不 走 - (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string方法
-
(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{ //string就是此时输入的那个字符 textField就是此时正在输入的那个输入框 返回YES就是可以改变输入框的值 NO相反if ([string isEqualToString:@"\n"]) //按会车可以改变
{
return YES;
}NSString * toBeString = [textField.text stringByReplacingCharactersInRange:range withString:string]; //得到输入框的内容
if (self.textFieldY == textField) //判断是否时我们想要限定的那个输入框
{
if ([toBeString length] > 1) { //如果输入框内容大于20则弹出警告
textField.text = [toBeString substringToIndex:20];
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:nil message:@"超过最大字数不能输入了" delegate:nil cancelButtonTitle:@"Ok" otherButtonTitles:nil, nil];
[alert show];
return NO;
}
}
return YES;
}
求大神 解答