Showing Morning, afternoon, evening, night message based on Time in java

Question

What i am trying to do::

Show message based on

• Good morning (12am-12pm)
• Good after noon (12pm -4pm)
• Good evening

Answer 1

java.time

I would advise to use Java 8 LocalTime.

Maybe create a class like this to handle your time of day problem.

public class GreetingMaker { // think of a better name then this.

  private static final LocalTime MORNING = LocalTime.of(0, 0, 0);
  private static final LocalTime AFTER_NOON = LocalTime.of(12, 0, 0);
  private static final LocalTime EVENING = LocalTime.of(16, 0, 0);
  private static final LocalTime NIGHT = LocalTime.of(21, 0, 0);

  private LocalTime now;

  public GreetingMaker(LocalTime now) {
    this.now = now;
  }

  public void printTimeOfDay() { // or return String in your case
    if (between(MORNING, AFTER_NOON)) {
      System.out.println("Good Morning");
    } else if (between(AFTER_NOON, EVENING)) {
      System.out.println("Good Afternoon");
    } else if (between(EVENING, NIGHT)) {
      System.out.println("Good Evening");
    } else {
      System.out.println("Good Night");
    }
  }

  private boolean between(LocalTime start, LocalTime end) {
    return (!now.isBefore(start)) && now.isBefore(end);
  }

}

Answer 2

Using Time4J (or Time4A on Android) enables following solutions which do not need any if-else-statements:

ChronoFormatter<PlainTime> parser =
    ChronoFormatter.ofTimePattern("hh:mm a", PatternType.CLDR, Locale.ENGLISH);
PlainTime time = parser.parse("10:05 AM");

Map<PlainTime, String> table = new HashMap<>();
table.put(PlainTime.of(1), "Good Morning");
table.put(PlainTime.of(12), "Good Afternoon");
table.put(PlainTime.of(16), "Good Evening");
table.put(PlainTime.of(21), "Good Night");
ChronoFormatter<PlainTime> customPrinter=
    ChronoFormatter
      .setUp(PlainTime.axis(), Locale.ENGLISH)
      .addDayPeriod(table)
      .build();
System.out.println(customPrinter.format(time)); // Good Morning

There is also another pattern-based way to let the locale decide in a standard way based on CLDR-data how to format the clock time:

ChronoFormatter<PlainTime> parser =
    ChronoFormatter.ofTimePattern("hh:mm a", PatternType.CLDR, Locale.ENGLISH);
PlainTime time = parser.parse("10:05 AM");

ChronoFormatter<PlainTime> printer1 =
    ChronoFormatter.ofTimePattern("hh:mm B", PatternType.CLDR, Locale.ENGLISH);
System.out.println(printer1.format(time)); // 10:05 in the morning

ChronoFormatter<PlainTime> printer2 =
    ChronoFormatter.ofTimePattern("B", PatternType.CLDR, Locale.ENGLISH)
        .with(Attributes.OUTPUT_CONTEXT, OutputContext.STANDALONE);
System.out.println(printer2.format(time)); // morning

The only other library known to me which can also do this (but in an awkward way) is ICU4J.

Answer 3

 private String getStringFromMilli(long millis) {

    Calendar c = Calendar.getInstance();
    c.setTimeInMillis(millis);
    int hours = c.get(Calendar.HOUR_OF_DAY);

    if(hours >= 1 && hours <= 12){
        return "MORNING";
    }else if(hours >= 12 && hours <= 16){
        return "AFTERNOON";
    }else if(hours >= 16 && hours <= 21){
        return "EVENING";
    }else if(hours >= 21 && hours <= 24){
        return "NIGHT";
    }
    return null;
}

Answer 4

When I write

Calendar c = Calendar.getInstance();
int timeOfDay = c.get(Calendar.HOUR_OF_DAY);

I didn't get output and it doesn't show any error. Just the timeOfDay won't get assigned any value in the code. I felt it was because of some threading while Calendar.getInstance() is executed. But when I collapsed the lines it worked for me. See the following code:

int timeOfDay = Calendar.getInstance().get(Calendar.HOUR_OF_DAY);

if(timeOfDay >= 0 && timeOfDay < 12){
        greeting.setText("Good Morning");
}else if(timeOfDay >= 12 && timeOfDay < 16){
        greeting.setText("Good Afternoon");
}else if(timeOfDay >= 16 && timeOfDay < 21){
        greeting.setText("Good Evening");
}else if(timeOfDay >= 21 && timeOfDay < 24){
        greeting.setText("Good Morning");
}

Answer 5

You should be doing something like:

Calendar c = Calendar.getInstance();
int timeOfDay = c.get(Calendar.HOUR_OF_DAY);

if(timeOfDay >= 0 && timeOfDay < 12){
    Toast.makeText(this, "Good Morning", Toast.LENGTH_SHORT).show();        
}else if(timeOfDay >= 12 && timeOfDay < 16){
    Toast.makeText(this, "Good Afternoon", Toast.LENGTH_SHORT).show();
}else if(timeOfDay >= 16 && timeOfDay < 21){
    Toast.makeText(this, "Good Evening", Toast.LENGTH_SHORT).show();
}else if(timeOfDay >= 21 && timeOfDay < 24){
    Toast.makeText(this, "Good Night", Toast.LENGTH_SHORT).show();
}

Answer 6

More specific

public static String getDayMessage() {
    Calendar c = Calendar.getInstance();
    int timeOfDay = c.get(Calendar.HOUR_OF_DAY);

    if (timeOfDay < 5) {
        return "Hi, Good Mid Night";
    }else if (timeOfDay < 6) {
        return "Hi, Good Late Night";
    } else if (timeOfDay < 12) {
        return "Hi, Good Morning";
    } else if (timeOfDay < 14) {
        return "Hi, Good Noon";
    } else if (timeOfDay < 16) {
        return "Hi, Good Afternoon";
    } else if (timeOfDay < 21) {
        return "Hi, Good Evening";
    } else {
        return "Hi, Good Night";
    }
}