Bind ModalBottomSheet, BottomSheetScaffold, date/time pickers, and Tooltip

[jonathanpeppers]

Follow-up to #6 — completes the user-facing pieces of #3 by binding the remaining Material 3 dialogs, sheets, pickers, and Tooltip. Rebased onto current main, which picks up the declarative [assembly: ComposeDefaults(...)] source generator from #8 and uses it for every new $default enum.

Composables added

Composable	Kt class	State holder
ModalBottomSheet	ModalBottomSheet_androidKt	SheetState via direct C# call to ModalBottomSheetKt.RememberModalBottomSheetState (NOT stripped)
BottomSheetScaffold	BottomSheetScaffoldKt	BottomSheetScaffoldState via direct C# call to BottomSheetScaffoldKt.RememberBottomSheetScaffoldState (NOT stripped)
DatePickerDialog	DatePickerDialog_androidKt	DatePickerState via JNI rememberDatePickerState-EU0dCGE
DatePicker	DatePickerKt	(uses DatePickerState)
TimePicker	TimePickerKt	TimePickerState via JNI rememberTimePickerState
TimePickerDialog	TimePickerDialogKt	(uses TimePickerState)
Tooltip (TooltipBox)	TooltipKt	TooltipState via JNI rememberTooltipState + TooltipDefaults.INSTANCE.rememberPlainTooltipPositionProvider-kHDZbjc

RememberModalBottomSheetState and RememberBottomSheetScaffoldState are present in the bound assembly, so the facades call them directly through C# instead of going through JNI — per the upstream binding shape noted in #6's description.

Intentionally NOT bound

#3 also listed BasicTooltipBox and BasicEdgeToEdgeDialog. Both live in androidx.compose.material3.internal — they're the foundation primitives that the public Tooltip / Dialog / AlertDialog / DatePickerDialog / TimePickerDialog / TooltipBox wrappers are built on top of, and there is no user-facing scenario where they're preferable to the public composables we already bind. (Confirmed empirically: BasicEdgeToEdgeDialog rendered as a fullscreen overlay with no way to dismiss it from the sample.) Skipped on purpose, with comments in Composables.cs explaining why.

Pattern

Each facade mirrors AlertDialog from #6 — slot composables exposed as named properties on the facade, optional slots tracked via the standard Compose $default bitmask. The 6 new bitmask enums are generated via the declarative attribute pattern from #8:

[assembly: ComposeDefaults("ModalBottomSheetDefault",
    "!onDismissRequest", "sheetState", "!modifier", ..., "dragHandle", "!content")]

!param consumes a bit position without emitting an enum member, covering the params the caller always provides.

JNI plumbing lives in ComposeBridges.cs: 7 composable bridges + 4 state-holder/helper bridges, with full mangled descriptors documented inline so future readers can verify against the AAR via javap.

Sample usage

// ModalBottomSheet — SheetState comes from the bound C# RememberModalBottomSheetState (no JNI).
new ModalBottomSheet(onDismissRequest: () => showSheet.Value = false)
{
    new Column
    {
        new Text("Modal bottom sheet"),
        new Text("Drag down or tap outside to dismiss."),
        new Button(onClick: () => showSheet.Value = false) { new Text("Hide") },
    },
}

// DatePickerDialog with a DatePicker as its body slot.
new DatePickerDialog(onDismissRequest: () => showDate.Value = false)
{
    ConfirmButton = new Button(onClick: () => showDate.Value = false) { new Text("OK") },
    DismissButton = new Button(onClick: () => showDate.Value = false) { new Text("Cancel") },
    Body          = new DatePicker(),
}

// TimePickerDialog with a TimePicker as its body slot.
new TimePickerDialog(onDismissRequest: () => showTime.Value = false)
{
    Title         = new Text("Pick a time"),
    ConfirmButton = new Button(onClick: () => showTime.Value = false) { new Text("OK") },
    DismissButton = new Button(onClick: () => showTime.Value = false) { new Text("Cancel") },
    Body          = new TimePicker(),
}

// Tooltip — long-press the anchor to show the tooltip popup.
new Tooltip
{
    Tip    = new Surface { new Text("Helpful hint") },
    Anchor = new Button(onClick: () => count++) { new Text("Long-press me") },
}

BottomSheetScaffold is bound but not exercised in the sample — the simpler ModalBottomSheet covers the smoke-test path; the scaffold variant is available for callers that need a persistent sheet.

Verification

• dotnet build src/ComposeNet.Compose/ComposeNet.Compose.csproj — clean (the source generator from Generate ComposeDefaults enums via declarative attribute #8 emits the 6 new enums correctly).
• dotnet build src/ComposeNet.Sample/ComposeNet.Sample.csproj -t:Install — clean.
• App launches on emulator-5554, no FATAL / AndroidRuntime errors in the app pid; each new dialog/sheet/picker can be opened and dismissed from the sample's button row.

Co-authored-by: Copilot 223556219+Copilot@users.noreply.github.com

[Copilot]

Pull request overview

This PR expands the ComposeNet Material 3 facade to cover additional “dialogs and sheets” UI primitives (sheets, picker dialogs, pickers, and tooltip), using the existing slot-property + $default bitmask pattern and adding the necessary JNI bridges where bindings are stripped/incomplete.

Changes:

• Added new public facades in Composables.cs for ModalBottomSheet, BottomSheetScaffold, DatePickerDialog/DatePicker, TimePickerDialog/TimePicker, and Tooltip (TooltipBox wrapper).
• Added new declarative [assembly: ComposeDefaults(...)] entries for the newly bridged composables’ $default masks.
• Added multiple new raw-JNI bridge methods in ComposeBridges.cs (composables + remember* state holders) and updated the sample to exercise the new UI.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 4 comments.

File	Description
src/ComposeNet.Sample/MainActivity.cs	Updates the sample UI to open/dismiss the newly added dialogs/sheets/pickers and demonstrate tooltip behavior.
src/ComposeNet.Compose/ComposeDefaults.cs	Adds new declarative ComposeDefaults definitions for the new composables’ $default bitmasks.
src/ComposeNet.Compose/ComposeBridges.cs	Introduces new JNI bridge entry points for stripped composables and state-holder remember* helpers.
src/ComposeNet.Compose/Composables.cs	Adds the new public facade node types and wires them to the bridges/defaults pattern.