NSString containsString crashes - ios

Question

I'm trying to filter an array according to one of it's string fields.
Both nameLower and filterLower has NSString value inside, and yet i keep getting:
__NSCFString containsString:]: unrecognized selector sent to instance 0x7f876b79e160
-(void) filterFriendsArray:(NSString*)filter {
[_filteredFriendsArray removeAllObjects];
for (FacebookUser* user in _friendsArray)
{
NSString* nameLower = [user.user.name lowercaseString];
NSString* filterLower = [filter lowercaseString];
if ([nameLower containsString:filterLower])
[_filteredFriendsArray addObject:user];
}
_displayedFriendsArray = _filteredFriendsArray;
}

Answer 1

If you want your code to work on iOS 7 as well as iOS 8 you should use one of the rangeOfString calls instead. Basically if the range returned has a length of zero, the substring is not there.
/* These methods return length==0 if the target string is not found. So, to check for containment: ([str rangeOfString:#"target"].length > 0). Note that the length of the range returned by these methods might be different than the length of the target string, due composed characters and such.
*/
- (NSRange)rangeOfString:(NSString *)aString;
- (NSRange)rangeOfString:(NSString *)aString options:(NSStringCompareOptions)mask;
- (NSRange)rangeOfString:(NSString *)aString options:(NSStringCompareOptions)mask range:(NSRange)searchRange;
- (NSRange)rangeOfString:(NSString *)aString options:(NSStringCompareOptions)mask range:(NSRange)searchRange locale:(NSLocale *)locale NS_AVAILABLE(10_5, 2_0);
Obviously it's trivial to implement containsString yourself in a category using rangeOfString:
#implementation NSString (Contains)
- (BOOL)myContainsString:(NSString*)other {
NSRange range = [self rangeOfString:other];
return range.length != 0;
}
#end

Answer 2

compare rangeOfString with NSNotFound
NSRange range = [self rangeOfString:other];
if(range.location != NSNotFound){
//do something
}

Answer 3

Use following:
if (![[NSString class] respondsToSelector:#selector(containsString)])
{
//ios 7
NSRange range = [mystring rangeOfString:other];
if(range.location != NSNotFound){
//do something
}
}
else //for iOS 8
{
if ([mystring containsString: other])
{
//do something
}
}

Answer 4

For those who encountered this in XLForm, make sure when you install XLForm using pods
platform :ios, '7'
pod 'XLForm'
It is already fixed in 3.1
from
if ([cellClassString contains:#"/"]) {
}
to
if ([cellClassString rangeOfString:#"/"].location != NSNotFound) {
}

Answer 5

I encapsulate my solution in YJKit, and you can call -[NSString containsString:] even for old version which below iOS 8.
bool _yj_streq(const char *str1, const char *str2, size_t length) {
for (int i = 0; i < length; i++) {
if (*str1++ != *str2++) {
return false;
}
}
return true;
}
- (BOOL)yj_containsString:(NSString *)string {
NSAssert(string != nil, #"*** -[%# containsString:] can not use nil argument.", [self class]);
size_t len1 = (size_t)self.length;
size_t len2 = (size_t)string.length;
if (len1 == 0 || len2 == 0 || len1 < len2) {
return NO;
}
const char *str1 = self.UTF8String;
const char *str2 = string.UTF8String;
for (size_t i = 0; i <= len1 - len2; i++) {
const char *substr1 = str1 + i;
if (_yj_streq(substr1, str2, len2)) {
return YES;
} else {
continue;
}
}
return NO;
}
Here is my source code:
https://github.com/huang-kun/YJKit/blob/master/YJKit/Base/Foundation/Categories/Generics/NSString%2BYJCompatible.m

Answer 6

Swift version of the answer given by w0mbat:
extension NSString {
func compatibleContainsString(string: NSString) -> Bool{
let range = self.rangeOfString(string as String)
return range.length != 0
}
}