如何防止以模态方式出现活动控制器？

Question

我们有 2 个控制器：MainVC 和 ProfileVC。从 MainVC 我们转到 ProfileVC profileButton 按（导航栏上的左侧项目）。

在个人资料 VC 中，我们在导航栏上有 2 个按钮：返回主界面 (leftItem) 和打开 alertView (rightItem)。

所以有简单的 KIF 测试（只需在导航栏上不断地左右点击）：

- (void)testProfileButtons
    {
        [tester waitForAnimationsToFinishWithTimeout:0.3];
        while (true)
        {
            [tester tapScreenAtPoint:CGPointMake(20, 20)];
            [tester waitForTimeInterval:0.1];
            [tester tapScreenAtPoint:CGPointMake(380, 20)];
            [tester waitForTimeInterval:0.1];
            [tester tapScreenAtPoint:CGPointMake(20, 20)];
            [tester waitForTimeInterval:0.1];
        }
    }

它使应用程序崩溃并出现错误：

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Application tried to present modally an active controller <UINavigationController: 0x7fe862ef82d0>.'

*** First throw call stack:
(
    0   CoreFoundation                      0x0000000110944c65 __exceptionPreprocess + 165
    1   libobjc.A.dylib                     0x00000001105dabb7 objc_exception_throw + 45
    2   UIKit                               0x000000010f44b80d -[UIViewController _presentViewController:withAnimationController:completion:] + 3238
    3   UIKit                               0x000000010f44d6c1 __62-[UIViewController presentViewController:animated:completion:]_block_invoke + 132
    4   UIKit                               0x000000010fa5e5ae -[_UIViewControllerTransitionCoordinator _applyBlocks:releaseBlocks:] + 217
    5   UIKit                               0x000000010fa5b8e5 -[_UIViewControllerTransitionContext _runAlongsideCompletions] + 123
    6   UIKit                               0x000000010fa5b670 -[_UIViewControllerTransitionContext completeTransition:] + 126
    7   UIKit                               0x000000010f2fe8a6 __53-[_UINavigationParallaxTransition animateTransition:]_block_invoke93 + 687
    8   UIKit                               0x000000010f387193 -[UIViewAnimationBlockDelegate _didEndBlockAnimation:finished:context:] + 326
    9   UIKit                               0x000000010f36e0f6 -[UIViewAnimationState sendDelegateAnimationDidStop:finished:] + 209
    10  UIKit                               0x000000010f36e42c -[UIViewAnimationState animationDidStop:finished:] + 76
    11  UIKit                               0x000000011daf3fdf -[UIViewAnimationStateAccessibility animationDidStop:finished:] + 48
    12  QuartzCore                          0x000000010f03e892 _ZN2CA5Layer23run_animation_callbacksEPv + 308
    13  libdispatch.dylib                   0x0000000111c67964 _dispatch_client_callout + 8
    14  libdispatch.dylib                   0x0000000111c52a59 _dispatch_main_queue_callback_4CF + 704
    15  CoreFoundation                      0x00000001108ac1f9 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 9
    16  CoreFoundation                      0x000000011086ddcb __CFRunLoopRun + 2043
    17  CoreFoundation                      0x000000011086d366 CFRunLoopRunSpecific + 470
    18  TurboChat UI Tests                  0x000000011b73ef69 -[KIFTestActor tryRunningBlock:complete:timeout:error:] + 425
    19  TurboChat UI Tests                  0x000000011b73f179 -[KIFTestActor runBlock:complete:timeout:] + 137
    20  TurboChat UI Tests                  0x000000011b73f304 -[KIFTestActor runBlock:timeout:] + 84
    21  TurboChat UI Tests                  0x000000011b73f73e -[KIFTestActor waitForTimeInterval:] + 174
    22  TurboChat UI Tests                  0x000000011b73c2ad -[TCProfileButtonsTest testProfileButtons] + 909
    23  CoreFoundation                      0x000000011083adec __invoking___ + 140
    24  CoreFoundation                      0x000000011083ac42 -[NSInvocation invoke] + 290
    25  XCTest                              0x000000011b79217a -[XCTestCase invokeTest] + 253
    26  XCTest                              0x000000011b792379 -[XCTestCase performTest:] + 150
    27  XCTest                              0x000000011b79bc35 -[XCTest run] + 260
    28  XCTest                              0x000000011b79108b -[XCTestSuite performTest:] + 379
    29  XCTest                              0x000000011b79bc35 -[XCTest run] + 260
    30  XCTest                              0x000000011b79108b -[XCTestSuite performTest:] + 379
    31  XCTest                              0x000000011b79bc35 -[XCTest run] + 260
    32  XCTest                              0x000000011b79108b -[XCTestSuite performTest:] + 379
    33  XCTest                              0x000000011b79bc35 -[XCTest run] + 260
    34  XCTest                              0x000000011b78e129 __25-[XCTestDriver _runSuite]_block_invoke + 56
    35  XCTest                              0x000000011b798edd -[XCTestObservationCenter _observeTestExecutionForBlock:] + 162
    36  XCTest                              0x000000011b78e060 -[XCTestDriver _runSuite] + 269
    37  XCTest                              0x000000011b78ea8d -[XCTestDriver _checkForTestManager] + 234
    38  XCTest                              0x000000011b79eb20 +[XCTestProbe runTests:] + 182
    39  Foundation                          0x000000010e5f21e5 __NSFireDelayedPerform + 387
    40  CoreFoundation                      0x00000001108ac174 __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ + 20
    41  CoreFoundation                      0x00000001108abd35 __CFRunLoopDoTimer + 1045
    42  CoreFoundation                      0x000000011086dd3d __CFRunLoopRun + 1901
    43  CoreFoundation                      0x000000011086d366 CFRunLoopRunSpecific + 470
    44  GraphicsServices                    0x00000001123a8a3e GSEventRunModal + 161
    45  UIKit                               0x000000010f30e8c0 UIApplicationMain + 1282
    46  TurboChat                           0x000000010cd1e75f main + 111
    47  libdyld.dylib                       0x0000000111c97145 start + 1
)

我在真实设备上测试时也得到了这个：

Presenting view controllers on detached view controllers is discouraged <TCProfileTableViewController: 0x14f6299c0>.

并让 alertView 出现在 MainVC 上，而不是 ProfileVC 上，下面是黑屏。

这就是我们在配置文件中显示警报的方式VC :

- (IBAction)menuButtonPressed:(id)sender
{
    [self.navigationController presentViewController:self.menuAlert animated:YES completion:nil];
}

警报视图：

self.menuAlert = [UIAlertController alertControllerWithTitle:[NSString stringWithFormat:@"%@?", NSLocalizedString(@"PROFILE_BTN_MENU", nil)]
                                                             message:nil
                                                      preferredStyle:UIAlertControllerStyleActionSheet];

有什么建议吗？

Answer 1

我认为你需要先关闭最后一个 viewcontroller，然后再返回当前模式转场，viewcontroller 处于活动状态，因此它会崩溃：

在从 mainVC 调用 segue 或你想返回的东西后使用这个：

[self dismissViewControllerAnimated:NO completion:nil]

或

[[self presentingViewController] dismissViewControllerAnimated:NO completion:nil]

或者使用 push segue，它会自动添加一个自动添加返回功能的返回按钮

Answer 2

我找到了解决方法

- (IBAction)menuButtonPressed:(id)sender
{
    [self.parentViewController presentViewController:self.menuAlert animated:YES completion:nil];
}

警报视图有时会出现在 menuVC 上，但它不会使应用程序崩溃并正常工作。在那里找到了答案：Warning :-Presenting view controllers on detached view controllers is discouraged

Answer 3

可能还有一种情况：

目标 ViewController 是在用户点击按钮后显示的吗？如果您有上述 ViewController.

的共享实例，则用户可能会点击两次，进行两次操作并打开相同的 ViewController 两次

尝试在操作进行时禁用按钮，显示进度指示器等。

Answer 4

为了防止这个异常。只需关闭当前显示的 ViewController 即可返回到您正在关闭的 ViewController 的调用方：

self.dismiss(animated: true, completion: nil)

Answer 5

您现在要做的就是为问题添加一个计时器。

@IBAction func onBtnMenu(_ sender: UIButton) {
    sender.isUserInteractionEnabled = false
    Timer.scheduledTimer(withTimeInterval: 1, repeats: false, block: { [weak sender] timer in
        sender?.isUserInteractionEnabled = true
    })
}

如何防止以模态方式出现活动控制器？

How to prevent present modally an active controller?

objective-c

presentmodalviewcontroller

ios