Google I/O 2021 Android精华内容
Google I/O 2021结束了, 都有什么精彩内容呢?
Android部分的Playlist附上: Android & Play at Google I/O 2021
Developer Keynote (Google I/O '21)
对于Android的部分来说, 主要是:
Android 12
- user safety.
- performance; improved app startup; customizable launch animations.
- user experience; widgets.
Create beautiful apps, easier
现代化的Android开发.
- Android Studio的升级.
- Kotlin: Kotlin Symbol Processing.
- Jetpack: 各种libraries和Compose.
Build across screens.
- 各种屏幕.
- Voice.
- Watches: Health services.
The top 3 things to know in Modern Android Development | Android @ Google I/O'21
Android开发的三个top topic:
- Jetpack: 一系列的Jetpack libraries发布了新版.
- Tooling: Android Studio的升级, 有了WorkManager Inspector, UI的Inspector支持了View和Compose.
- Kotlin.
What's new in Android | Keynote
Android 12 -> S.
@Deprecated-> deprecated.- Color.
- Widgets.
- Launch animations: 系统自带启动动画, 可以定制.
- Notifications: 新的template style;
Trampoline(?) 优化点开notification的那个短暂延迟. - Toasts: 带icon, 说明是哪个app弹的toasts; 控制个数.
- Picture in Picture的改善.
- ImageView有个setRenderEffect可以模糊照片了.
- 可以用theme定制模糊.
- list的弹力拉伸效果. (我自己起的名字, 其实人家叫stretch overscroll).
- Graphics: AVIF. 可以过滤支持的media类型.
- Privacy: 关于permission的一些改进; 剪贴板内容会有toast说明来源; foreground restrictions.
What’s new in Android development tools | Session
Android Studio版本号设计.
- Preview工具可以设置横屏, 定制尺寸, 显示blueprints, play animation. Compose的preview有交互模式.
- Accessibility test framework scanner.
- 适配多种屏幕: Layout validation.
- 折叠屏, 手表.
- 模拟器还可以模拟heart rate.
- snapshots test.
- WorkManager的tasks.
- Migrate to Non-Transitive R Classes...
What’s new in Jetpack | Session
解释了Jetpack的初衷和现状.
alpha和beta版本的意思.
- Experimental Annotations -> Stable.
- CameraX -> Stable.
- AppSearch -> Alpha.
- DataStore -> 用来取代SharedPreferences.
- Security Crypto -> Stable.
- Hilt -> Stable.
- WorkManager -> Stable. (Android Studio也推出了新的WorkManager Inspector.)
- Room -> Stable.
- ConstraintLayout -> Stable. MotionLayout + Motion Editor.
- Fragment -> Stable.
(详见release notes: https://developer.android.com/jetpack/androidx/releases/fragment.)
重建了FragmentManager; 新增了get result的callback; 废弃了一些API, 并且Fragment StrictMode可以检测项目中是否还在使用. - Navigation -> Alpha. 现在支持多个backstacks.
- Google Shortcuts -> Alpha.
- EmojiCompat -> Alpha. (AppCompat 1.4.0以后默认包含.)
- Paging -> Stable.
- Macrobenchmark -> Alpha. (app启动和滚动效率; local/CI.)
- Compose integrations.
What's new in Jetpack Compose | Session
为什么我们需要一个全新的UI Toolkit呢. -> 为了适应更加现代化的开发方式.
faster & easier.
Compose将数据转换成UI.
Checkbox的例子:
UI完全由参数控制. -> single source of truth. 没有其他的状态需要sync.
把参数和回调提到方法参数中去:
- You completely describe your UI for a given state.
- The framework updates your UI when the state changes.
这里有个图, 推荐ViewModel暴露一个Screen状态, 集中管理, 然后下发到每个composable.
这样也利于测试.
Compose实现了material design, 提供了组件, 还有theming system.
有一个owl app的实现解说.
和传统view的interop.
State of Kotlin on Android | Session
- Kotlin变得越来越流行, 不仅app, 还有server.
- Kotlin Symbol Processing目前发布了alpha.
- 编译器的升级.
- 好多好多的ktx库.
- protobuf的支持: https://developers.google.com/protocol-buffers/docs/kotlintutorial
- coroutines的debugger -> coming soon. 可以在线程之间跳转, 查看信息.
What’s new in Android Gradle plugin | Session
New APIs in the Android Gradle Plugin
Using Jetpack libraries in Compose | Session
Jetpack Compose和Jetpack中其他库可以很好的结合使用.
Top 12 tips to get ready for Android 12 | Session
Getting Ready for Android 12.
- Developer Options -> App Compatibility Changes.
- Foreground services were designed for multi-tasking and completing a user action. -> 从后台启动foreground services将被限制.
- Expedited Jobs with WorkManager APIs.
- User may turn off the mic and camera sensors using mic and camera toggles.
- Apps that have not been used for an extended period will be hibernated. (permissions, storage, services)
- Nearby device permission. Decouple Bluetooth scanning from Location.
- MAC address restriction.
- Safe component exporting. 有intent filter就必须显式声明exported.
- Custom notifications deprecation.
- App link improvements.
- WebView Samesite.
- New stretch overscroll.
