So, I want to do some basic animations of labels and later views.
I have a label, I'm trying to get it to move when a view loads, so I call the following method at the end of viewDidLoad:
- (void)animateView {
NSLog(#"animateView");
[UIView animateWithDuration:20 animations:^{
// set new position of label which it will animate to
self.dcFirstRunDaysLabel.frame = CGRectMake(20,320,280,215);
}];
}
Instead of animating, the label appears in position.
I've tried every tutorial and read through the docs. I get no errors.
Any thoughts?
Cheers.
Try calling your animateView method in viewDidAppear. Because in viewDidLoad your view isn't visible yet.
viewDidLoad:
Called after the controller’s view is loaded into memory.
viewDidAppear:
Notifies the view controller that its view was added to a view hierarchy.
Related
Am using xib to design my view using auto layout.Run time I want to change the content size of my scrollview in viewDidLayoutSubviews method but its not working.On orientation change the code written inside viewDidLayoutSubviews works but on load its not working.Please advice what could be the issue?
- (void)viewDidLayoutSubviews
{
scroll.contentSize = CGSizeMake(scroll.frame.size.width, attBtn.frame.origin.y+attBtn.frame.size.height+40);//atnBtn is added programatically
}
Usually when you want to have a view redraw you should call:
[self setNeedsDisplay: YES];
Granted I have never build on iOS, on OSX this code works every time. Also, for example, if you want your delegate to call a redraw for a view named someView:
[someView setNeedsDisplay: YES];
I'm adding 5 viewcontrollers to a scrollview with a page control so I can swipe from one viewcontroller to another.
At initialization I'm loading 3 viewcontrollers (left, middle, right)
My problem is that my three viewcontrollers are firing a viewDidAppear but only the center viewController is visible...
Is there a way to avoid the view controllers that aren't visible to call viewdidappear?
I'm adding my viewcontrollers to my scrollview like so :
if (controller != nil){
[self addChildViewController:controller];
[controller didMoveToParentViewController:self];
}
[scrollView addSubview:controller.view];
No, the viewDidAppear method is not related to the visibility of the view, if you get the documentation you will see
Notifies the view controller that its view was added to a view hierarchy.
So this method will be called when the view is added to the hierarchy. So the view was loaded, and added to the hierarchy, even in a non visible space of your mainView, it will call viewDidAppear.
To achieve what you want, you should implement the delegate of the scrollView, check the offset, and see in which page you are, then you can call a method on your viewController to do the job you want.
My goal is to make a custom segue with a custom animation as follows:
I want the segue to cover a button from the sourceViewController with a button from the destinationViewController with an effect similar to the navigation controller's push effect, i.e. the new button is supposed to push the old button away from right to left.
I have been able to make the old button (from the sourceViewController) move away as desired:
[UIView animateWithDuration:1.0 animations:^{
// set the target frame for animated view
sourceViewController.optionsButton.frame = leftButtonTargetFrame;
} completion:^(BOOL finished) {
[navigationController pushViewController:destinationViewController animated:NO];
// reset the button's frame back to its original frame
sourceViewController.optionsButton.frame = leftButtonInitFrame;
}];
But I am struggling to make the new button (from the destinationViewController) move in. The reason is that I cannot access the destinationViewController's view elements: While performing the segue they are not instantiated. And I cannot animate a button that is not instantiated.
So how can I replace a button in the sourceViewController with a button from the destinationViewController?
The view of the destination view controller hasn't been initialized/loaded at the time when you try to access the buttons. To load the view of the destination view controller, you can simply access the view property. Do this before using the buttons: [destinationViewController view];
destinationViewController.view; would also work, but it would generate a compiler warning.
Background Information:
If you access the view property and its value is currently nil, the view controller automatically calls the loadView method and returns the resulting view.
The method loadView loads the view that the controller manages. You should never call this method directly.
You are correct that you cannot animate an object that does not yet exist. However, you can fake it.
Create a place-holder button that will look identical to the button that will be in the new view controller.
Animate it to the correct place.
As the destination view controller comes in, its button should be invisible.
After the the view controller is in place (i.e. the segue has finished) the destination view controller can ensure the proper placement if its button and make its actual button visible.
Hope this helps.
I've been struggling with this for quite a while now.
I have to implement an user profile similar to what Instagram has in their ios app.
When clicking on the first to buttons on that tab bar like thing all the contents downwards from it changes. The tableview that is displayed on the bottom part has dynamic size so they keep account of that also.
I have something implemented where the top part is a UIView with 5 buttons and based on them the bottom part (witch is like a container view) changes content. And these two (top uiview and bottom container view) are part of UIScrollView. But this way I can't get information back in time on the size about the tableview's size that I want to display in the bottom part in order to modify the UIScrollView's size. And I have a feeling this is a flawed way to do it.
I would really appreciate any ideas oh how to implement this king of interaction. Thank you.
I believe it's a headerView on a UITableView or a UICollectionView, depending on which view mode you have selected. When you tap one of the buttons it changes out the UITableView to a UICollectionView or vice versa.
You want to keep track of the current contentOffset for whichever is being displayed (UICollectionView and UITableView are both subclasses of UIScrollView so you will be able to get this from both) and then set the contentOffset on the view you're switching to.
Setup an ivar for the UIView header subclass so you can easily re-use it.
This is what I have. My problem is that I'm mot getting back in useful time the tableview's frame height from the tableview controller to the UserProfileViewController in order to change the latter's scrollview size. I also feel that I'm somehow doing this backwards so any suggestions are more than welcome.
This view has two parts: an upper part and a lower part. The parent view is a scroll view. What I wanted to achieve with this is having a sort of tab bar in the upper part that will controll waht will appear in the lower part.
The upper part has a flip animation when the upper left button is pressed to reveal another view.
The way this is achieved is by having 2 views: a dummy view and the back view. The dummy view has the front view as a child. The front view is the one that containes all the buttons.
The code for this animation is achieved in this way:
- (IBAction)infoButtonPressed:(id)sender
{
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:1.0];
[UIView setAnimationTransition:UIViewAnimationTransitionFlipFromRight forView:self.hoverView cache:YES];
if ([self.headerView superview]) {
[self.headerView removeFromSuperview];
[self.hoverView addSubview:self.backOfHeaderView];
[self.infoButton removeFromSuperview];
[self.backOfHeaderView addSubview:self.infoButton];
} else {
[self.backOfHeaderView removeFromSuperview];
[self.hoverView addSubview:self.headerView];
[self.infoButton removeFromSuperview];
[self.headerView addSubview:self.infoButton];
}
[UIView commitAnimations];
}
The lower part is made out of a container view that acts as a place holder.
When a button is pressed a different view controller is displayed in the container view.
Each view controller has a container view of it's own. The specific view of that view controller (tableview) is added to it's container view when the controller is loaded. It also makes sure that if the tableview is already added to the container view it will be removed. All this is done in each specific view controller.
In the view controller of the User Profile view there is an instance of the container view and one of a UIViewController that also acts as a placeholder(named currentViewController from now on). When a specific button is pressed it checks if the an instance of the view controller that we want to display already exists. If not it will make one and will set it's tableview's frame to the bounds of the container view. After that it will remove the currentViewController's view from the superview and the currentViewController itself from the parent viewcontroller to make sure that if there is something assigned to these they will not be there. Then it goes and assigns the desired viewcontroller to the currentViewController. It also assigns the desired viewcontroller's containerView instance to the containerview in the parent viewcontroller (the User Profile viewcontroller). At the end it will add the desired viewcontroller as a child to the main viewcontroller (the User Profile viewcontroller) and desired viewcontroller's view to the containerView of the main viewcontroller.
This is the code for one of the buttons:
//Check if there is an instance of the viewcontroller we want to display. If not make one and set it's tableview frame to the container's view bounds
if(!_userWallViewController) {
self.userWallViewController = [[WallViewController alloc] init];
// self.userWallViewController.activityFeedTableView.frame = self.containerView.bounds;
}
[self.userWallViewController.containerView addSubview:self.userWallViewController.activityFeedTableView];
//If the currentviewcontroller adn it's view are already added to the hierarchy remove them
[self.currentViewController.view removeFromSuperview];
[self.currentViewController removeFromParentViewController];
//Add the desired viewcontroller to the currentviewcontroller
self.currentViewController = self.userWallViewController;
//Pass the data needed for the desired viewcontroller to it's instances
self.userWallViewController.searchURLString = [NSString stringWithFormat:#"event/user/%#/", self.userID];
self.userWallViewController.sendCommentURLString = [NSString stringWithFormat:#"event/message/%#", self.userID];
self.userWallViewController.totalCellHeight = ^(float totalCellHeight){
self.userWallViewController.numberOfCells = ^(float numberOfCells){
NSLog(#"The total number of cells: %f", numberOfCells);
NSLog(#"The total cell height: %f", totalCellHeight);
self.scrollView.contentSize = CGSizeMake(320.0, totalCellHeight + 172.0 + 33.0);
CGRect newFrame = self.userWallViewController.containerView.frame;
newFrame.size.height = totalCellHeight + 33.0;
self.userWallViewController.containerView.frame = newFrame;
NSLog(#"Container view: %f", self.containerView.frame.size.height);
NSLog(#"Scroll view: %f",self.scrollView.contentSize.height );
};
};
//Add this containerview to the desired viewcontroller's containerView
self.userWallViewController.containerView = self.containerView;
//Add the needed viewcontroller and view to the parent viewcontroller and the containerview
[self addChildViewController:self.userWallViewController];
[self.containerView addSubview:self.userWallViewController.view];
[self performSelector:#selector(changeScrollView) withObject:self afterDelay:0.5];
//CLEAN UP THE CONTAINER VIEW BY REMOVING THE PREVIOUS ADDED TABLE VIEWS
[self.userFansViewController.userSimpleTableView removeFromSuperview];
[self.fanOfViewController.userSimpleTableView removeFromSuperview];
[self.userPublishedMovellaListViewController.gridView removeFromSuperview];
[self.userPublishedMovellaListViewController removeFromParentViewController];
self.userPublishedMovellaListViewController = nil;
}
I know this answer is over a year late, but I wanted to state my hypothesis on it...just incase it might help someone else later. Im implementing a similar view and came to this conclusion. Anyone is welcomed to correct me if I'm wrong.
I think that perhaps the top view is a header view and the two options that seem like a collection view and a table view are both collection views.
Because the layout of collection views can be fine tuned to the most minute details, I think the view that looks like a table view is just a really specifically designed collection view. And when switching between the views, the collection view's data and properties are being swapped and reloaded.
I have a problem with my table view. When dismissing a modal view controller presented on top of it, it always scrolling to the top . I have tried observing the changes to contentOffset using KVO, but the one that messes my view goes behind it.
From the UITableViewController, when user finishes his task in the modal dialog, self.tableView.contentOffset is , I call:
[self dismissModalViewControllerAnimated:YES]
Subsequently, when the viewWillAppear:(BOOL)animated is called, the self.tableView.contentOffset is already set to 0,0.
Is this supposed to be happening? I am able to work around the issue by remembering the scroll position before presenting the modal view and restore it back in viewWillAppear after dismissing the modal view. But it seems wrong. Am I missing something?
I have found similar problem described in Dismiss modal view changes underlying UIScrollView.
It looks like this is default behavior of UITableViewController. I tested it in very simple app and It worked exactly as you said. If you don't like it, use UIViewController instead.
Here is how I work around this problem, so that the table view maintains the original scroll position. In my subclass of UITableViewController I have added:
#property (assign) CGPoint lastScrollPosition;
Then in the implementation, I have overridden the following:
- (void)viewWillAppear:(BOOL)animated
{
self.tableView.contentOffset = self.lastScrollPosition;
}
- (void)dismissModalViewControllerAnimated:(BOOL)animated
{
self.lastScrollPosition = self.tableView.contentOffset;
[super dismissModalViewControllerAnimated:animated];
}
If you want your table to initially appear scrolled to non-zero position, as I did, don't forget to initialize the lastScrollPosition in your viewDidLoad.