Develop Reference

get start and end date of the week

Actually i want to display a set of data with the start and end date of the week were that particular date falls on. In my emulator its working fine. Eg. If i give Apr 23 its giving me start date of the week as 22 Apr and end date as 28 Apr, but if i try to build the same code in my device its showing start date of the week as 27 Apr and end date as 28 Apr.
Piece of Code which i am using:
//to get first day of week
cal1.set(Calendar.DAY_OF_WEEK, 1);
int day1 = cal1.get(Calendar.DAY_OF_MONTH);
//to get last day of week
cal1.set(Calendar.DAY_OF_WEEK, 7);
int day7 = cal1.get(Calendar.DAY_OF_MONTH);

I don't know why you getting that data but this is how I get the first and last date, take look might help. (its written to give current week's first and last date, so might have to tweak it little bit.)
Calendar calendar = Calendar.getInstance();
Date date1 = calendar.getTime();
//current date to check that our week lies in same month or not
SimpleDateFormat checkformate = new SimpleDateFormat("MM/yyyy");
String currentCheckdate= checkformate.format(date1);
int weekn = calendar.get(Calendar.WEEK_OF_MONTH);
int month = calendar.get(Calendar.MONTH);
int year = calendar.get(Calendar.YEAR);
//resat calender without date
calendar.clear();
calendar.setFirstDayOfWeek(Calendar.MONDAY);
calendar.set(Calendar.WEEK_OF_MONTH,weekn);
calendar.set(Calendar.MONTH,month);
calendar.set(Calendar.YEAR,year);
SimpleDateFormat simpleDateFormat = new SimpleDateFormat("dd/MM/yyyy");
Date datef = calendar.getTime();
//move date to 6 days + to get last date of week
Long timeSixDayPlus = calendar.getTimeInMillis()+518400000L;
Date dateL = new Date(timeSixDayPlus);
String firtdate = simpleDateFormat.format(datef);
String lastdate = simpleDateFormat.format(dateL);
String firtdateCheck = checkformate.format(datef);
String lastdateCheck = checkformate.format(dateL);
//if our week lies in two different months then we show only current month week part only
if (!firtdateCheck.toString().equalsIgnoreCase(currentCheckdate)) {
firtdate = "1" + "/" + calendar.get(Calendar.MONTH) + "/" + calendar.get(Calendar.YEAR);
}
if (!lastdateCheck.toString().equalsIgnoreCase(currentCheckdate)) {
int ma = calendar.getActualMaximum(Calendar.DAY_OF_MONTH);
lastdate = String.valueOf(ma) + "/" + calendar.get(Calendar.MONTH) + "/" + calendar.get(Calendar.YEAR);
}
Log.e("current","=>>"+firtdate+" to "+lastdate);

To get the first day of the week -
initialize the Calendar as per your need. in this case, I am getting the current date calendar.
set the current day of the week to the first day of the week.
get the corresponding date.
Calendar calendar = Calendar.getInstance();
//optional step
calendar.setFirstDayOfWeek(Calendar.SUNDAY);
calendar.set(Calendar.DAY_OF_WEEK, Calendar.SUNDAY);
int firstDateOfWeek = calendar.get(Calendar.DATE);
To get the last date of the week -
follow the step as above to initialize.
set the day of the week as Saturday.
get the corresponding date.
Calendar calendar = Calendar.getInstance();
//optional step
calendar.setFirstDayOfWeek(Calendar.SUNDAY);
calendar.set(Calendar.DAY_OF_WEEK, Calendar.SATURDAY);
int lastDateOfWeek = calendar.get(Calendar.DATE);
In this way, you can get eh first and the last date for the week. one thing to keep in mind that I have set the first day of the week as SUNDAY. set as per your need. although it is purely optional to set the first day of the week. this gives you a more transparency in code.

Android Calendar : Changing the start day of week to Saturday

I have code to get the start date of week with current day as Sunday. But I want to start my week from Saturday-Friday.
How can I achieve this through android?

This should return date of last saturday and set it as a start of the date.
Calendar cal = Calendar.getInstance();
int i = cal.get(Calendar.DAY_OF_WEEK) - cal.getFirstDayOfWeek();
cal.add(Calendar.DATE, -i - 7);
cal.set(Calendar.DAY_OF_WEEK, Calendar.SATURDAY);
cal.setFirstDayOfWeek(Calendar.Saturday);

Calendar cal = Calendar.getInstance();
cal.setFirstDayOfWeek(Calendar.Saturday);
i think its help you.

Accessing hour,minute and second using Calendar class

I am trying to set an alarm on a particular day and time.So setting hour and minute using Calendar.But when i try to access the hour which is set in Calendar using cal.set,i get a different value than that was set by me manually.
Code
Calendar cal=Calendar.getInstance();
cal.set(Calendar.HOUR,7);
cal.set(Calendar.MINUTE,30);
cal.set(Calendar.SECOND, 0);
cal.set(Calendar.MILLISECOND, 0);
Toast.makeText(getApplicationContext(), "Alarm worked. "+cal.HOUR+cal.MINUTE,cal.SECOND Toast.LENGTH_LONG).show();
Result i want
Alarm worked. 7:30:0
What i get now
Alarm worked. 10:12:13
P.S
1.I found many posts which deal with Calendar issues but couldn't find my solution.
2.The result what i am getting i.e 10:12:13 is not my current time(current date,current minute,current second) either.So i don't know why and from where these data are coming.
3.I tried using HOUR_OF_DAY instead of HOUR but nothing useful.
Solution
Toast.makeText(getApplicationContext(), "Alarm worked. "+cal.get(Calendar.HOUR)+" "+cal.get(Calendar.MINUTE)+" "+cal.get(Calendar.SECOND), Toast.LENGTH_LONG).show();
This worked because Calendar.HOUR,Calendar.MINUTE are constants.See the answer of #PopoFibo to get the clear picture.

The problem is in your Toast, you are printing the constants of the Calendar class:
Calendar.HOUR = 10
Calendar.MINUTE = 12
Calendar.SECOND = 13
Instead, get the value at their respective indexes - like for HOUR it would be cal.get(Calendar.HOUR)
System.out.println(cal.get(Calendar.HOUR) + ":" + cal.get(Calendar.MINUTE) + ":" + cal.get(Calendar.SECOND));
Would give (correct output):
7:30:0
And, System.out.println(Calendar.HOUR + ":" + Calendar.MINUTE + ":" + Calendar.SECOND);
Would give (incorrect output):
10:12:13

Date s = cal.getTime();SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss a");String t = sdf.format(s);
Toast.makeText(this, t, Toast.LENGTH_SHORT).show(); for more ref. see http://www.asbhtechsolutions.com/android-tutorial/1-android-get-current-time-and-date

can you try with:
Calendar calendar = Calendar.getInstance();
calendar.setTimeInMillis(System.currentTimeMillis());
calendar.set(Calendar.HOUR_OF_DAY, 7);
calendar.set(Calendar.MINUTE, 30);
and then toast it

add these lines before setting time..
Cal.set(Calendar.MONTH , month);
Cal.set(Calendar.YEAR, year);
Cal.set(Calendar.DAY_OF_MONTH,day);

Getting Year, Month and Date in Android

I am trying to get today's Year, Month and Date using following code;
Calendar calendar = Calendar.getInstance();
int thisYear = calendar.get(Calendar.YEAR);
Log.d(TAG, "# thisYear : " + thisYear);
int thisMonth = calendar.get(Calendar.MONTH);
Log.d(TAG, "# thisMonth : " + thisMonth);
int thisDay = calendar.get(Calendar.DAY_OF_MONTH);
Log.d(TAG, "$ thisDay : " + thisDay);
But it gives "2012 for year 1 for month and 28 for date" which is not today's date. What I have done wrong?

Would I be correct in assuming this is running on a Emulator? If so, Set the emulator date correctly, and it should be correct.
From memory, that code should do what you expect.

Calendar calendar = Calendar.getInstance(TimeZone.getDefault());
calendar.get(Calendar.YEAR)

import java.util.Calendar;
import java.util.TimeZone;
import android.widget.Toast;
Calendar calendar = Calendar.getInstance(TimeZone.getDefault());
int currentYear = calendar.get(Calendar.YEAR);
int currentMonth = calendar.get(Calendar.MONTH) + 1;
int currentDay = calendar.get(Calendar.DAY_OF_MONTH);
Toast.makeText(this,"Today's Date: " + currentYear + currentMonth + currentDay, Toast.LENGTH_SHORT).show();
"TimeZone" will work great if your application targets for Android API 27 platform or above

The month starts from zero so you have to add 1 with the given month to show the month number we are familiar with.
int thisMonth = calendar.get(Calendar.MONTH);
Log.d(TAG, "# thisMonth : " + (thisMonth+1));
This will show you the current month starting with 1.

try this one..
Calendar instance = Calendar.getInstance();
currentMonth = instance.get(Calendar.MONTH);
currentYear = instance.get(Calendar.YEAR);
int month=currentMonth+1;

I tried your code and it is giving correct output. You should try checking time in your emulator/phone on which you are trying this code.
According to getInstance docs, it sets to current date and time by Default.

Try to use:
Date dt = new Date();
dt.getYear();
dt.getMonth();
dt.getDay();
and see if you get the same result.
If so, your system date is probably out of sync.
Check the Date class documentation for more details:

This gives the time and date of your android system so first check it.

You can use SimpleDateFormat
Initialising as #SuppressLint("SimpleDateFormat") final SimpleDateFormat dateAndTime = new SimpleDateFormat("DD-MM-yy", Locale.getDefault());
and String timeStamp = dateAndTime.format(new Date());

how to add no days to date object not calendar object

I have a Date object. Now I want to add days to that Date object.
So how that can be done? Actually using Calendar object that can be done I know.
But in my case, I haven't used a calendar objects. Instead only used date object.
For Example, suppose I have a date object
Date dtStartDate=o.getStartDate();
int x=28;
Now what I want to do is to add 28 to this date object, means if the dtStartDate is 1 July 2011
then after adding 28, dtStartDate will be 29 July 2011.
Please suggest it to me.
Thanks in advance

You can add Day using below
Calendar c1 = Calendar.getInstance();
c1.add(Calendar.DAY_OF_MONTH, 1);
Here 1 is number of Day you can add.
OR
Date dtStartDate=o.getStartDate();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm");
Calendar c = Calendar.getInstance();
c.setTime(dtStartDate);
c.add(Calendar.DATE, 3); // number of days to add
String dt = sdf.format(c.getTime()); // dt is now the new date
Toast.makeText(this, "" + dt, 5000).show();
May be your problem solved.

You could add the equivilent number of milliseconds to the time retrieved from Date, e.g.:
long millis = dtStartDate.getTime();
millis = millis + x*24*60*60*1000;
Date dtEndDate = new Date();
dtEndDate.setTime(millis);

You can easily do this in two simple ways my friend. First one is:
Calendar cal = Calendar.getInstance();
cal.add(Calendar.DAY_OF_MONTH, 1);
and the second one is:
Calendar cal = Calendar.getInstance();
cal.add(Calendar.HOUR_OF_DAY, 24);
I think you would like to find this thing. Though there are so many persons are there who choose the first method.
Thanks.