開發中遇到這個問題，想着還是總結下，剛開始只是限制UITextField的鍵盤為
UIKeyboardTypeASCIICapable，可是當用戶切換了中文鍵盤后依然沒解決問題，於是我給輸入框加了監聽事件，獲取輸入框最新的輸入內容，檢測輸入的內容中是否含有中文，如果有中文就替換成空字符串，具體實現如下：
infoView.userTF.keyboardType = UIKeyboardTypeASCIICapable;
//監聽輸入內容
[[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(textFiledEditChanged:)
name:@"UITextFieldTextDidChangeNotification"
object:infoView.userTF];
-(void)textFiledEditChanged:(NSNotification*)notification
{
UITextField*textField = notification.object;
NSString*str = textField.text;
for (int i = 0; i<str.length; i++)
{
NSString*string = [str substringFromIndex:i];
NSString *regex = @"[\u4e00-\u9fa5]{0,}$"; // 中文
// 2、拼接謂詞
NSPredicate *predicateRe1 = [NSPredicate predicateWithFormat:@"self matches %@", regex];
// 3、匹配字符串
BOOL resualt = [predicateRe1 evaluateWithObject:string];
if (resualt)
{
//是中文替換為空字符串
str = [str stringByReplacingOccurrencesOfString:[str substringFromIndex:i] withString:@""];
}
}
textField.text = str;
}