debugCheckZone method
- String entryPoint
Checks that the current Zone is the same as that which was used to initialize the binding.
If the current zone (Zone.current) is not the zone that was active when the binding was initialized, then this method generates a FlutterError exception with detailed information. The exception is either thrown directly, or reported via FlutterError.reportError, depending on the value of BindingBase.debugZoneErrorsAreFatal.
To silence the message displayed by debugCheckZone, ensure that the same
zone is used when calling ensureInitialized() as when calling the
framework in any other context (e.g. via runApp). For example, consider
keeping a reference to the zone used to initialize the binding, and using
Zone.run to use it again when calling into the framework.
Usage
The binding is considered initialized once BindingBase.initInstances has run; if this is called before then, it will throw an AssertionError.
The entryPoint parameter is the name of the API that is checking the
zones are consistent, for example, 'runApp'.
This function always returns true (if it does not throw). It is expected to be invoked via the binding instance, e.g.:
void startup() {
WidgetsBinding binding = WidgetsFlutterBinding.ensureInitialized();
assert(binding.debugCheckZone('startup'));
// ...
}
If the binding expects to be used with multiple zones, it should override this method to return true always without throwing. (For example, the bindings used with flutter_test do this as they make heavy use of zones to drive the framework with an artificial clock and to catch errors and report them as test failures.)
Implementation
@override
bool debugCheckZone(String entryPoint) {
// We skip all the zone checks in tests because the test framework makes heavy use
// of zones and so the zones never quite match the way the framework expects.
return true;
}