Android Weekly Issue #484

Don't let ViewModel know about framework level dependencies

ViewModel不應(yīng)該有framework的依賴.

文章里測試的寫法是那種嵌套的, 跟iOS很像的.

代碼: https://github.com/PatilShreyas/ViewModelGoodPractice

Testing Hybrid Jetpack Compose Apps

如何測試XML和Compose混合的UI.

Lift on scroll in Jetpack Compose

Top app bar在下面的內(nèi)容滾動上來以后, 會有一個(gè)高度提升顯示陰影的效果.

如何在Compose上實(shí)現(xiàn)這種liftOnScroll的效果呢.

val LazyListState.elevation: Dp
    get() = if (firstVisibleItemIndex == 0) {
        // For the first element, use the minimum of scroll offset and default elevation
        // i.e. a value between 0 and 4.dp
        minOf(firstVisibleItemScrollOffset.toFloat().dp, AppBarDefaults.TopAppBarElevation)
    } else {
        // If not the first element, always set elevation and show the shadow
        AppBarDefaults.TopAppBarElevation
    }

Composing palettes

Compose的調(diào)色板.
可以從Bitmap提取顏色.

demo: https://github.com/tkuenneth/android-demos/tree/master/misc/PaletteDemo

Effective Kotlin Item 50: Eliminate obsolete object references

我們要注意不要持有已經(jīng)不用的對象的引用.

尤其是這個(gè)對象很大或者很多的時(shí)候.

Exact alarm improvements-Android12

Android 12對鬧鐘的改進(jìn).

How to master Swipeable and NestedScroll modifiers in Jetpack Compose

要實(shí)現(xiàn)一個(gè)bottom sheet, 展開后是parent的全部高度, 內(nèi)容可以滾動, 但是header保持不動.

整體的實(shí)現(xiàn):
https://gist.github.com/arcadefire/7fe138c0ded1a36bee6dd57acdfa3d18

Using WorkManager on Android 12

Android 12加了前臺服務(wù)的啟動限制:
https://developer.android.com/about/versions/12/foreground-services

也就是說, 除了一些特殊情況, Android 12上不允許從后臺啟動前臺服務(wù).

所以在WorkManager 2.7開始, 對緊急的任務(wù)( expedited jobs)做了處理.

val request = OneTimeWorkRequestBuilder<HighPriorityWorker>()       
   .setExpedited(OutOfQuotaPolicy.RUN_AS_NON_EXPEDITED_WORK_REQUEST)   
   .build() 
WorkManager.getInstance(context).enqueue(request)

Controlling TextView MinWidth

關(guān)于TextView的最小寬度控制.

Seeing What Talkback Sees

可以查看Talkback看到的文字, debug accessibility的信息.

Code

• https://github.com/kojofosu/Quantitizer
• https://github.com/microsoft/surface-duo-window-manager-samples/tree/main/TravelPlanner
• https://github.com/manueldidonna/waves-timer-animation 倒計(jì)時(shí), 有一個(gè)水流向下的動畫.
• https://github.com/sarnavakonar/Gamebaaz 一個(gè)用kotlin做前后端的完整應(yīng)用.
• https://github.com/square/workflow-kotlin 狀態(tài)機(jī).

News

• Hilt extensions