This is not a grand refactor yet, it's just cleaning up what we have
already, so that people who keep using this API (e.g. dialogs) have
something coherent to deal with.
The major changes are that Navigator and NavigatorState have the same
API now, that most of the examples use `<void>` instead of `<Null>`,
that the navigator observer can see replaces, and that the `settings`
is moved from ModalRoute to Route. I also cleaned up some of the API
documentation.
Applies horizontal and bottom safe area insets to the Shrine demo in the
Gallery. Top insets are not applied due to the presence of the
omnipresent sliver app bar. Specifically, this ensures that the grid
cards are inset inside the iPhone X notch in horizontal mode, and that
the bottom of the grid is positioned above the iOS home indicator.
Rename State.config to State.widget
Rename State.didUpdateConfig to State.didUpdateWidget
Renamed all State subclasses' local variables named config to something else
This patch replaces uses of Flexible with Expanded where we're using
FlexFit.tight. We still need to think of a better name for the
FlexFit.loose variant.
Also, improve the docs for Row, Column, Flex, and RenderFlex to be more
problem-oriented and to give a complete account of the layout algorithn.
Fixes#6960Fixes#5169
These futures complete when the route is popped off the navigator. This
generalizes and simplifies a mechanism already in place for dialogs and
menus.
Fixes#5283
Anywhere that accepted IconData now accepts either an Icon or an
ImageIcon.
Places that used to take an IconData in an `icon` argument, notably
IconButton and DrawerItem, now take a Widget in that slot. You can wrap
the value that used to be passed in in an Icon constructor to get the
same result.
Icon itself now takes the icon as a positional argument, for brevity.
ThemeData now has an iconTheme as well as a primaryIconTheme, the same
way it has had a textTheme and primaryTextTheme for a while.
IconTheme.of() always returns a value now (though that value itself may
have nulls in it). It defaults to the ThemeData.iconTheme.
IconThemeData.fallback() is a new method that returns an icon theme data
structure with all fields filled in.
IconTheme.merge() is a new constructor that takes a context and creates
a widget that mixes in the new values with the inherited values.
Most places that introduced an IconTheme widget now use IconTheme.merge.
IconThemeData.merge and IconThemeData.copyWith act in a way analogous to
the similarly-named members of TextStyle.
ImageIcon is introduced. It acts like Icon but takes an ImageProvider
instead of an IconData.
Also: Fix the analyzer to actually check the stocks app.
Overview
========
This patch refactors images to achieve the following goals:
* it allows references to unresolved assets to be passed
around (previously, almost every layer of the system had to know about
whether an image came from an asset bundle or the network or
elsewhere, and had to manually interact with the image cache).
* it allows decorations to use the same API for declaring images as the
widget tree.
It requires some minor changes to call sites that use images, as
discussed below.
Widgets
-------
Change this:
```dart
child: new AssetImage(
name: 'my_asset.png',
...
)
```
...to this:
```dart
child: new Image(
image: new AssetImage('my_asset.png'),
...
)
```
Decorations
-----------
Change this:
```dart
child: new DecoratedBox(
decoration: new BoxDecoration(
backgroundImage: new BackgroundImage(
image: DefaultAssetBundle.of(context).loadImage('my_asset.png'),
...
),
...
),
child: ...
)
```
...to this:
```dart
child: new DecoratedBox(
decoration: new BoxDecoration(
backgroundImage: new BackgroundImage(
image: new AssetImage('my_asset.png'),
...
),
...
),
child: ...
)
```
DETAILED CHANGE LOG
===================
The following APIs have been replaced in this patch:
* The `AssetImage` and `NetworkImage` widgets have been split in two,
with identically-named `ImageProvider` subclasses providing the
image-loading logic, and a single `Image` widget providing all the
widget tree logic.
* `ImageResource` is now `ImageStream`. Rather than configuring it with
a `Future<ImageInfo>`, you complete it with an `ImageStreamCompleter`.
* `ImageCache.load` and `ImageCache.loadProvider` are replaced by
`ImageCache.putIfAbsent`.
The following APIs have changed in this patch:
* `ImageCache` works in terms of arbitrary keys and caches
`ImageStreamCompleter` objects using those keys. With the new model,
you should never need to interact with the cache directly.
* `Decoration` can now be `const`. The state has moved to the
`BoxPainter` class. Instead of a list of listeners, there's now just a
single callback and a `dispose()` method on the painter. The callback
is passed in to the `createBoxPainter()` method. When invoked, you
should repaint the painter.
The following new APIs are introduced:
* `AssetBundle.loadStructuredData`.
* `SynchronousFuture`, a variant of `Future` that calls the `then`
callback synchronously. This enables the asynchronous and
synchronous (in-the-cache) code paths to look identical yet for the
latter to avoid returning to the event loop mid-paint.
* `ExactAssetImage`, a variant of `AssetImage` that doesn't do anything clever.
* `ImageConfiguration`, a class that describes parameters that configure
the `AssetImage` resolver.
The following APIs are entirely removed by this patch:
* `AssetBundle.loadImage` is gone. Use an `AssetImage` instead.
* `AssetVendor` is gone. `AssetImage` handles everything `AssetVendor`
used to handle.
* `RawImageResource` and `AsyncImage` are gone.
The following code-level changes are performed:
* `Image`, which replaces `AsyncImage`, `NetworkImage`, `AssetImage`,
and `RawResourceImage`, lives in `image.dart`.
* `DecoratedBox` and `Container` live in their own file now,
`container.dart` (they reference `image.dart`).
DIRECTIONS FOR FUTURE RESEARCH
==============================
* The `ImageConfiguration` fields are mostly aspirational. Right now
only `devicePixelRatio` and `bundle` are implemented. `locale` isn't
even plumbed through, it will require work on the localisation logic.
* We should go through and make `BoxDecoration`, `AssetImage`, and
`NetworkImage` objects `const` where possible.
* This patch makes supporting animated GIFs much easier.
* This patch makes it possible to create an abstract concept of an
"Icon" that could be either an image or a font-based glyph (using
`IconData` or similar). (see
https://github.com/flutter/flutter/issues/4494)
RELATED ISSUES
==============
Fixes https://github.com/flutter/flutter/issues/4500
Fixes https://github.com/flutter/flutter/issues/4495
Obsoletes https://github.com/flutter/flutter/issues/4496
I was also going to implement sorting and emptying the cart but the
current data model doesn't make that easy, so I gave up on that. That's
why the TODOs are moved around though.
