在java中显示基于时间的早晨,下午,晚上,晚上的消息

Question

我想做什么::

显示基于的消息

• 早上好(上午12点至下午12点)
• 中午后(中午12点至下午4点)好
• 晚上好(下午4点到晚上9点)
• 晚安(晚上9点至早上6点)

---

码::

我使用24小时格式来获得这种逻辑

private void getTimeFromAndroid() {
        Date dt = new Date();
        int hours = dt.getHours();
        int min = dt.getMinutes();

        if(hours>=1 || hours<=12){
            Toast.makeText(this, "Good Morning", Toast.LENGTH_SHORT).show();
        }else if(hours>=12 || hours<=16){
            Toast.makeText(this, "Good Afternoon", Toast.LENGTH_SHORT).show();
        }else if(hours>=16 || hours<=21){
            Toast.makeText(this, "Good Evening", Toast.LENGTH_SHORT).show();
        }else if(hours>=21 || hours<=24){
            Toast.makeText(this, "Good Night", Toast.LENGTH_SHORT).show();
        }
    }

---

题:

• 这是最好的方式,如果没有这是最好的方式

Answer 1

你应该做的事情如下:

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 2

对于正在寻找@SMA答案的最新Kotlin语法的人，这里是帮助器函数：

fun getGreetingMessage():String{
    val c = Calendar.getInstance()
    val timeOfDay = c.get(Calendar.HOUR_OF_DAY)

    return when (timeOfDay) {
           in 0..11 -> "Good Morning"
           in 12..15 -> "Good Afternoon"
           in 16..20 -> "Good Evening"
           in 21..23 -> "Good Night"
             else -> {
              "Hello"
          }
      }
    }

Answer 3

我会将你的if/elseif陈述缩短为:

String greeting = null;
if(hours>=1 && hours<=12){
    greeting = "Good Morning";
} else if(hours>=12 && hours<=16){
    greeting = "Good Afternoon";
} else if(hours>=16 && hours<=21){
    greeting = "Good Evening";
} else if(hours>=21 && hours<=24){
    greeting = "Good Night";
}
Toast.makeText(this, greeting, Toast.LENGTH_SHORT).show();

Answer 4

时间

我建议使用 Java 8 LocalTime。

也许创建一个这样的类来处理您一天中的时间问题。

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);
  }

}