功能與 API 總覽

Android 14 為開發人員推出了強大的新功能和 API。下列說明 您將瞭解應用程式有哪些功能,並開始使用相關的 API。

如需新增、修改及移除 API 的詳細清單,請參閱 API 差異比較表。如要進一步瞭解新增的 API,請參閱 Android API 參考資料。 在 Android 14 中,找出在 API 級別 34 中新增的 API。如要瞭解平台變更可能對應用程式造成的影響,請務必查看指定 Android 14 的應用程式所有應用程式 的 Android 14 行為變更。

國際化

個別應用程式語言偏好

Android 14 進一步延伸 Android 13 (API 級別 33) 所推出的個別應用程式語言功能,並新增多項功能:

  • 自動產生應用程式的 localeConfig:自 Android Studio Giraffe Canary 7 和 AGP 8.1.0-alpha07 起,您可以將應用程式設為自動支援個別應用程式語言偏好設定。Android Gradle 外掛程式會根據您的專案資源產生 LocaleConfig 檔案,並在最終資訊清單檔案中為該檔案新增參照,為您省去手動建立或更新檔案的需求。AGP 會使用應用程式模組 res 資料夾中的資源和任何程式庫模組依附元件,以決定要納入 LocaleConfig 檔案的語言代碼。

  • 應用程式 localeConfig 的動態更新:請使用 法LocaleManager 中的 setOverrideLocaleConfig()getOverrideLocaleConfig() 方法,以動態方式更新應用程式在裝置的系統設定中的支援語言清單。如果應用程式使用伺服器端推送進行本地化,則可利用此彈性自訂各區域的支援語言清單、執行 A/B 實驗,或提供更新的語言代碼清單。

  • 輸入法編輯器 (IME) 的應用程式語言瀏覽權限:輸入法編輯器可透過 getApplicationLocales() 方法檢查當前應用程式的語言,並和輸入法編輯器的語言進行比對。

文法轉變 API

3 billion people speak gendered languages: languages where grammatical categories—such as nouns, verbs, adjectives, and prepositions—inflect according to the gender of people and objects you talk to or about. Traditionally, many gendered languages use masculine grammatical gender as the default or generic gender.

Addressing users in the wrong grammatical gender, such as addressing women in masculine grammatical gender, can negatively impact their performance and attitude. In contrast, a UI with language that correctly reflects the user's grammatical gender can improve user engagement and provide a more personalized and natural-sounding user experience.

為了協助你針對使用文法性別的語言,建構以使用者為中心的使用者介面,Android 14 採用了文法轉變 API,可讓你新增對文法性別的支援,而不必重構應用程式。

地區偏好設定

Regional preferences enable users to personalize temperature units, the first day of the week, and numbering systems. A European living in the United States might prefer temperature units to be in Celsius rather than Fahrenheit and for apps to treat Monday as the beginning of the week instead of the US default of Sunday.

New Android Settings menus for these preferences provide users with a discoverable and centralized location to change app preferences. These preferences also persist through backup and restore. Several APIs and intents—such as getTemperatureUnit and getFirstDayOfWeek— grant your app read access to user preferences, so your app can adjust how it displays information. You can also register a BroadcastReceiver on ACTION_LOCALE_CHANGED to handle locale configuration changes when regional preferences change.

To find these settings, open the Settings app and navigate to System > Languages & input > Regional preferences.

Regional preferences screen in Android system settings.
Temperature options for regional preferences in Android system settings.

無障礙設定

非線性字型縮放至 200%

Starting in Android 14, the system supports font scaling up to 200%, providing low-vision users with additional accessibility options that align with Web Content Accessibility Guidelines (WCAG).

To prevent large text elements on screen from scaling too large, the system applies a nonlinear scaling curve. This scaling strategy means that large text doesn't scale at the same rate as smaller text. Nonlinear font scaling helps preserve the proportional hierarchy between elements of different sizes while mitigating issues with linear text scaling at high degrees (such as text being cut off or text that becomes harder to read due to an extremely large display sizes).

Test your app with nonlinear font scaling

Enable the maximum font size in a device's accessibility settings to test your app.

If you already use scaled pixels (sp) units to define text sizing, then these additional options and scaling improvements are applied automatically to the text in your app. However, you should still perform UI testing with the maximum font size enabled (200%) to ensure that your app applies the font sizes correctly and can accommodate larger font sizes without impacting usability.

To enable 200% font size, follow these steps:

  1. Open the Settings app and navigate to Accessibility > Display size and text.
  2. For the Font size option, tap the plus (+) icon until the maximum font size setting is enabled, as shown in the image that accompanies this section.

Use scaled pixel (sp) units for text-sizes

Remember to always specify text sizes in sp units. When your app uses sp units, Android can apply the user's preferred text size and scale it appropriately.

Don't use sp units for padding or define view heights assuming implicit padding: with nonlinear font scaling sp dimensions might not be proportional, so 4sp + 20sp might not equal 24sp.

Convert scaled pixel (sp) units

Use TypedValue.applyDimension() to convert from sp units to pixels, and use TypedValue.deriveDimension() to convert pixels to sp. These methods apply the appropriate nonlinear scaling curve automatically.

Avoid hardcoding equations using Configuration.fontScale or DisplayMetrics.scaledDensity. Because font scaling is nonlinear, the scaledDensity field is no longer accurate. The fontScale field should be used for informational purposes only because fonts are no longer scaled with a single scalar value.

Use sp units for lineHeight

Always define android:lineHeight using sp units instead of dp, so the line height scales along with your text. Otherwise, if your text is sp but your lineHeight is in dp or px, it doesn't scale and looks cramped. TextView automatically corrects the lineHeight so that your intended proportions are preserved, but only if both textSize and lineHeight are defined in sp units.

相機與媒體

圖片的 Ultra HDR

標準動態範圍 (SDR) 與高動態範圍 (HDR) 圖片品質的比較圖。

Android 14 新增了對高動態範圍 (HDR) 圖片的支援,可在拍攝相片時保留更多感應器資訊,進而呈現鮮豔的色彩和更強烈的對比。Android 使用 Ultra HDR 格式,可與 JPEG 圖片完全相容,讓應用程式與 HDR 圖片無縫互動,並視需要以標準動態範圍 (SDR) 顯示。

當應用程式選擇為活動視窗使用 HDR UI (透過資訊清單項目或在執行階段呼叫 Window.setColorMode()),架構會自動在 UI 中以 HDR 格式轉譯這些圖片。您也可以在支援的裝置上拍攝壓縮的超高動態範圍靜態圖片。感應器可復原更多顏色,因此後製編輯的彈性更高。與 Ultra HDR 影像相關聯的 Gainmap 可用於使用 OpenGL 或 Vulkan 轉譯這些影像。

相機擴充功能提供縮放、對焦、貼文檢視畫面和其他功能

Android 14 會升級及改善相機擴充功能,讓應用程式能夠處理更長的處理時間,在支援裝置上使用低光源攝影等需要大量運算的演算法,改善圖片品質。這些功能可讓使用者在使用相機擴充功能時,享有更完善的體驗。這些改善措施包括:

感應器縮放功能

CameraCharacteristics 中的 REQUEST_AVAILABLE_CAPABILITIES_STREAM_USE_CASE 包含 SCALER_AVAILABLE_STREAM_USE_CASES_CROPPED_RAW 時,應用程式可以使用進階感應器功能,透過 CaptureRequest 和 RAW 目標 (其串流用途已設為 CameraMetadata.SCALER_AVAILABLE_STREAM_USE_CASES_CROPPED_RAW),為經裁剪的 RAW 串流提供與全景視野相同的像素。透過實作要求覆寫控制項,更新後的相機可在其他相機控制項準備就緒前,提供縮放控制選項。

無損 USB 音訊

Android 14 gains support for lossless audio formats for audiophile-level experiences over USB wired headsets. You can query a USB device for its preferred mixer attributes, register a listener for changes in preferred mixer attributes, and configure mixer attributes using the AudioMixerAttributes class. This class represents the format, such as channel mask, sample rate, and behavior of the audio mixer. The class allows for audio to be sent directly, without mixing, volume adjustment, or processing effects.

開發人員工作效率和工具

Credential Manager

Android 14 會新增 Credential Manager 做為平台 API,並透過使用 Google Play 服務的 Jetpack 程式庫,進一步支援 Android 4.4 (API 級別 19) 裝置。Credential Manager 的目標是透過 API 協助使用者輕鬆登入,這些 API 會透過使用者設定的憑證提供者擷取及儲存憑證。Credential Manager 可在單一 API 中支援多種登入方式,包括使用者名稱和密碼、密碼金鑰,以及聯合登入解決方案 (例如使用 Google 帳戶登入)。

密碼金鑰具有許多優點,舉例來說,密碼金鑰採用業界標準,可在不同作業系統和瀏覽器環境中運作,也能與網站和應用程式搭配使用。

如需更多資訊,請參閱 Credential Manager 和密碼金鑰說明文件,以及Credential Manager 和密碼金鑰相關網誌文章

Health Connect

Health Connect 是裝置端的使用者健康與健身資料存放區。這項功能可讓使用者在喜愛的應用程式之間分享資料,並透過單一介面控管要與這些應用程式分享的資料。

在 Android 14 以下版本的裝置上,Health Connect 可透過 Google Play 商店下載為應用程式。自 Android 14 起,Health Connect 將成為平台的一部分,並透過 Google Play 系統更新接收更新,無須另外下載。如此一來,Health Connect 就能經常更新,您的應用程式也可以在搭載 Android 14 以上版本的裝置上使用 Health Connect。使用者可以透過裝置的「設定」存取 Health Connect,系統設定中已整合隱私權控制選項。

使用者可以在搭載 Android 14 以上版本的裝置上開始使用 Health Connect,無須另外下載應用程式。
使用者可透過系統設定控管哪些應用程式可存取其健康與健身資料。

Health Connect 在 Android 14 中提供多項新功能,例如運動路線,可讓使用者分享健身路線,並在地圖上顯示。路線的定義是指在一段時間內儲存的地點清單,應用程式可將路線插入運動時段,將路線連結在一起。為確保使用者能完全控管這類私密資料,使用者必須允許與其他應用程式共用個別路線。

詳情請參閱 Health Connect 說明文件和「Android 健康資料新功能」一文。

OpenJDK 17 更新

Android 14 持續更新 Android 核心程式庫,以便與最新版 OpenJDK LTS 中的功能保持一致,其中包括程式庫更新以及應用程式與平台開發人員的 Java 17 語言支援。

新功能和改善項目如下:

  • 已將約 300 個 java.base 類別更新至可支援 Java 17。
  • 文字模塊已針對 Java 程式設計語言推出多行字串常值。
  • instanceof 的模式比對可讓您在 instanceof 中,不需要使用其他變數,即可將物件視為具有特定類型處理。
  • 密封類別可讓您限制可進行擴充或實作的類別與介面。

進行 Google Play 系統更新 (Mainline 計畫) 之後,超過 6 億部裝置將可收到包含這些變更的最新 Android 執行階段 (ART) 更新。這是我們承諾的一部分,讓應用程式在各種裝置上都能夠擁有更一致、安全的環境,同時為各平台版本的使用者提供新的功能與能力。

Java 和 OpenJDK 是 Oracle 和/或其關係企業的商標或註冊商標。

應用程式商店改善項目

Android 14 introduces several PackageInstaller APIs that allow app stores to improve their user experience.

Request install approval before downloading

Installing or updating an app might require user approval. For example, when an installer making use of the REQUEST_INSTALL_PACKAGES permission attempts to install a new app. In prior Android versions, app stores can only request user approval after APKs are written to the install session and the session is committed.

Starting with Android 14, the requestUserPreapproval() method lets installers request user approval before committing the install session. This improvement lets an app store defer downloading any APKs until after the installation has been approved by the user. Furthermore, once a user has approved installation, the app store can download and install the app in the background without interrupting the user.

Claim responsibility for future updates

The setRequestUpdateOwnership() method allows an installer to indicate to the system that it intends to be responsible for future updates to an app it is installing. This capability enables update ownership enforcement, meaning that only the update owner is permitted to install automatic updates to the app. Update ownership enforcement helps to ensure that users receive updates only from the expected app store.

Any other installer, including those making use of the INSTALL_PACKAGES permission, must receive explicit user approval in order to install an update. If a user decides to proceed with an update from another source, update ownership is lost.

Update apps at less-disruptive times

App stores typically want to avoid updating an app that is actively in use because this leads to the app's running processes being killed, which potentially interrupts what the user was doing.

Starting with Android 14, the InstallConstraints API gives installers a way to ensure that their app updates happen at an opportune moment. For example, an app store can call the commitSessionAfterInstallConstraintsAreMet() method to make sure that an update is only committed when the user is no longer interacting with the app in question.

Seamlessly install optional splits

With split APKs, features of an app can be delivered in separate APK files, rather than as a monolithic APK. Split APKs allow app stores to optimize the delivery of different app components. For example, app stores might optimize based on the properties of the target device. The PackageInstaller API has supported splits since its introduction in API level 22.

In Android 14, the setDontKillApp() method allows an installer to indicate that the app's running processes shouldn't be killed when new splits are installed. App stores can use this feature to seamlessly install new features of an app while the user is using the app.

應用程式中繼資料套件

從 Android 14 開始,Android 套件安裝程式可讓您指定應用程式中繼資料 (例如資料安全性做法),以加入 Google Play 等應用程式商店頁面。

在使用者擷取裝置螢幕畫面時偵測

To create a more standardized experience for detecting screenshots, Android 14 introduces a privacy-preserving screenshot detection API. This API lets apps register callbacks on a per-activity basis. These callbacks are invoked, and the user is notified, when the user takes a screenshot while that activity is visible.

使用者體驗

Sharesheet 自訂動作與改善排名

Android 14 updates the system sharesheet to support custom app actions and more informative preview results for users.

Add custom actions

With Android 14, your app can add custom actions to the system sharesheet it invokes.

Screenshot of custom actions on the sharesheet.

Improve ranking of Direct Share targets

Android 14 uses more signals from apps to determine the ranking of the direct share targets to provide more helpful results for the user. To provide the most useful signal for ranking, follow the guidance for improving rankings of your Direct Share targets. Communication apps can also report shortcut usage for outgoing and incoming messages.

Direct Share row in the sharesheet, as shown by 1

支援預測返回功能的內建和自訂動畫

影片:預測返回動畫

Android 13 推出了在開發人員選項背後顯示「預測返回主畫面」動畫的功能。只要使用支援的應用程式,並啟用開發人員選項,當您執行滑動返回的操作時,系統就會顯示動畫,指出返回手勢可讓應用程式結束並返回主畫面。

Android 14 內含多項改善項目,並提供有關預測返回手勢的全新指南:

在這個 Android 14 預先發布版本中,所有預測返回相關功能都保留在開發人員選項後方。請參閱開發人員指南,瞭解如何讓應用程式改用預測返回功能,以及如何建立自訂的應用程式內轉場效果

大螢幕裝置製造商個別應用程式覆寫值

個別應用程式覆寫值可讓裝置製造商變更大螢幕裝置上的應用程式行為。舉例來說,即使應用程式資訊清單中已設定 resizeableActivity="false"FORCE_RESIZE_APP 覆寫值仍會指示系統根據螢幕尺寸調整應用程式大小 (避免大小相容性模式)。

覆寫設定的用意是改善大螢幕的使用者體驗。

新的資訊清單屬性可讓您為應用程式停用部分裝置製造商覆寫值。

大螢幕使用者個別應用程式覆寫值

Per-app overrides change the behavior of apps on large screen devices. For example, the OVERRIDE_MIN_ASPECT_RATIO_LARGE device manufacturer override sets the app aspect ratio to 16:9 regardless of the app's configuration.

Android 14 QPR1 enables users to apply per‑app overrides by means of a new settings menu on large screen devices.

分享應用程式畫面

分享應用程式畫面功能可讓使用者在錄製螢幕內容時,分享應用程式視窗,而非整個裝置畫面。

透過應用程式螢幕分享功能,系統會從共用畫面中排除狀態列、導覽列、通知和其他系統 UI 元素。只會分享所選應用程式的內容。

應用程式螢幕分享功能可讓使用者執行多個應用程式,但只分享單一應用程式的內容,進而提升工作效率和隱私權。

Pixel 8 Pro 上的 Gboard 支援 LLM 智慧回覆功能

On Pixel 8 Pro devices with the December Feature Drop, developers can try out higher-quality smart replies in Gboard powered by on-device Large Language Models (LLMs) running on Google Tensor.

This feature is available as a limited preview for US English in WhatsApp, Line, and KakaoTalk. It requires using a Pixel 8 Pro device with Gboard as your keyboard.

To try it out, first enable the feature in Settings > Developer Options > AiCore Settings > Enable Aicore Persistent.

Next, open a conversation in a supported app to see LLM-powered Smart Reply in Gboard's suggestion strip in response to incoming messages.

Gboard utilizes on-device LLMs to provide higher-quality smart replies.

圖形

路徑可供查詢及內插

Android 的 Path API 是一種強大且靈活的機制,可用於建立和算繪向量圖形,並具有描邊或填入路徑、從線段或二次方或三次方曲線建構路徑、執行布林運算以取得更複雜的形狀,或同時執行所有這些操作的功能。但有一個限制,就是無法找出路徑物件中的實際內容;物件的內部部分在建立後,無法明確顯示於呼叫端。

如要建立 Path,您必須呼叫 moveTo()lineTo()cubicTo() 等方法,以便新增路徑區隔。不過,您無法透過對該路徑提出詢問以瞭解確切的區隔,因此必須在建立時保留該資訊。

自 Android 14 起,您便可查詢路徑,找出其中的內容。首先,您需要使用 Path.getPathIterator API 取得 PathIterator 物件:

Kotlin

val path = Path().apply {
    moveTo(1.0f, 1.0f)
    lineTo(2.0f, 2.0f)
    close()
}
val pathIterator = path.pathIterator

Java

Path path = new Path();
path.moveTo(1.0F, 1.0F);
path.lineTo(2.0F, 2.0F);
path.close();
PathIterator pathIterator = path.getPathIterator();

接下來,您可以呼叫 PathIterator 逐一疊代區隔,並擷取每個區隔的所有必要資料。本範例使用封裝資料的 PathIterator.Segment 物件:

Kotlin

for (segment in pathIterator) {
    println("segment: ${segment.verb}, ${segment.points}")
}

Java

while (pathIterator.hasNext()) {
    PathIterator.Segment segment = pathIterator.next();
    Log.i(LOG_TAG, "segment: " + segment.getVerb() + ", " + segment.getPoints());
}

PathIterator 也提供 next() 的非分配式版本,可供您傳入緩衝區,以便保留單點資料。

內插類型是查詢 Path 資料的重要用途之一。例如,您可能想要在兩個不同路徑之間建立動畫 (或 變形)。為進一步簡化該使用情境,Android 14 也在 Path 中加入 interpolate() 方法。假設兩個路徑具有相同的內部結構,interpolate() 方法會使用該內插結果建立新的 Path。此範例會傳回形狀介於 pathotherPath 之間半行 (0 .5 的線性內插) 的路徑:

Kotlin

val interpolatedResult = Path()
if (path.isInterpolatable(otherPath)) {
    path.interpolate(otherPath, .5f, interpolatedResult)
}

Java

Path interpolatedResult = new Path();
if (path.isInterpolatable(otherPath)) {
    path.interpolate(otherPath, 0.5F, interpolatedResult);
}

Jetpack graphics-path 程式庫也會為舊版 Android 啟用類似的 API。

使用頂點和片段著色器的自訂網格

Android 一直支援使用自訂著色繪製三角形網格,但輸入網格格式僅限於少數預先定義的屬性組合。Android 14 新增了自訂網格支援功能,可將其定義為 三角形三角形條,並視需要編入索引。這些網格會使用自訂屬性、頂點步幅、變化,以及以 AGSL 編寫的頂點和片段著色器指定

頂點著色器會定義變化,例如位置和顏色,而片段著色器則可選擇定義像素的顏色,通常是使用頂點著色器建立的變化。如果片段著色器提供顏色,系統會使用繪製網格時選取的混合模式,將該顏色與目前的 Paint 顏色混合。統一變數可傳遞至片段和頂點著色器,以提供更多彈性。

Canvas 的硬體緩衝區轉譯器

為協助使用 Android 的 Canvas API 以硬體加速繪製至 HardwareBuffer,Android 14 推出了 HardwareBufferRenderer。如果您的用途涉及透過 SurfaceControl 與系統合成器通訊,以便繪製低延遲畫面,這個 API 就特別實用。