因为"CharSequence仅包含Unicode数字"， (引用您的

Because that "CharSequence contains only Unicode digits" (quoting your linked documentation).

所有字符对于

All of the characters return true for Character.isDigit:

某些包含数字的Unicode字符范围:

Some Unicode character ranges that contain digits:

• "\ u0030"至"\ u0039"，ISO-LATIN-1数字("0"至"9")
• '\ u0660'至'\ u0669'，阿拉伯文-印度数字
• 从'\ u06F0'到'\ u06F9'，扩展的阿拉伯语-印度数字
• '\ u0966'至'\ u096F'，梵文数字
• '\ uFF10'至'\ uFF19'，全角数字

其他许多字符范围也包含数字.

Many other character ranges contain digits as well.

१२३是梵文数字:

• १是 DEVANAGARI DIGIT ONE，\u0967
• २是 DEVANAGARI DIGIT TWO，\u0968
• ३是 DEVANAGARI数字三，\u0969