背景及问题

  • Platform： RK3399
  • OS： Android7.1.2
  • Kernel： v4.4.103

在新的产品开发中，需要设置系统时间。发现使用老产品中的那一套报错,无法用date命令去设置，使用的代码及报错如下：

String.format("date -s %04d%02d%02d.%02d%02d%02d", year, month, day, hour, min, sec);

date: Unknown option s

解决及扩展

  • 后面发现在Android shell里面的date命令没有-s选项。使用help查看：

    usage: date [-u] [-r FILE] [-d DATE] [+DISPLAY_FORMAT] [-D SET_FORMAT] [SET]

Set/get the current date/time. With no SET shows the current date.

Default SET format is "MMDDhhmm[[CC]YY][.ss]", that's (2 digits each)
month, day, hour (0-23), and minute. Optionally century, year, and second.
Also accepts "@UNIXTIME[.FRACTION]" as seconds since midnight Jan 1 1970.

-d	Show DATE instead of current time (convert date format)
-D	+FORMAT for SET or -d (instead of MMDDhhmm[[CC]YY][.ss])
-r	Use modification time of FILE instead of current date
-u	Use UTC instead of current timezone

+FORMAT specifies display format string using these escapes:

%% literal %             %n newline              %t tab
%S seconds (00-60)       %M minute (00-59)       %m month (01-12)
%H hour (0-23)           %I hour (01-12)         %p AM/PM
%y short year (00-99)    %Y year                 %C century
%a short weekday name    %A weekday name         %u day of week (1-7, 1=mon)
%b short month name      %B month name           %Z timezone name
%j day of year (001-366) %d day of month (01-31) %e day of month ( 1-31)
%s seconds past the Epoch

%U Week of year (0-53 start sunday)   %W Week of year (0-53 start monday)
%V Week of year (1-53 start monday, week < 4 days not part of this year)

%D = "%m/%d/%y"    %r = "%I : %M : %S %p"   %T = "%H:%M:%S"   %h = "%b"
%x locale date     %X locale time           %c locale date/time

  • 在Android shell设置系统时间需使用如下命令（需要root权限）：

    #格式为date MMddHHmmyyyy.ss set
date 123012002018.59 set

    如需使用UTC时间，则需要加上-u选项

  • 如果需要同步更新到硬件RTC中，则还需要使用hwclock

    usage: hwclock [-rswtluf]
 
-f FILE Use specified device file instead of /dev/rtc (--rtc)
-l      Hardware clock uses localtime (--localtime)
-r      Show hardware clock time (--show)
-s      Set system time from hardware clock (--hctosys)
-t      Set the system time based on the current timezone (--systz)
-u      Hardware clock uses UTC (--utc)
-w      Set hardware clock from system time (--systohc)

    常用的是：

    • hwclock -w –从系统时间设置到硬件时钟
    • hwclock -s –从硬件时钟设置到系统时间