iOS 9兼容版NSTimer scheduledTimerWithTimeInterval：重复：阻止：？

Question

I'm using the following code in iOS 10 but when I run it in iOS 9 it crashes. I don't think NSTimer scheduledTimerWithTimeInterval:repeats:block: supports iOS 9. How can I implement a timer that will work in iOS 8 - 10?

static NSTimer* timer = nil;

- (void)documentInteractionControllerWillBeginPreview:(UIDocumentInteractionController *)controller
{
    timer = [NSTimer scheduledTimerWithTimeInterval:0.1 repeats:YES block:^(NSTimer * _Nonnull timer) {
        [[UIApplication sharedApplication] setStatusBarHidden:YES];
    }];
}

-(void)documentInteractionControllerDidEndPreview:(UIDocumentInteractionController *)controller
{
    [timer invalidate];
    [[UIApplication sharedApplication] setStatusBarHidden:YES];
}

Answer 1

You appear to be using a function introduced in iOS10. Further down the page you linked is a function that was in iOS 2.

https://developer.apple.com/documentation/foundation/nstimer/1408356-timerwithtimeinterval?language=objc

Use that instead.

Answer 2

This fixed it:

static NSTimer* timer = nil;

- (void)documentInteractionControllerWillBeginPreview:(UIDocumentInteractionController *)controller
{
    timer = [NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:@selector(hideStatusBar) userInfo:nil repeats:YES];
}

-(void)hideStatusBar
{
    [[UIApplication sharedApplication] setStatusBarHidden:YES];
}

-(void)documentInteractionControllerDidEndPreview:(UIDocumentInteractionController *)controller
{
    [timer invalidate];
    [[UIApplication sharedApplication] setStatusBarHidden:YES];
}