IOS UITextView 和 UITextField 联想输入法字数限制

UITextField 输入限制

[_tfTextFeild
addTarget:self
action:@selector(limitLength:)
forControlEvents:UIControlEventEditingChanged];

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
if (textField == _tfTextFeild)
{
if (string.length == 0) return YES;

NSInteger existedLength = textField.text.length;
NSInteger selectedLength = range.length;
NSInteger replaceLength = string.length;
if (existedLength - selectedLength + replaceLength > TEXT_MAXLENGTH)
{
return NO;
}
}

return YES;
}

- (void)limitLength:(UITextField *)textField
{
if (textField == _tfTextFeild)
{
if (textField.text.length > TEXT_MAXLENGTH)
{
textField.text = [textField.text substringToIndex:TEXT_MAXLENGTH];
}
}
}

UITextView输入限制

[[NSNotificationCenter
defaultCenter] addObserver:self
selector:@selector(textViewEditChanged)
name:UITextViewTextDidChangeNotification
object:nil];

- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text
{
if (textView == _contentTextView)
{
if (text.length == 0) return YES;

NSInteger existedLength = textView.text.length;
NSInteger selectedLength = range.length;
NSInteger replaceLength = text.length;
if (existedLength - selectedLength + replaceLength > TEXT_MAXLENGTH)
{
return NO;
}
}

return YES;
}

- (void)textViewEditChanged
{
if (_contentTextView.text.length > TEXT_MAXLENGTH)
{
_contentTextView.text = [_contentTextView.text substringToIndex:TEXT_MAXLENGTH];
}
}