Self-Contained Components for iOS
Two-file (.h / .m) useful components and utility classes that are dead-easy to drop into your iOS projects.
License: MIT (free for any use, no attribution required).
Follow us on twitter: @SoloComponents.
Note: I want to collect as many open-source components as possible, not just publish my own ones. If you have a useful iOS class that does not depend on anything, feel free to fork, add and send me a pull request!
ATPagingView
ATPagingView is a wrapper around UIScrollView in (horizontal) paging mode, with an API similar to UITableView.
Status: production-ready, used by at least one App Store app.
You provide the page views by implementing two delegate methods:
- (NSInteger)numberOfPagesInPagingView:(ATPagingView *)pagingView {
return 10;
}
- (UIView *)viewForPageInPagingView:(ATPagingView *)pagingView atIndex:(NSInteger)index {
UIView *view = [pagingView dequeueReusablePage];
if (view == nil) {
view = [[[DemoPageView alloc] init] autorelease];
}
return view;
}
You are also notified when the user navigates between pages:
- (void)currentPageDidChangeInPagingView:(ATPagingView *)pagingView {
self.navigationItem.title = [NSString stringWithFormat:@"%d of %d", pagingView.currentPageIndex+1, pagingView.pageCount];
}
You can use ATPagingView directly or derive your view controller from ATPagingViewController.
ATPagingViewController is similar to UITableViewController and:
- defines
loadViewto create ATPagingView automatically, - sets itself as a delegate of ATPagingView,
- calls
reloadDatainviewWillAppear:if the paging view is empty, - additionally it forwards orientation events to the paging view (see below).
If you want to use ATPagingView without ATPagingViewController, you need to:
-
provide your delegate object using the
delegateproperty, -
call
reloadDatato populate the view, -
if you want to support rotation, you need to invoke
willAnimateRotationanddidRotatemethods from your view controller:- (void)willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration { [self.pagingView willAnimateRotation]; } - (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation { [self.pagingView didRotate]; }
ATArrayView
A container that arranges its items in rows and columns similar to the thumbnails screen in Photos.app, the API is modeled after UITableView.
Status: beta.
Enjoy the familiar delegate methods:
- (NSInteger)numberOfItemsInArrayView:(ATArrayView *)arrayView {
return 97;
}
- (UIView *)viewForItemInArrayView:(ATArrayView *)arrayView atIndex:(NSInteger)index {
DemoItemView *itemView = (DemoItemView *) [arrayView dequeueReusableItem];
if (itemView == nil) {
itemView = [[[DemoItemView alloc] init] autorelease];
}
return itemView;
}
There's ATArrayViewController which further reduces the amount of boilerplate code you have to write. Similar to UITableViewController, it:
- overrides
loadViewto create ATArrayView automatically, - sets itself as a delegate of the array view,
- calls
reloadDatainviewWillAppear:if the array view is empty.
ATByteImage
Allows to easily use an image (CGImageRef) backed by a malloc'ed chunk of memory. This means you can read or manipulate image bytes directly.
Status: ready for production use.
Using ATByteImage:
ATByteImage *blurred = [[ATByteImage alloc] initWithSize:blurredSize];
[blurred clear];
ATByteImageContext *blurredContext = [blurred newContext];
CGContextSetBlendMode(blurredContext.CGContext, kCGBlendModeNormal);
... draw using blurredContext.CGContext ...
[blurredContext release];
UIImage *myOverlay = [blurred extractImage];
Here's another example. The following function is useful in background image loading code:
// Returns an uncompressed (decoded) UIImage, optimized for drawing speed.
//
// This is a middle ground between [UIImage imageNamed:] and a plain
// [UIImage imageWithContentsOfFile:], as follows:
//
// * [UIImage imageWithContentsOfFile:] loads image data from disk and
// decodes it each time you display the image.
//
// If you are using CATiledLayer to display a large image (and you should,
// since UIImageView is not recommended for images bigger than ~1024x1024),
// the whole JPEG will decoded for EACH tile you display.
//
// * [UIImage imageNamed:@"xxx"] only ever decodes the image once, just as you
// wanted. However it also caches the image and seems to sometimes (always?)
// not release the data even after you release your UIImage.
//
// An app that loads several large images via 'imageNamed' will thus crash
// quite soon with unfamous "error 0".
//
// Another undesired quality of 'imageNamed' is that the image is loaded and
// decoded when it is displayed for the first time, which means you can't
// really do the decoding in a background thread.
//
// * DecompressUIImage([UIImage imageWithContentsOfFile:@"xx.jpg"]) is the
// sweet spot between the two β it returns a fully decoded image which can
// be displayed quickly, and memory management is entirely up to you.
//
UIImage *DecompressUIImage(UIImage *image) {
ATByteImage *byteImage = [[[ATByteImage alloc] initWithImage:image] autorelease];
return [byteImage extractImage];
}