QLineEdit限制输⼊格式
使⽤正则表达式QRegExp，在Qt帮助⽂档中有详细使⽤说明。
1.限制普通输⼊
拿ip设置输⼊框为例：
在输⼊框所在界⾯构造函数中写⼊：
QRegExp regExp("[0-9.]{1,15}");
ui->lineEdit_ipv4_addr->tValidator(new QRegExpValidator(regExp,this));
ui->lineEdit_ipv4_netmask->tValidator(new QRegExpValidator(regExp,this));
其中：
有谁共鸣张国荣
[0-9.]表⽰只允许0-9之间的数字和特殊符号.的输⼊，如果需要限制字母，则改为[a-zA-Z]即可。
{1,15}表⽰匹配1次，并且最多允许输⼊15个元素。
2.按照⼀定的格式限制输⼊
还是拿ip输⼊框为例：
要求输⼊类似192.168.1.1这种ip地址，并且点不⽤⾃⼰输⼊，直接显⽰在输⼊框，输⼊3个数字后⾃动跳转点后⾯继续输⼊：
QString ipRangeStr = "(?:[0-1]?[0-9]?[0-9]|2[0-4][0-9]|25[0-5])";//限制最⼤输⼊255
QRegExp ipRegex ("^" + ipRangeStr
合生元分销平台+ "\\." + ipRangeStr
+ "\\." + ipRangeStr
+ "\\." + ipRangeStr + "$");
auto ipValidator = new QRegExpValidator(ipRegex,this);//检查其有效性
ui->lineEdit_ipv4_addr->tValidator(ipValidator);
大黄功效
ui->lineEdit_ipv4_addr->tInputMask("000.000.000.000");
更多⽤法：
Character Meaning
A
ASCII alphabetic character required. A-Z, a-z.
a生活因友谊而精彩
利莫里亚ASCII alphabetic character permitted but not required.
N
ASCII alphanumeric character required. A-Z, a-z, 0-9.
n桂花样子
ASCII alphanumeric character permitted but not required.
X
Any character required.
x
Any character permitted but not required.
Any character permitted but not required.
9
ASCII digit required. 0-9.
ASCII digit permitted but not required.
D
ASCII digit required. 1-9.
爱之
d
ASCII digit permitted but not required (1-9).
#
ASCII digit or plus/minus sign permitted but not required.
H
Hexadecimal character required. A-F, a-f, 0-9.
h
Hexadecimal character permitted but not required.
B
Binary character required. 0-1.
b
Binary character permitted but not required.
>
怎么锻炼臂力
All following alphabetic characters are uppercad.
<
All following alphabetic characters are lowercad.
!
Switch off ca conversion.
\
U \ to escape the special characters listed above to u them as parators.只需在双引号中标明要⽤的格式
“000.000.000.000;”是⼀个IP地址
“HH:HH:HH:HH:HH:HH;0”是⼀个MAC地址。
“\\0\\xHHHH;0”是只允许输⼊⼀个16位的⼗六进制数。
