What I do now:
I have a UITableView that displays results from a search query, when I touch a result in the TableView it loads a subview that displays details of that result. I can swipe across that subview to switch between results like next and previous. All it does is change out the displayed data but it uses the same view
What I want to do:
I want it to show an animation when swiping between results, similar to the photos app, however since the number of results can be quite large I seem to be having issues figuring out a simple way to switch views when swiping without loading a new view for each result to start with.
Does anyone know of an easy way to do this? Perhaps Apple has already made this easy and I am just unaware.
Thanks in advance.
Instead of instantiating a new view for each result, you could have an array with a few views (3 for example), and reuse them, kinda like the UITableView. When you swipe, you retrieve from your array a view that is not visible on the screen, replace its content, and display it. I guess at the end of your animation, one view will get out of the screen, so it will be available for reuse later on.
A second idea, which is a little more complex and tricky to code, is to use a UITableView as your subview, rotate it by 90 degrees (so it scrolls horizontally), and rotate all the views you put in its cells by -90 degrees. Then you'll benefit from the tableview's reuse mechanism.
Related
How can one enable horizontal and vertical scrolling at same time in a grid view?
If I have a 4x4 grid of thumbnail images, I want to implement swiping in both directions, left/right and top/bottom. Currently I am done with left and right swipe, but if I select the second cell and swipe towards the top, the 2nd row should be scrolled like a Rubik's cube.
Please share if any one have any idea.
It's been quite a while since your question but as I've been struggling with the same thing I'm gonna answer it for future reference...
Sadly I could not find a good solution anywhere so after a lot of hours of experimenting I came up with this: https://github.com/AlvinNutbeij/DWGridController
It's still a work in progress but very usable for your purpose I'd say!
How have you currently implemented what you have? Your mention of 'cell' makes it sound like you are using a UITableView. You won't manage to make one of those scroll in both directions, you'll need to work with a UIScrollView.
I suggest you watch "Designing apps with Scroll Views" from WWDC 2010, then "Advanced Scrollview Techniques" from WWDC 2011. That'll teach you about how you implement tiling and infinite scrolling.
Essentially what you want to do is implement some kind of view recycling yourself, that works like the way UITableView recycles its cells. When things are scrolled off one side of the scroll view, you remove the views for the things that just scrolled off screen and put them in a queue. When things scroll onto the screen, you pull views out of the queue (or create new ones if the queue is empty) and lay those views out in the correct place.
To do the infinite scrolling, you fake it: when your scroll view gets near its edge, you reposition everything inside it, you move the scroll view's content offset to where you've repositioned the views, and then you continue from there: it's all done at once so the user never notices.
The videos will explain these techniques better than I can sum up here: watch those as your first point of call.
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 need a "PickerView", that behaves like a normal UIPickerView, but only shows one row of data and has a custom design.
Something like you see in the image, showing the transition from subview 1 to subview 2. After the user lifts his finger and after the scrolling stops, only one subview will be shown:
IMAGE
So basically a scrollview which:
is endless in both, positive and negative directions by showing the same entries over and over
uses paging across several subviews
only shows one subview when not scrolling, and no more than two subviews when scrolling.
I can get a endless scrollview to work, but not with paging enabled. Paging will always limit my scrolling to the next subview.
So I'm thinking about creating my own UIView subclass which custom scrolling behaviour to mimic a UIPickerView. But before doing so, I wanted to get some opinions about the idea in general. Is creating a custom UIView the right way to go? Anyone has some experience with the expected performace? (There will be timers to handle the scrolling algorithm, which has to be recreated of course... :)
Another approach would be to subclass UIScrolView and implement the paging myself. I know when the scrollView starts decelerating
, so maybe there is a way to overwrite the contentOffset to have it scroll into the right position...?!
Any help is appreciated! Thanks!
Here is a great custom component, which seems to be able to do everything you need:
http://dev.doukasd.com/2011/04/infinite-scrolling-dial-control-for-ios/
It's not endless, but rather a modified UITableView with a huge number of cells.
Would it be feasible to just use a UIPickerView, but clipped to the middle row? You could turn off showsSelectionIndicator to remove the overlay and have the delegate pass back custom row views.
I am trying to create a excel like view in my app. To do that I wanted to achieve both horizontal n vertical swipes at the same time .i.e., if the vertical scroll would fill with rows and the horizontal with columns.. have no clue hw to begin with.
This is an interesting question. For sure I would say start with UIScrollView, and set the content size bigger than the screen size, exactly how big is up to you.
Next you'll want to make some kind of implementation that efficiently figures out what cells are on screen. If I were you I would do something similar to how UITableView is done, i.e. make a custom object that keeps track of what indexes should be on screen based on the offset of the scroll view.
Next you'll need this custom object to either directly or indirectly get the visible cells to display themselves on screen when they are visible, and remove them from the superview when they aren't. I'd also recommend reusing the views that are offscreen.
This is a moderately challenging thing you are trying to make, so be sure you are very organized and don't be scared to make a few new custom object to perform specific tasks.
Sample interface file:
#protocol doubleTableViewDelegate
-(NSInteger)heightForRow:(NSInteger)row;
-(NSInteger)widthForCol:(NSInteger)col;
-(NSInteger)numberOfRows:(NSInteger)rows;
-(NSInteger)numberOfCols:(NSInteger)cols;
-(UIView *)cellForRow:(NSInteger)row col:(NSInteger)col; //get the custom table view to store and dequeue these, i.e. store them in an NSSet when they go offscreen, and give them back when a certain function is called.
//There's probably a few functions missing here still.
#end
#interface doubleTableView: UIScrollView {
id<doubleTableViewDelegate> infoDelegate;
}
//your functions to show and remove cells as needed
#end
You'll need to work out the rest, but keep updating this page and I'll try to help out.
Good luck with this, let me know how it goes.
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