行为变更：以 Android 17 或更高版本为目标平台的应用

与之前的版本一样，Android 17 包含一些可能会影响应用的行为变更。以下行为变更仅影响以 Android 17 或更高版本为目标平台的应用。如果您的应用以 Android 17 或更高版本为目标平台，您应该修改自己的应用以支持这些行为（如果适用）。

无论应用的 targetSdkVersion 为何，都请务必查看对 Android 17 上运行的所有应用都有影响的行为变更列表。

注意： 本页面列出了一些较为重要的变更。如需了解详情，请参阅 Android 17 版本说明。

用户体验和系统界面

Android 17 包含以下变更，旨在打造更一致、更直观的用户体验。

内存上限微件

从 Android 17 开始，系统会对以 Android 17（API 级别 37）或更高版本为目标平台的应用的 RemoteViews 更新强制执行严格的内存限制。当应用将 RemoteViews 对象传递给 AppWidgetManager.updateAppWidget 时，system_server 会计算载荷中每个方向和大小存储桶中所有图片数据的总内存占用。如果总内存超出系统上限 (mMaxWidgetBitmapMemory)，系统会拒绝更新并抛出 IllegalArgumentException：

java.lang.IllegalArgumentException: RemoteViews for widget update exceeds maximum bitmap memory usage (used: XXXXX, max: YYYYY)

对于以 API 级别 36 或更低级别为目标平台的应用，系统会将此内存违规行为记录为警告 (Slog.w)，而不会抛出异常。

Android skills

在 GitHub 上查看

管理 AppWidget 更新和位图内存

使用 AppWidget 更新和内存 Android 技能，对 widget 位图进行降采样，删除重复的自适应图片，并确保 Glance 和传统 AppWidgetProvider widget 均符合 Android 17 RemoteViews 内存限制。

如需从 Android CLI 安装技能，请运行以下命令：

android skills add glance-appwidget-updates-and-memory

系统如何计算内存上限

系统会将活跃显示配置的 widget 位图内存预算设置为 6 * width * height 字节（1.5 * 4 * width * height，相当于全屏 ARGB_8888 缓冲区大小的 1.5 倍）。在 API 级别 37 及更高级别下，此计算包括以下两项：

• 存储在 RemoteViews.mBitmapCache 中的内存中 Bitmap 和位图支持的 Icon 对象（Icon.TYPE_BITMAP 和 Icon.TYPE_ADAPTIVE_BITMAP），例如对 setImageViewBitmap、Icon.createWithBitmap、Icon.createWithAdaptiveBitmap 或 Jetpack Glance ImageProvider(bitmap) 的调用。mBitmapCache 中每个唯一的 Bitmap 或位图支持的 Icon 实例在每个 RemoteViews 层次结构中都会被计数一次。
• URI 支持的图片（Icon.createWithContentUri、setImageViewUri 或 Glance ImageProvider(uri)）不计入 system_server 中的 RemoteViews IPC 字节上限，但 widget 宿主进程会以完整分辨率将引用的 content:// 文件解码到其自己的堆中。在通过 FileProvider URI 公开降采样图片之前，请务必先将其写入 context.cacheDir。

缓解步骤

为了确保在手机、平板电脑和可折叠设备上，微件更新不会超出内存上限，请执行以下操作：

1. 根据 WindowMetrics 计算运行时内存预算：在 API 级别 30 及更高级别，从 WindowManager.currentWindowMetrics.bounds 而不是 resources.displayMetrics 读取活动窗口边界。在多分辨率设备和可折叠设备上，displayMetrics 可能会报告非活动显示屏尺寸。将总微件图片预算估算为 6L * bounds.width() * bounds.height()，如以下示例所示：

   private const val FALLBACK_MAX_BYTES = 15_000_000L
   
   fun calculateWidgetMemoryCapBytes(context: Context): Long {
       if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
           val wm = context.getSystemService(WindowManager::class.java)
               ?: return FALLBACK_MAX_BYTES
           val bounds = wm.currentWindowMetrics.bounds
           return 6L * bounds.width().toLong() * bounds.height().toLong()
       }
       val dm = context.resources.displayMetrics
       return 6L * dm.widthPixels.toLong() * dm.heightPixels.toLong()
   }
   

2. 将图片降采样到微件的可查看尺寸，并使用 RGB_565：使用 2 的幂 BitmapFactory.Options.inSampleSize 值（大小为微件的最大显示尺寸 [maxWidthDp x maxHeightDp]）解码位图，并对不透明的照片和缩略图使用 Bitmap.Config.RGB_565（每个像素 2 字节）而不是 ARGB_8888（每个像素 4 字节）。

3. 在 Jetpack Glance 中，将位图解码提升到 provideContent 之外：使用 SizeMode.Responsive 或 SizeMode.Exact 时，Glance 会针对每个尺寸分桶调用一次 provideContent lambda。在调用 provideContent 之前，在 provideGlance 中对每个共享的 Bitmap 解码一次，以便所有大小存储桶都引用 RemoteViews.mBitmapCache 中的同一 Bitmap 实例。

4. 替换图片时使用完整的 updateAppWidget 调用：在传统 AppWidgetProvider 实现中，避免调用 AppWidgetManager.partiallyUpdateAppWidget 来交换 Bitmap 或 Icon 视图。部分更新会将新操作合并到 system_server 中的现有 RemoteViews 树中，而不会逐出之前缓存的映像操作。构建完整的 RemoteViews 布局，并改为调用 updateAppWidget。

5. 提供错误后备布局：在 Jetpack Glance 中，替换 onCompositionError，以便在更新失败时呈现零位图 RemoteViews 后备。

您可以通过运行以下命令，在已连接的设备上检查微件当前的序列化位图内存用量：

adb shell dumpsys appwidget

核心功能

Android 17 包含以下变更，这些变更会修改或扩展 Android 系统的各种核心功能。

MessageQueue 的全新无锁实现

从 Android 17 开始，以 Android 17（API 级别 37）或更高版本为目标平台的应用会收到 android.os.MessageQueue 的全新无锁实现。新实现可提升性能并减少丢帧，但可能会破坏反映 MessageQueue 私有字段和方法的客户端。

如需了解详情（包括缓解措施），请参阅 MessageQueue 行为变更指南。

静态 final 字段现在不可修改

在 Android 17 或更高版本上运行且以 Android 17（API 级别 37）或更高版本为目标平台的应用无法更改 static final 字段。如果应用尝试使用反射来更改 static final 字段，则会导致 IllegalAccessException。尝试通过 JNI API（例如 SetStaticLongField()）修改其中一个字段会导致应用崩溃。

无障碍

Android 17 进行了以下更改，以改进无障碍功能。

复杂 IME 实体键盘输入的无障碍支持

This feature introduces new AccessibilityEvent and TextAttribute APIs to enhance screen reader spoken feedback for CJKV language input. CJKV IME apps can now signal whether a text conversion candidate has been selected during text composition. Apps with edit fields can specify text change types when sending text changed accessibility events. For example, apps can specify that a text change occurred during text composition, or that a text change resulted from a commit. Doing this enables accessibility services such as screen readers to deliver more precise feedback based on the nature of the text modification.

App adoption

• IME Apps: When setting composing text in edit fields, IMEs can use TextAttribute.Builder.setTextSuggestionSelected() to indicate whether a specific conversion candidate was selected.

• Apps with Edit Fields: Apps that maintain a custom InputConnection can retrieve candidate selection data by calling TextAttribute.isTextSuggestionSelected(). These apps should then call AccessibilityEvent.setTextChangeTypes() when dispatching TYPE_VIEW_TEXT_CHANGED events. Apps targeting Android 17 (API level 37) that use the standard TextView will have this feature enabled by default. (That is, TextView will handle retrieving data from the IME and setting text change types when sending events to accessibility services).

• Accessibility Services: Accessibility services that process TYPE_VIEW_TEXT_CHANGED events can call AccessibilityEvent.getTextChangeTypes() to identify the nature of the modification and adjust their feedback strategies accordingly.

隐私权

Android 17 包含以下旨在改进用户隐私保护的变更。

已启用 ECH（加密客户端 Hello）

Android 17 introduces platform support for Encrypted Client Hello (ECH), a TLS extension that enhances user privacy by encrypting the Server Name Indication (SNI) in the TLS handshake. This encryption helps prevent network observers from easily identifying the specific domain your app is connecting to.

For apps targeting Android 17 (API level 37) or higher, ECH is used for TLS connections. ECH is active only if the networking library used by the app (for example, HttpEngine, WebView, or OkHttp) has integrated ECH support and the remote server also supports the ECH protocol. If ECH cannot be negotiated, the client sends an ECH extension with randomized contents (a mechanism called ECH GREASE). See RFC 9849 for more details on how ECH GREASE works.

To allow apps to customize this behavior, Android 17 adds a new <domainEncryption> element to the Network Security Configuration file. Developers can use <domainEncryption> within <base-config> or <domain-config> tags to select an ECH mode (for example, "enabled" or "disabled") on a global or per-domain basis.

For more information, see the Encrypted Client Hello documentation.

以 Android 17 为目标平台的应用需要本地网络权限

Android 17 introduces the ACCESS_LOCAL_NETWORK runtime permission to protect users from unauthorized local network access. Because this falls under the existing NEARBY_DEVICES permission group, users who have already granted other NEARBY_DEVICES permissions aren't prompted again. This new requirement prevents malicious apps from exploiting unrestricted local network access for covert user tracking and fingerprinting. By declaring and requesting this permission, your app can discover and connect to devices on the local area network (LAN), such as smart home devices or casting receivers.

Apps targeting Android 17 (API level 37) or higher now have two paths to maintain communication with LAN devices: Adopt system-mediated, privacy-preserving device pickers to skip the permission prompt, or explicitly request this new permission at runtime to maintain local network communication.

For more information, see the Local network permission documentation.

Note: In Android 16, apps could opt in to local network permissions. Beginning with Android 17, enforcement is mandatory for apps that target Android 17 (API level 37) or higher.

在实体设备上隐藏密码

If an app targets Android 17 (API level 37) or higher and the user is using a physical input device (for example, an external keyboard), the Android operating system applies the new show_passwords_physical setting to all characters in the password field. By default, that setting hides all password characters.

The Android system shows the last-typed password character to help the user see if they mistyped the password. However, this is much less necessary with larger external keyboards. In addition, devices with external keyboards often have larger displays, which increases the danger of someone seeing the typed password.

If the user is using the device's touchscreen, the system applies the new show_passwords_touch setting.

针对标准短信的动态密码保护

Beginning with Android 17, Android is extending its SMS OTP protection to apply to standard SMS messages (SMS messages containing an OTP that do not use the WebOTP or SMS Retriever formats). For most apps targeting Android 17 (API level 37) or higher, these SMS messages do not become available until three hours after receipt. This delay is intended to help prevent OTP hijacking. During this three hour delay, the SMS_RECEIVED_ACTION broadcast is withheld and SMS provider database queries are filtered. The SMS message is available to these apps after the delay.

Certain apps such as the default SMS assistant app, connected device companion apps, etc., are exempted from this delay. All apps that rely on reading SMS messages for OTP extraction should transition to using SMS Retriever or SMS User Consent APIs to ensure continued functionality.

Note: Additional SMS OTP protections for WebOTP and SMS Retriever format messages apply to all apps, regardless of their target API level. For more information, see SMS OTP protection in the Behavior changes for all apps documentation.

安全

Android 17 对设备和应用安全性进行了以下改进。

Activity 安全性

In Android 17, the platform continues its shift toward a "secure-by-default" architecture, introducing a suite of enhancements designed to mitigate high-severity exploits such as phishing, interaction hijacking, and confused deputy attacks. This update requires developers to explicitly opt in to new security standards to maintain app compatibility and user protection.

Key impacts for developers include:

• BAL hardening & improved opt-in: We are refining Background Activity Launch (BAL) restrictions by extending protections to IntentSender. Developers must migrate away from the legacy MODE_BACKGROUND_ACTIVITY_START_ALLOWED constant. Instead, you should adopt granular controls like MODE_BACKGROUND_ACTIVITY_START_ALLOW_IF_VISIBLE, which restricts activity starts to scenarios where the calling app is visible, significantly reducing the attack surface.
• Adoption tools: Developers should utilize strict mode and updated lint checks to identify legacy patterns and ensure readiness for future target SDK requirements.

默认启用 CT

If an app targets Android 17 (API level 37) or higher, certificate transparency (CT) is enabled by default. (On Android 16, CT is available but apps had to opt in.)

更安全的原生 DCL - C

If your app targets Android 17 (API level 37) or higher, the Safer Dynamic Code Loading (DCL) protection introduced in Android 14 for DEX and JAR files now extends to native libraries.

All native files loaded using System.load() must be marked as read-only. Otherwise, the system throws UnsatisfiedLinkError.

We recommend that apps avoid dynamically loading code whenever possible, as doing so greatly increases the risk that an app can be compromised by code injection or code tampering.

限制 CP2 数据视图中的 PII 字段

对于以 Android 17（API 级别 37）及更高版本为目标平台的应用，Contacts Provider 2 (CP2) 会限制数据视图中包含个人身份信息 (PII) 的某些列。启用此变更后，系统会从数据视图中移除这些列，以加强用户隐私保护。 受限列包括：

• ACCOUNT_NAME
• ACCOUNT_TYPE
• ACCOUNT_TYPE_AND_DATA_SET

使用 ContactsContract.Data 中这些列的应用可以改为通过与 RAW_CONTACT_ID 联接，从 ContactsContract.RawContacts 中提取这些列。

在 CP2 中强制执行严格的 SQL 检查

对于以 Android 17（API 级别 37）及更高版本为目标平台的应用，如果在没有 READ_CONTACTS 权限的情况下访问 ContactsContract.Data 表，Contacts Provider 2 (CP2) 会强制执行严格的 SQL 查询验证。

做出此项更改后，如果应用没有 READ_CONTACTS 权限，则在查询 ContactsContract.Data 表时会设置 StrictColumns 和 StrictGrammar 选项。如果查询使用的模式与这些模式不兼容，则会被拒绝并导致抛出异常。

智能

Android 17 包含对系统智能的以下变更。

废弃 setContentCaptureEnabled

Content Capture is enabled by default on certain devices to allow on-device AI features to analyze screen contents for intelligent experiences.

Starting in Android 17, the ContentCaptureManager.setContentCaptureEnabled(boolean) API method is deprecated. For apps that target Android 17 (API level 37) or higher, calling setContentCaptureEnabled(false) no longer disables Content Capture.

If your app needs to continue disabling Content Capture or restrict screen contents from being captured by the system, you must transition to using the FLAG_SECURE window layout parameter.

To disable Content Capture, set the FLAG_SECURE flag on your window as shown in the following example:

Kotlin

window.setFlags(
    WindowManager.LayoutParams.FLAG_SECURE,
    WindowManager.LayoutParams.FLAG_SECURE
)

Java

getWindow().setFlags(
    WindowManager.LayoutParams.FLAG_SECURE,
    WindowManager.LayoutParams.FLAG_SECURE
);

For more details, see the WindowManager.LayoutParams.FLAG_SECURE reference documentation.

媒体

Android 17 包含以下媒体行为变更。

后台音频强化

Beginning with Android 17, the audio framework enforces restrictions on background audio interactions including audio playback, audio focus requests, and volume change APIs to ensure that these changes are started intentionally by the user.

Some audio restrictions apply to all apps. However, the restrictions are more stringent if an app targets Android 17 (API level 37). If one of these apps interacts with audio while it is in the background, it must have a foreground service running. In addition, the app must meet one or both of these requirements:

• The foreground service must have while-in-use (WIU) capabilities.
• The app must have the exact alarm permission and be interacting with USAGE_ALARM audio streams.

For more information, including mitigation strategies, see Background audio hardening.

设备规格

Android 17 包含以下变更，旨在提升各种尺寸和外形规格的设备上的用户体验。

平台 API 变更，在大屏设备 (sw>=600dp) 上忽略屏幕方向、尺寸调整和宽高比限制

We introduced Platform API changes in Android 16 to ignore orientation, resizability, and aspect ratio restrictions on large screens (sw >= 600dp) for apps targeting API level 36 or higher. Developers have the option to opt out of these changes with SDK 36, but this opt-out will no longer be available for apps that target Android 17 (API level 37) or higher.

For more information, see Restrictions on orientation and resizability are ignored.

连接

Android 17 引入了以下变更，以提高一致性并与蓝牙 RFCOMM 套接字的标准 Java InputStream 行为保持一致。

RFCOMM 的 BluetoothSocket read() 行为保持一致

对于以 Android 17（API 级别 37）为目标平台的应用，当套接字关闭或连接断开时，从基于 RFCOMM 的 BluetoothSocket 获取的 InputStream 的 read() 方法现在会返回 -1。

此项变更使 RFCOMM 套接字行为与 LE CoC 套接字保持一致，并与标准 InputStream.read() 文档保持一致，该文档指出，当到达数据流末尾时，会返回 -1。

仅依赖于捕获 IOException 来跳出读取循环的应用可能会受到此变更的影响，应更新 BluetoothSocket 读取循环，以明确检查返回值是否为 -1。这样可确保在远程设备断开连接或套接字关闭时，循环正确终止。如需查看推荐实现的示例，请参阅传输蓝牙数据指南中的代码段。