java - 重置其他字段后如何重置日历对象中的时间参数？

Question

我获取当前的Calendar对象并记录其值

Calendar now = Calendar.getInstance();
Log.v(TAG,now.toString())

我现在设置时间并记录值

now.set(Calendar.HOUR, 20 % 12);
now.set(Calendar.MINUTE,00);
now.set(Calendar.HOUR_OF_DAY,20);
now.set(Calendar.SECOND,0);
now.set(Calendar.MILLISECOND,0);
Log.v(TAG,now.toString())

当我并排比较两个日志时，我发现了差异

java.util.GregorianCalendar[time=1498086510685,areFieldsSet=true... 
java.util.GregorianCalendar[time=?,areFieldsSet=false... 

所有其他字段似乎都相同

我想我有两个问题

1. 如何将时间设置为正确的值？
2. 如果我重置 time 参数，areFieldsSet 是否会自动设置？

Answer 1

如果您阅读了 java.util.Calendar 的 Javadocs(您应该这样做)，您就会看到

set(f, value) changes calendar field f to value. In addition, it sets an internal member variable to indicate that calendar field f has been changed. Although calendar field f is changed immediately, the calendar's time value in milliseconds is not recomputed until the next call to get(), getTime(), getTimeInMillis(), add(), or roll() is made.

调用指定的函数之一。