使用分配的IBAction（UIButton）点按IBOutlet后，iOS应用程序崩溃无任何异常

Question

My task is to create custom UIAlertView with multiline text input field and everything works pretty much well up to the point where I need to do some actions if dismiss button was tapped. As example I'm using: http://iphonedevelopment.blogspot.co.uk/2010/05/custom-alert-views.html

I have created very simple popup for testing purpose. Basically it's UIViewController xib with single button in it. The main class is demonstrated below:

#import "testViewController.h"

@interface testViewController ()

@end

@implementation testViewController

- (id)init
{
    self = [super initWithNibName:@"testViewController" bundle:nil];

    return self;
}

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

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

- (void)showInView:(UIView *)view
{
    [view addSubview:[self view]];
    [[self view] setFrame: [view bounds]];
    [[self view] setCenter:[view center]];
}

- (IBAction)onTap:(id)sender {
    NSLog(@"All OK");
}

@end

then in root UIViewController I'm calling my custom alert:

- (IBAction)showAlert:(id)sender
{
    dispatch_async(dispatch_get_main_queue(), ^{
        testViewController *alert = [[testViewController alloc] init];
        [alert showInView:[self view]];
    });
}

So far I have tried Main thread or global queue or even synchronous dispatch, but everything ends up with break on:

int main(int argc, char * argv[]) {
    @autoreleasepool {
        return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class])); <-- Thread 1:EXC_BAD_ACCESS (code=1, address=0xa000000c)
    }
}

tried to add observer for the button but still no go..

Any help is much appreciated

Answer 1

Check if your UIButton is assigned multiple IBoutlets or multiple IBActions. This a common issue which happens without our notice sometimes.

Answer 2

事实证明，我的testViewController是在我点击按钮之前由ARC发布的

Answer 3

Here what happing is "if you want to add one viewcontroller view to other viewcontroller's view then after adding of views you should convey to the compiler that second view controller is going to be child to the first"

ie pre intimation of parent to child relationship has to be done.

now just modify your showAlert method with the following . it is working 100%.

- (IBAction)showAlert:(id)sender {

    dispatch_async(dispatch_get_main_queue(), ^{
        testViewController *alert = [[testViewController alloc] init];
        [alert showInView:[self view]];

        [self addChildViewController:alert];
        [alert didMoveToParentViewController:self];
    });
}