I'd like to present an UIImagePickerController with the following code:
self.pickerController = [[UIImagePickerController alloc] init];
self.pickerController.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
self.pickerController.delegate = self;
[self presentViewController:self.pickerController animated:YES completion:nil];
It's working fine for iOS 7 and below, but in iOS 8 I got the following glitch:
While transitioning to the image picker controller (vertical cover animation), the background colour of the picker controller is invisible, revealing the presenting view controller beneath. After transition is finished, the picker's table view will be displayed abruptly without animation.
Sometimes, the picker's table view is not displayed at all, and instead I got a blank black screen. The navigation bar is still there, but no bar button items whatsoever, so user has to force quit the application.
Anyone know what's going on here?
So I managed to find the cause and fix for these problems and want to document it here:
The first problem occurred when I tried to compile to iOS 8 device from XCode 5.1. I switched to XCode 6 beta 2 and now it's working just fine.
The second problem occurred when I tried to reuse an UIImagePickerController that has been displayed before. Create a new instance instead before displaying, and it would be fixed.
Cheers.
Related
Here is my code. This may sound like redundant question but my scenario is different as I am not adding QLPreviewController as a subview but present as a controller.
After downloading from dropbox, I present it like-
self.pdfViewController = [[QLPreviewController alloc] init];
self.pdfViewController.delegate = self;
self.pdfViewController.dataSource = self;
[self presentViewController:self.pdfViewController animated:YES completion:nil];
and I also have QLPreviewControllerDataSource, QLPreviewControllerDelegate listed as the protocol. Besides, it is working if being run in earlier than iOS 10.0.
Please help me.
It looks like iOS 10 has changed the way that QLPreviewController is presented. On iOS 9 when I preview an image by presenting the QLPreviewController modally I see a nice zoom effect and the initial state of the preview is with a black background and the navigation and toolbar hidden. I can tap the image to make the bars visible (which changes the background to white). Tapping again toggles the state.
On iOS 10 the same code results in the white background view appearing and the zoom animation being incorrect (it seems to appear from off the bottom of the screen).
I found that implementing this practically undocumented new data source method for iOS 10 fixed the issue:
- (UIView* _Nullable)previewController:(QLPreviewController *)controller
transitionViewForPreviewItem:(id <QLPreviewItem>)item
{
return [self.tableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:MIDPhotoImageRowIndex_Image inSection:MIDPhotoSectionIndex_Image]];
}
The view I return is the same view that previewController:frameForPreviewItem:inSourceView: is using as the reference for the original content's frame (i.e. the image view in my table cell).
The documentation for this delegate method at the time of writing just says "No overview available".
Implementing that method did mean that the previewController:frameForPreviewItem:inSourceView: is now called on iOS 10. I just wish there was a way to default to the original black background without navigation bars.
i have a simple ios implementation. There is a tableviewcontroller embedded in a navigationcontroller and a qlviewcontroller in this implementation, navigationcontroller is embedded in a tabbarcontroller too.
Actual tab lists a lot of image files, if a cell is selected in the tableviewcontroller, a qlpreviewcontroller will be instantiated and image file will be shown. another tab shows only settings of app.
i have subclassed the qlpreviewcontroller. The instance of this subclass will be created with the following code part;
XYQLPreviewController *qlpvc = [[XYQLPreviewController alloc] init];
qlpvc.hidesBottomBarWhenPushed = YES;
[self.navigationController pushViewController:qlpvc animated:YES];
i want to hide tabbar in the preview controller so that there is enough place to preview.
these all work very well with ios 6 and below but with ios 7 i have the following problems;
Back button of navigation bar in qlpreviewcontroller doesnt respond, its not clickable.
if i back navigate with this new cool slide transition of ios 7, ta ta my tabbar got lost, i see only a white layer at the tabbar not my cool tabbar.
i see the following log message in log screen,if i select an image file and instantiate the subclass of previewcontroller.
"Container view is expected to be populated at this point"
what a problem can it be , i have no idea.
Please help.
PS:i have only a xib file not the storyboard.
If you want to hide the tab bar, I would say your best bet is to present the preview controller as a modal instead of pushing it onto the stack. Then when the user closes it (instead of hits back), it will bring them back to the tab bar view.
[self.navigationController presentViewController:qlpvc animated:YES completion:nil];
I have a problem in iOS 7. In my project, I have a UIViewController that contains an actionsheet with same options, selected one and app loads new UIViewController from navitationbar (push).
I want display a alertview in this new UIViewController but I cant do it. I have same tests and I have concluded that the problem is the actionsheet becouse I delete it from app , alertview displays in screen.
Log Error (when I try display an alertview):
2013-10-24 08:40:02.078 app1[17406:a0b] Warning: Attempt to present <_UIModalItemsPresentingViewController: 0x17c19ea0> on <_UIModalItemAppViewController: 0x1667a1c0> which is already presenting <_UIModalItemsPresentingViewController: 0x15395af0>
In iOS 6 works always.
Thanks
It would say it's a bug that this works on iOS6 which has been fixed in iOS7. Since both UIActionSheet and UIAlertView are modal view controllers displaying them simultaneously introduces airspace issues.
I think you've got no choice but to dismiss the UIActionSheet before displaying the UIAlertView which makes sense.
Im making an ios app in xcode 4 and I need a way of changing what is displayed on the screen when the device orientation changes.
does anyone know how to do this?
thanks.
probably you need to check first how to detect if the device orientation changes
see here: how to detect orientation change
then on the example on the link, you should know ho to change the view which is displayed on the screen. You can do it by using methods such as addSubview, presentModalViewController, pushViewController(for NavigationController)
eg:
[self presentModalViewController:aView animated:YES];
[self addSubview:aView];
[self.navigationController pushViewController:aView animated:YES];
I have a strange problem when using a UIScrollView controller combined with iPhone 4 and iOS 5.1.
I have a UIScrollView which has a content size of 640x480 (double screen effectively) and in addition to the swipe to switch between the two "screens" I also permit the user to tap the screen in response to which I call something like...
[scrollView scrollRectToVisible:(CGRectMake 320,0,320,480) animated:YES];
the first 320 would be 0 if the tap occurred whilst the right hand side of the scroll view was displayed (note the scroll view has paging enabled so it can only come to rest either fully left or fully right).
I also have a situation where I sometimes display an additional view controller modally using presentModalViewController over this view controller containing the scroll view.
Everything works perfectly until the modal view controller is presented and subsequently dismissed after which the scrollRectToVisible method will no longer work if animated is set to YES (if I change animated to NO then it works as expected). Note, the tap is still being registered and the scrollRectToVisible being called, it just doesn't do anything when animated is set to YES).
Here's the kicker, this bug only occurs on an iPhone 4 runnings iOS 5.x.
It works perfectly (even after the modal view controller has been displayed) on my:
iPhone 3G running 4.x,
iPhone 3GS running 3.x,
iPod touch (2nd Gen) running 4.x
and most surprisingly the simulator running 5.x.
I wondered if this was a bug in the animation system so disabled the animation on the modal view controller presentation and dismiss and this had no effect, problem still occurred on the iPhone 4 with iOS 5.1.
Anyone got any ideas as to what might be causing this and how I might work around it?
Finally tracked this down. what a pig...
I'm embedding a view from a view controller as a subview of another view controllers view. So my scroll view contains a view which also has an associated view controller.
Prior to iOS 5.x the methods viewWillAppear, viewWillDisappear, viewDidAppear and viewWillDisappear are never called on the sub views view controllers, only the main view controller. Already knowing this I set up my main view controller to manually call the sub views view controllers methods when these events happen.
However it appears that in iOS 5.x this issue has been "fixed" so where I was manually passing the call to viewWillAppear to my sub view controller I no longer need do this under 5.x as the method automatically gets called under 5.x - as a result it's now being called twice under 5.x but still only once when running on a 4.x or earlier device.
As a result, under 5.x my NSTimer used to call my updateUI method is being created twice, but because in viewDidDisappear I only destroy the timer if it is non nil it only gets destroyed once - therefore I'm leaking NSTimers under 5.x through double allocation where I'm not under 4.x.
As a result of multiple NSTimers hanging around all repeatedly calling my updateUI method is that the constant updating of the UI is killing the animation system and so the animation for the scrollView fails when running on an actual device. I guess it continued working OK on the simulator running 5.x as the CPU in the Mac is more than capable of handling the extra workload and still performing the animations correctly.
A simple check in my viewWillAppear method to ensure the NSTimer hasn't already been created has fixed the problem and has kept compatibility with 4.x and earlier.
I frustratingly run up against these kinds of issues every time Apple update their iOS by major versions... The morale of this story is don't assume that long standing classes still exhibit the same behaviour under different revisions of the OS.
I had the same problem. I realized that after modalViewController is dismissed my UIScrollerView shifts downs by 20px, which is the same height as status bar. So, it means when my UIViewController is loaded and UIScrollView is created, UIScrollView thinks there is no status bar, when actually it is there.
So I tried to put in viewDidLoad:
[[UIApplication sharedApplication] setStatusBarHidden:NO];
Now my UIScrollView always stays under status bar, with Y position 20px. It never shifts down.
I finally managed to get this working on an iPhone4 running 5.1. Ensuring the bounces horizontally property for the scroll view is set fixed the problem, though why having this unchecked should cause the problem in the first place is beyond me - I'm pretty certain this is a bug in iOS.