I am making an iOS application that has a UIPageViewController that is loaded with a default page if there aren't any others added yet, and a user can add pages as he progresses through the app. However, the initial view never changes as others are added.
I've tried the answers from these questions:
Is it possible to Turn page programmatically in UIPageViewController?
Changing UIPageViewController's page programmatically doesn't update the UIPageControl
Removing a view controller from UIPageViewController
Refresh a UIPageViewController
None of them work for me. The view still remains at the initial page until I reload the application, after which, the pages show fine, and I can add as many as I want.
This is the code I have for making the PageView and the pages
- (void)viewDidLoad
{
[super viewDidLoad];
self.pageController = [[UIPageViewController alloc] initWithTransitionStyle:UIPageViewControllerTransitionStyleScroll navigationOrientation:UIPageViewControllerNavigationOrientationHorizontal options:nil];
self.pageController.dataSource = self;
[[self.pageController view] setFrame:[[self pageControllerView] bounds]];
UIViewController *initialViewController = [self viewControllerAtIndex:0];
__block Page1ViewController *blocksafeSelf = self;
// This doesn't work either... :(
void (^completionBlock)(BOOL) = ^(BOOL finished)
{
// It seems that whenever the setViewControllers:
// method is called with "animated" set to YES, UIPageViewController precaches
// the view controllers retrieved from it's data source meaning that
// the dismissed controller might not be removed. In such a case we
// have to force it to clear the cache by initiating a non-animated
// transition.
usleep(1);
dispatch_async(dispatch_get_main_queue(), ^(){
[blocksafeSelf.pageController setViewControllers:#[initialViewController]
direction:UIPageViewControllerNavigationDirectionForward
animated:NO
completion:nil];
});
};
[self.pageController setViewControllers:#[initialViewController]
direction:UIPageViewControllerNavigationDirectionForward
animated:YES
completion:completionBlock];
[self addChildViewController:self.pageController];
[[self view] addSubview:[self.pageController view]];
[self.pageController didMoveToParentViewController:self];
}
- (void)reloadViews
{
[[self childViewControllers] makeObjectsPerformSelector:#selector(removeFromParentViewController)];
[[self.view subviews] makeObjectsPerformSelector:#selector(removeFromSuperview)];
[self.pageController willMoveToParentViewController:nil];
[self.pageController removeFromParentViewController];
[self.pageController.view removeFromSuperview];
self.pageController = nil;
self.pageController = [[UIPageViewController alloc] init];
[self.view setNeedsDisplay];
}
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController
{
NSUInteger index = ((SomethingViewController *)viewController).index;
index++;
if (index >= [Settings somethings].count)
{
return nil;
}
return [self viewControllerAtIndex:index];
}
- (UIViewController *)viewControllerAtIndex:(NSUInteger)index
{
UIStoryboard *sb = [UIStoryboard storyboardWithName:#"Storyboard_iPhone"
bundle:nil];
if ([Settings somethings].count == 0 && index == 0)
{
NoSomethingViewController *vc = [sb instantiateViewControllerWithIdentifier:#"NoSomethingViewController"];
vc.index = index;
return vc;
}
SomethingViewController *childViewController = [sb instantiateViewControllerWithIdentifier:#"SomethingViewController"];
childViewController.something = [[Settings somethings] somethingAtIndex:index];
childViewController.index = index;
return childViewController;
}
When a new page should be created, by adding a something in the somethings array, I call reloadViews from the View controller that did the adding of the something. The code then hits the second part of viewControllerAtIndex, but that is not shown on the page that I see on the phone, as I still see the NoSomethingViewController and it's view.
If you need more code, I'll provide.
add the following code in the pageViewController viewWillAppear method
dataSource = self
and in the viewWillDisappear add
dataSource = nil
this will force the pageViewController to reload its dataSource
To show the current dot, dont forget you have to update the page indicator
- (NSInteger)presentationIndexForPageViewController:(UIPageViewController *)pageViewController
Example how to update your UIPageControl indicator https://stackoverflow.com/a/22576250/3897011
After a long time and after wasting a support ticket with Apple, I decided to go with another approach.
In my Storyboard I created 2 different navigation controllers, one for each case (if there are somethings and if there aren't any), and I have an initial view Controller that, on viewDidAppear, instantiates one of the two and presents it. This way, I make sure that the entire navigation controller gets reloaded correctly.
UINavigationController *nc;
if ([Settings somethings].count)
{
nc = [self.storyboard instantiateViewControllerWithIdentifier:#"NavigationController"];
}
else
{
nc = [self.storyboard instantiateViewControllerWithIdentifier:#"NoSomethingNavigationController"];
}
self.nc = nc;
[self presentViewController:nc animated:NO completion:nil];
In order to reload UIPageViewController you can use the following code:
[self.pageController setViewControllers:#[yourCurrentController]
direction:UIPageViewControllerNavigationDirectionForward
animated:NO
completion:nil];
Also please implement
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(UIViewController *)viewController
method.
Related
I use a UIPageViewController for two view controllers. In the first view controller I have a 'NEXT' button to go to the second view controller. My question is: How can I wire it up?
In my first and second view controllers I do not have code yet. However, in my RootViewController I have this code:
- (void)viewDidLoad {
self.pageViewController = [self.storyboard instantiateViewControllerWithIdentifier:#"PageViewController2"];
self.pageViewController.dataSource = self;
SeekerRegistrasiViewController *tvc = [self.storyboard instantiateViewControllerWithIdentifier:#"seeker1"];
Seeker2RegistrasiViewController *pvc;
self.array =[NSArray arrayWithObjects:tvc, pvc, nil];
[self.pageViewController setViewControllers:self.array direction:UIPageViewControllerNavigationDirectionForward animated:YES completion:nil];
self.pageViewController.view.frame = CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height -60);
self.pageViewController.view.backgroundColor = [UIColor clearColor];
[self addChildViewController:pageViewController];
[self.view addSubview:pageViewController.view];
[self.pageViewController didMoveToParentViewController:self];
}
-(UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(UIViewController *)viewController{
if ([viewController isKindOfClass:[Seeker2RegistrasiViewController class]]) {
SeekerRegistrasiViewController *pvc = [self.storyboard instantiateViewControllerWithIdentifier:#"seeker1"];
return pvc;
}
else return nil;
}
-(UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController{
if ([viewController isKindOfClass:[SeekerRegistrasiViewController class]]) {
Seeker2RegistrasiViewController *tvc = [self.storyboard instantiateViewControllerWithIdentifier:#"seeker2"];
return tvc;
}
else return nil;
}
- (NSInteger)presentationCountForPageViewController:(UIPageViewController *)pageViewController {
return 2;
}
- (NSInteger)presentationIndexForPageViewController:(UIPageViewController *)pageViewController {
return 0;
}
I would appreciate any help that would guide me in the right direction.
You can do it using setViewControllers:direction:animated:completion:.
Look at this answer: Is it possible to Turn page programmatically in UIPageViewController?
You basically set again all the view controllers (already switched), define a direction (which the animation will use, for example, UIPageViewControllerNavigationDirectionForward), use YES for animated and a completion block for processing afterwards (like updating the currentPage index you manage).
When a user presses the center UITabBarItem I present a modal UIView. Think of it like Instagram.
-(BOOL)tabBarController:(UITabBarController *)tabBarController shouldSelectViewController:(UIViewController *)viewController{
if(viewController == [self.viewControllers objectAtIndex:2])
{
CameraViewController *cameraVC = [[UIStoryboard storyboardWithName:#"Main" bundle:nil] instantiateViewControllerWithIdentifier:#"cameraVC"];
UINavigationController* navController = [[UINavigationController alloc] initWithRootViewController:cameraVC];
navController.navigationBar.barStyle = UIStatusBarStyleLightContent;
[self presentViewController:navController animated:YES completion:nil];
return NO;
}
else
{
return YES;
}
}
This works perfectly.
When I'm done taking a picture in CameraViewController I want the view to be dismissed and the 4th UITabBarItem to be selected for the results of the picture (HistoryViewController).
This is how I do that in CameraViewController (who is modally pushed):
[self dismissViewControllerAnimated:YES completion:nil];
[(UITabBarController *)self.presentingViewController setSelectedIndex:3];
And this is where it gets buggy.
As you can see the text in the 4th tab is selected, but the first tab icon is still selected. Also the presented view is the one from the first tab.
After 10 seconds or so it eventually changes the view to the, correct, 4th tab.
I'm trying to find out what process creates this slowdown so I've set up a lot of NSLog's.
The approximate 10 second slowdown is between [(UITabBarController *)self.presentingViewController setSelectedIndex:3]; in the CameraViewController and viewDidLoad in HistoryViewController.
What is happening in between these calls/methods that could cause the slowdown?
Edit:
In CameraViewController:
- (void)scan {
dispatch_queue_t scanTesseract = dispatch_queue_create("scanTesseract", NULL);
dispatch_async(scanTesseract, ^(void) {
dispatch_async(dispatch_get_main_queue(), ^{
[SVProgressHUD setForegroundColor:[UIColor ht_mintDarkColor]];
[SVProgressHUD showProgress:0 status:#"Scanning"];
});
//background processing goes here
[self.tesseract setImage:self.imgToScan.blackAndWhite];
[self.tesseract recognize];
[self filterResults:[self.tesseract recognizedText]];
dispatch_async(dispatch_get_main_queue(), ^{
[SVProgressHUD dismiss];
});
[self scanningDone];
});
}
- (void)scanningDone {
[LastScan getInstance].hasBeenViewed = FALSE;
[self dismissViewControllerAnimated:YES completion:nil];
[(UITabBarController *)self.presentingViewController setSelectedIndex:3];
}
In HistoryViewController:
- (void)viewDidLoad {
[super viewDidLoad];
NSLog(#"ViewDidLoad");
self.navigationController.navigationBar.barStyle = UIStatusBarStyleLightContent;
self.collectionView.backgroundColor = [UIColor whiteColor];
}
You are calling your scanningDone from within a background queue. Execute that method on the main Queue.
dispatch_async(dispatch_get_main_queue(), ^{
[self scanningDone];
});
What about this?
[self dismissViewControllerAnimated:YES completion:^{
[(UITabBarController *)self.presentingViewController setSelectedIndex:3];
}];
I am making an app with different view controllers. My home screen is in main.storyboard. Rest of the view controllers have their own xib, .h & .m files. I am trying this for navigation from home screen.
-(IBAction)btnSignUpTapped:(id)sender
{
SignUpWithEmailViewController * login = [[SignUpWithEmailViewController alloc] init];
UINavigationController *nav = [[UINavigationController alloc]
initWithRootViewController:login];
[self presentViewController:nav animated:YES completion:NULL];
}
This code works fine for navigating to different viewcontroller (in this case SignUpwithEmailViewController). On SignUpWithEmailViewController I have a back button which is supposed to bring me back to home screen. This is what I got so far:
-(IBAction)btnBackTapped:(id)sender
{
ViewController * homeScreen = [[ViewController alloc] init];
UINavigationController *nav = [[UINavigationController alloc]
initWithRootViewController:homeScreen];
[self presentViewController:nav animated:YES completion:NULL];
}
But as result of this code, screen turns black and nothing happens. How do I solve this problem? For hiding the nav bar I am using
-(void) viewWillAppear:(BOOL)animated
{
[[self navigationController] setNavigationBarHidden:YES animated:NO];
}
Yes, you have to insert you called viewController to NavigationController,
but if you wont to use modal flow - to close presentedViewController just call:
[self dismissViewControllerAnimated:YES completion:^{
}];
EDITED:
may be it will be more helpful, it just example, put it to you main view controller:
- (void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
UIViewController *c = [[UIViewController alloc] init];
c.view.backgroundColor = [UIColor redColor];
[self presentViewController:c animated:YES completion:^{
[self dismissViewControllerAnimated:YES completion:^{
}];
}];
}
I have the following code to create a UIPageViewController:
- (void)viewDidLoad
{
[super viewDidLoad];
self.index = 0;
self.pageContainer = [[UIPageViewController alloc] initWithTransitionStyle:UIPageViewControllerTransitionStyleScroll navigationOrientation:UIPageViewControllerNavigationOrientationHorizontal options:nil];
self.pageContainer.dataSource = self;
[[self.pageContainer view] setFrame:[[self view] bounds]];
DMSignUp1ViewController *first = [[DMSignUp1ViewController alloc] init];
DMSignUp2ViewController *second = [[DMSignUp2ViewController alloc] init];
self.viewControllers = [[NSArray alloc] initWithObjects:first, second, nil];
[self.pageContainer setViewControllers:self.viewControllers direction:UIPageViewControllerNavigationDirectionForward animated:NO completion:nil];
[self addChildViewController:self.pageContainer];
[[self view] addSubview:[self.pageContainer view]];
[self.pageContainer didMoveToParentViewController:self];
}
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(UIViewController *)viewController
{
if(self.index == 0) {
return nil;
}
self.index--;
return [self.viewControllers objectAtIndex:self.index];
}
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController
{
if(self.index == 1) {
return nil;
}
self.index++;
return [self.viewControllers objectAtIndex:self.index];
}
I have two UIViewControllers: DMSignUp1 and 2 which I create and then place in the viewControllers array.
When I go to run it, I get the following error: 'The number of view controllers provided (2) doesn't match the number required (1) for the requested transition'
Which I understand is because I am passing the array to use as the view controller. So how do I set that I want to use the first view controller in the array?
Add the following method at the end of the ViewController.m file
- (DMSignUp1ViewController *)viewControllerAtIndex:(NSUInteger)index {
DMSignUp1ViewController *first= [[DMSignUp1ViewController alloc] initWithNibName:#"APPChildViewController" bundle:nil];
first.index = index;
return childViewController;
}
And, replace the following code
DMSignUp1ViewController *first = [[DMSignUp1ViewController alloc] init];
DMSignUp2ViewController *second = [[DMSignUp2ViewController alloc] init];
self.viewControllers = [[NSArray alloc] initWithObjects:first, second, nil];
With
APPChildViewController *initialViewController = [self viewControllerAtIndex:0];
NSArray *viewControllers = [NSArray arrayWithObject:initialViewController];
[self.pageController setViewControllers:viewControllers direction:UIPageViewControllerNavigationDirectionForward animated:NO completion:nil];
Hope this might help you...
If you have the UIPageViewController spineLocation set to anything other than UIPageViewControllerSpineLocationMid when you're using [self.pageContainer setViewControllers: you can only pass an array with one view controller. The API isn't very clear really with it saying Controllers. You then provide the additional viewControllers when the UIPageViewController requests them through the dataSource.
Link to the spine reference.
here is a piece of my code, but in this way, when I push the third level view controller, the tabbar won't show.
//at first level
SecondLevelViewController *_2vc = [[SecondLevelViewController alloc]initWithNibName:#"SecondLevelViewController" bundle:nil];
_2vc.hidesBottomBarWhenPushed = YES;
[self.navigationController pushViewController:_2vc animated:YES];
//at second level
ThirdLevelViewController *_3vc = [[ThirdLevelViewController alloc]initWithNibName:#"ThirdLevelViewController" bundle:nil];
_3vc.hidesBottomBarWhenPushed = NO;
[self.navigationController pushViewController:_3vc animated:YES];
// Load the view
AddViewController *aController = [[AddViewController alloc] init];
// Set the view title
aController.title = #"Add View";
// hide tabbar
aController.hidesBottomBarWhenPushed = YES;
// add it to stack.
[[self navigationController] pushViewController:aController animated:YES];
-(void)viewWillAppear: (BOOL)animated
{
[super viewWillAppear:animated];
[self.tabBarController.tabBar setHidden:YES];
}
-(void)viewWillDisappear: (BOOL)animated
{
[super viewWillDisappear:animated];
[self.tabBarController.tabBar setHidden:NO];
}
Instead of setting the values of hidesBottomBarWhenPushed when you initialise the view controllers, you should instead handle the hiding mechanism in the -(void)viewWillAppear:(BOOL)animated in the view controllers instead.
An example of this implementation would be:
In SecondLevelViewController.m
-(void)viewWillAppear:(BOOL)animated
{
[_bottomBar setHidden:YES];
}
In ThirdLevelViewController.m
-(void)viewWillAppear:(BOOL)animated
{
[_bottomBar setHidden:NO];
}