Bring back this convenience API -- it disappeared somewhere along the
line while we were building Paper. This is totally trivial, but
conveniently won't break if you layer-back a leaf node.
Closes#278.
This adds new initializer methods to ASDisplayNode:
```objc
initWithViewBlock:(ASDisplayNodeViewBlock)viewBlock
initWithLayerBlock:(ASDisplayNodeLayerBlock)layerBlock
```
Sometimes a view can't be constructed with `-[initWithViewClass:]` but you want to use it with ASDK, so these new methods provide a way to wrap an existing view in a node.
The API is meant to preserve ASDisplayNode's behavior, so you can still construct and set properties on the node on a background queue before its view is loaded; even though the view was created a priori, it is not considered to be loaded until `node.view` is accessed.
Using the API looks like this:
dispatch_async(backgroundQueue, ^{
ASDisplayNode *node = [ASDisplayNode alloc] initWithViewBlock:^{
// Guaranteed to run on the main queue
UIButton *button = [UIButton buttonWithType:UIButtonTypeSystem];
[button sizeToFit];
node.frame = button.frame;
return button;
}];
// Use `node` as you normally would...
node.backgroundColor = [UIColor redColor];
});
The main thing this bridging API doesn't do (can't do?) is layout. Methods like `-[ASDisplayNode calculateSizeThatFits:]` and `-[ASDisplayNode layout]` cannot delegate to `[UIView sizeThatFits:]` and `[UIView layoutSubviews]` since the UIView methods must run on the main thread. If ASDK were internally asynchronous and could dispatch its layout methods to different threads (sort of like how ASTableView computes its cells' layouts) then we could mark nodes with externally provided views/layers as having "main-queue affinity" and delegate its layout to UIKit.
Test cases are included and all existing tests pass.
ASDisplayNodes now have an overidable method -placeholderImage that lets you provide a custom UIImage to display while a node is displaying asyncronously. The default implementation of this method returns nil and thus does nothing. A provided example project also demonstrates using the placeholder API.
Postpone manual display until a future release when it can be called on any thread. Provide the current node manual display logic as a category on ASDisplayNode only available for ASRangeController. Deprecate -displayImmediately.
Add a `usleep(1.0 * USEC_PER_SEC)` delay to ASBasicImageDownloader and
slowly scroll through the Kittens sample project. Without this patch,
you'll see that images only start downloading after their purple
placeholders appear onscreen. With it, images can download and render
before you scroll them onscreen, thanks to the working range.
Rename the ASDisplayNode property to match its _ASDisplayLayer
counterpart -- `displaySuspended` is more succinct and is a more
plausible name for a Cocoa BOOL property.
This is a remnant from before `willAppear` and `didDisappear` were
renamed to better reflect their hierarchy-change status (being added to
the hierarchy != being visible). May be useful for turians.
* Reorganise and rename `_flags` for clarity and consistency.
* Remove ambiguity between `implementsDisplay` and `hasClassDisplay`.
* Delete useless `hasWillDisplayAsyncLayer` check -- make it a simple
subclass override point, as with `didDisplayAsyncLayer:`.
* Minor comment cleanup.
Added a sample project that will demonstrate how to manually display nodes. Removed the UIWindow hack that coupled display of nodes with Core Animation transactions.
ASImageNode and ASHighlightOverlayLayer were both using
[[UIScreen mainScreen] scale] directly. Bad. No cookie. Use
ASDisplayNodeScreenScale() instead.
(Also, regenerate Xcode project with Xcode 6 and current CocoaPods.)
Fixes:
- Usage of UIScreen in -[ASDisplayNode init]
(the offending individual will be prosecuted)
- #38: Proper teardown of nodes owned by ASTableView / ASRangeController
- #34: Fix infinite recursion in very rare subclassing scenario
- #30: Avoid animating cell and section additions to ASTableView
- #19: Set a more reasonable default for maximum display concurrency
r=nadi
ASDisplayNode and several subclasses had previously cleared memory-heavy
objects like the backing store and text layout manager when the node's
view
or layer is removed from a visible heirarchy. This works great in any
system
that uses a "working range", where exiting the range removes the node
from
the hierarchy and reclaiming memory at that time is important.
However, for
standard UIViewController patterns (unused in Paper), this behavior
causes
highly undesirable thrashing (leading to visible flashes & wasteful
re-rendering of content).
After this change, node subclasses should implement -reclaimMemory if
they
need to perform any other cleanup besides backing store destruction
when they
leave a working range or other scenario where memory reduction is
valuable.
To trigger this behavior, calling code should use
-recursivelyReclaimMemory.
r=nadi
`-[ASDisplayNode addSubnodeAsynchronously::]` and
`-replaceSubnodeAsynchronously:::` are unused and confusingly increase
AsyncDisplayKit's API surface. `-addSubnode:` and friends are
thread-safe and can be used on background threads, so removing these
methods does not constitute a decrease in functionality.
Introduce `ASTableView`, a UITableView subclass that uses `ASCellNode`
instead of UITableViewCell. Add working range support via
`ASRangeController`, which observes the visible range, maintains a
working range, and handles most ASDK machinery. ASRangeController is
loosely-enough coupled that it should be easily adapted to
UICollectionView if that's desired in the future.
Notable considerations in the ASRangeController architecture:
* There's no sense rewriting UITableView -- the real win comes from
using nodes instead of UITableViewCells (easily parallelisable
computation, large number of cells vs. few table views, etc.). So,
use a UITableView with empty cells, using UITableViewCell's
contentView as a host for arbitrary node hierarchies.
* Instead of lazy-loading cells the instant they're needed by
UITableView, load them in advance. Preload a substantial number of
nodes in the direction of scroll, as well as a small buffer in the
other direction.
* Maintain compatibility with UITableView's API, with one primary change
-- consumer code yields configured ASCellNodes, not UITableViewCells.
* Don't use -tableView:heightForRowAtIndexPath:. Nodes already compute
their preferred sizes and cache results for use at layout-time, so
ASTableView uses their calculatedSizes directly.
* Corollary: ASTableView is only aware of nodes that have been sized.
This means that, if a cell appears onscreen, it has layout data and
can display a "realistic placeholder", e.g. by making its subnodes'
background colour grey.
Other improvements:
* Remove dead references and update headers (fixes#7, #20).
* Rename `-[ASDisplayNode sizeToFit:]` to `-measure:` and fix
`constrainedSizeForCalulatedSize` typo (fixes#15).
* Rename `-willAppear` and `-didDisappear` to `-willEnterHierarchy` and
`-didExitHierarchy`. Remove `-willDisappear` -- it was redundant, and
there was no counterpart `-didAppear`.
* Rename `viewLoaded` to `nodeLoaded`.
Summary:
* Fixes#3
* Ordering: atomicity, then [optional] readonly, then value semantics (retain/copy/assign)
* Removed redundant `readwrite`
* No spaces between "getter = name" ("getter=name" instead)
* Property method overrides renamed as well
* self.isBlah, while technically not entirely correct, still resolves to [self blah], so left alone (@kimon had advice on this sort of naming issue last summer), and largely inconsequential
Test Plan:
* Compile and run
