Reordering UIView subviews - ios

In my app I am trying bring a subview to front, then put it back to its original layer position later. The code should be pretty simple:
To bring the subview to front (inside my custom UIView class):
[self.superview bringSubviewToFront:self];
Easy. I store the original z position in an instance variable called, you guessed it, zPosition. So, the line before -bringSubviewToFront: is:
zPosition = [self.superview.subviews indexOfObject:self];
So, all of the code I use to bring my subview to front is:
zPosition = [self.superview.subviews indexOfObject:self];
[self.superview bringSubviewToFront:self];
This works as it should. The problem is when I try to put the subview back where it was. I'm simply doing this:
[self.superview exchangeSubviewAtIndex:zPosition withSubviewAtIndex:
[self.superview.subviews indexOfObject:self]];
Using this code, if I have two subviews, this is what happens:
Let's say I have view A and view B. View A is above view B. I tap view B, it comes to the front. I tap view B again (it should go back to where it was), and nothing happens, so it's now on view A. If I now tap view A, it comes to the front, but when I tap it again (so it should go back to its original z position: below view B), all of its sibling views disappear!
Does anyone see what could be causing this problem?

There is no need to remove from superview:
[self.superview insertSubview:self atIndex:zPosition];

exchangeSubviewAtIndex may well put the view back in the right place, but it will also swap another view on top, which wont be what you started with. You might need to do something like this instead of exchangeSubviewAtIndex :
[self retain];
UIView *superview = self.superview;
[self removeFromSuperview];
[superview insertSubview:self atIndex:zPosition];
[self release];

[ Swift solution ]
As other guys said, there is no need to remove and re-add your subviews.
Instead I've found that the most convenient method is:
superView.insertSubview(subviewYouWantToReorder, aboveSubview: subviewWhichShouldBeBelow)

This question and answers were very helpful to me.
I had the requirement to place an overlay between the viewstack which views are above and below the overlay, and i wanted to keep it dynamic.
That is, a view can tell it is hidden or not.
I used the following algorithm to reorder the views.
Thanks to AW101 below for the "No need to remove view".
Here is my algorithm:
- (void) insertOverlay {
// Remember above- and belowcounter
int belowpos = 0, abovepos = 0;
// Controller mainview
UIView *mainview = [self currentMainView];
// Iterate all direct mainview subviews
for (UIView* view in mainview.subviews) {
if ([self isAboveOverlay:view]) {
// Re-insert as aboveview
[mainview insertSubview:view atIndex:belowpos + (abovepos++)];
}
else {
// Re-insert as belowview
[mainview insertSubview:view atIndex:belowpos++];
}
}
// Put overlay in between above and below.
[mainview insertSubview:_overlay atIndex:belowpos];
}

Related

How to remove view on touch?

I have a button hooked up in the storyboard to a method onButtonPress. In that method I call [pressedButton removeFromSuperview] but the view is not removed. I have even tried [_scrollView setNeedsDisplay]; and [_scrollView setNeedsLayout]; with no luck. I am assuming this is a restriction on being able to remove the button I have pressed. Is there a way I can signal to the view controller to call a method in the future to remove this button?
you can just hide it,
- (IBAction)celebritiesButtonPressed:(id)sender {
self.button.alpha = 0;
//[self.peopleButton removeFromSuperview]; //as you intend
}
Nevermind, actually. I was making a silly mistake.
The view I was pressing is part of a custom table I implemented to avoid the tableview in the scrollview. What I was doing was removing all the table cells from the table then re-adding them with the exception of the one that was clicked. Except right before I looped through the array which held the views and called [view removeFromSuperview], I removed the view I pressed from that array. Therefore, it was never calling that method.
So I was doing
[_taskViewCells removeObject:t];
for (id taskViewCell in _taskViewsCells) {
[taskViewCell removeFromSuperview];
// Remove all the task views
}
Pretty silly...

UIView inside an UIScrollView did not refresh itself despite call of method "setNeedDisplay"

I've got an UIScrollView with inside, some views loaded from a xib file.
The UIScrollView loads only three Views. The current, the left one and the right one.
For exemple, I have one view at the left and one view at the right of the current View. If I scroll to the right, the UIScrollView will delete the view to the left, scroll to the right to the new current View and load the new view to the right of the new current View.
In addition, I have a button outside the UIScrollView. When I click on it, it changes the background color of the current view displayed on the UIScrollView.
It works well but sometimes, I don't know why, when I click on the button to change the background color of the view is well changed, but the view is not refresh so the user can't see the change of background color.
The UIScrollView:
container = [[UIScrollView alloc] initWithFrame:frame];
[container setBackgroundColor:[UIColor clearColor]];
[container setCanCancelContentTouches:NO];
[container setClipsToBounds:NO];
[container setShowsHorizontalScrollIndicator:NO];
[container setPagingEnabled:YES];
The method call when I click on the button to change the background color of the current view
- (void)menuColor:(MenuPickerViewController *)controller didPickOption:(UIView *)button
{
// Get the object containing the data of the product linked with the view.
MyProduct *product = (MyProduct *)[MyProduct getProduct:[_slider getCurrentContentDisplayed]];
// Get the the superview of the button sender to have an access for the attributes of this button (color selected, ...)
ColorButtonMenu *colorView = (ColorButtonMenu *)[button superview];
// Get the current UIView displayed in the UIScrollView
MyView *myView = (MyView *)[self sliderGetViewWithID:[_slider getCurrentContentDisplayed] FromSlider:_slider];
// I check with debugger, the color is well setted
product.color = colorView.color;
// "border" is a view in my xib that I want change its background color.
IFPrint(#"myView.border backgorund color before: %#\n", myView.border.backgroundColor.description);
[myView.border setBackgroundColor:[Utilities colorFromHexString:colorView.color]];
[myView.border setNeedsDisplay];
IFPrint(#"myView.border backgorund color after: %#\n", myView.border.backgroundColor.description);
IFPrint(#"=== DEBUG ===\n");
IFPrint(#"isMainThread ? : %i\n", [NSThread isMainThread]); // Always return YES
IFPrint(#"myView: %#\n", myView); // Always return the address of a valid pointer
IFPrint(#"myView border: %#\n", myView.border); // Always return the address of a valid pointer
IFPrint(#"=============\n\n");
}
So, as you can see at the end of the method, I tried to call method setNeedsDisplay on the view loaded from a xib and the other view inside "border" but nothings work.
Moreover, my method is always called on the main thread.
Any suppositions ?
Thanks !
Edit:
Obviously, I have tested if the view return by sliderGetViewWithID is the correct view. All the attributes are well set. In my opinion it's truly a refresh problem.
are you sure the view you're trying to set background color for is actually visible? I guess it might be offscreen so you see nothing happening.
You might want to trap that event by finding the intersection between scrollview's bounds and myView's frame. if there's no intersection, that means myView is not actually visible.
so the code is:
BOOL intersects = CGRectIntersectsRect(scrollview.bounds, myView.frame);
if(intersects == NO)
{
NSLog(#"myView is offscreen");
}
Problem solved :
After setting the background color of the view. I remove the view from the UIScrollView and I re add it inside the UIScrollView. It's a bit tricky but it works good !
[myView removeFromSuperView];
[myScrollView addSubview:myView];

Can I add a subview inside a subview?

I have added a view inside ViewController using [self.view addSubview:newView]. newView is a UIView type object.
Inside newView I added added a few views using [self addSubview:polyg];.
Polygs also inherit from UIView. But they never get drawn. drawRect:(CGRect)rect is never called.
I'm new to iOS and have no idea what I'm doing wrong.
It probably has something to do with the fact that I did not use self.view when adding views to newView. I can't even use self.view inside newView.
how can I make this work?
edit:
When i create these polyg objects I'm using initWithFrame and sending newView's frame, like this: [[Polyg alloc] initWithFrame:self.frame];
Could this be the cause? Polyg is going to be a movable and resizable polygon, so I figured each should be able to draw on the entire screen.
edit:
I created a method inside newView called touchX:Y that is called from the viewController whenever I touch my finger on the screen. Inside I wrote this: NSLog(#"subview = %i", self.subviews.count);. Whenever I touch the screen I see this on the console: subview = 89 so I'm pretty sure the subviews were added to newView.
I tried adding this to the same touchX:Y method:
for (UIView* subview in self.subviews) {
[subview setNeedsDisplay];
}
But the subviews' drawRect is never called.
The most likely possibility is that newView is either completely off the screen or have a size of (0,0). Right before you add the ployg subviews, use the debugger to print out the frame of newView.

uitableview with header like instagram user profile

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.

ios display views and viewcontrollers on part of the screen

I have this bug that I'm struggling with for a few days now. I basically want to make a profile much like Instagram has.
When you click on one of the first two buttons in the upper "tab bar" the content is displayed in the lower part. The upper part of the screen stays the same. I have some UIViewControllers and some UITableViewController. I have like 5 buttons that are suppose to display the viewcontrollers. My problem is that I can display a tableviewcontroller but if I try to display the second and then go back to the first, for instance, it gets stuck to the last one I displayed. I hope this is clear enough. here is the code for displaying the viewcontroller.
- (IBAction)wallButtonPressed:(id)sender
{
if(!_userWallViewController) {
self.userWallViewController = [[WallViewController alloc] init];
self.userWallViewController.activityFeedTableView.bounds = self.containerView.bounds;
}
[self.currentViewController.view removeFromSuperview];
[self.currentViewController removeFromParentViewController];
self.currentViewController = self.userWallViewController;
self.userWallViewController.searchURLString = [NSString stringWithFormat:#"/event/user/%#", self.userID];
self.userWallViewController.containerView = self.containerView;
[self.containerView addSubview:self.userWallViewController.view];
[self addChildViewController:self.userWallViewController];
[self.userWallViewController.view setNeedsDisplay];
[self.userWallViewController viewWillAppear:YES];
}
containerView is an UIView that takes the whole lower part of the screen. currentViewController is a placeholder viewController and userWallViewController is a UITableViewController.
Any kind of help is much appreciate. This is a real bugging situation. Thanks
I was doing a stupid mistake that was hard to identify bu #Matt's suggestion helped.
[self.fanOfViewController.containerView addSubview:self.fanOfViewController.userSimpleTableView];
[self.currentViewController.view removeFromSuperview];
[self.currentViewController removeFromParentViewController];
self.fanOfViewController.containerView = self.containerView;
[self addChildViewController:self.fanOfViewController];
[self.containerView addSubview:self.fanOfViewController.view];
//CLEAN UP THE CONTAINER VIEW BY REMOVING THE PREVIOUS ADDED TABLE VIEWS
[self.userWallViewController.activityFeedTableView removeFromSuperview];
[self.userFansViewController.userSimpleTableView removeFromSuperview];
Each time I was adding a new tableView from it's view controller by pressing the corresponding button I was stacking it in the current's view container. When I was trying to remove the corresponding viewController from the hierarchy and then add it again the viewDidLoad method was not called (it was only called the first time). The was where I had my logic of removing the tableView.
Now I'm also adding it when the button is pressed and remove the other tableViews from the "stack". It may not be the very best way but I do plan to optimize it. I hope this is clear enough and helps anybody that comes across this problem.

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