I'm working on an app that can display a graph with some data, one every day. I'll call this "dayGraph".
I'd like to build an interface similar to the iPhone home screen, aka pageControl, with one dayGraph per page. (but i don't need the small dots!)
I tried with the standard pageControl example from Apple, and it's working, but only with a small number of pages. I need to display even 100 possible dayGraph, if the user wants, but the pageControl is going crazy when the page number exceed 50.
I know that the photo app is doing a similar thing, and it can work with many photos.
My question is: How can i do that? Is there any "Apple way" of doing it, or i should begin to make my own method for swapping the dayGraphs?
Thank you very much!
If your goal is to enable swipe-based paging, the view you want to use is a UIScrollView. Set its pagingEnabled property to YES. Then add each graph as a subview of your UIScrollView, setting the frame of each graph to position each one on its own page extending beyond the bounds of your UIScrollView to the right. Finally, update the contentSize property of your UIScrollView to encompass all of your pages.
Now the user can swipe left and right to flip between the pages of your scroll view.
Note: If you add 50+ subviews to your scrollview, it's likely that you'll run into memory problems. To avoid this, you'll probably want just keep subviews loaded for the current page, plus the adjacent pages to the right and left. Set a delegate on your UIScrollView to an object that implements scrollViewDidEndDecelerating:. In that method, remove any subviews that aren't on the current or adjacent pages, and make sure each adjacent page has its subview loaded. That way you'll never have more than 3 pages of content in memory at one time.
Related
I want to be able to dynamically populate UIScrollView. Like how it is done for row views in UITableView. I have a class that takes in some parameters and creates the respective view when it scrolls. Currently I have 8 views.
These 8 views have different background image, image and label according to the page number it is currently in. However the basic skeleton for this view is the same. What i am doing right now is in ViewDidLoad I am creating 8 views and add them as subviews and scroll over.
I don't want to do this. I want to create three views and the rest i want to populate when the user scrolls a page and then a page etc. How do i do this? ANy pointers/tutorial?
First of all you calculate the ContentSize for the scrollview (when you want to use the iPad in landscapemode with 8 pages then the width should be 1024*8 = 8192px and the height 768px).
Then you should implement the UIScrollView Delegate method:
scrollViewDidEndDecelerating:
In this Method you check on which page you currently are with the contentOffset property of the scrollview and start updating your left and right hidden views..
Hope this helps you a bit.
Check the two most recent WWDC videos for two excellent sessions regarding expert use of UIScrollViews. Additionally you can review a brief tutorial here, written by the well known cocoa expert, Matt Gallagher.
I have an application with several (8) different Views in a UIScrollView. They are circling so that you get to the first when you try to get "behind" the last and vice versa.
My problem is how to create a titlebar like in the Stream of the Google+ App. There the titles are circling with the pages and show the current visible page.
How could I realize that? Would it be possible to create a general class to use such a view in many different apps?
I've already tried to solve this problem with some different approaches, but they all didn't work (well). I can display labels above my scrollView and move them, but how far and with which text seems to be difficult for me.
So now I'm looking forward to your answers ;D
Try using two UIScrollView, one for the content and one for the headers. The header UIScrollView would be controlled by your view controller that is also a delegate of the main UIScrollView. Update the header UIScrollView whenever you receive a -scrollViewDidScroll: message from the main UIScrollView.
I think you need to add label in customview and then add customviews in scrollView, you will get events for individual view, so you can rotate that view according to angle and keep label at fix place...
I have a page enabled scrollview on an iPad. On the first page, I have a child scrollview that scrolls horizontally through image buttons. The buttons scroll the outer scroll view to the correct page. Its basically like a table of contents that jumps to the correct page.
My end goal is to be able to categorize the buttons seen in the child scroll view. So there would be a segmented control that changes what buttons you can see. So maybe one category would be ALL, and another category would be A-M, and another would be N-Z for example.
My question is, should I use a uiscrollview or a uitableview?
Right now I use a scrollview and it is really easy to get the buttons in. I could implement the different categories kind of gimmicky by having all of the buttons in the scrollview and then just showing or hiding the buttons accordingly. I feel that it'd be bad memory usage though.
For a uiscrollview i was looking at using EasyTableView, butI'm not 100% sure if this is compatible with what i want to do or if it'd even be better.
Any ideas for what the best way to implement this is? Specifically, I'm not sure of the best way to change the buttons when I change categories.
Thanks!
Use a tableview when you are dealing with data that is best expressed as sections and rows.
I think for your situation I'd have a UIView subclass that can display the images you need for a given category. Stick that on the outer scrollview as needed. You can keep memory low by only keeping the currently visible view and the ones on either side on the scrollview. When you scroll to a new location you can recreate the view needed for that page, and the ones surrounding it. Then you release the ones that are far away and let the system reclaim their memory if needed.
I'm working on a app that has a paging UIScrollView that contains three scrollViews as subviews which display images that you can pinch and zoom on. The code came from Apple's "PhotoScroller" sample code but I've stripped out the tiling functionality because I'm trying to master the basics first.
I can zoom in on my different images and page through them, which is great. When I leave an image that has been zoomed in to go to the next "page" of the pagingScrollView I want it to be restored to it's original zoom size, right now it stays at the zoom level that I left it at.
I imagine I need to write some code that tells the zoomed UIScrollView to go back to the appropriate zoom scale when I get to the next page. My question is how do I do that?
So far I've been working with UIScrollView's Delegate method "scrollViewDidScroll" and and the "contentOffset" property. Another thought is somehow getting a notification that the pagingScrollView has moved to the next "page."
Any ideas?
If you're interested in knowing when the scroll view has stopped (e.g. the user has let go and the scroll view has snapped into position on a new page) you can use scrollViewDidEndDecelerating:. However, the user may scroll several pages before allowing the scroller to fully stop, so the last page the user stopped on may not be the immediately preceding or immediately following page. You can keep a pointer to the current page and each time the user stops on a page restore the previously current page to the default zoom level before updating the current page pointer.
I have been facing the same nested UIScrollView problem for long time.I tried some open source codes like Scrolling madness ,three-20 and others but all fails finaly.I am trying to make a photo Viewer application same as iPhone.For that I have created the structure like this:-
1)one View controller.
2)on view of view controller one UIScrollView (i.e inner/parent scroll view) as a child.
3)on inner/parent scroll view number of child scroll views(i.e. outer/child scroll views) ,each represents one page of photos application.
4)On each scroll view one image View on which i am displaying my image.
So what I want is when user scrolls the outer scroll view it should scroll horizontally with all the child views so I will get the look and feel of paging in photos application.Also when user is on one specific image(i.e. child/outer scroll view) he should be able to zoom in/out,swipes and perform single/double tapping.I was able to make it work in sdk 2.1,but it dosnt work since sdk 3.0.Please tell me the idea behind your project.Means which scroll view you are subclassing ,in which view to detect touches.How this completely child - parent relation should be.
If possible provide any sample code also.
There is a WWDC session from 2010 that deals with this very issue.
Here's the short of it:
You need a single scroll view that is paginated and scrolls horizontally. Each "page" of that scroll view is another scroll view containing a photo.
First, it looks like you want to subclass UIScrollView? Every interaction method you need is provided for you in either the delegate callbacks or the touch methods. (Many of Apple's more advanced classes, such as UIScrollView, react poorly to subclassing.)
Second, it sounds like you have a first responder problem. IOW, your innermost scrollview isn't getting the first crack at the touch events.
Andrew
I also struggled with this for a long time trying samples you mentioned. I could finally figure it out with the samples provided by apple (iphone dev center).
http://developer.apple.com/iphone/library/samplecode/Scrolling/Introduction/Intro.html
http://developer.apple.com/iphone/library/samplecode/ScrollViewSuite/Introduction/Intro.html
The first one is pretty basic and probably what u already have. The second one is all about zooming, etc. Just study these and the samples you already have, I think you will be able to figure it out. On specific topics just come back here search for answers or post another question.
EDIT: I forgot this one check out these examples by Andrey Tarantsov hosted on github. This is what you want... http://github.com/andreyvit/ScrollingMadness