This provides internal features on _ASAsyncTransaction and ASDisplayNode to facilitate
implementing public API that allows clients to choose if they would prefer to block
on the completion of unfinished rendering, rather than allow a placeholder state to
become visible.
The internal features are:
-[_ASAsyncTransaction waitUntilComplete]
-[ASDisplayNode recursivelyEnsureDisplay]
Also provided are two such implementations:
-[ASCellNode setNeverShowPlaceholders:], which integrates with both Tables and Collections
-[ASViewController setNeverShowPlaceholders:], which should work with Nav and Tab controllers.
Lastly, on ASDisplayNode, a new property .shouldBypassEnsureDisplay allows individual node types
to exempt themselves from blocking the main thread on their display.
By implementing the feature at the ASCellNode level rather than ASTableView & ASCollectionView,
developers can retain fine-grained control on display characteristics. For example, certain
cell types may be appropriate to display to the user with placeholders, whereas others may not.
Follow-up work will include unit tests, revisiting names, and the header locations of definitions.
Accomodate and document unusual cases in which it is necessary to remove views when clearing backing stores.
ASDK layout and display calls don't depend on UIView in any way, so this
will achieve the necessary behavior of the render range while eliminating significant
UIView-specific overhead from heirarchy manipulation.
There is an unsolved issue with this optimization that may cause crashes
in certain cases. Reverting until it's properly resolved. It doesn't
appear to be possible to cause the issue in the test apps used to develop it.
This reverts commit 3f982b5c9a7e4a557c102268f11f71b58085ffef.
- In -layoutSubviews of table and collection views, detect changes that cause a different constrained size for nodes, and trigger relayout immediately.
- Orientation change can be handled by this solution. So, no need to observe to its events.
- Update Kittens example to support iPad (easier to catch bugs on these devices) and add a title to navigation bar (looks a bit nicer).
Introduced ASIndexPath for efficient handling of index paths in C++ vectors,
while maintaining the readability of ".section" and ".row" instead of
".first" and ".second" inside of complicated business logic.
Confirmed that the working range calls are firing appropriately during
ASTableViewStressTest, including the deallocation of the rich text placeholders
provided by ASTextNode.
This diff resolves all known consistency issues with ASTableView and ASCollectionView.
It includes significantly more aggressive thrash-testing in ASTableViewStressTest,
which now passes on a variety of device and simulator configurations. It also updates
the unit tests run on every commit to ensure any regression is caught quickly.
A few of the salient changes in this diff:
- ASTableView now uses Rene's ASCollectionViewLayoutController, and actually uses a
UICollectionViewFlowLayout without any UICollectionView. This resolves an issue where
ASFlowLayoutController was generating slightly out-of-bounds indicies when programmatically
scrolling past the end of the table content. Because the custom implementation is likely
faster, I will revisit this later with profiling and possibly returning to the custom impl.
- There is now a second copy of the _nodes array maintained by ASDataController. It shares
the same node instances, but this does add some overhead to manipulating the arrays. I've
filed a task to follow up with optimization, as there are several great opportunities to
make it faster. However, I don't believe the overhead is a significant issue, and it does
guarantee correctness in even the toughest app usage scenarios.
- ASDataController no longer supports calling its delegate /before/ edit operations. No
other class was relying on this behavior, and it would be unusual for an app developer to
use ASDataController directly. However, it is possible that someone with a custom view
that integrates with ASDataController and ASRangeController could be affected by this.
- Further cleanup of organization, naming, additional comments, reduced code length
wherever possible. Overall, significantly more accessible to a new reader.
- Introduce ASLayoutNode and its subclasses.
- ASDisplayNode measures its ASLayoutNode and cache the result (ASLayout). Calculated size and position of each subnode can be retrieved from the calculated layout.
- Custom nodes need to override -layoutNodeThatFits:(CGSize) instead of -calculateSizeThatFits:(CGSize).
- Custom nodes do not need to layout its subnodes (in -layout:) anymore. ASDisplayNode can handle the job most of the time, by walking through its layout tree.
- ASCompositeNode is used to embed (display) subnodes to a node's layout. That way, each subnode will also be measured while the parent node is measuring. And the parent node knows where its subnodes are within its layout.
