Why I am getting just opposite time using Calender in android studio?

Question

When I am selecting time 06.30 Am or 06.30 (24 hour format), I get out put as 18.30. And when I am selecting time 18.00 or 06.00PM , I getting 06.00 as output. My code is this...

private void handleTimeButton() {
    final Calendar calendar = Calendar.getInstance();
    int HOUR = calendar.get(Calendar.HOUR);
    int MINUTE = calendar.get(Calendar.MINUTE);

    TimePickerDialog timePickerDialog = new TimePickerDialog(this, new TimePickerDialog.OnTimeSetListener() {
        @Override
        public void onTimeSet(TimePicker timePicker, int hour, int minute) {
            Calendar calendar1 = Calendar.getInstance();
            calendar1.set(Calendar.HOUR, hour);
            calendar1.set(Calendar.MINUTE, minute);
            String text = (String) DateFormat.format("HH:mm", calendar1);
            etTime.setText(text); //this is my output
        }
    }, HOUR, MINUTE, true); // tried both true and false
    timePickerDialog.show();
}

I want my output to be in 24 hours format.

Answer 1

java.time

The java.util Date-Time API and their formatting API, SimpleDateFormat are outdated and error-prone. It is recommended to stop using them completely and switch to the modern Date-Time API^*.

Also, quoted below is a notice from the home page of Joda-Time:

Note that from Java SE 8 onwards, users are asked to migrate to java.time (JSR-310) - a core part of the JDK which replaces this project.

Solution using java.time, the modern Date-Time API: Create a LocalTime with hour and minute, and get the value of LocalTime#toString to be set to etTime.

Demo:

import java.time.LocalTime;

public class Main {
    public static void main(String[] args) {
        // Test
        String text = getTimeString(6, 30);
        System.out.println(text);

        text = getTimeString(18, 30);
        System.out.println(text);
    }

    static String getTimeString(int hour, int minute) {
        return LocalTime.of(hour, minute).toString();
    }
}

Output:

06:30
18:30

ONLINE DEMO

The modern Date-Time API is based on ISO 8601 and thus the LocalTime#toString returns the string in ISO 8601 format (which is also your desired format).

Learn more about the modern Date-Time API from Trail: Date Time.

Just for the sake of completeness:

Just for the sake of completeness, given below is the solution using the legacy API:

import java.text.SimpleDateFormat;
import java.util.Calendar;

public class Main {
    public static void main(String[] args) {
        // Test
        String text = getTimeString(6, 30);
        System.out.println(text);

        text = getTimeString(18, 30);
        System.out.println(text);
    }

    static String getTimeString(int hour, int minute) {
        Calendar calendar = Calendar.getInstance();
        calendar.set(Calendar.HOUR_OF_DAY, hour);
        calendar.set(Calendar.MINUTE, minute);

        return new SimpleDateFormat("HH:mm").format(calendar.getTime());
    }
}

Output:

06:30
18:30

ONLINE DEMO

---

^{* For any reason, if you have to stick to Java 6 or Java 7, you can use ThreeTen-Backport which backports most of the java.time functionality to Java 6 & 7. If you are working for an Android project and your Android API level is still not compliant with Java-8, check Java 8+ APIs available through desugaring and How to use ThreeTenABP in Android Project.}

Answer 2

You can do either this,

` val hour = calendar.get(Calendar.HOUR)
    val minute = calendar.get(Calendar.MINUTE)
    val timePickerDialog = TimePickerDialog(this@MainActivity, this, hour, minute,
            DateFormatis24HourFormat(this))
    timePickerDialog.show()`

or

You can refer here for your AM PM confusions

24-hour format to 12-hour format

12 hour format timepicker android

How to set Time with the help of Timepicker? with 12 hour format