tap button cause app crash on side bar

问题

I have two view controllers, one is the home view, one is the side menu view; all of the objects and created with storyboard.

there is a bar button 'item' on home view, when clicking it, it will invoke a custom segue, to slide out the side menu from left to right. So far so good.

On side menu, there is a button to slide back to home view. However, I simply click the button, the app will terminated, Xcode does not print out the crash log overtime.

I tried to add a breakpoint on (IBAction)SlideBack:(id)sender, seems like it did not get invoked. So something series happened.

Xcode break at

return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class]));

and saying Thread 1: exc_bad_access(code=EXC_i386_GPFLT)

I suspect the custom segue may interfere the view and view controllers hierarchy. But could not find out.

home view implementation:
@implementation HomeViewController
@end

side bar implementation:

@implementation SideBarController
- (IBAction)SlideBack:(id)sender {
    NSLog(@"sliding back");
}

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}


The custom slide out segue is:
@implementation CustomSegue

- (void)perform {
    UIViewController *contentVC = self.sourceViewController;
    UIViewController *sideBarVC = self.destinationViewController;
    CGRect sideFrame = sideBarVC.view.frame;
    [sideBarVC.view setFrame: CGRectMake(-(contentVC.view.frame.size.width),
                                         0,
                                         contentVC.view.frame.size.width/2,
                                         contentVC.view.frame.size.height)];
    CGRect animationFrame = contentVC.view.frame;
    sideFrame = sideBarVC.view.frame;
    animationFrame.size.width = contentVC.view.frame.size.width / 2;
    sideBarVC.view.alpha = 0;
    [[[contentVC.view superview] window] addSubview:sideBarVC.view];
    [UIView animateWithDuration:1
                          delay:0.0
                        options:UIViewAnimationOptionCurveEaseOut
                     animations:^{
        sideBarVC.view.frame = animationFrame;
        sideBarVC.view.alpha = 1;
    }
                     completion:^(BOOL finished) {
        sideBarVC.view.alpha = 1;
        sideBarVC.view.frame = animationFrame;

    }];
}

回答1:

After seeking helps, I found I misunderstand the segue logic. [[[contentVC.view superview] window] addSubview:sideBarVC.view]; is not enough.

Instead, below code should be right:

[contentVC addChildViewController:sideBarVC];
[[[contentVC.view superview] window] addSubview:sideBarVC.view]
[sideBarVC didMoveToParentViewController:contengVC];

来源：https://stackoverflow.com/questions/27959170/tap-button-cause-app-crash-on-side-bar

标签

ios

objective-c

segue

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