App crash when presenting UIAlertController [duplicate]

问题

My app's crashing when trying to present a UIAlertController.

I have a UIViewController that gets presented modally, then on that presented view controller when a certain button is tapped I want to present a actionSheet alert.

Somehow the app crashes when doing this and I cannot figure it out why.

Here's the code:

let alertController = UIAlertController(title: nil, message: nil, preferredStyle: .actionSheet)
alertController.addAction(UIAlertAction(title: "Image from Camera", style: .default, handler: { (_) in
    let cameraController = CameraController()
    self.present(cameraController, animated: true, completion: nil)
}))
alertController.addAction(UIAlertAction(title: "Image from Library", style: .default, handler: {(_) in
    let imagePickerController = UIImagePickerController()
    imagePickerController.delegate = self
    imagePickerController.allowsEditing = true
    self.present(imagePickerController, animated: true, completion: nil)
}))
alertController.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil))
alertController.view.tintColor = UIColor.rgb(red: 46, green: 94, blue: 120)
self.present(alertController, animated: true, completion: nil)

The crash log:

libc++abi.dylib: terminating with uncaught exception of type NSException

When I backtrace the error it shows this:

    * thread #1, queue = 'com.apple.main-thread', stop reason = signal SIGABRT
    frame #0: 0x00000001101a7fce libsystem_kernel.dylib`__pthread_kill + 10
    frame #1: 0x00000001101e1150 libsystem_pthread.dylib`pthread_kill + 333
    frame #2: 0x000000010fe650e7 libsystem_c.dylib`abort + 127
    frame #3: 0x000000010fbf791f libc++abi.dylib`abort_message + 245
    frame #4: 0x000000010fbf7abb libc++abi.dylib`default_terminate_handler() + 265
    frame #5: 0x0000000109b341be libobjc.A.dylib`_objc_terminate() + 97
    frame #6: 0x000000010fc13159 libc++abi.dylib`std::__terminate(void (*)()) + 8
    frame #7: 0x000000010fc12e0a libc++abi.dylib`__cxa_rethrow + 99
    frame #8: 0x0000000109b340dc libobjc.A.dylib`objc_exception_rethrow + 40
    frame #9: 0x000000010a424a39 CoreFoundation`CFRunLoopRunSpecific + 537
    frame #10: 0x0000000112faf9c6 GraphicsServices`GSEventRunModal + 62
    frame #11: 0x000000010bd325e8 UIKit`UIApplicationMain + 159
    frame #13: 0x000000010fd92d81 libdyld.dylib`start + 1
    frame #14: 0x000000010fd92d81 libdyld.dylib`start + 1

I even tried to dispatch on main queue the presentation, but it still doesn't work.

Any hint?

Thank you.

EDIT

In order to filter some problems I've implemented a simple alert controller and it still crash using .actionSheet but not with .alert

let alert = UIAlertController(title: "title", message: "message", preferredStyle: UIAlertControllerStyle.actionSheet)
present(refreshAlert, animated: true, completion: nil)

Doing this it crashes, but if I use .alert it does not.

Why is this happening

回答1:

So I figure out the problem.

Unfortunately Xcode doesn't help with their crash logs, which are vague.

The problem is that since I'm testing this UIAlertController on an iPad I should implement the alert controller's source view.

In order to do so, I've added the following code and everything is working as expected:

if UIDevice.current.userInterfaceIdiom == .pad {
    guard let button = self.header?.profileImageButton else { return }
    alertController.popoverPresentationController?.permittedArrowDirections = .right
    alertController.popoverPresentationController?.sourceView = button
}
self.present(alertController, animated: true, completion: nil)

回答2:

Alert PopUp

This is help me i think this is help for you

     let refreshAlert = UIAlertController(title: "Refresh", message: "All data will be lost.", preferredStyle: UIAlertControllerStyle.alert)

    refreshAlert.addAction(UIAlertAction(title: "Ok", style: .default, handler: { (action: UIAlertAction!) in
        print("Handle Ok logic here")
    }))

    refreshAlert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: { (action: UIAlertAction!) in
        print("Handle Cancel Logic here")
    }))

    present(refreshAlert, animated: true, completion: nil)

Action Sheet

    let actionSheetController: UIAlertController = UIAlertController(title: nil, message: nil, preferredStyle: .actionSheet)

     create an action
       let firstAction: UIAlertAction = UIAlertAction(title: "First Action", style: .default) { action -> Void in

            print("First Action pressed")
        }

        let secondAction: UIAlertAction = UIAlertAction(title: "Second Action", style: .default) { action -> Void in

            print("Second Action pressed")
        }

        let cancelAction: UIAlertAction = UIAlertAction(title: "Cancel", style: .cancel) { action -> Void in }

    // add actions
    actionSheetController.addAction(firstAction)
    actionSheetController.addAction(secondAction)
    actionSheetController.addAction(cancelAction)

     present an actionSheet...
    present(actionSheetController, animated: true, completion: nil)

}

来源：https://stackoverflow.com/questions/47176379/app-crash-when-presenting-uialertcontroller

标签

ios

swift

ios11

uialertcontroller