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I have an NSString category class (NSString+URLEncoding.h).
I am running into and unknown selector crash, because the string I am calling the category method has been optimized into an NSCFConstantString by iOS.
-[__NSCFConstantString URLEncodedString]: unrecognized selector sent to instance 0x290174
I learned of the NSCFConstantString vs. NSCFString optimizations in iOS 5 from:
http://www.cocoanetics.com/2012/03/beware-of-nsstring-optimizations/
Is anyone aware of how I can get the NSString category to include the Constant strings or even force the var to be an NSString/NSCFString and not an NSCFConstantString?
Cheers, Z
-edit-
-ObjC -all_load are both already implementedI am adding a sharing service to ShareKit 2.0
header:
@interface NSString (OAURLEncodingAdditions)
- (NSString *)URLEncodedString;
implementation:
@implementation NSString (OAURLEncodingAdditions)
- (NSString *)URLEncodedString
{
NSString *result = (NSString *)CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault,
(CFStringRef)self,
NULL,
CFSTR("!*'();:@&=+$,/?%#[]"),
kCFStringEncodingUTF8);
[result autorelease];
return result;
}
214
Once a string has been initialized using NSString, the only way to append text to the string is to create a new NSString object. While doing so, you can append string constants, NSString objects, and other values.
An NSString object can be initialized from or written to a C buffer, an NSData object, or the contents of an NSURL . It can also be encoded and decoded to and from ASCII, UTF–8, UTF–16, UTF–32, or any other string encoding represented by NSStringEncoding .
The Swift string is one character long, as expected. The NSString says it has a length of seven — this matches with the length of the Swift string's utf16 view, since NSStrings are backed by UTF-16: 09:02 The Swift string's unicodeScalars view returns a count of four.
To check if a string contains another string in objective-c, we can use the rangeOfString: instance method where it returns the {NSNotFound, 0} if a 'searchString' is not found or empty (""). Output: string contains you!
There's an issue with the linker that can cause its dead-code stripping to completely omit any object files that only contain obj-c categories (or that are otherwise unreferenced). Theoretically passing the -ObjC flag to the linker should fix this, but that doesn't seem to always work. You can work around this issue by providing the -all_load linker flag, which will cause the linker to always link in all object files.
Note that you might have to set -all_load on the parent project if your category is part of a sub-project or library that you-re including somewhere.
Update: I believe -ObjC is reliable now and has been for years so you can stop using -all_load for this issue.
191
Just spent 30 minutes figuring out exactly the same issue. After fiddling with linker I found out that the category wasn't present in Compile Sources list in my target's Build Phases. Be sure to check it's there.
27
__NSCFConstantString is a subclass of NSString, so any categories on NSString apply to __NSCFConstantString too.
Either you're not linking in your category, or your category doesn't define a URLEncodedString method in its @implementation.
20
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