行为变更:以 Android 15 或更高版本为目标平台的应用

与以前的版本一样,Android 15 包含一些行为变更,这些变更可能会影响您的应用。以下行为变更仅影响以 Android 15 或更高版本为目标平台的应用。如果您的应用以 Android 15 或更高版本为目标平台,您应该修改自己的应用以适当地支持这些行为(如果适用)。

此外,请务必查看对 Android 15 上运行的所有应用都有影响的行为变更列表(无论应用的 targetSdkVersion 如何)。

核心功能

Android 15 修改或扩展了 Android 系统的各种核心功能。

前台服务的变更

我们将对 Android 15 中的前台服务做出以下更改。

数据同步前台服务超时行为

Android 15 introduces a new timeout behavior to dataSync for apps targeting Android 15 or higher. This behavior also applies to the new mediaProcessing foreground service type.

The system permits an app's dataSync services to run for a total of 6 hours in a 24-hour period, after which the system calls the running service's Service.onTimeout(int, int) method (introduced in Android 15). At this time, the service has a few seconds to call Service.stopSelf(). When Service.onTimeout() is called, the service is no longer considered a foreground service. If the service does not call Service.stopSelf(), the system throws an internal exception. The exception is logged in Logcat with the following message:

Fatal Exception: android.app.RemoteServiceException: "A foreground service of
type dataSync did not stop within its timeout: [component name]"

To avoid problems with this behavior change, you can do one or more of the following:

  1. Have your service implement the new Service.onTimeout(int, int) method. When your app receives the callback, make sure to call stopSelf() within a few seconds. (If you don't stop the app right away, the system generates a failure.)
  2. Make sure your app's dataSync services don't run for more than a total of 6 hours in any 24-hour period (unless the user interacts with the app, resetting the timer).
  3. Only start dataSync foreground services as a result of direct user interaction; since your app is in the foreground when the service starts, your service has the full six hours after the app goes to the background.
  4. Instead of using a dataSync foreground service, use an alternative API.

If your app's dataSync foreground services have run for 6 hours in the last 24, you cannot start another dataSync foreground service unless the user has brought your app to the foreground (which resets the timer). If you try to start another dataSync foreground service, the system throws ForegroundServiceStartNotAllowedException with an error message like "Time limit already exhausted for foreground service type dataSync".

Testing

To test your app's behavior, you can enable data sync timeouts even if your app is not targeting Android 15 (as long as the app is running on an Android 15 device). To enable timeouts, run the following adb command:

adb shell am compat enable FGS_INTRODUCE_TIME_LIMITS your-package-name

You can also adjust the timeout period, to make it easier to test how your app behaves when the limit is reached. To set a new timeout period, run the following adb command:

adb shell device_config put activity_manager data_sync_fgs_timeout_duration duration-in-milliseconds

新增媒体处理前台服务类型

Android 15 introduces a new foreground service type, mediaProcessing. This service type is appropriate for operations like transcoding media files. For example, a media app might download an audio file and need to convert it to a different format before playing it. You can use a mediaProcessing foreground service to make sure the conversion continues even while the app is in the background.

The system permits an app's mediaProcessing services to run for a total of 6 hours in a 24-hour period, after which the system calls the running service's Service.onTimeout(int, int) method (introduced in Android 15). At this time, the service has a few seconds to call Service.stopSelf(). If the service does not call Service.stopSelf(), the system throws an internal exception. The exception is logged in Logcat with the following message:

Fatal Exception: android.app.RemoteServiceException: "A foreground service of
type mediaProcessing did not stop within its timeout: [component name]"

To avoid having the exception, you can do one of the following:

  1. Have your service implement the new Service.onTimeout(int, int) method. When your app receives the callback, make sure to call stopSelf() within a few seconds. (If you don't stop the app right away, the system generates a failure.)
  2. Make sure your app's mediaProcessing services don't run for more than a total of 6 hours in any 24-hour period (unless the user interacts with the app, resetting the timer).
  3. Only start mediaProcessing foreground services as a result of direct user interaction; since your app is in the foreground when the service starts, your service has the full six hours after the app goes to the background.
  4. Instead of using a mediaProcessing foreground service, use an alternative API, like WorkManager.

If your app's mediaProcessing foreground services have run for 6 hours in the last 24, you cannot start another mediaProcessing foreground service unless the user has brought your app to the foreground (which resets the timer). If you try to start another mediaProcessing foreground service, the system throws ForegroundServiceStartNotAllowedException with an error message like "Time limit already exhausted for foreground service type mediaProcessing".

For more information about the mediaProcessing service type, see Changes to foreground service types for Android 15: Media processing.

Testing

To test your app's behavior, you can enable media processing timeouts even if your app is not targeting Android 15 (as long as the app is running on an Android 15 device). To enable timeouts, run the following adb command:

adb shell am compat enable FGS_INTRODUCE_TIME_LIMITS your-package-name

You can also adjust the timeout period, to make it easier to test how your app behaves when the limit is reached. To set a new timeout period, run the following adb command:

adb shell device_config put activity_manager data_sync_fgs_timeout_duration duration-in-milliseconds

对启动前台服务的 BOOT_COMPLETED 广播接收器的限制

There are new restrictions on BOOT_COMPLETED broadcast receivers launching foreground services. BOOT_COMPLETED receivers are not allowed to launch the following types of foreground services:

If a BOOT_COMPLETED receiver tries to launch any of those types of foreground services, the system throws ForegroundServiceStartNotAllowedException.

限制在应用拥有 SYSTEM_ALERT_WINDOW 权限的情况下启动前台服务

Previously, if an app held the SYSTEM_ALERT_WINDOW permission, it could launch a foreground service even if the app was currently in the background (as discussed in exemptions from background start restrictions).

If an app targets Android 15, this exemption is now narrower. The app now needs to have the SYSTEM_ALERT_WINDOW permission and also have a visible overlay window. That is, the app needs to first launch a TYPE_APPLICATION_OVERLAY window and the window needs to be visible before you start a foreground service.

If your app attempts to start a foreground service from the background without meeting these new requirements (and it does not have some other exemption), the system throws ForegroundServiceStartNotAllowedException.

If your app declares the SYSTEM_ALERT_WINDOW permission and launches foreground services from the background, it may be affected by this change. If your app gets a ForegroundServiceStartNotAllowedException, check your app's order of operations and make sure your app already has an active overlay window before it attempts to start a foreground service from the background. You can check if your overlay window is currently visible by calling View.getWindowVisibility(), or you can override View.onWindowVisibilityChanged() to get notified whenever the visibility changes.

Testing

To test your app's behavior, you can enable these new restrictions even if your app is not targeting Android 15 (as long as the app is running on an Android 15 device). To enable these new restrictions on starting foreground services from the background, run the following adb command:

adb shell am compat enable FGS_SAW_RESTRICTIONS your-package-name

更改了应用何时可以修改勿扰模式的全局状态

以 Android 15 为目标平台的应用无法再更改设备上的全局状态或勿扰 (DND) 政策(通过修改用户设置或关闭 DND 模式)。相反,应用必须提供一个 AutomaticZenRule,系统会将后者合并到一个具有现有最严格的政策胜出方案的全局政策中。调用之前影响全局状态的现有 API(setInterruptionFiltersetNotificationPolicy)会导致创建或更新隐式 AutomaticZenRule,该 AutomaticZenRule 根据这些 API 调用的调用周期而开启或关闭。

请注意,只有在应用调用 setInterruptionFilter(INTERRUPTION_FILTER_ALL) 且预期调用会停用之前由其所有者激活的 AutomaticZenRule 时,此变更才会影响可观察的行为。

OpenJDK 17 变更

Android 15 continues the work of refreshing Android's core libraries to align with the features in the latest OpenJDK LTS releases.

One of these changes can affect app compatibility for apps targeting Android 15 (API level 35):

  • Changes to string formatting APIs: Validation of argument index, flags, width, and precision are now more strict when using the following String.format() and Formatter.format() APIs:

    For example, the following exception is thrown when an argument index of 0 is used (%0 in the format string):

    IllegalFormatArgumentIndexException: Illegal format argument index = 0
    

    In this case, the issue can be fixed by using an argument index of 1 (%1 in the format string).

  • Changes to component type of Arrays.asList(...).toArray(): When using Arrays.asList(...).toArray(), the component type of the resulting array is now an Object—not the type of the underlying array's elements. So the following code throws a ClassCastException:

    String[] elements = (String[]) Arrays.asList("one", "two").toArray();
    

    For this case, to preserve String as the component type in the resulting array, you could use Collection.toArray(Object[]) instead:

    String[] elements = Arrays.asList("two", "one").toArray(new String[0]);
    
  • Changes to language code handling: When using the Locale API, language codes for Hebrew, Yiddish, and Indonesian are no longer converted to their obsolete forms (Hebrew: iw, Yiddish: ji, and Indonesian: in). When specifying the language code for one of these locales, use the codes from ISO 639-1 instead (Hebrew: he, Yiddish: yi, and Indonesian: id).

  • Changes to random int sequences: Following the changes made in https://bugs.openjdk.org/browse/JDK-8301574, the following Random.ints() methods now return a different sequence of numbers than the Random.nextInt() methods do:

    Generally, this change shouldn't result in app-breaking behavior, but your code shouldn't expect the sequence generated from Random.ints() methods to match Random.nextInt().

安全

Android 15 包含一些有助于提升系统安全性的变更,以帮助保护应用和用户免受恶意应用的侵害。

安全的后台 activity 启动

Android 15 protects users from malicious apps and gives them more control over their devices by adding changes that prevent malicious background apps from bringing other apps to the foreground, elevating their privileges, and abusing user interaction. Background activity launches have been restricted since Android 10 (API level 29).

Block apps that don't match the top UID on the stack from launching activities

Malicious apps can launch another app's activity within the same task, then overlay themselves on top, creating the illusion of being that app. This "task hijacking" attack bypasses current background launch restrictions because it all occurs within the same visible task. To mitigate this risk, Android 15 adds a flag that blocks apps that don't match the top UID on the stack from launching activities. To opt in for all of your app's activities, update the allowCrossUidActivitySwitchFromBelow attribute in your app's AndroidManifest.xml file:

<application android:allowCrossUidActivitySwitchFromBelow="false" >

The new security measures are active if all of the following are true:

  • The app performing the launch targets Android 15.
  • The app on top of the task stack targets Android 15.
  • Any visible activity has opted in to the new protections

If the security measures are enabled, apps might return home, rather than the last visible app, if they finish their own task.

Other changes

In addition to the restriction for UID matching, these other changes are also included:

  • Change PendingIntent creators to block background activity launches by default. This helps prevent apps from accidentally creating a PendingIntent that could be abused by malicious actors.
  • Don't bring an app to the foreground unless the PendingIntent sender allows it. This change aims to prevent malicious apps from abusing the ability to start activities in the background. By default, apps are not allowed to bring the task stack to the foreground unless the creator allows background activity launch privileges or the sender has background activity launch privileges.
  • Control how the top activity of a task stack can finish its task. If the top activity finishes a task, Android will go back to whichever task was last active. Moreover, if a non-top activity finishes its task, Android will go back to the home screen; it won't block the finish of this non-top activity.
  • Prevent launching arbitrary activities from other apps into your own task. This change prevents malicious apps from phishing users by creating activities that appear to be from other apps.
  • Block non-visible windows from being considered for background activity launches. This helps prevent malicious apps from abusing background activity launches to display unwanted or malicious content to users.

更安全的 intent

Android 15 引入了新的安全措施,旨在提高 intent 的安全性和稳健性。这些更改旨在防范潜在漏洞和滥用被恶意应用利用的 intent。Android 15 对 intent 的安全性做出了两项主要改进:

  • 匹配目标 intent 过滤器:以特定组件为目标的 intent 必须准确匹配目标的 intent 过滤器规范。如果您发送 intent 来启动其他应用的 activity,则目标 intent 组件需要与接收 activity 声明的 intent 过滤器保持一致。
  • intent 必须有操作:没有操作的 intent 将不再匹配任何 intent 过滤器。这意味着,用于启动 activity 或服务的 intent 必须具有明确定义的操作。

Kotlin


fun onCreate() {
    StrictMode.setVmPolicy(VmPolicy.Builder()
        .detectUnsafeIntentLaunch()
        .build()
    )
}

Java


public void onCreate() {
    StrictMode.setVmPolicy(new VmPolicy.Builder()
            .detectUnsafeIntentLaunch()
            .build());
}

用户体验和系统界面

Android 15 包含一些旨在打造更一致、更直观的用户体验的变更。

窗口边衬区更改

Android 15 中有两个与窗口边衬区相关的变更:默认强制执行无边框模式;还存在配置变更,例如系统栏的默认配置。

全面强制执行

如果应用以 Android 15 为目标平台,则在搭载 Android 15 的设备上默认采用无边框应用。

应用以 Android 14 为目标平台且在 Android 15 设备上并非全屏显示的应用。


一个以 Android 15 为目标平台且在 Android 15 设备上实现无边框的应用。此应用主要使用可自动应用边衬区的 Material 3 Compose 组件。此屏幕不会受到 Android 15 无边框强制执行的影响。

这是一项重大变更,可能会对应用的界面产生负面影响。这些更改会影响以下界面区域:

  • 手势手柄导航栏
    • 默认为透明。
    • 底部偏移已停用,因此除非应用边衬区,否则内容会绘制在系统导航栏后面。
    • setNavigationBarColorR.attr#navigationBarColor 已废弃,不会影响手势导航。
    • setNavigationBarContrastEnforcedR.attr#navigationBarContrastEnforced 仍然对手势导航没有影响。
  • “三按钮”导航
    • 不透明度默认设置为 80%,颜色可能与窗口背景匹配。
    • 已停用底部偏移,因此内容绘制在系统导航栏后面,除非应用边衬区。
    • 默认情况下,setNavigationBarColorR.attr#navigationBarColor 设置为与窗口背景匹配。窗口背景必须是彩色可绘制对象,才能应用此默认设置。此 API 已废弃,但会继续影响“三按钮”导航。
    • setNavigationBarContrastEnforcedR.attr#navigationBarContrastEnforced 默认情况下为 true,这会在“三按钮”导航中添加 80% 的不透明背景。
  • 状态栏
    • 默认为透明。
    • 顶部偏移量已停用,因此,除非应用边衬区,否则内容会显示在状态栏后面。
    • setStatusBarColorR.attr#statusBarColor 已废弃,对 Android 15 没有任何影响。
    • setStatusBarContrastEnforcedR.attr#statusBarContrastEnforced 已废弃,但在 Android 15 上仍然有效。
  • 刘海屏
    • 非浮动窗口的 layoutInDisplayCutoutMode 必须为 LAYOUT_IN_DISPLAY_CUTOUT_MODE_ALWAYSSHORT_EDGESNEVERDEFAULT 会被解释为 ALWAYS,这样用户就不会看到由刘海屏导致的黑条,而无边框。

以下示例展示了以 Android 15 为目标平台之前和之后以及应用边衬区前后的应用。

应用以 Android 14 为目标平台且在 Android 15 设备上并非全屏显示的应用。
一个以 Android 15 为目标平台且在 Android 15 设备上实现无边框的应用。不过,由于 Android 15 的无边框强制措施,许多元素现在被状态栏、“三按钮”导航栏或刘海屏遮挡。被遮盖的界面包括 Material 2 顶部应用栏、悬浮操作按钮和列表项。
如果应用以 Android 15 为目标平台,则可以在 Android 15 设备上全屏显示,并会应用边衬区来避免界面被遮挡。
检查应用是否已无边框的检查方法

如果您的应用已经无边框并应用了边衬区,则基本上不受影响,下列场景除外。不过,即使您认为自己不受影响,我们也建议您测试自己的应用。

  • 您有一个非浮动窗口,例如,使用 SHORT_EDGESNEVERDEFAULT(而非 LAYOUT_IN_DISPLAY_CUTOUT_MODE_ALWAYS)的 Activity。如果您的应用在启动时崩溃,这可能是由于启动画面所致。您可以将核心启动画面依赖项升级到 1.2.0-alpha01 或更高版本,也可以设置 window.attributes.layoutInDisplayCutoutMode = WindowManager.LayoutInDisplayCutoutMode.always
  • 可能存在流量较低且界面被遮挡的屏幕。验证这些访问较少的屏幕没有被遮挡的界面。流量较低的屏幕包括:
    • 初始配置或登录屏幕
    • “设置”页面
如果您的应用还不是无边框应用的,请检查哪些内容

如果您的应用尚未边缘化,那么您很有可能受到影响。除了已实现无边框应用的场景之外,您还应考虑以下事项:

  • 如果应用在 Compose 中使用 Material 3 组件 (androidx.compose.material3)(例如 TopAppBarBottomAppBarNavigationBar),这些组件可能不会受到影响,因为它们会自动处理边衬区。
  • 如果应用在 Compose 中使用 Material 2 组件 (androidx.compose.material),这些组件不会自动处理边衬区。不过,您可以访问边衬区并手动应用边衬区。在 androidx.compose.material 1.6.0 及更高版本中,使用 windowInsets 参数为 BottomAppBarTopAppBarBottomNavigationNavigationRail 手动应用边衬区。同样,请为 Scaffold 使用 contentWindowInsets 参数。
  • 如果您的应用使用视图和 Material 组件 (com.google.android.material),大多数基于视图的 Material 组件(例如 BottomNavigationViewBottomAppBarNavigationRailViewNavigationView)会处理边衬区,无需额外的工作。不过,如果使用 AppBarLayout,则需要添加 android:fitsSystemWindows="true"
  • 对于自定义可组合项,请手动应用边衬区作为内边距。如果您的内容位于 Scaffold 内,您可以使用 Scaffold 内边距值消耗边衬区。否则,请使用 WindowInsets 之一应用内边距。
  • 如果您的应用使用的是视图和 BottomSheetSideSheet 或自定义容器,请使用 ViewCompat.setOnApplyWindowInsetsListener 应用内边距。对于 RecyclerView,请使用此监听器应用内边距,并添加 clipToPadding="false"
检查应用是否必须提供自定义后台保护的事项

如果您的应用必须为“三按钮”导航或状态栏提供自定义后台保护,则应使用 WindowInsets.Type#tappableElement() 获取“三按钮”导航栏高度或 WindowInsets.Type#statusBars,将可组合项或视图放置在系统栏后面。

其他无边框资源

如需了解应用边衬区的其他注意事项,请参阅边缘视图Edge to Edge Compose 指南。

已弃用的 API

以下 API 现已废弃:

稳定配置

如果您的应用以 Android 15 或更高版本为目标平台,Configuration 将不再排除系统栏。如果您在 Configuration 类中使用屏幕尺寸计算布局,则应根据需要将其替换为合适的 ViewGroupWindowInsetsWindowMetricsCalculator 等更好的替代方案。

从 API 1 开始,Configuration 一直可用。它通常从 Activity.onConfigurationChanged 获取。它可提供窗口密度、方向和大小等信息。从 Configuration 返回的窗口大小的一个重要特征是它之前排除了系统栏。

配置大小通常用于资源选择(如 /res/layout-h500dp),这仍然是一个有效的用例。不过,我们一直不建议将其用于布局计算。如果这样做,您应该立即离开。您应该根据自己的使用场景,将 Configuration 替换为更合适的代码。

如果您使用其计算布局,请使用适当的 ViewGroup,例如 CoordinatorLayoutConstraintLayout。如果您使用它来确定系统导航栏的高度,请使用 WindowInsets。如果您想知道应用窗口的当前大小,请使用 computeCurrentWindowMetrics

以下列表介绍了受此更改影响的字段:

EnglishTextHeight 属性默认为 true

对于以 Android 15 为目标平台的应用,elegantTextHeight TextView 属性默认变为 true,将默认使用的紧凑字体替换为一些具有较大垂直指标的脚本,并且这种字体更易于阅读。紧凑字体的引入是为了防止破坏布局;Android 13(API 级别 33)允许文本布局利用 fallbackLineSpacing 属性拉伸垂直高度,以防止许多此类破坏。

在 Android 15 中,紧凑字体仍保留在系统中,因此您的应用可以将 elegantTextHeight 设置为 false,以获得与之前相同的行为,但即将在未来版本中提供支持。因此,如果您的应用支持以下文字:阿拉伯语、老挝语、缅甸、泰米尔语、古吉拉特语、卡纳达语、马拉雅拉姆语、奥里亚语、泰卢固语或泰语,请将 elegantTextHeight 设置为 true,以测试应用。

以 Android 14(API 级别 34)及更低版本为目标平台的应用的 elegantTextHeight 行为。
以 Android 15 为目标平台的应用的 elegantTextHeight 行为。

复杂字母形状的 TextView 宽度变化

In previous versions of Android, some cursive fonts or languages that have complex shaping might draw the letters in the previous or next character's area. In some cases, such letters were clipped at the beginning or ending position. Starting in Android 15, a TextView allocates width for drawing enough space for such letters and allows apps to request extra paddings to the left to prevent clipping.

Because this change affects how a TextView decides the width, TextView allocates more width by default if the app targets Android 15 or higher. You can enable or disable this behavior by calling the setUseBoundsForWidth API on TextView.

Because adding left padding might cause a misalignment for existing layouts, the padding is not added by default even for apps that target Android 15 or higher. However, you can add extra padding to preventing clipping by calling setShiftDrawingOffsetForStartOverhang.

The following examples show how these changes can improve text layout for some fonts and languages.

Standard layout for English text in a cursive font. Some of the letters are clipped. Here is the corresponding XML:

<TextView
    android:fontFamily="cursive"
    android:text="java" />
Layout for the same English text with additional width and padding. Here is the corresponding XML:

<TextView
    android:fontFamily="cursive"
    android:text="java"
    android:useBoundsForWidth="true"
    android:shiftDrawingOffsetForStartOverhang="true" />
Standard layout for Thai text. Some of the letters are clipped. Here is the corresponding XML:

<TextView
    android:text="คอมพิวเตอร์" />
Layout for the same Thai text with additional width and padding. Here is the corresponding XML:

<TextView
    android:text="คอมพิวเตอร์"
    android:useBoundsForWidth="true"
    android:shiftDrawingOffsetForStartOverhang="true" />

EditText 的语言区域感知型默认行高

在以前的 Android 版本中,文本布局拉伸了文本的高度,使其适应与当前语言区域匹配的字体的行高。例如,如果内容是日语,由于日语字体的行高比拉丁字体的行高略大,因此文本的高度就略大了。不过,尽管行高存在这些差异,但无论使用何种语言区域,EditText 元素的大小都是一致的,如下图所示:

三个表示 EditText 元素的框,这些框可以包含英语 (en)、日语 (ja) 和缅甸语 (my) 的文本。EditText 的高度相同,即使这两种语言的行高不同。

对于以 Android 15 为目标平台的应用,系统现在会为 EditText 预留最小行高,以匹配指定语言区域的参考字体,如下图所示:

三个表示 EditText 元素的框,这些框可以包含英语 (en)、日语 (ja) 和缅甸语 (my) 的文本。EditText 的高度现在包含空间,可适应这些语言字体的默认行高。

如果需要,您的应用可以通过将 useLocalePreferredLineHeightForMinimum 属性设置为 false 来恢复之前的行为,并且可以通过 Kotlin 和 Java 中的 setMinimumFontMetrics API 设置自定义最小行业指标。

摄像头和媒体

对于以 Android 15 或更高版本为目标平台的应用,Android 15 对相机和媒体行为做出了以下变更。

请求音频焦点的限制

Apps that target Android 15 must be the top app or running an audio-related foreground service in order to request audio focus. If an app attempts to request focus when it does not meet one of these requirements, the call returns AUDIOFOCUS_REQUEST_FAILED.

A foreground service is considered audio-related if its type is mediaPlayback, camera, microphone, or phoneCall.

You can learn more about audio focus at Manage audio focus.

更新后的非 SDK 限制

Android 15 包含更新后的受限非 SDK 接口列表(基于与 Android 开发者之间的协作以及最新的内部测试)。在限制使用非 SDK 接口之前,我们会尽可能确保有可用的公开替代方案。

如果您的应用并非以 Android 15 为目标平台,其中一些变更可能不会立即对您产生影响。不过,虽然您的应用可以访问某些非 SDK 接口(具体取决于应用的目标 API 级别),但使用任何非 SDK 方法或字段始终存在导致应用出问题的显著风险。

如果您不确定自己的应用是否使用了非 SDK 接口,则可以测试该应用进行确认。如果您的应用依赖于非 SDK 接口,则应开始计划迁移到 SDK 替代方案。不过,我们知道某些应用具有使用非 SDK 接口的有效用例。如果您无法为应用中的功能找到无需使用非 SDK 接口的替代方案,则应请求新的公共 API

如需详细了解此 Android 版本中的变更,请参阅 Android 15 中有关限制非 SDK 接口的更新。如需全面了解有关非 SDK 接口的详细信息,请参阅对非 SDK 接口的限制