Disabling a specific warning in a specific line in Xcode

问题

I'm writing an iPhone app against the Base 4.0 SDK, but I'm targeting OS 3.1.3 so OS 3 users can use the app.

I call:

[[UIApplication sharedApplication] setStatusBarHidden:YES animated:YES];

which is deprecated in iOS 4.0. I'm aware of this, and have measures in place to call the newer "withAnimation" version if we are running under iOS 4.0 or greater.

However, I'm getting a warning that I'm calling a deprecated SDK.

I'd like to disable this specific warning in this specific place. I want all other warnings (including the same deprecated warning in other locations)

Can this be accomplished in Xcode?

回答1:

For CLANG, this works:

#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
  // Here I like to leave a comment to my future self to explain why I need this deprecated call
  NSString *myUDID = [[UIDevice currentDevice] uniqueIdentifier];
#pragma clang diagnostic pop

You can use it inside a method, which allows you to be very specific about the line that causes the warning you want to have ignored.

回答2:

You might be able to use GCC pragmas. This should disable the deprecated warning for the enclosed function.

#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdeprecated"
-(void)foo{
    // As Georg Fritzsche notes below, the pragmas only work outside of functions
    [[UIApplication sharedApplication] setStatusBarHidden:YES animated:YES];
}
#pragma GCC diagnostic pop

I don't know if this will work with Clang, but it should work with GCC.

Basically, it saves the state of the warnings/errors, disables the deprecated warning, compiles the function, then restores the state of the diagnostics.

回答3:

You can use NSInvocation to get around the warnings independent of the compiler used:

UIApplication *app = [UIApplication sharedApplication];
SEL sel = @selector(setStatusBarHidden:animated:);
NSMethodSignature *sig = [app methodSignatureForSelector:sel];
NSInvocation *inv = [NSInvocation invocationWithMethodSignature:sig];
BOOL b = YES;
[inv setTarget:app];
[inv setSelector:sel];
[inv setArgument:&b atIndex:2];
[inv setArgument:&b atIndex:3];
[inv invoke];

Or in a less error-tolerant way:

UIApplication *app = [UIApplication sharedApplication];
SEL sel = @selector(setStatusBarHidden:animated:);
IMP imp = [app methodForSelector:sel];
imp(app, sel, YES, YES);

回答4:

you can perform it like this to overcome the warnings at once

#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
(void) methodUsingDeprecatedStuff { //use deprecated stuff }

or

Just paste this line before using your deprecated stuffs every time to avoid warnings

#pragma GCC diagnostic warning "-Wdeprecated-declarations"

this will remove the warnings.

Hope it will help you.

来源：https://stackoverflow.com/questions/3137414/disabling-a-specific-warning-in-a-specific-line-in-xcode