有四个文本框,在用户输入时需要放入两个限制。一个是用户只能输入大写字母,并且最多只能有2个字符。代码如下:
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range
replacementString:(NSString *)string {
// Below logic is for All 4 Modifer Textfields
// we are restrict the user to enter only max 2 characters in modifier textfields.
if (textField==txt_modifier1 || textField==txt_modifier2 || textField==txt_modifier3 ||
textField==txt_modifier4) {
textField.text = [textField.text stringByReplacingCharactersInRange:range
withString:[string
uppercaseStringWithLocale:[NSLocale currentLocale]]];
NSUInteger newLength = [textField.text length] + [string length] - range.length;
return (newLength > 2) ? NO : YES;
}
return YES;
}
但是运行之后,我输入任何字符都会附加一个新字符,并且也没用成功限制2个字符的数量。
请高手指点一下,谢谢。