在Android中添加月+1到日历月的日历问题。-CalendarissueinAddingmonth+1totocalendarmonthinAndroid

45  

you can see the +1 to set field is adding 30 days date different to your dates(observed from your output.)

您可以看到+1设置字段，添加30天的日期与您的日期不同(从您的输出中观察)。

if you want months then use the code

如果你想要几个月，那就使用代码

Calendar cal = Calendar.getInstance();
System.out.println("Before "+cal.getTime());  //Before Thu Jan 31 10:16:23 IST 2013

cal.add(Calendar.MONTH, 1);
System.out.println("After "+cal.getTime()); //After Thu Feb 28 10:16:23 IST 2013

7  

You have to use add() like,

你必须使用add() like，

cal.add(Calendar.MONTH, 1);

OUTPUT ->

输出- >

Before Thu Jan 31 10:15:04 IST 2013
After Thu Feb 28 10:15:04 IST 2013

2  

cal.set(Calendar.MONTH, cal.get( Calendar.MONTH ) + 1 );

The reason it shows Mar 3 anyway, is because it apparently adds 30 days, which is Feb 31st which does not exist, so it goes to Mar 3.

它显示3月3日的原因，是因为它显然增加了30天，也就是2月31日不存在，所以是3月3日。

If you wanted the last day of the next month instead, you would do something like this:

如果你想要在下个月的最后一天，你可以这样做:

int mOnth= cal.get( Calendar.MONTH );
cal.set(Calendar.MONTH, cal.get(Calendar.MONTH) + 1);
if( cal.get( month ) > month + 1 ) {
    cal.set( Calendar.MONTH, month + 1 );
    cal.set( Calendar.DAY, /* here comes your day amount finding algorithm */ );
}

1  

This kind of date-time work is easier using either:

这种约会时间的工作更容易使用:

• Joda-Time 2.3 library
  • Popular replacement for the java.util.Date & .Calendar classes bundled with Java
  • 常用的java.util替换。与Java绑定的日期和.Calendar类
  • Open source
  • 开源
  • Free of cost
  • 免费的
  • Actively maintained (as of 2014-02)
  • 积极维护(2014-02)
• Joda-Time 2.3库是java.util的流行替代品。日期和.Calendar类与Java开放源码捆绑在一起，无需积极维护(从2014-02年起)
• java.time package
  • New in Java 8
  • 新的Java 8
  • Inspired by Joda-Time, but re-architected
  • 受到Joda-Time的启发，但重新架构
  • Defined by JSR 310
  • JSR 310定义的
  • Tutorial available
  • 教程中可用
• java。Java 8中的时间包受到Joda-Time的启发，但是重新架构了JSR 310教程的定义

DateTimeZone timeZOne= DateTimeZone.forID( "Europe/Paris" ); // Or, DateTimeZone.UTC
DateTime dateTime = new DateTime( timeZone );
DateTime mOnthAgo= dateTime.plusMonths( -1 ); // Smartly handles various month lengths, leap year, and so on.
DateTime mOnthLater= dateTime.plusMonths( 1 );

Dump to console…

转储控制台……

System.out.println( "dateTime: " + dateTime );
System.out.println( "monthAgo: " + monthAgo );
System.out.println( "monthAgo start of day: " + monthAgo.withTimeAtStartOfDay() );
System.out.println( "monthLater: " + monthLater );

When run…

运行时……

dateTime: 2014-02-24T01:53:22.386+01:00
monthAgo: 2014-01-24T01:53:22.386+01:00
monthAgo start of day: 2014-01-24T00:00:00.000+01:00
monthLater: 2014-03-24T01:53:22.386+01:00