Two new methods on `UxFile`, both designed to keep large file content
out of the platform-channel buffer (the failure mode of file_selector
on Android: a ~200 MB video PUT through the Pigeon codec OOM'd the
JVM via `byte[size]` allocation in `FileSelectorApiImpl`).
`UxFile.pick({mimeTypes})` returns `UxPickedFile?` with `path`, `name`,
`mimeType`, `size`. The platform channel reply carries only the
metadata; bytes never cross.
- Android: `ACTION_OPEN_DOCUMENT` + `EXTRA_MIME_TYPES`, registered
as `ActivityResultListener`. On result, stream-copies the SAF
content URI to `cacheDir/ux_pick/<ts>_<safeName>` via an 8 KB
buffer (no full-file allocation in JVM heap), returns the cache
path.
- iOS: `UIDocumentPickerViewController(documentTypes:in: .import)`
— `.import` mode copies the picked file into the app's
Documents/Inbox so the URL is stable. Strong-retained delegate
(the picker's delegate ref is weak).
- macOS: `NSOpenPanel` with `allowedFileTypes`. Sheet-modal when a
Flutter window exists; free-modal otherwise.
`UxFile.videoThumbnail({path, atMs, maxWidth})` returns
`UxVideoThumbnail?` (PNG bytes + dims).
- Android: `MediaMetadataRetriever.getFrameAtTime(..., OPTION_CLOSEST_SYNC)`,
`Bitmap.createScaledBitmap` to maxWidth, PNG-encode via
`ByteArrayOutputStream`, recycle bitmaps in `finally`, release
retriever in `finally`.
- iOS: `AVAssetImageGenerator` with `appliesPreferredTrackTransform = true`,
`maximumSize = (maxWidth, 0)` (preserve aspect), ±500 ms tolerance
for keyframe alignment, decode on `userInitiated` queue.
- macOS: same generator, encoded via `NSBitmapImageRep`.
Compatible with the package's existing iOS 13 / macOS 10.15 deployment
targets — uses legacy `kUTType*` + `UTTypeCreatePreferredIdentifierForTag`
instead of `UTType` (iOS 14 / macOS 11).
Fix several race conditions in the iOS interactive dismiss flow:
- Don't skip keyboard close notifications during pan tracking, which
left Dart unaware the keyboard was dismissed
- Guard resignFirstResponder with generation check so reopened keyboards
aren't killed by stale dismiss completions
- Block pan tracking from starting during an in-flight dismiss animation
- Always reset keyboard view bounds when the keyboard opens, not just
when the dismiss animator is still running
- Handle duration=0 keyboard notifications by snapping immediately
- Gate adaptive learning debug output behind kDebugMode
Rewrite the example as a chat UI demonstrating ListenableBuilder,
scroll freeze during interactive dismiss, and proper bottom inset
handling with max(keyboardHeight, safeBottom).
Modernize example Android project from v1 to v2 embedding with
current AGP/Gradle versions.
