问题
Background & Short Summary
I am using WkWebview in order to show web pages for my app. I have it so that you can choose an image from camera or photo library. However there seems to be an issue with the app crashing on selecting the image.
Specs
I am running on IOS 10.0.2 on Tablet , and IOS 10.0 on the simulator using Swift 3. I am running both from XCode 8.
On the simulator I am getting an "error" when trying to upload images
I get the following message:
2016-10-19 02:15:36.150670 z4[31561:14708540] [Generic]
Creating an image format with an unknown type is an error
The image is fine and I am able to use it for upload. This behavior I thought was weird but I read that it has to do with memory management on IOS
On the tablet itself I get the following
Terminating app due to uncaught exception 'NSGenericException',
reason: 'Your application has presented a
UIAlertController (<UIAlertController: 0x151e80350>)
of style UIAlertControllerStyleActionSheet.
The modalPresentationStyle of a UIAlertController
with this style is UIModalPresentationPopover.
You must provide location information for this
popover through the alert controller's popoverPresentationController.
You must provide either a sourceView and sourceRect or a barButtonItem.
If this information is not known when you present the alert controller,
you may provide it in the UIPopoverPresentationControllerDelegate method
-prepareForPopoverPresentation.'
The app seems to crash in the AppDelegate. I have no idea how to do their recommendations. I also don't know if this is part of a deeper issue, or if I am missing something really simple.
Code that I have related to UIAlerts
The following are 3 functions I have related to UIAlertController
func webView(_ webView: WKWebView, runJavaScriptAlertPanelWithMessage message: String, initiatedByFrame frame: WKFrameInfo, completionHandler: @escaping () -> Void) {
let alertController = UIAlertController(title: nil, message: message, preferredStyle: .actionSheet)
alertController.addAction(UIAlertAction(title: "Ok", style: .default, handler: { (action) in
completionHandler()
}))
self.popoverPresentationController?.sourceView = self.view
self.popoverPresentationController?.sourceRect = self.view.bounds
self.present(alertController, animated: true, completion: nil)
}
func webView(_ webView: WKWebView, runJavaScriptConfirmPanelWithMessage message: String, initiatedByFrame frame: WKFrameInfo, completionHandler: @escaping (Bool) -> Void) {
let alertController = UIAlertController(title: nil, message: message, preferredStyle: .actionSheet)
alertController.addAction(UIAlertAction(title: "Yes", style: .default, handler: { (action) in
completionHandler(true)
}))
alertController.addAction(UIAlertAction(title: "No", style: .default, handler: { (action) in
completionHandler(false)
}))
self.popoverPresentationController?.sourceView = self.view
self.popoverPresentationController?.sourceRect = self.view.bounds
self.present(alertController, animated: true, completion: nil)
}
func webView(_ webView: WKWebView, runJavaScriptTextInputPanelWithPrompt prompt: String, defaultText: String?, initiatedByFrame frame: WKFrameInfo, completionHandler: @escaping (String?) -> Void) {
let alertController = UIAlertController(title: nil, message: prompt, preferredStyle: .actionSheet)
alertController.addTextField { (textField) in
textField.text = defaultText
}
alertController.addAction(UIAlertAction(title: "Yes", style: .default, handler: { (action) in
if let text = alertController.textFields?.first?.text {
completionHandler(text)
} else {
completionHandler(defaultText)
}
}))
alertController.addAction(UIAlertAction(title: "No", style: .default, handler: { (action) in
completionHandler(nil)
}))
self.popoverPresentationController?.sourceView = self.view
self.popoverPresentationController?.sourceRect = self.view.bounds
self.present(alertController, animated: true, completion: nil)
}
How can I handle this exception and fix this problem so my app doesn't crash on me? I can provide more details and code if needed. Thank you for your help in advance.
回答1:
You have to do small changes in your code to work in iPad. I am adding the missing line of your code.
self.popoverPresentationController = alertController.popoverPresentationController
alertController.modalPresentationStyle = .Popover
Add these two lines of code in your 3 functions.
回答2:
Please use below Objective-C code as reference. So it may be work for you.
- (void)showAlertWithTitle:(NSString *)title withMessage:(NSString *)message withStyle:(UIAlertControllerStyle) alertStyle andActions:(NSArray *)actions andSource:(UIView *)sourceView{
UIAlertController *alertController= [UIAlertController
alertControllerWithTitle:title
message:message
preferredStyle:alertStyle];
for (UIAlertAction *action in actions) {
[alertController addAction:action];
}
UIWindow *alertWindow = [[UIWindow alloc]initWithFrame:[UIScreen mainScreen].bounds];
alertWindow.rootViewController = [[UIViewController alloc]init];
alertWindow.windowLevel = UIWindowLevelAlert + 1;
[alertWindow makeKeyAndVisible];
if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) {
[alertController setModalPresentationStyle:UIModalPresentationPopover];
UIPopoverPresentationController *popPresenter = [alertController
popoverPresentationController];
popPresenter.sourceView = sourceView;
popPresenter.sourceRect = sourceView.bounds;
}
[alertWindow.rootViewController presentViewController:alertController animated:YES completion:nil];
}
- (void)dismissAlertController{
UIWindow *topWindow = [UIApplication sharedApplication].windows.lastObject;
[topWindow.rootViewController dismissViewControllerAnimated:YES completion: nil];}
To use above methods, Here is the sample.
__weak typeof(self) weakSelf = self;
UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:@"Cancel" style:UIAlertActionStyleCancel handler:^(UIAlertAction *action) {
// Cancel button tappped.
[weakSelf dismissAlertController];
}];
UIAlertAction *removeAction = [UIAlertAction actionWithTitle:@"Remove" style:UIAlertActionStyleDestructive handler:^(UIAlertAction *action) {
[weakSelf dismissAlertController];
//Do your actions
}];
if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone) {
[self showAlertWithTitle:@"Are you sure you want to remove?" withMessage:nil withStyle:UIAlertControllerStyleActionSheet andActions:@[removeAction,cancelAction]];
}
else if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad){
[self showAlertWithTitle:@"Are you sure you want to remove?" withMessage:nil withStyle:UIAlertControllerStyleActionSheet andActions:@[removeAction,cancelAction] andSource:sender];
}
来源：https://stackoverflow.com/questions/40123838/ipad-simulator-fine-but-ipad-crashes-app-when-uploading-image-using-wkwebview