I'm using Indexed UITableView by implementing the following delegate methods:
- (NSInteger)tableView:(UITableView *)tableView sectionForSectionIndexTitle:(NSString *)title atIndex:(NSInteger)index
- (NSArray *)sectionIndexTitlesForTableView:(UITableView *)tableView
The index is displayed on the right of the table.
I was wondering if the index can be displayed on the left instead.
Thanks,
You can move the tableView index view to the left, but just a little bit so you don't get your app rejected )). Here is how:
// somewhere in your code for example in table view delegate method add this code
// take the index view, which is the last subview on the tableView
UIView *indexView = [[self.tableView subviews]lastObject];
// now take its frame and play with it
CGRect indexViewRect = indexView.frame;
indexViewRect.origin.x -= 50; // move it to the left by -50
indexView.frame = indexViewRect; // set the new frame
Thats it :)
By the way, I dont think Apple will reject your app if you move the index view to the most left, because I saw this on their contacts app on the iPad, but anyway at your risk.
Update: Fully customizable and easy to use ScrollBar you can find here:
https://github.com/BasheerSience/BRScrollBar
No, the style and position of this index is not configurable (unfortunately).
I don't think the api exposes that component. So sadly, you'd have to suppress rotations and hold the phone upside down, and this would be a very poor user experience. (Just a joke, don't downvote me)
Even not officially exposed by iOS APIs, it should be possible to move the index, by "hacking" a bit.
First you have to locate the the index in the UITableView subviews tree.
One simple way to do this is to put a breakpoint at runtime and use that:
po [myTableView recursiveDescription]
This will print the views tree and by analyzing it you should find a way to programmatically find the UIView that interests you and just move it (view.frame.origin), and that, without using any private API
But before trying this, think twice. That index is on right side for a good reason, most people are right handed with the thumb on that right side... It would be hard to use on other side.
Related
My UIPageViewController was working fine in iOS 5. But when iOS 6 came along, I wanted to use the new scroll transition style (UIPageViewControllerTransitionStyleScroll) instead of the page curl style. This caused my UIPageViewController to break.
It works fine except right after I've called setViewControllers:direction:animated:completion:. After that, the next time the user scrolls manually by one page, we get the wrong page. What's wrong here?
My workaround of this bug was to create a block when finished that was setting the same viewcontroller but without animation
__weak YourSelfClass *blocksafeSelf = self;
[self.pageViewController setViewControllers:viewControllers direction:UIPageViewControllerNavigationDirectionForward animated:YES completion:^(BOOL finished){
if(finished)
{
dispatch_async(dispatch_get_main_queue(), ^{
[blocksafeSelf.pageViewController setViewControllers:viewControllers direction:UIPageViewControllerNavigationDirectionForward animated:NO completion:NULL];// bug fix for uipageview controller
});
}
}];
This is actually a bug in UIPageViewController. It occurs only with the scroll style (UIPageViewControllerTransitionStyleScroll) and only after calling setViewControllers:direction:animated:completion: with animated:YES. Thus there are two workarounds:
Don't use UIPageViewControllerTransitionStyleScroll.
Or, if you call setViewControllers:direction:animated:completion:, use only animated:NO.
To see the bug clearly, call setViewControllers:direction:animated:completion: and then, in the interface (as user), navigate left (back) to the preceding page manually. You will navigate back to the wrong page: not the preceding page at all, but the page you were on when setViewControllers:direction:animated:completion: was called.
The reason for the bug appears to be that, when using the scroll style, UIPageViewController does some sort of internal caching. Thus, after the call to setViewControllers:direction:animated:completion:, it fails to clear its internal cache. It thinks it knows what the preceding page is. Thus, when the user navigates leftward to the preceding page, UIPageViewController fails to call the dataSource method pageViewController:viewControllerBeforeViewController:, or calls it with the wrong current view controller.
I have posted a movie that clearly demonstrates how to see the bug:
http://www.apeth.com/PageViewControllerBug.mov
EDIT This bug will probably be fixed in iOS 8.
EDIT For another interesting workaround for this bug, see this answer: https://stackoverflow.com/a/21624169/341994
Here is a "rough" gist I put together. It contains a UIPageViewController alternative that suffers from Alzheimer (ie: it doesn't have the internal caching of the Apple implementation).
This class isn't complete but it works in my situation (namely: horizontal scroll).
As of iOS 12 the problem described in the original question seems to be almost fixed. I came to this question because I experienced it in my particular setup, in which it does still happen, hence the word "almost" here.
The setup I experienced this issue was:
1) the app was opened via a deep link
2) based on the link the app had to switch to a particular tab and open a given item there via push
3) described issue happened only when the target tab was not previously selected by user (so that UIPageViewController was supposed to animate to that tab) and only when setViewControllers:direction:animated:completion: had animated = true
4) after the push returning back to the view controller containing the UIPageViewController, the latter was found to be a big mess - it was presenting completely wrong view controllers, even though debugging showed everything was fine on the logic level
I supposed that the root of the problem was that I was pushing view controller very quick after setViewControllers:direction:animated:completion: called, so that the UIPageViewController had no chance to finish something (maybe animation, or caching, or something else).
Simply giving UIPageViewController some spare time by delaying my programmatic navigation in UI via
DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + 1) { ... }
fixed the issue for me. And it also made the programmatic opening of the linked item more user friendly visually.
Hope this helps someone in similar situation.
Because pageviewVC call multi childVC when swipe it. But we just need last page that visible.
In my case, I need to change index for segmented control when change pageView.
Hope this help someone :)
extension ViewController: UIPageViewControllerDelegate {
func pageViewController(_ pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool) {
guard let pageView = pageViewController.viewControllers?.first as? ChildViewController else { return }
segmentedControl.set(pageView.index)
}
}
This bug still exists in iOS9. I am using the same workaround that George Tsifrikas posted above, but a Swift version:
pageViewController.setViewControllers([page], direction: direction, animated: true) { done in
if done {
dispatch_async(dispatch_get_main_queue()) {
self.pageViewController.setViewControllers([page], direction: direction, animated: false, completion: {done in })
}
}
}
Another simple workaround in Swift: Just reset the UIPageViewController's datasource. This apparently clears its cache and works around the bug. Here's a method to go directly to a page without breaking subsequent swipes. In the following, m_pages is an array of your view controllers. I show how to find currPage (the index of the current page) below.
func goToPage(_ index: Int, animated: Bool)
{
if m_pages.count > 0 && index >= 0 && index < m_pages.count && index != currPage
{
var dir: UIPageViewController.NavigationDirection
if index < currPage
{
dir = UIPageViewController.NavigationDirection.reverse
}
else
{
dir = UIPageViewController.NavigationDirection.forward
}
m_pageViewController.setViewControllers([m_pages[index]], direction: dir, animated: animated, completion: nil)
delegate?.tabDisplayed(sender: self, index: index)
m_pageViewController.dataSource = self;
}
}
How to find the current page:
var currPage: Int
{
get
{
if let currController = m_pageViewController.viewControllers?[0]
{
return m_pages.index(of: currController as! AtomViewController) ?? 0
}
return 0
}
}
STATEMENT:
It seems that Apple has spotted that developers are using UIPageViewController in very different applications that go way beyond the
originally intended ones Apple based their design-choices on in the first place. Rather than using it in a gesture driven linear fashion
PVC is often used to programmatically jump to random
positions within a structured environment. So they have enhanced their implementation of UIPageViewController and the class is now calling both DataSource
callbacks
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(UIViewController *)viewController
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController
after setting a new contentViewController on UIPageViewController with
[self.pageViewController setViewControllers:viewControllers direction:UIPageViewControllerNavigationDirectionForward animated:YES completion:nil];
even if an animated turn of pages rather suggests a linear progress in an e.g. page hierarchy like a book or PDF with consecutive pages. Although - I doubt that Apple from a HIG standpoint
is very fond of seeing PVC being used this way, but - it doesn't break backwards compatibility, it was an easy fix, so - they eventually did it. Actually it is just one more call of one of the two DataSource methods that is absolutely unnecessary in a linear environment where pages (ViewControllers) have already been cashed for later use.
However, even if this enhancement might come in very handy for certain use-cases the initial behavior of the class is NOT to be considered a bug. The fact that a lot of developers do - also in other
posts on SO that accuse UIPageViewController of misbehavior - rather emphasizes a widely spread misconception of its design, purpose and functionality.
Without trying to offend any of my fellow developers here in this great facility I nonetheless decided not to remove my initial 'disquisition' that clearly explains to the OP the mechanics of PVC and why his assumption is wrong that he has to deal with a bug here.
This might also be of use for any other fellow developer too who struggles with some intricacies in the implementation of UIPageViewController!
ORIGINAL ANSWER:
After having read all the answers over and over again - included the
accepted one - there is just one more thing left to say...
The design of UIPageViewController is absolutely FLAWLESS and all the
hacks you submit in order to circumvent an alleged bug is nothing but
remedies for your own faulty assumptions because you goofed it up in the
first place!!!
THERE IS NO BUG AT ALL! You are just fighting the framework. I'll explain why!
There is so much talk about page numbers and indices! These are concepts the
controller knows NOTHING about! The only thing it knows is - it is showing
some content (btw. provided by you as a dataViewController) and that it can
do something like a right/left animation in order to imitate a page turn.
CURL or SCROLL...!!!
In the pageViewController's world there only exists a current SPACE (let's call
it just this way to avoid confusion with pages and indices).
When you initially set a pageViewController it only minds about this very SPACE.
Only when you start panning its view it starts asking its DataSource what it
eventually should display in case a left/right flip should happen. When you start
panning to the left the PVC asks first for the BEFORE-SPACE and then for the
AFTER-SPACE, in case you start to the right it does it the other way round.
After the completed animation (a new SPACE is displayed by the PVC's view) the
PVC considers this SPACE as its new center of the universe and while it is at it, it
asks the DataSource about the one it still does not know anything about. In case of
a completed turn to the right it wants to know about the new AFTER space and in
case of a completed turn to the left it asks for a new BEFORE space.
The old BEFORE space (from before the animation) is in case of a completed turn to
the right completely obsolete and gets deallocated as soon as possible. The old center
is now the new BEFORE and the former AFTER is the new center. Everything just
shifted one step to the right.
So - no talk of 'which page' or 'whatever index' - just simply - is there a BEFORE or
an AFTER space. If you return NIL to one of the DataSource callbacks the PVC just
assumes it is at one extreme of your range of SPACES. If you return NIL to both
callbacks it assumes it is showing the one and only SPACE there is and will never
ever again call a DataSource callback anymore! The logic is up to you! You define
pages and indices in your code! Not the PVC!!!
For the user of the class there are two means of interacting with the PVC.
A pan-gesture that indicates whether a turn to the BEFORE/AFTER space is desired
A method - namely setViewControllers:direction:animated:completion:
This method does exactly the same than the pan gesture is doing. You are indicating the
direction (e.g. UIPageViewControllerNavigationDirectionBackward/Forward)
for the animation - if there is one intended - which in other words just means -> going to
BEFORE or AFTER...
Again - no mentioning of indices, page-numbers etc....!!!
It is just a programmatically way of achieving the same a gesture would!
And the PVC is doing right by showing the old content again when moving back
to the left after having moved to the right in the first place. Remember
- it is just showing content (that you provide) in a structured way - which is a 'single page turn' by design!!!
That is the concept of a page turn - or BOOK, if you like that term better!
Just because you goof it up by submitting PAGE 8 after PAGE 1 doesn't mean the PVC
cares at all about your twisted opinion of how a book should work. And the user of your
apps neither. Flipping to the right and back to the left should definitely result in reaching
the original page - IF done with an animation. And it is up to YOU to correct the goof by
finding a solution for the disaster. Don't blame it on the UIPageViewController. It is doing
its job perfectly!
Just ask yourself - would you do the same thing with a PAGE-CURL animation? NO ?
Well, neither should you with a SCROLL animation!!! An animated page turn is a page turn and only a page turn!
In either mode!
And if you decide to tear out PAGE 2 to PAGE 7 of your BOOK that's perfectly fine!
But just don't expect UIPageViewController to invent a non-existing PAGE 7 when turning back to the recent page unless YOU tell it that things have changed...
If you really want to achieve an uncoordinated jump to elsewhere, well - do it without an
animation! In most cases this will not be very elegant but - it's possible... -
And the PVC even plays nicely along! When jumping to a new SPACE without animation
it will ask you further down the road for both - the BEFORE and AFTER controller. So your application-logic can keep up with the PVC...
But with an animation you are always conveying - move to the previous/next space (BEFORE -
AFTER). So logically there is no need at all for the PVC to ask again about a space it already
knows about when animating page turns!!!
If you wanna see PAGE 7 when flipping back to the left after having animated from PAGE 1
to the right - well, I would say - that's definitely your very own problem!
And just in case you are looking for a better solution than the 'completion-block' hack from
the accepted answer (because with it you are doing work beforehand for something that might
possibly not even get used further down the road) use the gesture recognizer delegate:
- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
Set your PVC's DataViewController here (without animation) if you really intend to go back
left to PAGE 7 and the DataSource will be asked for BEFORE and AFTER and you can submit
whatever page you like! With a flag or ivar that you should have stashed away when doing your uncontrolled
jump from PAGE 1 to 8 this should be no problem...
And when people keep on complaining about a bug in the PVC - doing 2 page turns when it is
supposed to do 1 turn only - point them to this article.
Same problem - triggering an un-animated setViewControllers: method within the transition gesture
will cause exactly the same havoc. You think you set the new center - the DataSource is asked
for the new BEFORE - AFTER dataController - you reset your index count... - Well, that seems OK...
But - after all that business the PVC ends its transition/animation and wants to know about the
next (still unknown to it) dataViewController (BEFORE or AFTER) and also triggers the DataSource. That's totally justified ! It needs to know where in its small BEFORE - CENTER - AFTER
world it is and be prepared for the next turn.
But your program-logic adds another index++ count to its logic and suddenly got 2 page turns !!!
And that is one off from where you think you are.
And YOU have to account for that! Not UIPageViewController !!!
That is exactly the point of the DataSourceProtocol only having two methods! It wants to be as generic as possible - leaving you the space and freedom to define your own logic and not being stuck with somebody else's special ideas and use-cases! The logic is completely up to you. And only because you find functions like
- (DataViewController *)viewControllerAtIndex:(NSUInteger)index storyboard:(UIStoryboard *)storyboard position:(GSPositionOfDataViewController)position;
- (NSUInteger)indexOfViewController:(DataViewController *)viewController;
in all the copy/pasted sample applications in the cloud doesn't necessarily mean that you have to eat that pre-cook food! Extend them any way you like! Just look above - in my signature you will find a 'position:' argument! I extended this to know later on if a completed page turn was a right or a left turn. Because the delegate unfortunately just tells you whether your turn completed or not! It doesn't tell you about the direction! But this sometimes matters for index-counting, depending on your application's need...
Go crazy - they are your's...
HAPPY CODING !!!
The UITableView object I have in my storyboard theoretically should have its delegate set, but it does not. I dragged the UITableView object from storyboard into the header and added it as an IBOutlet property and synthesized it. However, I checked and only the data source method is being called. So something seems to be wrong with the way I'm implementing the main delegate protocol. As you can see in the images below, I seem to be doing everything standardly? But the delegate is not being set still! Thoughts?
I think the reason your solution is not working is because you are using a TableView inside of a UiViewController instead of a UiTableViewController. I had this same issue a while back. Here is what I did. Create an IBOutlet to the header file and synthesize it in the implementation file (I believe you have already completed this step). Go back to the storyboard. control + click on your table view and drag the connector to the view controller (the yellow circle with the white box). Select datasource. Repeat this step again and instead of selecting datasource select delegate. In the menu on the right-hand side you should be able to see your outlets if it is set up correctly. This should fix your delegate problems.
See the screenshot from my example below:
Try changing your numberOfRows method (for better debugging).
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
int rows = [allParties count];
NSLog(#"number of rows: %d", rows);
return rows;
}
If you're returning 0, it won't work.
Also in the future, please paste your code instead of taking screen shots.
You have put a log in both numberOfRowsInSection: which is being called but not the one in cellForRowAtIndexPath: which shows that no cells are being created for your table. You simply are returning 0 as number of rows for the table. Check for that.
And the delegate method didSelectRowAtIndexPath: will be called when you select a row, but for that, you have to have a row first in your table.
I have a viewController which contains a tableView; I have a UIView in the header of the table and have dragged a searchDisplayController into the view, along with a segmented control. (I didnt want to use the scope for some reasons, incase u were wondering). Now my problem is that this check
if (tableView==self.searchDisplayController.searchResultsTableView)
in cellForRow fails even when the user is typing in the searchBar. I have no idea why??!! As far as I know all the delegates etc are hooked up automatically when u drag the controller into a view. The check is only true once the user presses the search button on the keyboard and then scrolls the table a little, and I know this is not how its supposed to work!?
Can anyone shed some light on what might be going on here? Its driving me crazy!
Many thanks
Jules
You could also use self.searchDisplayController.active, for example:
if (self.searchDisplayController.active) {
return [searchResultArray count];
} else {
return [regularDataArray count];
}
Hope this helps! Although, if you're trying to do this the right way, you should have to a separate data source, one for search and one for the default version.
i couldnt figure this out so i did it another way. Using a BOOL isSearchTable and setting this in willShowSearchResultsTableView, and willHideSearchResultsTableView.
I am trying to add a couple characters that are inconveniently located in the normal keyboard, and place them in a toolbar so that the user can use them just like normal keys.
Does anyone have a useable way to do this?
I found an article explaining how to do this by simulating a "Paste" operation, (remove pasteboard contents, replace with my character, paste into field, return original pasteboard contents) but my trouble is that I'm trying to do this with a UISearchBar, which seems to have no paste selector.
Update
I found a lead:
UIKIT_CLASS_AVAILABLE(2_0) #interface UISearchBar : UIView {
#private
UITextField *_searchField;
Since it is documented that there's a UITextField in a search bar, if I were to root through the searchbar's subviews and locate said text field, (assuming with 99% certainty that the text field has a delegate) would it make sense that I could "steal" the text field and make my class the delegate, then forward the messages to the original delegate once I'm done with them?
This is definitely tricky. UISearchBar doesn't give you inputAccessoryView and nor do you get selectedRange.
You can paste in a UISearchBar. If you want to get your tricky characters to the pasteboard, you could get a button to execute something such as:
[[UIPasteboard generalPasteboard] setString:#"[*]"];
and then get the user to use paste in the UISearchBar. Pretty awkward for the user though.
Rooting through the subviews to find the UITextField might work. If you do this, you'd need to grab the existing delegate and make yourself the delegate. Then your delegate would need to transmit messages on. The process is described in this stackoverflow question and answer. Potential challenges here: (a) the Apple implementation could change between iOS updates and even, though unlikely, change the delegate during the lifetime of the UISearchBar; (b) Apple might see this as using a private API and reject the app. (I don't have any hard evidence of (b), but it's something to consider.)
One approach might be to use the bookmark button. The UISearchBar delegate can detect this. You could use that to insert your special characters or offer up a menu of special character insertions. Of course, you won't know where the cursor is. But, depending on your use case, appending the special characters at the end might be OK. Perhaps this doesn't get you anything over a button on your interface that just appends something.
[[self searchBar] setText: [NSString stringWithFormat:#"%#[*]", [[self searchBar] text]]].)
Implementing your own search bar might be the best way to go as already suggested #hyperbole. I've done this successfully by adding a custom UITextField (with my own magnifying glass in the leftView slot etc.) and adding it as the titleView of my navigationBar. But, if I understand your question aright, that still won't be enough, as UITextField doesn't provide selectedRange and its delegate doesn't provide an equivalent of textViewDidChangeSelection:. You might have a go with a UITextView that is fixed to one line (with scrolling clamped down if required - it often seems to be).
Can't you simply set the text of the UISearchBar? Of course, the tricky part is to determine the cursor position. For that, you can register a UITapGestureRecognizer on the UISearchBar, determine the tap co-ordinates & calculate the cursor position using - (CGSize)sizeWithFont:(UIFont *)font forWidth:(CGFloat)width lineBreakMode:(UILineBreakMode)lineBreakMode or its variants.
You may also have to register a UIPanGestureRecognizer, as the user can change the cursor position by tapping, dragging & then releasing the finger.
HTH,
Akshay
i Have some problem. i have 25 records in my NSMutableArray and i want to display them 5 records at a time when user press Next button then another 5 records to display and when user press back button then previous 5 records to display.
How can i do this any help from you would be great.
Thank You.
Make an ivar in your table view controller that tracks which records you should display. Set the ivar in your Next/Back buttons action method and send [self.tableView reloadData]. Use the ivar in -tableView:numberOfRowsInSection: and -tableView:cellForRowAtIndexPath: to determine how many and which cells to display.
First of all, I recommend against this design. Tableviews on iPhone apps are great to scroll with your fingers, and having buttons like this defeats this. However, I don't know what you're doing, so I'll assume it's cool.
My suggestion is to use slices of the larger array as follows:
- (NSArray *)itemsForPage:(NSUInteger)p {
NSIndexSet *indexes = [NSIndexSet indexSetWithIndexesInRange:NSMakeRange(5*p,5)];
return [_thatOneLargeArray objectsAtIndexes:indexes];
}
Note that I've refactored this code into a method. Let me know if this is helpful!