问题
Here is my code,where the crash occurs:-
let URL = NSURL(string: "http://files.parsetfss.com/fa80bc63-88d4-412d-a478-2451cffc92a9/tfss-1d2a321d-b02e-4745-a589-e31536f648df-XXXXX%20CAT15%2030.p0001.jpg")
NSLog("Loading page with URL: \(URL)")
The app crashes with EXC_BAD_ACCESS
回答1:
The first argument of NSLog() is a format string, and contains
format specifiers (starting with %) which are expanded by the
following variable argument list. In your case %20C is a format specifier, but
no matching argument is supplied. That causes undefined behavior,
it can crash or produce incomplete or wrong output.
If you want to use NSLog() then a general safe method is
NSLog("%@", "Loading page with URL: \(URL)")
In this particular case,
NSLog("Loading page with URL: %@", URL)
works as well, since NSURL is a NSObject subclass and can be used
with the %@ format.
回答2:
You should use println instead of NSLog.
let URL = NSURL(string: "http://files.parsetfss.com/fa80bc63-88d4-412d-a478-2451cffc92a9/tfss-1d2a321d-b02e-4745-a589-e31536f648df-XXXXX%20CAT15%2030.p0001.jpg")!
println("Loading page with URL: \(URL)")
I have added the option sign ! at the end to unwrap.
来源：https://stackoverflow.com/questions/35335885/nslog-crashes-with-certain-nsurl-ios-9-2