class ViewRefInstalled
Defined at line 2314 of file fidling/gen/sdk/fidl/fuchsia.ui.views/fuchsia.ui.views/hlcpp/fuchsia/ui/views/cpp/fidl.h
A method of enabling ViewRef holders to determine if a ViewRef has been
"installed" in the view tree: the time it is first connected, transitively,
to the root view. Typically, after installation, view focus may be
transferred to that ViewRef.
Note: It's important to distinguish between a ViewRef's installed status and
current connected-to-view-tree status. The former undergoes a state
change once, from "no" to "yes". The latter may change continuously,
depending on view tree topology. As such, "installed" cannot imply
"currently connected to view tree"; even a hypothetical
"ViewRefConnected" protocol is fundamentally racy.
Public Members
static const char[] Name_Public Methods
void ~ViewRefInstalled ()void Watch (::fuchsia::ui::views::ViewRef view_ref, WatchCallback callback)Sets up a callback to fire when the requested |view_ref| is installed.
- If |view_ref| has not already been installed, the |Watch| response
will fire when it is.
- If |view_ref| has already been installed, the |Watch| response will
fire immediately.
- If |view_ref| is invalid, or becomes invalid (perhaps because the view
was destroyed), the |Watch| call returns with an error. The error is
not guaranteed to be immediate, but a ViewRef holder can itself
determine ViewRef validity by listening for ZX_EVENTPAIR_PEER_CLOSED.
Flow control: The caller is allowed multiple |Watch| calls on multiple
ViewRefs. There is at most one response per call back to the client.
Note: Prior to installation, this |Watch| call is kept alive as long as
the ViewRef is valid.