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[1]
Developer Keynote (Google I/O '21) [2]
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[3]
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[4]
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[5]
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[6]
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[7]
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[8]
•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[9]
可以直接去看文章: New APIs in the Android Gradle Plugin[10]
Using Jetpack libraries in Compose | Session[11]
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[12]
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.
