EXC_BAD_ACCESS when trying to get iPhone screen dimensions

问题

I'm trying to make certain elements resize according to the screen dimensions when the interface orientation changes. I've read in various places (including a few answers on here) that the way to get the bounds of the screen is to use [[UIScreen] mainScreen] bounds]. So I've added this code to see how it behaves:

- (void) willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration
{
    NSLog(@"view dimensions: (%@, %@)", [[UIScreen mainScreen] bounds].size.width, [[UIScreen mainScreen] bounds].size.height);
}

But when running it, as soon as I rotate the screen I get an EXC_BAD_ACCESS message. Is there something about the scope of the willRotateToInterfaceOrientation function that doesn't allow me to call for the screen bounds? If so, how would I go about it?

回答1:

%@ format specifier expects format parameter to be objective-c object, while what you provide is plain float. To print float numbers use %f specifier:

NSLog(@"view dimensions: (%f, %f)", [[UIScreen mainScreen] bounds].size.width, [[UIScreen mainScreen] bounds].size.height);

来源：https://stackoverflow.com/questions/7710903/exc-bad-access-when-trying-to-get-iphone-screen-dimensions