tvOS 应用程序 - UIAlertController 与 UIAlertAction 崩溃

tvOS app - UIAlertController crashes with UIAlertAction

我有一个单视图 tvOS 应用程序。它有一个包含 24 个 collectionviewcell 的集合视图。选择 collectionviewcell 时,我会触发警报。我正在使用 Apple 参考文档(粘贴在下面)中的默认代码。

 UIAlertController* alert = [UIAlertController alertControllerWithTitle:@"My Alert"
                                               message:@"This is an alert."
                                               preferredStyle:UIAlertControllerStyleAlert];

 UIAlertAction* defaultAction = [UIAlertAction actionWithTitle:@"OK" 
                                               style:UIAlertActionStyleDefault
                                               handler:^(UIAlertAction * action) {}];

[alert addAction:defaultAction]; // This is what I comment out
[self presentViewController:alert animated:YES completion:nil];

当我没有将 defaultAction 添加到警报时(注释掉 [alert addAction:defaultAction];),警报会正确显示但无法关闭。当我将 defaultAction 添加到警报时,警报会显示 'OK' 按钮,但一旦它出现在屏幕上就会收到可怕的 SIGABRT 错误

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', 
reason: '-[_UIAlertControllerActionView image]: unrecognized selector
 sent to instance 0x7fe571ddee10'

此处的堆栈跟踪:

2015-11-10 19:42:02.927 AppABC[1701:97632] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[_UIAlertControllerActionView image]: unrecognized selector sent to instance 0x7fefd3ddaf10'
*** First throw call stack:
(
0   CoreFoundation                      0x000000010de0a0b5 __exceptionPreprocess + 165
1   libobjc.A.dylib                     0x000000010d884deb objc_exception_throw + 48
2   CoreFoundation                      0x000000010de126dd -[NSObject(NSObject) doesNotRecognizeSelector:] + 205
3   CoreFoundation                      0x000000010dd6005a ___forwarding___ + 970
4   CoreFoundation                      0x000000010dd5fc08 _CF_forwarding_prep_0 + 120
5   IsItGood                            0x000000010d381170 __82-[ViewController collectionView:didUpdateFocusInContext:withAnimationCoordinator:]_block_invoke78 + 48
6   UIKit                               0x000000010e260df4 +[UIView(UIViewAnimationWithBlocks) _setupAnimationWithDuration:delay:view:options:factory:animations:start:animationStateGenerator:completion:] + 582
7   UIKit                               0x000000010e2612ec +[UIView(UIViewAnimationWithBlocks) animateWithDuration:animations:] + 63
8   IsItGood                            0x000000010d380ca8 -[ViewController collectionView:didUpdateFocusInContext:withAnimationCoordinator:] + 536
9   UIKit                               0x000000010ea24e09 -[UICollectionView _didUpdateFocusInContext:withAnimationCoordinator:] + 1181
10  UIKit                               0x000000010eb15a5e _UIFocusEnvironmentDidUpdateFocus + 628
11  UIKit                               0x000000010e4fe102 __36-[UIScreen _updateFocusWithContext:]_block_invoke + 88
12  UIKit                               0x000000010e4fe161 __36-[UIScreen _updateFocusWithContext:]_block_invoke + 183
13  UIKit                               0x000000010e4fdb9f -[UIScreen _updateFocusWithContext:] + 1912
14  UIKit                               0x000000010e4feca9 -[UIScreen updateFocusIfNeeded] + 597
15  UIKit                               0x000000010e1c1e4a _runAfterCACommitDeferredBlocks + 317
16  UIKit                               0x000000010e1d53d9 _cleanUpAfterCAFlushAndRunDeferredBlocks + 95
17  UIKit                               0x000000010e1e1312 _afterCACommitHandler + 90
18  CoreFoundation                      0x000000010dd35ab7 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 23
19  CoreFoundation                      0x000000010dd35a27 __CFRunLoopDoObservers + 391
20  CoreFoundation                      0x000000010dd2b67b __CFRunLoopRun + 1147
21  CoreFoundation                      0x000000010dd2af78 CFRunLoopRunSpecific + 488
22  GraphicsServices                    0x0000000111582ad2 GSEventRunModal + 161
23  UIKit                               0x000000010e1b608d UIApplicationMain + 171
24  AppABC                              0x000000010d3826af main + 111
25  libdyld.dylib                       0x000000011050d9e9 start + 1
26  ???                                 0x0000000000000001 0x0 + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException

有什么想法吗??

我尝试了您的代码并创建了一个新的单视图应用程序,具有一个按钮和一个按钮操作。按钮操作包含您的代码片段:

- (IBAction)action:(id)sender {


    UIAlertController* alert = [UIAlertController alertControllerWithTitle:@"My Alert"
                                                                   message:@"This is an alert."
                                                            preferredStyle:UIAlertControllerStyleAlert];

    UIAlertAction* defaultAction = [UIAlertAction actionWithTitle:@"OK"
                                                            style:UIAlertActionStyleDefault
                                                          handler:^(UIAlertAction * action) {}];

    [alert addAction:defaultAction]; // This is what I comment out
    [self presentViewController:alert animated:YES completion:nil];
}

它工作正常。该错误必须在解除 UIAlertViewController 后发生(这是在触摸 OK 后自动完​​成的)。这部分代码丢失了。在代码的所有相关部分添加断点并检查它会继续跟踪此错误的位置。

根据您的堆栈跟踪,您的视图控制器是这里的问题:您试图在未实现该方法的对象上调用 image 方法,这就是导致此崩溃的原因。

看看您对 -[ViewController collectionView:didUpdateFocusInContext:withAnimationCoordinator:] 的实现,看看您在什么地方调用 image:看起来您假设该对象属于一种类型,而实际上它是另一种类型。

我写了三个不同的例子

import UIKit

class FirstViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }


    @IBAction func alertDone(sender: AnyObject) {
        let title = "Download Complete"
        let message = "Your game download completed"

        let buttonTitle = "OK"

        let alert = UIAlertController(title: title, message: message, preferredStyle: .Alert)

        let doneAction = UIAlertAction(title: buttonTitle, style: UIAlertActionStyle.Default) { _ in
            print("Done was pressed")
        }

        alert.addAction(doneAction)

        presentViewController(alert, animated: true, completion: nil)

    }


    @IBAction func alertError(sender: AnyObject) {
        let title = "Error Complete"
        let message = "Please try again later."

        let okButton = "OK"
        let retryButton = "Retry Download"

        let alertError = UIAlertController(title: title, message: message, preferredStyle: .Alert)
        let okAction = UIAlertAction(title: okButton, style: .Default, handler: nil)

        let retryAction = UIAlertAction(title: retryButton, style: .Cancel) { _ in
            print("Retry was pressed")
        }

        alertError.addAction(okAction)
        alertError.addAction(retryAction)

        presentViewController(alertError, animated: true, completion: nil)


    }

    @IBAction func alertConfirm(sender: AnyObject) {
        let title = "Are you sure"
        let message = "Please try again later."

        let cancelButton = "Cancel"
        let deleteButton = "Delete"

        let alertError = UIAlertController(title: title, message: message, preferredStyle: .Alert)
        let cancelAction = UIAlertAction(title: cancelButton, style: .Default, handler: nil)

        let deleteAction = UIAlertAction(title: deleteButton, style: .Cancel) { _ in
            print("Retry was pressed")
        }

        alertError.addAction(cancelAction)
        alertError.addAction(deleteAction)

        presentViewController(alertError, animated: true, completion: nil)

    }

}