格式不是字符串文字，没有格式参数（不涉及NSLog）

Question

(I am new to objective c so apologies if this seems to be a simple question)

I researched the following message here

format not a string literal and no format arguments

and most of the responses involve an NSLog statement. However, my error shows up with this line

NSString *path = [[self applicationDocumentsDirectory] stringByAppendingFormat:[NSString stringWithFormat:@"/%@", [managedObject Name]]];

I am troubleshooting a set of code and don't seem to understand why the error is occuring here. any assistance on this would be appreciated.

Answer 1

The below should fix it.

NSString *path = [[self applicationDocumentsDirectory] stringByAppendingFormat:[NSString stringWithFormat:@"/%@", [managedObject Name]], nil];

Alternatively

NSString *path = [[self applicationDocumentsDirectory] stringByAppendingFormat:@"/%@", [managedObject Name]];

Should also do it.

You were calling two methods that expected a format parameter, you were passing one into the [NSString stringWithFormat] but not the stringByAppendingFormat method.

Answer 2

除了其他人所说的，你应该研究一下

- (NSString *)stringByAppendingPathComponent:(NSString *)aString

Answer 3

You are using stringByAppendingFormat , and then using stringWithFormat . Pick one or the other. Fix:

NSString *path = [[self applicationDocumentsDirectory] stringByAppendingFormat:@"/%@", [managedObject Name]];

Answer 4

[NSString stringWithFormat:@"/%@", [managedObject Name]

will return a string with the %@ already replaced by the value of [managedObject Name] . Therefore, the method stringByAppendingFormat is not getting the formatting string and any arguments.

BTW, the convention is to use method names beginning with lowercase alphabets, unlike in [managedObject Name]