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

We are making the following changes to foreground services with Android 15.

• Data sync foreground service timeout behavior
• New media processing foreground service type
• Restrictions on BOOT_COMPLETED broadcast receivers launching foreground services
• Restrictions on starting foreground services while an app holds the SYSTEM_ALERT_WINDOW permission

Data sync foreground service timeout behavior

Android 15 针对以目标平台为目标平台的应用为 dataSync 引入了新的超时行为 Android 15 或更高版本。这一行为也适用于新的 mediaProcessing 前台服务类型。

系统允许应用的 dataSync 服务总共运行 6 小时 之后，系统会调用正在运行的服务的 Service.onTimeout(int, int) 方法（在 Android 中引入） 15）。此时，服务有几秒钟的时间来调用 Service.stopSelf().调用 Service.onTimeout() 时， 服务不再被视为前台服务。如果该服务没有 调用 Service.stopSelf() 时，系统会抛出内部异常。通过 Logcat 中会记录以下异常：

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

注意： 6 小时的时间限制由应用的所有 dataSync 前台使用 服务。例如，如果应用运行 dataSync 服务 4 小时， 之后启动另一项 dataSync 服务，则第二项服务将只能 允许其投放两小时不过，如果用户将应用调到 计时器会重置，并且应用还有 6 小时的可用时间。

为避免这种行为变更出现问题，您可以执行下列一项或多项操作 以下：

1. 让您的服务实现新的 Service.onTimeout(int, int) 方法。 当您的应用收到回调时，请务必在stopSelf() 几秒。（如果您不立即停止应用，则系统会生成 失败。）
2. 确保应用的 dataSync 服务运行的总时间不超过 在任何 24 小时内为 6 小时（除非用户与应用互动； 重置计时器）。
3. 仅在用户执行直接操作后启动 dataSync 项前台服务 互动；由于服务启动时您的应用位于前台 您的服务在应用转入后台后的完整运行 6 小时。
4. 请不要使用 dataSync 前台服务，而应使用 替代 API。

如果您的应用的 dataSync 前台服务在过去 6 小时内运行过 24，除非用户dataSync 已将您的应用调到前台（这会重置计时器）。如果您尝试 启动另一个 dataSync 前台服务时，系统会抛出 ForegroundServiceStartNotAllowedException 并显示类似“前台服务的时限已用尽”的错误消息 type dataSync”。

测试

如需测试应用的行为，您可以启用数据同步超时（即使应用也是如此） 未以 Android 15 为目标平台（只要应用在 Android 15 上运行即可） 设备）。如需启用超时功能，请运行以下 adb 命令：

adb shell am compat enable FGS_INTRODUCE_TIME_LIMITS your-package-name

您还可以调整超时期限，以便更轻松地测试 在达到该限制时，应用的行为。要设置新的超时期限，请运行 以下 adb 命令：

adb shell device_config put activity_manager data_sync_fgs_timeout_duration duration-in-milliseconds

New media processing foreground service type

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]"

Note: The 6-hour time limit is shared by all of an app's mediaProcessing foreground services. For example, if an app runs a mediaProcessing service for four hours, then starts a different mediaProcessing service, that second service will only be allowed to run for two hours. However, if the user brings the app to the foreground, the timer resets and the app has 6 hours available.

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 media_processing_fgs_timeout_duration duration-in-milliseconds

Restrictions on BOOT_COMPLETED broadcast receivers launching foreground services

在启动 BOOT_COMPLETED 广播接收器方面存在新限制 前台服务。BOOT_COMPLETED 接收器不能启动 以下前台服务类型：

• dataSync
• camera
• mediaPlayback
• phoneCall
• mediaProjection
• microphone（系统针对 microphone 实施了此限制， Android 14）

如果 BOOT_COMPLETED 接收器尝试启动任何上述类型的前台 服务，系统会抛出 ForegroundServiceStartNotAllowedException。

测试

如需测试应用的行为，即使您的 应用并非以 Android 15 为目标平台（只要该应用在 Android 15 上运行即可） 设备）。运行以下 adb 命令：

adb shell am compat enable FGS_BOOT_COMPLETED_RESTRICTIONS your-package-name

如需在不重启设备的情况下发送 BOOT_COMPLETED 广播， 运行以下 adb 命令：

adb shell am broadcast -a android.intent.action.BOOT_COMPLETED your-package-name

Restrictions on starting foreground services while an app holds the SYSTEM_ALERT_WINDOW permission

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

Apps that target Android 15 can no longer change the global state or policy of Do Not Disturb (DND) on a device (either by modifying user settings, or turning off DND mode). Instead, apps must contribute an AutomaticZenRule, which the system combines into a global policy with the existing most-restrictive-policy-wins scheme. Calls to existing APIs that previously affected global state (setInterruptionFilter, setNotificationPolicy) result in the creation or update of an implicit AutomaticZenRule, which is toggled on and off depending on the call-cycle of those API calls.

Note that this change only affects observable behavior if the app is calling setInterruptionFilter(INTERRUPTION_FILTER_ALL) and expects that call to deactivate an AutomaticZenRule that was previously activated by their owners.

OpenJDK API 变更

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

Some 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:

  • String.format(String, Object[])
  • String.format(Locale, String, Object[])
  • Formatter.format(String, Object[])
  • Formatter.format(Locale, String, Object[])

  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:

  • Random.ints(long)
  • Random.ints(long, int, int)
  • Random.ints(int, int)
  • Random.ints()

  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().

The new SequencedCollection API can affect your app's compatibility after you update compileSdk in your app's build configuration to use Android 15 (API level 35):

• Collision with MutableList.removeFirst() and MutableList.removeLast() extension functions in kotlin-stdlib

  The List type in Java is mapped to the MutableList type in Kotlin. Because the List.removeFirst() and List.removeLast() APIs have been introduced in Android 15 (API level 35), the Kotlin compiler resolves function calls, for example list.removeFirst(), statically to the new List APIs instead of to the extension functions in kotlin-stdlib.

  If an app is re-compiled with compileSdk set to 35 and minSdk set to 34 or lower, and then the app is run on Android 14 and lower, a runtime error is thrown:

  java.lang.NoSuchMethodError: No virtual method
  removeFirst()Ljava/lang/Object; in class Ljava/util/ArrayList;
  

  The existing NewApi lint option in Android Gradle Plugin can catch these new API usages.

  ./gradlew lint
  
  MainActivity.kt:41: Error: Call requires API level 35 (current min is 34): java.util.List#removeFirst [NewApi]
        list.removeFirst()
  

  To fix the runtime exception and lint errors, the removeFirst() and removeLast() function calls can be replaced with removeAt(0) and removeAt(list.lastIndex) respectively in Kotlin. If you're using Android Studio Ladybug | 2024.1.3 or higher, it also provides a quick fix option for these errors.

  Consider removing @SuppressLint("NewApi") and lintOptions { disable 'NewApi' } if the lint option has been disabled.

• Collision with other methods in Java

  New methods have been added into the existing types, for example, List and Deque. These new methods might not be compatible with the methods with the same name and argument types in other interfaces and classes. In the case of a method signature collision with incompatibility, the javac compiler outputs a build-time error. For example:

  Example error 1:

  javac MyList.java
  
  MyList.java:135: error: removeLast() in MyList cannot implement removeLast() in List
    public void removeLast() {
                ^
    return type void is not compatible with Object
    where E is a type-variable:
      E extends Object declared in interface List
  

  Example error 2:

  javac MyList.java
  
  MyList.java:7: error: types Deque<Object> and List<Object> are incompatible;
  public class MyList implements  List<Object>, Deque<Object> {
    both define reversed(), but with unrelated return types
  1 error
  

  Example error 3:

  javac MyList.java
  
  MyList.java:43: error: types List<E#1> and MyInterface<E#2> are incompatible;
  public static class MyList implements List<Object>, MyInterface<Object> {
    class MyList inherits unrelated defaults for getFirst() from types List and MyInterface
    where E#1,E#2 are type-variables:
      E#1 extends Object declared in interface List
      E#2 extends Object declared in interface MyInterface
  1 error
  

  To fix these build errors, the class implementing these interfaces should override the method with a compatible return type. For example:

  @Override
  public Object getFirst() {
      return List.super.getLast();
  }
  

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。

限制后台 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 introduces new security measures to make intents safer and more robust. These changes are aimed at preventing potential vulnerabilities and misuse of intents that can be exploited by malicious apps. There are two main improvements to the security of intents in Android 15:

• Match target intent-filters: Intents that target specific components must accurately match the target's intent-filter specifications. If you send an intent to launch another app's activity, the target intent component needs to align with the receiving activity's declared intent-filters.
• Intents must have actions: Intents without an action will no longer match any intent-filters. This means that intents used to start activities or services must have a clearly defined action.
• Pending intents: The creator of the pending intent is treated as the sender of the enclosing intent, not the sender of the pending intent

Important: Strict Mode can be enabled to help catch potential issues in your app. To see detailed logs about Intent usage violations, add the following method:

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

在搭载 Android 15 的设备上，应用会默认采用全屏 以 Android 15（API 级别 35）为目标平台。

重要提示： 如果应用尚未实现无边框，应用的某些部分 必须处理边衬区这项工作可能有，也可能根据具体应用而定 没有显著的意义。Material 3 Scaffold 组件可以减少 与 Android 15 全面屏强制执行兼容所需的工作。

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一款以 Android 14 为目标平台且在 Android 设备上未处于无边框的应用 Android 15 设备。

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一款以 Android 15（API 级别 35）为目标平台且采用无边框的应用 在 Android 15 设备上。此应用主要使用 Material 3 Compose 组件 自动应用边衬区此屏幕不会受到 Android 15 全屏强制执行。

这是一项可能会对应用的界面产生负面影响的破坏性更改。通过 更改会影响以下界面区域：

• 手势手柄导航栏
  • 默认透明。
  • 底部偏移量已停用，因此内容绘制在系统导航栏后面 栏。
  • setNavigationBarColor和R.attr#navigationBarColor 已弃用，不会影响手势导航。
  • setNavigationBarContrastEnforced和 R.attr#navigationBarContrastEnforced不会对 手势导航。
• “三按钮”导航
  • 默认不透明度设为 80%，颜色可能与窗口一致 背景。
  • 底部偏移值已停用，因此内容绘制在系统导航栏后面 除非应用了边衬区。
  • setNavigationBarColor和R.attr#navigationBarColor 默认设置为与窗口背景匹配。窗口背景 必须是颜色可绘制对象，才能应用此默认值。此 API 是 但会继续影响“三按钮”导航。
  • setNavigationBarContrastEnforced和 R.attr#navigationBarContrastEnforced 默认为 true，这会添加一个 “三按钮”导航模式显示 80% 不透明的背景。
• 状态栏
  • 默认透明。
  • 顶部偏移量已停用，因此除非 边衬区。
  • setStatusBarColor和R.attr#statusBarColor 已废弃，对 Android 15 没有任何影响。
  • setStatusBarContrastEnforced和 R.attr#statusBarContrastEnforced 已弃用，但仍具有 对 Android 15 的影响。
• 刘海屏
  • layoutInDisplayCutoutMode 的非浮动窗口必须是 LAYOUT_IN_DISPLAY_CUTOUT_MODE_ALWAYS。SHORT_EDGES、NEVER和 系统会将 DEFAULT 解读为 ALWAYS，这样用户就不会看到黑色图标 长条形尺寸，显示为无边框。

以下示例展示了定位前和定位后的应用 Android 15（API 级别 35）以及应用边衬区之前和之后。

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如果应用以 Android 15（API 级别 35）为目标平台， Android 15 设备并应用边衬区，这样界面就不会 已隐藏。

检查应用是否已采用全屏的检查步骤

如果您的应用已经采用无边框且应用了边衬区， 基本未受影响，但下列情况除外。但即使您认为 您不会受到影响，但我们建议您测试自己的应用。

• 您的非浮动窗口（例如 Activity）使用 SHORT_EDGES、NEVER 或 DEFAULT，而不是 LAYOUT_IN_DISPLAY_CUTOUT_MODE_ALWAYS。如果您的应用在启动时崩溃 可能是启动画面所致您可以升级核心 初始屏幕依赖项更改为 1.2.0-alpha01 或更高版本，或者设置 window.attributes.layoutInDisplayCutoutMode = WindowManager.LayoutInDisplayCutoutMode.always。
• 可能会有流量较低的屏幕显示被遮挡的界面。验证这些 访问较少的屏幕也不会显示被遮挡的界面。流量较低的屏幕包括： <ph type="x-smartling-placeholder">
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  • 初始配置或登录屏幕
  • “设置”页面

如何检查应用尚未实现无边框

如果您的应用还没有全面屏，那么您很可能会受到影响。在 除了针对已经采用无边框的应用的情况之外， 请考虑以下事项：

• 如果您的应用使用 Material 3 组件 ( androidx.compose.material3)，例如 TopAppBar， BottomAppBar 和 NavigationBar，那么这些组件可能不 会受到影响，因为它们会自动处理边衬区。
• 如果您的应用使用 Material 2 组件 ( androidx.compose.material），那么这些组件 不会自动处理边衬区。不过，您可以使用边衬区 并手动应用这些设置在 androidx.compose.material 1.6.0 中 然后使用 windowInsets 参数手动应用边衬区 BottomAppBar、TopAppBar、 BottomNavigation 和 NavigationRail。 同样，对以下内容使用 contentWindowInsets 形参： Scaffold。
• 如果您的应用使用视图和 Material 组件 (com.google.android.material)，大多数基于 View 的 Material 如 BottomNavigationView、BottomAppBar、 NavigationRailView 或 NavigationView，处理边衬区，不需要 额外工作。但是，您需要将 android:fitsSystemWindows="true" 如果使用 AppBarLayout，则会发生此错误。
• 对于自定义可组合项，请手动将边衬区作为内边距应用。如果您的 内容位于 Scaffold 内，因此您可以使用 Scaffold 来使用边衬区 内边距值。否则，使用 WindowInsets。
• 如果您的应用使用的是视图和 BottomSheet、SideSheet 或自定义 使用 ViewCompat.setOnApplyWindowInsetsListener。对于 RecyclerView，使用此监听器应用内边距，同时添加 clipToPadding="false"。

检查应用是否必须提供自定义后台保护的注意事项

如果您的应用必须为“三按钮”导航或 状态栏，则应用应将可组合项或视图放在系统栏后面 使用 WindowInsets.Type#tappableElement() 获取三按钮 导航栏高度或 WindowInsets.Type#statusBars。

其他无边框资源

请参阅无边框视图和无边框 Compose 了解应用边衬区的其他注意事项。

已弃用的 API

以下 API 现已弃用：

• R.attr#enforceStatusBarContrast
• R.attr#navigationBarColor
• R.attr#navigationBarDividerColor
• R.attr#statusBarColor
• Window#getNavigationBarColor
• Window#getNavigationBarDividerColor
• Window#getStatusBarColor
• Window#isStatusBarContrastEnforced
• Window#setDecorFitsSystemWindows
• Window#setNavigationBarColor
• Window#setNavigationBarDividerColor
• Window#setStatusBarColor
• Window#setStatusBarContrastEnforced

稳定配置

If your app targets Android 15 (API level 35) or higher, Configuration no longer excludes the system bars. If you use the screen size in the Configuration class for layout calculation, you should replace it with better alternatives like an appropriate ViewGroup, WindowInsets, or WindowMetricsCalculator depending on your need.

Configuration has been available since API 1. It is typically obtained from Activity.onConfigurationChanged. It provides information like window density, orientation, and sizes. One important characteristic about the window sizes returned from Configuration is that it previously excluded the system bars.

The configuration size is typically used for resource selection, such as /res/layout-h500dp, and this is still a valid use case. However, using it for layout calculation has always been discouraged. If you do so, you should move away from it now. You should replace the use of Configuration with something more suitable depending on your use case.

If you use it to calculate the layout, use an appropriate ViewGroup, such as CoordinatorLayout or ConstraintLayout. If you use it to determine the height of the system navbar, use WindowInsets. If you want to know the current size of your app window, use computeCurrentWindowMetrics.

The following list describes the fields affected by this change:

• Configuration.screenWidthDp and screenHeightDp sizes no longer exclude the system bars.
• Configuration.smallestScreenWidthDp is indirectly affected by changes to screenWidthDp and screenHeightDp.
• Configuration.orientation is indirectly affected by changes to screenWidthDp and screenHeightDp on close-to-square devices.
• Display.getSize(Point) is indirectly affected by the changes in Configuration. This was deprecated beginning in API level 30.
• Display.getMetrics() has already worked like this since API level 33.

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

In previous versions of Android, the text layout stretched the height of the text to meet the line height of the font that matched the current locale. For example, if the content was in Japanese, because the line height of the Japanese font is slightly larger than the one of a Latin font, the height of the text became slightly larger. However, despite these differences in line heights, the EditText element was sized uniformly, regardless of the locale being used, as illustrated in the following image:

Three boxes representing EditText elements that can contain text from English (en), Japanese (ja), and Burmese (my). The height of the EditText is the same, even though these languages have different line heights from each other.

For apps targeting Android 15, a minimum line height is now reserved for EditText to match the reference font for the specified Locale, as shown in the following image:

Three boxes representing EditText elements that can contain text from English (en), Japanese (ja), and Burmese (my). The height of the EditText now includes space to accommodate the default line height for these languages' fonts.

If needed, your app can restore the previous behavior by specifying the useLocalePreferredLineHeightForMinimum attribute to false, and your app can set custom minimum vertical metrics using the setMinimumFontMetrics API in Kotlin and Java.

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

以 Android 15 为目标平台的应用必须是顶级应用或运行前台服务，才能请求音频焦点。如果应用在不符合其中任何一项要求时尝试请求焦点，该调用将返回 AUDIOFOCUS_REQUEST_FAILED。

您可以参阅管理音频焦点，详细了解音频焦点。

更新后的非 SDK 限制

Android 15 包含更新后的受限非 SDK 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，使用任何非 SDK 均可 方法或字段总是很有破坏应用的风险。

如果您不确定自己的应用是否使用了非 SDK 接口，可以 测试您的应用，找出答案。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。 尽管如此，我们了解到，某些应用具有 非 SDK 接口。如果您无法找到使用非 SDK 的替代方案 应用某项功能的界面，您应该 请求新的公共 API。

To learn more about the changes in this release of Android, see Updates to non-SDK interface restrictions in Android 15. To learn more about non-SDK interfaces generally, see Restrictions on non-SDK interfaces.