I am sure this question has been answered in numerous places but I have no idea what keyword to search for to answer this question. If anyone can link me to the answer that'd be great.
I'm not sure how to control which UIImageViews (which are all subviewed to the same view) cover the others visually. In other words, if I subview a UIImageView to the same location as another UIImageView, the 2nd one that was added is always covering the first one. I'm not sure how to do this either in the UI editor or in code. So far I've been adding them in the order I want them to show up but I can't always do that. Especially if I need to set UIImageView that's an IBOutlet and I need it to be on top of all the UIImageViews that I add programmatically.
Can someone show me how to do this programmatically and possibly how to set values in the UI editor? Thanks.
UIView has several APIs to deal with these issues:
When adding a subview:
insertSubview:aboveSubview:
insertSubview:atIndex:
insertSubview:belowSubview:
Moving subviews around in their z-ordering:
bringSubviewToFront:
sendSubviewToBack:
exchangeSubviewAtIndex:withSubviewAtIndex:
More details on all of these can be found in the UIView documentation (of which UIImageView is a subclass.)
This is done at the UIView layer and is not specific to UIImageViews.
Views can be programmatically 'relayered' with the following UIView methods:
– addSubview:
– bringSubviewToFront:
– sendSubviewToBack:
– removeFromSuperview
– insertSubview:atIndex:
– insertSubview:aboveSubview:
– insertSubview:belowSubview:
– exchangeSubviewAtIndex:withSubviewAtIndex:
To do it to the XIB in Interface Builder, reorder the views listed on this view, bottom row is the frontmost object:
Related
This one is really bugging me! What is the name of this UIView subclass? I'm not talking about the compass itself, but the two dots at the bottom of the view. I know it's not a private API because I have seen it before. Or am I confused and this is not a UIView at all, but a UIViewController. Which UIView / UIViewController subclass is shown here. It acts like a UIScrollView, but has distinct pages, and has the dots at the bottom of the screen that show the users relative progress through the pages. I have checked this link about UIView subclasses, but became lost after about the 45th one. http://www.themusingsofalostprogrammer.com/2010/09/list-of-every-uiview-subclass.html
(source: tqn.com)
Thankyou for your time.
It is a UIPageControl. It corresponds (or is supposed to correspond) to the number of "pages" the user can scroll to, sideways. Normally, it indicates how many pages there are, and which one we are on, plus it typically provides a way to scroll sideways (by tapping to its left or right).
If I may add to what matt said...
To use a UIPageControl effectively, you also need a UIScrollView that contains the content. An update to the page control should result in a change to the contentOffset of the scrollView as shown in the code below. UIScrollView has a pagingEnabled property that should be set to YES to complete the illusion of paging.
- (IBAction)pageValueChanged:(UIPageControl *)sender
{
// self.pagedView is an IBOutlet to a UIScrollView
[self.pagedView setContentOffset:CGPointMake( sender.currentPage * 320, 0 ) animated:YES];
}
I have a requirement in my app to display a bunch of information that includes both text and images. It will be quite long, so it will need to be scrollable to access all the content.
I know that I can achive this by programmatically adding different UILabels, UIImages etc to a UIScrollView. But this is a proof of concept, so I'm looking for something a little quicker than having to work out all the positioning and code required. The information is static anyway, and does not need to interact with code.
Is there a way to do this using the interface builder (storyboard or xib is fine)?
you definitely can do that if you simply want a quick interface
1.> you might need to know how long is your scroll view, for example in my case, i set it to 1568
2.> Then i drag all the controls that will fit for the first 568 pixel view onto the scroll view and position them.
3.> Then change the Y value for that scroll view to something like - 500, so you can see the rest of the scroll view, and put everything you need there.
4.> After you have all your controls, and remember to set the frame back to 0,0,320,568
5.> last step, in your code, set SCROLLVIEW.contentSize = CGSizeMake(320, 1568);
I would still suggestion don't hard code all those values, but if you are looking for a quick way to do your interface, hope that gives you some ideas.
Just start a new project with a single view, it will come with a xib or storyboard for its single ViewController.
Create a UIView by dragging it into the workspace and place as many Labels, Images and UI Elements as you want.
Open the xib / storyboard and drag a UIScrollView in as your root VC's root view. Drag the view containing your layout into the scrollview, making it the scrollviews only subview.
Done (almost)!
If you launch your app at this point, you'll notice you can't scroll. That is because the scrollview is "too stupid" to adjust the size of its contentSize property on its own.
You'll need some code here, but it is only a tiny snippet and you won't need to touch it again:
Create a new Category on UIScrollView.
In your category's implementation, do:
#implementation UIScrollView (MyHandyCategory)
-(void)awakeFromNib {
NSArray *subViews = [self subviews];
UIView *contentView = [subViews objectAtIndex:0];
[self setContentSize:contentView.frame.size];
}
#end
Done (for real this time)! This will check the size of the view your scrollview contains and ajust the contentSize after it has been initialized. You can change the size of your content view as you like, no need to play around with hardcoded values or even Interface Builder values!
If it’s just proof of concept I’d have a WebView and a local HTML page you load. Easy-peasy.
I would suggest UICollectionView. It's fairly straightforward. There's a good tutorial here:
http://www.raywenderlich.com/22324/beginning-uicollectionview-in-ios-6-part-12
I have a UIView which contains, let's say, 7 objects (UILabel). The size is fixed.
In some case, I must hide some of the objects. I do it with setHidden:YES.
The problem is that the appearance of the view is not very appealing, because the position of the objects is fixed. It could be better if the objects can freely move up and down when space is available...
I found a solution, I am not 100% comfortable with. The technique use a for loop over all the objects/view we want to slide up/down. The solution is here
I build category to update constraints easily:
To hide uiview, just do it:
//Hide View
[myView1 setConstraintConstant:0 forAttribute:NSLayoutAttributeHeight];
Answer here:
Hide autolayout UIView : How to get existing NSLayoutConstraint to update this one
I wrote a little UIView subclass to show a progress HUD. That HUD view works perfect but I faced a little problem in the last days.
In my application I'm presenting a UIViewController in a custom way. When the user selects a row in a tableView I'm creating an instance of my second viewController, move it to the current VC, set it's view's height to zero, add it as subview of the curren VC's view (at the position of the selected cell) and animate the height back to original.
The behaviour looks pretty cool and works great.
But when the second view is added as subview, I'm adding a HUD to this view. When the second view is resizing to the original height, the HUD sticks to the top of the view and is just a few pixels high:
I played around a bit with NSLayoutConstraints... But I didn't get it working until now...
Has someone a good idea on that one? Or does anybody know good and well explained resources on these constraints?
The HUD is actually a background view with the little window as subview. All other elements (the progress view, labels and so on) are subviews of the little window.
In terms of good resources, I definitely recommend WWDC2012's 3 videos: Introduction to Auto Layouts for OSX/iOS, Auto Layout by Example, and Best Practises for Mastering Auto Layout. These have some tips for looking at ambiguity in the layout and dealing with conflicts
Another great reference is Erica Sadun's iOS6 recipe book.
Re your problem. I'm assuming that you're not seeing an error message and you're laying out the progress HUD entirely in the XIB. If so, it sounds like you have two constraints that aren't behaving as you'd like from the xib - the height from the top of the superView and the height of the HUD
Firstly, create an outlet for the constraints to the .h file
#property (strong) IBOutlet NSLayoutConstraint *HUDSuperViewToHUDConstraint;
#property (strong) IBOutlet NSLayoutConstraint *HUDHeight;
Next, in the method in which you open the new viewController with the HUD remove the constraints so that there is no conflict when you first show the new view
[HUDSuperView removeConstraint:self.HUDSuperViewToHUDViewConstraint];
[HUDSuperView removeConstraint:self.HUDHeight];
After you've called [HUDSuperView layoutIfNeeded] for the first time, in the animation or wherever, add the constraints and call layoutIfNeeded again
[HUDSuperView addConstraint:self.HUDSuperViewToHUDViewConstraint];
[HUDSuperView addConstraint:self.HUDHeight];
[HUDSuperView layoutIfNeeded];
If you call these within an animateWithDuration it may even animate the appearance...cheesey
Hope this helps - it's probably more of a step toward the solution rather than the solution itself. Recommend minutes 17 and 53 in the AutoLayout by Example video too.
Steve
Im trying to create a secondary view to my main view. This subview needs to be of small height and it needs to fit another big UIView with a label in it.
Problem is that when I'm using UIView addSubview, the third UIView will be shown out of bounds of secondary UIView.
For ease of understanding my situation, I have created those Subviews using Interface builder with the photo and the result on simulator with the photo.
Any help would be much appreciated.
Thanks
Interface Builder
http://postimage.org/image/ofi3m05v3/
Simulator
http://postimage.org/image/x2qps3w2f/
You need to activate the clip to bounds property of some of those views.
fooView.clipsToBounds=YES;
That should solve your problem. Just set the appropriate views to clip to their bounds.