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。

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

Beginning with Android 17, the system enforces a strict memory limit on RemoteViews updates for apps targeting Android 17 (API level 37) or higher. When an app passes a RemoteViews object to AppWidgetManager.updateAppWidget, system_server calculates the total memory footprint of all image data across every orientation and size bucket in the payload. If the total memory exceeds the system ceiling (mMaxWidgetBitmapMemory), the system rejects the update and throws an IllegalArgumentException:

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

For apps targeting API level 36 or lower, the system logs this memory violation as a warning (Slog.w) without throwing an exception.

How the system calculates the memory ceiling

The system sets the widget bitmap memory budget at 6 * width * height bytes (1.5 * 4 * width * height, equivalent to 1.5 times the size of a full-screen ARGB_8888 buffer) for the active display configuration. Under API level 37 and higher, this calculation includes both of the following:

  • In-memory Bitmap and bitmap-backed Icon objects (Icon.TYPE_BITMAP and Icon.TYPE_ADAPTIVE_BITMAP) stored in RemoteViews.mBitmapCache (such as calls to setImageViewBitmap, Icon.createWithBitmap, Icon.createWithAdaptiveBitmap, or Jetpack Glance ImageProvider(bitmap)). Each unique Bitmap or bitmap-backed Icon instance in mBitmapCache is counted once per RemoteViews hierarchy.
  • URI-backed images (Icon.createWithContentUri, setImageViewUri, or Glance ImageProvider(uri)) don't count toward the RemoteViews IPC byte cap in system_server, but the widget host process decodes the referenced content:// file at full resolution into its own heap. Prefer passing a downsampled Bitmap directly in memory (androidx.glance.ImageProvider(bitmap) or setImageViewBitmap), as FileProvider URI permission grants fail when a work-profile widget is placed on a personal home screen. If your widget must use a FileProvider URI, always write a downsampled image into context.cacheDir first.

Mitigation steps

To keep your widget updates within the memory ceiling across phones, tablets, and foldables, do the following:

  1. Compute your runtime memory budget from WindowMetrics: On API level 30 and higher, read the active window bounds from WindowManager.currentWindowMetrics.bounds rather than resources.displayMetrics. On multi-resolution devices and foldables, displayMetrics can report inactive display dimensions. Estimate your total widget image budget at 6L * bounds.width() * bounds.height() as shown in the following example:

    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. Downsample images to the widget's viewable dimensions and use RGB_565: Decode bitmaps with power-of-two BitmapFactory.Options.inSampleSize values sized to the widget's maximum display dimensions (maxWidthDp by maxHeightDp), and use Bitmap.Config.RGB_565 (2 bytes per pixel) instead of ARGB_8888 (4 bytes per pixel) for opaque photographs and thumbnails.

  3. Hoist bitmap decoding outside provideContent in Jetpack Glance: When using SizeMode.Responsive or SizeMode.Exact, Glance invokes your provideContent lambda once per size bucket. Decode each shared Bitmap once inside provideGlance before calling provideContent so all size buckets reference the same Bitmap instance in RemoteViews.mBitmapCache.

  4. Use full updateAppWidget calls when replacing images: In classic AppWidgetProvider implementations, avoid calling AppWidgetManager.partiallyUpdateAppWidget to swap Bitmap or Icon views. Partial updates merge new actions into the existing RemoteViews tree in system_server without evicting previously cached image actions. Build a complete RemoteViews layout and call updateAppWidget instead.

  5. Provide an error fallback layout: In Jetpack Glance, override onCompositionError to render a zero-bitmap RemoteViews fallback if an update fails.

You can inspect your widget's current serialized bitmap memory usage on a connected device by running the following:

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

Beginning with Android 17, apps targeting Android 17 (API level 37) or higher receive a new lock-free implementation of android.os.MessageQueue. The new implementation improves performance and reduces missed frames, but may break clients that reflect on MessageQueue private fields and methods.

For more information, including mitigation strategies, see MessageQueue behavior change guidance.

静态 final 字段现在不可修改

Apps running on Android 17 or higher that target Android 17 (API level 37) or higher cannot change static final fields. If an app attempts to change a static final field by using reflection, it will cause an IllegalAccessException. Attempting to modify one of these fields through JNI APIs (such as SetStaticLongField()) will cause the app to crash.

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.

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

从 Android 17 开始，Android 将扩展其短信动态密码保护功能，使其适用于标准短信（包含动态密码但不使用 WebOTP 或短信检索器格式的短信）。对于大多数以 Android 17（API 级别 37）或更高版本为目标平台的应用，这些短信在收到 3 小时后才可供使用。此延迟旨在帮助防止动态密码被劫持。在这 3 小时的延迟期间，SMS_RECEIVED_ACTION 广播会被扣留，短信提供商数据库查询会被过滤。延迟后，这些应用便可收到短信。

某些应用（例如默认短信助理应用、已连接设备的配套应用等）不受此延迟的影响。所有依赖读取短信来提取动态密码的应用都应改用 SMS Retriever 或 SMS User Consent API，以确保功能正常运行。

安全

Android 17 对设备和应用安全性进行了以下改进。

Activity 安全性

在 Android 17 中，平台继续向“默认安全”架构转变，引入了一系列旨在缓解高严重性漏洞利用（例如钓鱼式攻击、互动劫持和混淆代理攻击）的增强功能。此次更新要求开发者明确选择启用新的安全标准，以保持应用兼容性并保护用户。

对开发者产生的主要影响包括：

  • BAL 强化和改进的选择启用：我们正在优化后台 activity 启动 (BAL) 限制，将保护范围扩展到 IntentSender。开发者必须停止使用旧版 MODE_BACKGROUND_ACTIVITY_START_ALLOWED 常量。相反，您应该采用精细控制，例如 MODE_BACKGROUND_ACTIVITY_START_ALLOW_IF_VISIBLE，它会将 activity 启动限制在调用应用可见的场景中，从而显著减少攻击面。
  • 采用工具：开发者应利用严格模式和更新后的 lint 检查来识别旧版模式，并确保为未来的目标 SDK 要求做好准备。

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

For apps targeting Android 17 (API level 37) and higher, Contacts Provider 2 (CP2) restricts certain columns containing Personally Identifiable Information (PII) from the data view. When this change is enabled, these columns are removed from the data view to enhance user privacy. The restricted columns include:

Apps that are using these columns from ContactsContract.Data can extract them from ContactsContract.RawContacts instead, by joining with RAW_CONTACT_ID.

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

在某些设备上，内容捕获功能默认处于启用状态，以便设备端 AI 功能分析屏幕内容，从而提供智能体验。

从 Android 17 开始，ContentCaptureManager.setContentCaptureEnabled(boolean) API 方法已被废弃。对于以 Android 17（API 级别 37）或更高版本为目标平台的应用，调用 setContentCaptureEnabled(false) 不再会停用内容捕获功能。

如果您的应用需要继续停用内容捕获功能或限制系统捕获屏幕内容，您必须改用 FLAG_SECURE 窗口布局参数。

如需停用内容捕获，请在窗口中设置 FLAG_SECURE 标志，如以下示例所示：

Kotlin

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

Java

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

如需了解详情，请参阅 WindowManager.LayoutParams.FLAG_SECURE 参考文档。

媒体

Android 17 包含以下媒体行为变更。

后台音频强化

从 Android 17 开始，音频框架会对后台音频互动（包括音频播放、音频焦点请求和音量更改 API）施加限制，以确保这些更改是由用户有意发起的。

部分音频限制适用于所有应用。不过，如果应用以 Android 17（API 级别 37）为目标平台，则限制会更加严格。如果其中一个应用在后台运行时与音频互动，则必须运行前台服务。此外，应用还必须满足以下一项或两项要求：

  • 前台服务必须具有“仅在使用时允许”(WIU) 功能。
  • 应用必须具有精确闹钟权限，并且正在与 USAGE_ALARM 音频串流互动。

如需了解详情（包括缓解措施），请参阅后台音频安全加固。

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

我们在 Android 16 中引入了平台 API 变更，以便针对以 API 级别 36 或更高级别为目标平台的应用，忽略大屏设备（sw >= 600dp）上的屏幕方向、尺寸调整和宽高比限制。开发者可以选择在 SDK 36 中选择退出这些变更，但对于以 Android 17（API 级别 37）或更高版本为目标平台的应用，此选择退出选项将不再可用。

如需了解详情，请参阅系统会忽略对屏幕方向和可调整大小性的限制。

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

For apps targeting Android 17 (API level 37), the read() method of the InputStream obtained from an RFCOMM-based BluetoothSocket now returns -1 when the socket is closed or the connection is dropped.

This change makes RFCOMM socket behavior consistent with LE CoC sockets and aligns with the standard InputStream.read() documentation, which states that -1 is returned when the end of the stream is reached.

Apps that rely solely on catching an IOException to break out of a read loop may be impacted by this change and should update the BluetoothSocket read loops to explicitly check for a return value of -1. This ensures the loop terminates correctly when the remote device disconnects or the socket is closed. For an example of the recommended implementation, see the code snippet in the Transfer Bluetooth data guide.