记录一下限制输入字符的判断。不仅局限于中文或英文
- 首先在 ViewDidLoad 中注册通知
[[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(textFieldEditChanged:)
name:@"UITextFieldTextDidChangeNotification" object:self.userTF];- 下面是判断逻辑 由于需求有中文键盘下的字母数字输入，所以其中那部分判断如不需要可以去除
// 输入字符判断
-(void)textFieldEditChanged:(NSNotification *)obj {
UITextField *textField = (UITextField *)obj.object;
NSString *toBeString = textField.text;
NSString *lang = [textField.textInputMode primaryLanguage];
if ([lang isEqualToString:@"zh-Hans"])// 简体中文输入
{
//获取高亮部分
UITextRange *selectedRange = [textField markedTextRange];
UITextPosition *position = [textField positionFromPosition:selectedRange.start offset:0];
// 没有高亮选择的字，则对已输入的文字进行字数统计和限制
if (!position || !selectedRange)
{
if (toBeString.length > MAX_CHINESE_LENGTH)
{
NSRange rangeIndex = [toBeString rangeOfComposedCharacterSequenceAtIndex:MAX_CHINESE_LENGTH];
if (rangeIndex.length == 1)
{
textField.text = [toBeString substringToIndex:MAX_CHINESE_LENGTH];
}
else
{
NSRange rangeRange = [toBeString rangeOfComposedCharacterSequencesForRange:NSMakeRange(0, MAX_CHINESE_LENGTH)];
textField.text = [toBeString substringWithRange:rangeRange];
}
}
if (toBeString.length > MAX_ENGLISH_LENGTH)
{
NSRange rangeIndex = [toBeString rangeOfComposedCharacterSequenceAtIndex:MAX_ENGLISH_LENGTH];
if (rangeIndex.length == 1)
{
textField.text = [toBeString substringToIndex:MAX_ENGLISH_LENGTH];
}
else
{
NSRange rangeRange = [toBeString rangeOfComposedCharacterSequencesForRange:NSMakeRange(0, MAX_ENGLISH_LENGTH)];
textField.text = [toBeString substringWithRange:rangeRange];
}
}
}
}
// 中文输入法以外的直接对其统计限制即可，不考虑其他语种情况
else
{
if (toBeString.length > MAX_ENGLISH_LENGTH)
{
NSRange rangeIndex = [toBeString rangeOfComposedCharacterSequenceAtIndex:MAX_ENGLISH_LENGTH];
if (rangeIndex.length == 1)
{
textField.text = [toBeString substringToIndex:MAX_ENGLISH_LENGTH];
}
else
{
NSRange rangeRange = [toBeString rangeOfComposedCharacterSequencesForRange:NSMakeRange(0, MAX_ENGLISH_LENGTH)];
textField.text = [toBeString substringWithRange:rangeRange];
}
}
}
}