iOS应用程序异常-由于未捕获的异常'NSInvalidArgumentException'而终止应用程序

Question

I am getting the following exception, which is terminating the app.

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSArrayM objectForKey:]: unrecognized selector sent to instance 0x7abe4f90'

Following is the code:

- (NSMutableData*)dataForConnection:(URLConnection*)connection {       
NSMutableData *data = [receivedData objectForKey:connection.tagKey]; // Exception Here
return data;
}

Could anyone please suggest how to fix it? Thank you in advance!

Answer 1

[__NSArrayM objectForKey:]

NSArray have not method called objectForKey:

Your object receivedData is NSArray class , change to NSDictionary .

Answer 2

Problem is due to not allocating receivedData properly, since you have declared it as instance variable, so you should make it using the property declaration like this:

@property(nonatomic, strong) NSMutableDictionary *receivedData;

This will ensure that receivedData does not get released and reference this using self.receivedData in your code. Maybe this is helpful