IOS 根据输入值改变button颜色

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{

if (textField == _rightNameTextFeild)
{
//未改变之前的长度
NSInteger length = _rightNameTextFeild.text.length;
NSInteger location = range.location;

if ( length > location )
{
_commitBtn.backgroundColor = [CHUtil  colorWithHexString:@"d6d7d9"];
}
else
{
length += string.length;
_commitBtn.backgroundColor = [CHUtil  colorWithHexString:@"fa4a26"];
}
}

return YES;
}