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How to convert date String from JSON to time span

The time value I get from JSON response is of format "sun dd/mm/yyyy - HH:mm" and I want to convert it to a time span instead (10 min ago, 2 days ago...). For that I made a method converts given String of dataTimeFormant into "X Hours Ago" format and returns x hours ago in a string format then I can put in a textView.
Everything seems correct, I think, but the app crashes on start with a NullPonterException to a line of my code, so probably I have made things wrong.
#RequiresApi(api = Build.VERSION_CODES.N)
public String dateConverter(String dateStringFormat) {
Date date = null;
SimpleDateFormat currentDateFormat = new SimpleDateFormat("yyyy-MM-dd'T'hh:mm:ss'Z");
try {
date = currentDateFormat.parse(dateStringFormat);
} catch (ParseException e) {
e.printStackTrace();
}
SimpleDateFormat requireDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String currentDate = requireDateFormat.format(date);
long currentTimeInMilis = 0;
try {
Date currentDateObject = requireDateFormat.parse(currentDate);
currentTimeInMilis = currentDateObject.getTime();
} catch (ParseException e) {
e.printStackTrace();
}
CharSequence timeSpanString = DateUtils.getRelativeTimeSpanString(currentTimeInMilis, System.currentTimeMillis(), DateUtils.MINUTE_IN_MILLIS);
return timeSpanString.toString();
}
My adapter onBindView method:
#Override
public void onBindViewHolder(ViewHolder viewHolder, final int i) {
//...
//...
//...
DateConvert converter = new DateConvert();
String postTime = converter.dateConverter(this.news.get(i).getCreated());
viewHolder.articleCreatedDate.setText(postTime);
}
The logcat error points to:
String currentDate = requireDateFormat.format(date);
and :
String postTime = converter.dateConverter(this.post.get(i).getCreated());
I'm unable to find the cause because if I remove the call to that function everything works perfectly, probably there are better ways to achieve this?
Thanks.

I am new here, hopefully I can help.
The first thing I notice is there is no closing single quotation after 'Z:
SimpleDateFormat currentDateFormat = new SimpleDateFormat("yyyy-MM-dd'T'hh:mm:ss'Z'");
Besides, the problem is the "currentDateFormat" does not portray the proper date input format which causes it not to be able to parse properly. If the input is "sun dd/MM/yyyy - HH:mm" then the format should be:
SimpleDateFormat currentDateFormat = new SimpleDateFormat("EEE MM/dd/yyyy '-' HH:mm");
Or
SimpleDateFormat currentDateFormat = new SimpleDateFormat("EEE MM/dd/yyyy - HH:mm");
Then date = currentDateFormat.parse(dateStringFormat); should be able to parse properly and the "date" will not have "null" value.
Hope this helps.

how to change format of date from string date

I have date as a string like this
String date = "11-12-2018"
I want to change it to "2018-12-11"
with the same variable. So, I tried the code below but it doesn't give me the output I expect.
String date = "11-12-2018"
SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd");
Date d = df.parse(date);
results in:
"0012-06-09"
I want
"2018-12-11"

You can do this 3 ways. First is using SimpleDateFormat and Date and second using DateTimeFormatter and LocalDate and third you can use Split.
1. Using Date and SimpleDateFormat
String date = "11-12-2018";
SimpleDateFormat df = new SimpleDateFormat("dd-mm-yyyy");
java.util.Date d = df.parse(date);
String finalDate = new SimpleDateFormat("yyyy-MM-dd").format(d);
System.out.println(finalDate);
Here we have our actual date String date = "11-12-2018"; we know we want to change it to 2018-12-11
So lets parse that date into a Date object using this code
SimpleDateFormat df = new SimpleDateFormat("dd-mm-yyyy");
java.util.Date d = df.parse(date);
Okay so now we have a date object of our actual date, Now lets format it to our new date.
String finalDate = new SimpleDateFormat("yyyy-MM-dd").format(d);
2. Using LocalDate and DateTimeFormatter
Alright here we define our date again and 2 DateTimeFormatter.
DateTimeFormatter oldFormatter = DateTimeFormatter.ofPattern("dd-MM-yyyy");
DateTimeFormatter newFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd");
The first formatter is our old date format, and the second one is the new one that we are gonna convert the old date into.
Alright lets use them now!
Now we make a new LocalDate object using our oldFormatter by parsing our dateString with the oldFormatter object
LocalDate dateTime = LocalDate.parse(date, oldFormatter);
Alright now lets format it.
String reformattedDate = dateTime.format(newFormatter);
as simple as that! Here is the full code.
String date = "11-12-2018";
DateTimeFormatter oldFormatter = DateTimeFormatter.ofPattern("dd-MM-yyyy");
DateTimeFormatter newFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd");
LocalDate dateTime = LocalDate.parse(date, oldFormatter);
String reformattedDate = dateTime.format(newFormatter);
System.out.println(reformattedDate);
3. Using String::Split
Okay this part is pretty simple. Lets split the date using -
String[] dates = date.split("-");
We already know the order of the date lets format it using String::format
String reformattedDate = String.format("%s-%s-%s", dates[2], dates[1], dates[0]);
Here is the full code
String date = "11-12-2018";
String[] dates = date.split("-");
String reformattedDate = String.format("%s-%s-%s", dates[2], dates[1], dates[0]);
System.out.println(reformattedDate);

Try code below that will work for your case:
First parse your input format from string,
String date = "11-12-2018";
SimpleDateFormat df = new SimpleDateFormat("dd-MM-yyyy");
Then convert it to desired format,
Date dateTobeParse = null;
try {
dateTobeParse = df.parse(date);
} catch (ParseException e) {
e.printStackTrace();
}
if (dateTobeParse != null) {
SimpleDateFormat outFormat = new SimpleDateFormat("yyyy-MM-dd");
String outputDate = outFormat.format(dateTobeParse);
}

This is the common function which I use for date and time conversion
public String convertDateAndTime(String date, String oldFormat, String newFormat) {
SimpleDateFormat sdf = new SimpleDateFormat(oldFormat);
Date currentdate;
String converted = "";
try {
currentdate = sdf.parse(date);
SimpleDateFormat sdf2 = new SimpleDateFormat(newFormat);
converted = sdf2.format(currentdate);
} catch (ParseException e) {
e.printStackTrace();
}
return converted;
}
You just have to pass the date string and their old and new formats.
In your case call this function like this
String converteddate = convertDateAndTime("11-12-2018","dd-mm-yyyy","yyyy-MM-dd");

Try the code below that will work
1) Make method like below
public String changeDateFormat(String currentFormat, String requiredFormat, String dateString) {
String result = "";
SimpleDateFormat formatterOld = new SimpleDateFormat(currentFormat, Locale.getDefault());
SimpleDateFormat formatterNew = new SimpleDateFormat(requiredFormat, Locale.getDefault());
Date date = null;
try {
date = formatterOld.parse(dateString);
} catch (ParseException e) {
e.printStackTrace();
}
if (date != null) {
result = formatterNew.format(date);
}
return result;
}//end of changeDateFormat()
1st argument of the method is your current date format in your case it will be 'dd-MM-yyyy'
2nd argument is output or requires date format in your case it will be 'yyyy-MM-dd'
3rd argument is your date that you want to change the format
2) Run the method like below
String oldFormatDate = "11-12-2018";
String myDate = changeDateFormat("dd-MM-yyyy", "yyyy-MM-dd", oldFormatDate);
Log.d(TAG, "Old formatted Date : " + oldFormatDate);
Log.d(TAG, "New Date is : " + myDate);
3) Output:
Old formatted Date : 11-12-2018
New Date is : 2018-12-11

Convert only time part in android from string to time

I need to convert a time stamp that currently is in string format "08.00" to a valid time in java so I later can compare time. How do I convert this string to time?

Something like this
DateFormat sdf = new SimpleDateFormat("hh:mm");
Date date = sdf.parse(time);

Instead of using the Date and/or SimpleDateFormat classes, perhaps consider LocalTime
String time = "08:00";
LocalTime lt = LocalTime.parse(time);
System.out.println(lt);
Output:
08:00
And can compare to other times easily with LocalTime::isBefore() or LocalTime::isAfter()
Example

Try below code,
String time = "08.00";
try {
DateFormat sdfInput = new SimpleDateFormat("hh.mm");
Date date = sdfInput.parse(time);
DateFormat sdfOutput = new SimpleDateFormat("hh:mm");
Log.e( "Time: ", sdfOutput.format(date));
} catch (Exception e) {
e.printStackTrace();
}
Output -> Time: 08:00

The easiest way to do so is with a SimplDateFormatter:
DateFormat sdf = new SimpleDateFormat("hh:mm")
Then you can call Date date = sdf.parse(*your time string*)
Now you have your time as a valid Date object.

I have timeformat like this hhmmss="151918"
so you can use any format instead of hhmmss according to your current time format like
"hh.mm" or hh:mm:ss etc
and you can call this method form any where you needed.
fun convertTimeFormat(time:String):String{
var formattedTime=""
try {
val inputFormat: DateFormat = SimpleDateFormat("hhmmss")
val timeObj = inputFormat.parse(time)
Log.d("timeObj",""+timeObj)
formattedTime=SimpleDateFormat("hh:mm aa").format(timeObj)
} catch (e: ParseException) {
e.printStackTrace()
}
return formattedTime
}

How to format date/time string? (Java)

Hi can anyone help please? I am trying to format a date and time string.
Currently it looks like this "20160112T110000Z" and I need it to be "2016-01-12T11:00:00Z"
The string without the special characters are returned from a 3rd party recurrence library. I need to convert it to have the special characters before parsing it to a Calendar object.
Can anyone help please?
The code that I have so far looks like:
final String TIMEFORMAT = "yyyy-MM-dd'T'HH:mm:ss'Z'";
String string = "20160112T110000Z";
SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
Date date = format.parse(string);
System.out.println(date);
However this just does not work.
Any suggestions are appreciated

You have to read the string with a format matching the source, this gives you a correct Date.
Then simply write it with the format you want :
String string = "20160112T110000Z";
String originalStringFormat = "yyyyMMdd'T'HHmmss'Z'";
String desiredStringFormat = "yyyy-MM-dd'T'HH:mm:ss'Z'";
SimpleDateFormat readingFormat = new SimpleDateFormat(originalStringFormat);
SimpleDateFormat outputFormat = new SimpleDateFormat(desiredStringFormat);
try {
Date date = readingFormat.parse(string);
System.out.println(outputFormat.format(date));
} catch (ParseException e) {
e.printStackTrace();
}

try this
DateFormat formatter = new SimpleDateFormat("dd/MM/yyyy");
// you can change format of date
Date date = formatter.parse(strDate);
Timestamp timeStampDate = new Timestamp(date.getTime());
return timeStampDate;

How to convert String of datetime to date using GWT?

In mysql, i have a field time_entered of type datetime (sample data: 2012-06-20 16:00:47). I also have a method, getTimeEntered(), that returns the value as String. I want to display the date in this format 2012-06-20 using DateTimeFormat from GWT.
here's my code:
String date = aprHeaderDW.getTimeEntered();
DateTimeFormat fmt = DateTimeFormat.getFormat("MM-dd-yyyy");
dateEntered.setText("" + fmt.format(date));
The problem is, the format method doesn't accept arguments as String. So if there's only a way I could convert the date from String to Date type, it could probably work. I tried typecasting but didn't work.

You should be able to just use DateTimeFormat.
Date date = DateTimeFormat.getFormat("yyyy-MM-dd HH:mm:ss").parse("2012-06-20 16:00:47");
String dateString = DateTimeFormat.getFormat("yyyy-MM-dd").format(date);
Otherwise there is a light-weight version of SimpleDateFormat that supports this pattern.
Date date = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").parse("2012-06-20 16:00:47");

Hi There are two options.
The first is as it is already a string you could use a regular expression to modify the format.
The second is using a SimpleDateFormater you can parse the string to a date then back again.
For example:
public class DateMerge {
public static void main(String arg[])
{
String out = dateConvert("2012-06-20 16:00:47");
System.out.println(out);
}
public static String dateConvert (String inDate)
{
try {
DateFormat formatter ;
Date date ;
formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
date = (Date)formatter.parse(inDate);
formatter = new SimpleDateFormat("dd-MM-yyyy");
String outDate = formatter.format(date);
return outDate;
} catch (ParseException e)
{System.out.println("Exception :"+e); }
return null;
}
}

You may use like this.
String date = "2012-06-20 16:00:47";
SimpleDateFormat sf=new SimpleDateFormat("yyyy-MM-dd");
String lDate=sf.format(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").parse(date));
System.out.println(lDate);
Output:
2012-06-20

After trying a lot of times I came up with a solution, based on #Keppil and adding my own code.
Here's Keppil's suggested solution for converting String datetime into Date type:
Date date = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").parse("2012-06-20 16:00:47");
...but my second requirement is to display just the date like 2012-06-20. Even though I removed HH:mm:ss, it still displayed the time like this 2012-06-20 00:00:00.
Here's my final solution:
Date date = null;
String d = rs.getString(SQL_CREATION_TIME); // assigns datetime value from mysql
// parse String datetime to Date
try {
date = new SimpleDateFormat("yyyy-MM-dd").parse(d);
System.out.println("time entered: "+ date);
} catch (ParseException e) { e.printStackTrace(); }
// format the Date object then assigns to String
Format formatter;
formatter = new SimpleDateFormat("yyyy-MM-dd");
String s = formatter.format(date);