I'm trying to implement a scrollview where the cells auto zoom as they near a certain point in. As a cell nears the point it will start enlarging and as it moves away - it will shrink. I've been trying to find some tutorials around this but haven't had much luck. Any help would be greatly appreciated.
UICollectionView with a custom layout seems like the right way to do this. A UICollectionViewLayout gets to define the layout attributes for each item, including size and position. All you need to do is define a layout that positions the cells in a grid or however you like, but adjusts the size of the cells according to their distance from the point of interest.
You might find some sample code associated with the collection view talks from WWDC 2012 -- there were some interesting layouts shown there.
Related
I was wondering if there is a UICollectionView implementation around for displaying views (images) in a grid as shown below.
I started to build it with UITableView, but it is getting really complicated if an item doesn't fit in the same row with its predecessor/successor.
I came across this the other day, which is similar to what you want to do and may work out:
http://pierceboggan.com/post/56951869926/pinterest-style-uicollectionviews-in-xamarin-ios
It is a modification of a UICollectionView made to work like the waterfall layout that Pinterest uses.
The default UICollectionViewFlowLayout, in horizontal mode, can do a lot of what you need, but it can't do the yellow cells, spanning multiple rows.
You could subclass the flow layout, and modify the layout attributes for each cell to have the correct position and size.
I'm trying to build a custom, reusable UIScrollView that can be added to multiple views. The scroll view is going to be a weight picker. For the life of me, I can't find a decent example for how to implement this neatly or cleanly.
I would love for someone to point me to an existing library or tutorial that shows me how to do this. I've hacked apart a few examples, but so far, nothing is very good or reusable. Please help!!
For what it's worth, I have an image that individual ticks for the weight. So I can select to the tenth of the number (e.g. 160.4). The image has the first tick bold and larger than the remaining 9. I'd like to have the weight/number centered over the large tick. I'll update the points to my label/datasource after scrolling stops.
UPDATE
I need to make this. I have the custom font, background, and ticker image.
I would not do this through an UIScrollView. I think it would be more complex and you would certainly end up having issues when trying to add you custom picker into another scroll view.
What I would do is:
building the picker view by means of a series of CALayers, each one representing a "building block" of your picker view; see attached image:
each building block would represent a specific value by mixing a UILabel (the text) and an image;
use a pan gesture recognizer, or alternatively define touchesBegin/Moved/Ended method to deal with panning;
when a pan is done, you displace the view content to the left or right according to the panning;
when panning, you also add new building blocks to the left or right end of the picker to account for empty areas that would be revealed by the displacement done at point 4.
I think that having a look at another kind of custom control source code would be of great help to you. You would not possibly find your custom picker already implemented, but could get some guidance. Have a look then at cocoa controls.
Hope this helps.
If I were going to implement this, I would create a really wide image that had every weight on it I'd ever need - I would probably create this in code when the app started up. This image is then used as the contentView of your picker. You get all the scrolling features "for free", and you could even update the values shown in the other parts of the view during scrolling (or dragging.
The scrollView is just the area with the tick marks and weight numbers, and resides in a subview above the background, but below the centered vertical line that shows the actual weight.
EDIT: on second thought, forget the image. If you have the code to draw the image, you can do the drawing in a custom UIView. So you get the draw rect, you know the contentOffset, so you can draw just what you need.
Im trying to implement a nice accordion effect on my app. My goal is to "open up" a cell when the user tap on it, diplaying additionnal content (such as text) as the cell height increase.
The perfect sample code for that is the TableView Animations & Gestures sample code provided by Apple. However I am experiencing a strange behavior, that ruins the whole effect.
It appears that depending on the order in which the tableview will display its cells (top --> Bottom or Bottom-->up) the cells textviews will overlap each other or not.
As its a bit difficult to explain with word so here is it with images.
Those screenshots were taken from the TVAnimationsGestures Sample Code, without any changes made to it. It comes from the first version of the sample code without storyboard:
Now the version with the storyboard, first behaved well, but after a while, and without me touching the code it started drawing this :
And I have the exact problem on my custom with my custom cells.
It took me a while to understand what I think the problem comes from. If cells are drawn from the Top cell to the bottom, there is no such problem. However if cells are drawn bottom to the top, they will stack in reverse and therefore overlap each other. I don't think it is possible to control this behavior.
What gave me the hint, is that when I scroll down, forcing the top cell to redraw, they actually redraw nicely, and the screen looks like this:
A Mixture of overlapping cells and "good" cells.
Again, this all comes directly from Apple sample code, without any changes.
Does anyone knows whats going on?
Thanks a lot for your help.
You can increase the cell height by pinching on the cell.
I'm building a cell-based game that essentially works like dominoes: you start with one tile in the center, then connect additional tiles to it that can branch out in all directions. I have my game table all set up and working great... now I just need to make it scroll to accommodate the expanding content.
So, this doesn't seem to fit easily into a UIScrollView's built-in behavior. For one thing, cells expand in all directions – potentially going into the negative coordinate space of the UIScrollView. As far as I can tell, UIScrollView does not allow an actual CGRect with size AND origin to be defined for the scrolling content area. It appears you can only define a width and height for the content area that extends from point (0,0). Is this true, or am I missing something?
Assuming my understanding of the content area limitations are correct, how would one ideally handle this problem? My go-to idea would be to shift all subviews into positive coordinate space as the game board expands, then update the ScrollView's contentOffset property to counter the shift and make the transition invisible. I just want to make sure I'm not reinventing an inferior wheel before I start developing this.
Thanks in advance for any and all ideas!
I believe your idea is the good one, every time a tile is added, you may need to adjust your content view in order to be able to center on the tile that just was added.
Hence if this is "backward" (-x or -y) and your on top of your view (or nearly), you'll have to extend your contentView (surely the same way you do for +x, +y) and thus, adjust every of your tiles with the translation you did to your contentView's down-right corner.
Following up... yep, that did it. I set up the display so that it redraws the grid of cells from the upper-left corner. Whenever a new row or column of cells is added to the top or the left, the UIScrollView's contentOffset shifts by the newly added pixels to hide the change in content position.
I'm trying to figure out if I can get what I want out of UIScrollView through some trickery or whether I need to roll my own scroll view
I have a series of items in row that I want to scroll through. One item should always be centered in the view, but other items should be visible to either side. In other words, I want normal scrolling and edge bouncing, but I want the deceleration when the user ends a touch to naturally settle at some specified stop point. (Actually now that I think of it, this behavior is similar to coverflow in this respect.)
Take a look at this project: SwipeView
Good luck
I'd check out https://github.com/nicklockwood/iCarousel, it's awesome.
You should take a look at the "pageingEnabled" property of a UIScrollView. Basically you can define a size of a segment and the number of segments. Then it will automatically stop to adjust to that specific segment like you want. If you set the segments to be smaller than the actual width of the screen I think you should get the behaviour you are looking for.