xcode “应用程序试图在 UIImagePicker 中使用 UIAlertController 以模态方式呈现活动控制器”
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"Application tried to present modally an active controller" in UIImagePicker with UIAlertController
提问by SagittariusA
In my app I want the user to keep the iphone as horizzontally flat as possibile while he/she takes a picture, so I thought to show an alert when the tilt is too bad:
在我的应用程序中，我希望用户在他/她拍照时尽可能保持 iphone 水平平坦，所以我想在倾斜太严重时显示警报：
@IBAction func takeSnapshot(sender: UIButton) {
self.imagePicker = UIImagePickerController()
self.imagePicker.delegate = self
self.imagePicker.sourceType = .Camera
self.startMotionManager()
presentViewController(imagePicker, animated: true, completion: nil)
}
func startMotionManager() {
let alertController = UIAlertController(title: "Attenzione!", message: "Mantieni l'iphone il più orizzontale possibile!", preferredStyle: .Alert)
var showAlert:Bool = false
self.motionManager.deviceMotionUpdateInterval = 0.01
self.motionManager.startDeviceMotionUpdatesUsingReferenceFrame(CMAttitudeReferenceFrame.XArbitraryZVertical, toQueue: NSOperationQueue.currentQueue()!, withHandler:{
deviceManager, error in
print(deviceManager?.gravity)
/* se inclino troppo o troppo poco l'iphone */
if ((deviceManager?.gravity.z >= -0.999) && (deviceManager?.gravity.z <= -0.980)) {
if ((!alertController.isViewLoaded()) || (alertController.view.window == nil)) {
self.imagePicker.presentViewController(alertController, animated: true, completion: nil)
}
}
/* se l'iphone è inclinato bene allora nascondo l'alert */
else {
if ((alertController.view.window != nil) || (alertController.isViewLoaded())) {
alertController.dismissViewControllerAnimated(true, completion: nil)
}
}
})
}
Sometimes, either while the user is taking the photo or even at the very beginning, I get this error:
有时，无论是在用户拍照时还是在刚开始时，我都会收到此错误：
Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Application tried to present modally an active controller <UIImagePickerController: 0x168ec800>.'
Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Application tried to present modally an active controller <UIImagePickerController: 0x168ec800>.'
I have also tried with something simpler like:
我也尝试过一些更简单的东西，比如：
func startMotionManager() {
let alertController = UIAlertController(title: "Attenzione!", message: "Mantieni l'iphone il più orizzontale possibile!", preferredStyle: .Alert)
var showAlert:Bool = false
self.motionManager.deviceMotionUpdateInterval = 0.01
self.motionManager.startDeviceMotionUpdatesUsingReferenceFrame(CMAttitudeReferenceFrame.XArbitraryZVertical, toQueue: NSOperationQueue.currentQueue()!, withHandler:{
deviceManager, error in
print(deviceManager?.gravity)
/* se inclino troppo o troppo poco l'iphone */
if ((deviceManager?.gravity.z >= -0.999) && (deviceManager?.gravity.z <= -0.980)) {
if (!showAlert:Bool) {
showAlert = true
self.imagePicker.presentViewController(alertController, animated: true, completion: nil)
}
}
/* se l'iphone è inclinato bene allora nascondo l'alert */
else {
if (showAlert) {
showAlert = false
alertController.dismissViewControllerAnimated(true, completion: nil)
}
}
})
}
but it doesn't work either. I have read many discussions about this in SO and tried other configurations but they don't work. How can I fix it?
但它也不起作用。我在 SO 中阅读了许多关于此的讨论并尝试了其他配置，但它们不起作用。我该如何解决？
回答by Oleg Gordiichuk
Try to replace this line:
尝试替换此行：
presentViewController(imagePicker, animated: true, completion: nil)
With this
有了这个
self.navigationController?.pushViewController(imagePicker, animated: YES)
