just multiply it by 1000 and it'll be fine.
See the docs
Just multiply it by 1000 to get correct date
fun convertLongToDate(time: Long): String =
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
DateTimeFormatter.ofPattern("dd MMMM yyyy").format(
Instant.ofEpochMilli(time*1000)
.atZone(ZoneId.systemDefault())
.toLocalDate())
} else {
SimpleDateFormat("dd MMMM yyyy").format(
Date(time * 1000)
)
}
I have some things in my Android application that need to update once per day.
It's pretty simple I think, but I have no idea in what format I need to format the date and time (if time is needed) and how to check if an update has been done today (where today is between 00:01am and 23:59pm in the user's local time). The update should not be done if it was already done for today.
Here's what I DO know how to do:
Save the last update date in SharedPreferences (but how do I get a
string of it, I do not know)
Get things from SharedPreferences (but I
don't know how to compare dates in string format)
It is irrelevant what format you choose. It is just matter of recalculations.
I'd suggest using milliseconds since epoch, as all system calls use it, so it would be easier for you to use the same.
As 1000 millis is 1 second it's easy to figure out that 1000*60*60*24 equals to one day (24hrs). So, if storedMillis is bigger than NOW - 1000*60*60*24, (and NOW is i.e. System.currentTimeMillis()), then it is too early to do the check. If storedMillis is smaller, then save your NOW timestamp and do the check:
long now = System.currentTimeMillis();
long diffMillis = now - lastCheckedMillis;
if( diffMillis >= (3600000 * 24) ) {
// store now (i.e. in shared prefs)
// do the check
} else {
// too early
}
EDIT
I am interested in doing it when the app is first opened for the
current day, even if the last update was done 10 minutes ago.
It's just the matter how to get the proper millis to compare against. Replace long now = System.currentTimeMillis(); from above code with following code block:
Calendar cal = Calendar.getInstance();
cal.clear(Calendar.HOUR);
cal.clear(Calendar.HOUR_OF_DAY);
cal.clear(Calendar.MINUTE);
cal.clear(Calendar.SECOND);
cal.clear(Calendar.MILLISECOND);
long now = cal.getTimeInMillis();
which shall do the trick.
If you store your date in format 20121122 (YYYYmmdd) then you can compare is like 20121122 > 20121123. But it must be stored as int or cast to int when comparing.
Store the timestamp (System.currentTimeMillis() ) of the Last execution and compair it with the currient one. If the difference is more than 24 hours... You know it or?
Set up an Alarm with AlarmManager that executes every 24 hours, then do stuff
Check this question: Alarm Manager Example
It's a more complicated approach than the rest, but makes sure things are done, while with the other options the app must be executed in order to check if it has to update whatever.
Here is the method
public boolean runOnceADay() {
SharedPreferences shp= c.getSharedPreferences(Constants.GENERAL_SHP, MODE_PRIVATE);
SharedPreferences.Editor editor= shp.edit();
long lastCheckedMillis = shp.getLong(Constants.ONCE_A_DAY, 0); // "KEY" you may change yhe value
long now = System.currentTimeMillis();
long diffMillis = now - lastCheckedMillis;
if (diffMillis >= (3600000 * 24)) { // set up your time circulation
editor.putLong(Constants.ONCE_A_DAY, now);
editor.commit();
Util.showMessage(c, "Once a Day Test");
return false;
} else {
Util.showMessage(c, "Too Early");
return true;
}
}