Trivial “+[NSTimer scheduledTimerWithTimeInterval:repeats:block:]: unrecognized selector” error

问题:

I am banging my head against an odd error after a move to 10.12/Sierra and Xcode 8.1:

+[NSTimer scheduledTimerWithTimeInterval:repeats:block:]:       unrecognized selector sent to class 0x7fff78f1fa88 

The most minimal code (default settings of create a new project) to reproduce this is:

//  AppDelegate.m //  #import "AppDelegate.h"  @interface AppDelegate ()  @property (weak) IBOutlet NSWindow *window; @property (strong, nonatomic) NSTimer * timer; @end  @implementation AppDelegate  - (void)applicationDidFinishLaunching:(NSNotification *)aNotification {     self.timer = [NSTimer scheduledTimerWithTimeInterval:10                             repeats:YES                               block:^(NSTimer * _Nonnull timer)     {         NSLog(@"Ping from %@", timer);     }]; } 

The linking includes the (Core)Foundation classes and 'all_load'. Must be something totally trivial - but fail to what it is.

Any and all help appreciated.

Thanks,

Dw.

回答1:

+[NSTimer scheduledTimerWithTimeInterval:repeats:block:] is an iOS 10.0+ method. Are you maybe trying to run it on iOS 9.x?

https://developer.apple.com/reference/foundation/nstimer/2091889-scheduledtimerwithtimeinterval?language=objc

文章来源: Trivial “+[NSTimer scheduledTimerWithTimeInterval:repeats:block:]: unrecognized selector” error