There is a UIScrollView and I'd like to programmatically put subviews in it. It's ok, but how can I lay automatically the subviews next to each other?
Thanks in advance!
You can't. The view hierarchy in UIKit--like the view hierarchy in most UI frameworks--uses explicit layout.
Your comment asks about HTML-like floating; the box model stuff that HTML/CSS uses was designed to serve a very different goal (flowing document layout) than what UIKit is for, and so there's no real analogy in the framework.
UIViews do support automatic re-layout on resize/frame change of the parent view (you can say whether a subview should resize, how, and where it should be "pinned" to), through the autoresizing mask property, but I don't think that's what you're asking for.
You could, if you were inclined, build a set of methods, perhaps as a category on UIView, that let you add subviews that had their frame origins adjusted automatically based on existing subviews.
The position of the subviews is dictated by their frame property. So you need to set their frames such that they line up next to each other.
If they are all the same size you can do with some simple math and CGRectMake(). If they will have different sizes, you can use CGRectDivide() to break a large rect into smaller rects. CGRectInset() is also useful, in case you want some padding between them.
Related
So, i am new to xcode and iOS7 and i'm trying to create simple container with two elements inside.
I prefer to make it 100% programmatically. (no IB)
I want to create container with two elements Image and Label.
I want to achieve variable width depends on the text element inside.
Here is example:
Based on user action i want to change text on the fly. Let's assume longer text, and main container have to change width too.
And now the question is: What is best approach to to that?
UIView with subviews or something else i'm just expecting direction.
Code examples with be gratefully appreciated.
Thank you in advance.
What you have described is exactly what a UIButton does automatically: it is a container containing an image and a title (text) and it resizes itself automatically when the text changes.
Let us assume, however, that you want to do this yourself. That is, let's say you want a UIView ("container") containing two other UIViews (subviews). Then we need to discuss this requirement:
Based on user action i want to change text on the fly. Let's assume longer text, and main container have to change width too.
This is not going to happen automatically. You can use constraints (auto layout) to describe the size / position of the subviews in relation to the superview, but it works the other way: the superview changes, and the subviews obey. So you will have to change the superview size manually after you change the text.
You can still use auto layout to help you. Let's say the text is in a UILabel. Well, a UILabel wants to change width automatically when the text changes. So far so good. But you must still change the container view width yourself. You can call systemLayoutSizeFittingSize: to learn what the size of the container should be, using constraints, working from the inside out; but then you will have to change its size yourself to that size.
(You can easily create the view, the subviews, and the auto layout constraints in code.)
If you don't want to use autolayout, then you will just calculate the sizes and positions of everything when the text changes and adjust it all yourself (in code). You can learn the size the label needs to be, to fit its text, by calling sizeThatFits: (or sizeToFit which will actually resize it correctly).
When I try to place objects using the Interface Builder in Xcode into a NSScrollView, they appear fine until runtime in the application, where they do not appear at all for some reason. I want it to be so that I can place multiple buttons and labels in the view, and have the user be able to scroll down to see more.
Am I not meant to use NSScrollView for this purpose?
Is there another way to go about implementing it I am not aware of?
You need to check the where you added the UI objects.
You need to consider these :
Is your autolayout enabled?
Did you flipped the view?
Resizing mask is working good as per your requirement.
Am I not meant to use NSScrollView for this purpose?
No, you picked the correct control for the requirement. NSScrollView is indeed for same kind of use.
I have a window whose size I need to change when the user clicks on it. I am using [self setFrame:windowFrame display:YES animate:YES] to accomplish this.
Even though the window successfully changes size (I increase its height), it moves the contents of the window up with it. How do I prevent this from happening? I want the contents to remain in place.
I am on OSX Mountain Lion developing an app for OSX using Objective-C and Cocoa.
EDIT: Constraints and/or Springs and Struts will not work as I need to move the contents around after the window is resized.
Constraints and/or Springs and Struts will not work as I need to move the contents around after the window is resized.
In that case, you should use NSViewAnimation.
A single view animation can actually perform multiple animations to multiple views, and you can even do one to a window, despite the class's name and the fact that windows aren't views in Cocoa.
You create a view animation with initWithViewAnimations:, which takes an array of dictionaries. Each dictionary identifies the target (NSViewAnimationTargetKey) and what to do to it: Either change the target's frame (NSViewAnimationStartFrameKey and NSViewAnimationEndFrameKey) or fade the target in or out (NSViewAnimationEffectKey). For your case, you'll be changing the targets' frames.
When the user does the thing that causes the resize of the window, you'll need to compute the desired overall size of the window (taking care to adjust its frame's position so it doesn't grow off the screen), as well as the new frames—both positions and sizes—of your views. Everything that will move and/or change size, create a dictionary for it and throw it into the array. Then create the view animation.
An NSViewAnimation is a kind of NSAnimation, which provides all the methods for starting and stopping the animation, monitoring its progress, hooking into it, and chaining multiple NSAnimations together. If nothing else, you'll need to start the animation.
If you are using the Interface Builder to build these views, then I believe one approach is to set the "struts and springs." These are available under the "size inspector" and are the red arrows and bars above the "autosizing" label. Play around with these to get the effect that you want, but the general idea is that the arrows control how the size of the view adjusts to changes in the size of the parent view, and the bars control the relationship of the edges of the view to the edges of the parent view as the size changes.
In constraint-based layout, set the views around the edge of your window to be a fixed distance from their superview's edge.
Xcode will infer a lot of resizability from that; if anything still isn't resizing properly, adjust its constraints so that its width and/or height is no longer constant.
The easiest way is to move your views until blue lines show up in the editor. Each blue line corresponds to a rule in the HIG about how things should be lain out, and if you drop the view there, Xcode will create constraints matching those guidelines. For example, if you set a view 20 points from the right edge of its superview, you'll get a blue line for that, and if you drop the view there, you'll create a constraint that the view must remain that distance from that edge.
The superview isn't the only view with which you can create HIG-based constraints. You can also create guideline constraints between sibling views. For example, if you put a button next to another button at the appropriate distance, you'll get a blue line across that distance, and if you drop it, you'll create a constraint that those two buttons must remain that distance from each other.
If you want to do something really custom, the three buttons in the lower-right corner of the nib editor will let you create any constraint you want. What you have selected determines what constraints you can create; the nib editor's outline view will help you make sure you have the selection you want.
You are going to have to iterate through all of your subviews and change their frame positions based on the delta of your window frame.
so if you expand your window frame by 20 in all directions, all your subviews are going to have to increase their frame positions by (20,20) to offset the windows movement.
So I wrote a custom subclass of UIScrollView that basically displays rectangles in a 2-column grid, but while the width of each is fixed to half the width of the iPhone/iPad screen, the height varies, depending on the dimensions of the picture within it. All's well and good now, but I can imagine that after adding lots of these subviews to my UIScrollView subclass, things are going to lag. So I'm trying to implement lazy loading analogous to UITableView's dequeueing reusable cell method.
I've looked at a handful of other questions on SO, but they all involve paging based on full-screen photos, including Apple's WWDDC PhotoScroller example.
Anyone have any insight? Thanks.
You basically want to keep track of the views that are scrolled off screen and reuse them.
You might want to check out ATArrayView. It implements a recycling mechanism like what the UITableView has except with a UIScrollView with an arbitrary number of rows and columns?
I've used it as the basis for my own image scrolling code and is pretty good. It's delegate methods follow the spirit of UITableView data source and delegate protocols.
Good luck
Tim
I'm trying to add a way for my app to display data in an easily comprehensible form. I tried doing this with graphs, but found it to be a bit awkward, so I'm off to find a better solution.
Here's a problem:
I want to show up to 30 days of data, with user reported events plotted against a timeline.
The events should align vertically, to visually provide a reference of when certain events cluster together.
To solve the problem, I thought of using a UITableView with a background which has a scale, and superimpose upon that background a set of "pins", indicating user events. As the table is scrolled, the events would align one under another, providing a good indication historic event development:
I know that this is possible to be done with a UIScrollView, where I can just position a series of rulers and add events as pins. In order to do this efficiently, I'll have to use Tiling, a technique that I don't have much experience with.
I'm interested in knowing if this is possible with a UITableView, where caching and tiling is already done for me.
I tried adding UIImageViews to a tableViewCell.backgroundview , but this does not produce the desired results. I'd like to be able to dynamically add any number of subviews to the table cell. I can do this by adding a certain pre-determined number of images to an .xib and then trying to reposition them, but this does not seem like an ideal solution.
Is what I'm trying to do possible with UITableView, or should I abandon these efforts and look at UIScrollView with tiling?
Thank you!
yes this should be possible. Add the ruler image to the background of the UITableViewCell.
Then create a subclass of UITableViewCell that takes an array of pins objects that it will place within its view. The pin objects would contain the pin image and a horizontal location on the scale. Then in the tableView dataSource method cellForRowAtIndexPath method you set the tableViewCell's pin array to the correct array (or NSSet) of pins.
To make it even more lightweight, you could draw the pins yourself in the UITableViewCell subclasses drawRect method. Then you could just pass the locations of the pins.
Good luck