Easy way to use an UIScrollView - cocoa-touch

Does someone have an "easy way" to make a view like camera roll app? I need to display miniature photos (buttons) and push new views from them. I don't know how to display miniature images in a scroll view. The number of miniatures is large, so they don't fit the screen, and I think UIScrollView is the only solution.

Check out TTThumbsViewController, part of Three20; this should pretty much do what you want (and it's open source if you need to change it).

A scroll view really just controls the visible region of a single content view. If you want a grid of small images, you'll need to create a view that contains a number of image views or otherwise displays the grid of images. Make this the content view of the scroll view. Also, it'd be a good idea to construct your image grid view such that it only loads and draws the images that are visible, particularly if you're going to display a large number of such images.

Related

How to build below screen in titanium?

below i attached an app help guide screen. I am understanding how to build this screen.
If any body have idea please share here
View with semi transparent background color (backgroundColor:"rgba(0,0,0,0.5)";) and some images on top of it.
So, using images is bad. You'll need images for translations and if you do this as one image you'll need to ensure all devices are covered so your arrows point to the right element.
Minimise images == smaller app.
First thing you'll need to do is a create a blocker view -- so that's a view that will fill the screen and have a black background with opacity.
You can't apply that to the window as everything in it will be semi-transparent so:
Create a transparent Window that fills the screen.
Add to that window a view that fills the window and has opacity say 0.5 and black background
Add to the Window (not the view you just created) the other elements and button -- ideally, these should be individual graphics of the arrows, sized in such a way that you can position them based on the host element (the item they are pointing to / referring to). Use real text so you can handle translations / reduce file size.
So you'll need a way to associate each tip with a control they are anchored too, and that will ensure that regardless of the screen size, the tip will appear in the correct place.
First of all, always give a try before putting questions anywhere because it makes you learn things on your own for long time.
The easiest step for you to do this is to ask your designer to create a complete image just like that & you just have to show it on top.
If you have to show that image in different translations, then you can ask your designer to provide you required translations images.

Efficiently Scroll and Zoom Photos Using UIScrollView and UIImageView

I need a simple way of scrolling through photos and zooming each photo as needed. Just like original Apple's Photo app. I understand the concept: UIScrollView has many UIScrollView subviews as pages and each of those has a UIImageView to zoom in.
However, I've also seen an example, which I can no longer find, with more efficient way of doing this - using only 3 pages (UIScrollView's) for as many photos as there are to save memory usage. So basically, if there are 10 photos, only 3 pages shown (centered visible, left hidden, right hidden) and as you scroll left or right new images are being placed into those pages to simulate an effect of continuous scroll.
My question is how is this done or is there an existing example so I do not reinvent the wheel?
You might wanna take a look at MWPhotoBrowser, it's pretty the same as the Photo app.
https://github.com/mwaterfall/MWPhotoBrowser

How to draw in code an imageview

I have a problem. I want for each record in my core data database to draw an UIImage view on screen. But the problem is that I want to make a sort of grid. On the link below you see what I want to achieve.
picture
So my question is, how do I draw an image on screen in code. And place those images in a sort of a grid. using a collection view is no option, because the app should be running on all IOS devices.
While you could implement a custom UIView and implement the drawRect: method and draw UIImages there, I suggest just using multiple UIImageViews as subviews on your "main" view. Your view might be embedded in a UIScrollView, or you could use a UITableView with custom UITableViewCells. Whichever is easier is probably related to how you can interact with the view.
Building that one huge image view is something that I'd definitely try to avoid - it costs many many (probably unnecessary) memory, and it might be slow as well. Definitely not very flexible to handle, and a pain to update dynamically.
A quick cheat for something like this is to use a Table View and then in each cell to place another TableView but rotated at 90 degrees.
You can then use this second TableView to display the pictures etc...
This will give you a table that scrolls up and down and then each cell can scroll left to right.
I'd suggest subclassing UITableViewCell and setting it up as a UITableViewDelegate and UITableViewDatasource.
You will also have to remember to rotate the content of these "sub"tables by 90 degrees also so that they are the right way up.
This sounds like a lot of work but if you push the management of the sub Tables into the cells then it actually becomes quite easy.

How does the Reeder Mac app animate lists when switching folders?

Initially I was under the impression that it uses the table row slideup/down animations while inserting/deleting new rows but I doubt if it's doing that as it does it so fluidly even with thousands of items in the list (otherwise it would take a lot of time for the deletions/insertions to work).
Am I right in my assumption that it's simply attaching a new instance of the News list at the bottom of the screen, shrinking the above one while the one at the bottom expands to fill up space?
UPDATE:
Please see this video of what I mean: http://dl.dropbox.com/u/4960327/ReederAnim.mov
I can not tell you exactly how Silvio Rizzi made this, but as you see in the playback, a list view is added behind the shown list view, and the front list view fades out (.alpha = 0.0;) while the list view behind it expands its height per row.
When you desicate it frame by frame it becomes quite clear what he does, and it is really not that advanced. But I have to admit, with the white "milky" polished interface, it looks quite neat.
In addition, you can see that while animating, the background list view only renders the top 7 entries (hopefully calculated by dividing the view height with the average height of the cells shown) making the list view quick to load. Then afterwards, he can load an extended array of cells once you start scrolling, or in a background thread starting once the animation is complete.

Simple slideshow in a UIImageView

I got trouble to add slideshow to my application.
Currently, I have a UIView composed of a segmentedControl.
I made ​​two "views" that I hide or display depending on the selected button.
I'm looking to make a simple slideshow in one of my two views. I made a UIImageView because it is simple to display pictures.
So I'd like to display my pictures one by one and it is possible to move from one image to another by sliding your finger to the right or left (just as in the native app "Photos").
I tried to adapt example codes from the documentation, but without succes.
So I'ml looking for help.
Thanks,
jb crestot
SO, I've actually done this and it's fairly easy. The ingredient that you are missing is a UISCrollView. My implementation did exactly what you describe (allow the user to go back and forth between a set of images).
Basically, add a UIScrollView to your View in interface builder and you will be creating the UIImage views with code (a simple for loop) and setting their images the same way. I did this safely with no memories issues with about 15 images (PNG's). There could be a potential performance issue with this message if you are working with a large number of images (say 40?)
I hope this helps, let me know if you need a code sample to see how this works.
You may consider using a custom class, such as iCarousel, linked below. Each of these views could be your image, and then tapping on them could launch a fullscreen view for example.
Keep us posted!
http://cocoacontrols.com/platforms/ios/controls/icarousel
See apple's page control sample application.