mirror of
https://github.com/flutter/flutter.git
synced 2026-02-20 02:29:02 +08:00
a9e12287f6
This introduces `PlatformDispatcher.implicitView`, a low-level primitive for the framework's bootstrapping. Most code, including the framework after bootstrapping, will use `View.of(context)` instead of this new API. This new primitive will let us deprecate the `window` global.
Goals:
1. **Enable multi-window**. The `PlatformDispatcher.implicitView` is nullable. If `null`, the app must create a window to get a view it can draw into.
2. **Backwards compatibility**. For "single window" apps, `PlatformDispatcher.instance.implicitView` should behave as similar to `window` as possible.
1. The `PlatformDispatcher.instance.implicitView.viewId` should be `0`.
1. The `PlatformDispatcher.instance.implicitView` must be available synchronously at root isolate startup. This allows the framework to determine if it can make single window assumptions at startup.
2. The `PlatformDispatcher.instance.implicitView` reference must not change after startup: if it is null at startup, it must always be null; if it is non-null at startup, it must always be non-null. If "single window" app enters headless mode, the implicit view must remain non-null.
In the future, the embedder will control whether an implicit view is created: mobile & legacy desktop apps will have an implicit view, multi-window desktop apps won't have an implicit view. This requires updating the engine's embedder API and is out-of-scope for this change. For now, all apps will have an implicit view.
Part of https://github.com/flutter/flutter/issues/120306