与以前的版本一样,Android 14 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 14(API 级别 34)或更高版本为目标平台的应用。如果您的应用以 Android 14 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 14 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
前台服务类型是必需的
If your app targets Android 14 (API level 34) or higher, it must specify at least one foreground service type for each foreground service within your app. You should choose a foreground service type that represents your app's use case. The system expects foreground services that have a particular type to satisfy a particular use case.
If a use case in your app isn't associated with any of these types, it's strongly recommended that you migrate your logic to use WorkManager or user-initiated data transfer jobs.
在 BluetoothAdapter 中强制执行 BLUETOOTH_CONNECT 权限
对于以 Android 14(API 级别 34)或更高版本为目标平台的应用,Android 14 会在调用 BluetoothAdapter
getProfileConnectionState()
方法时强制执行 BLUETOOTH_CONNECT
权限。
此方法已需要 BLUETOOTH_CONNECT
权限,但未被强制执行。请确保您的应用在应用的 AndroidManifest.xml
文件中声明 BLUETOOTH_CONNECT
(如以下代码段所示),并在调用 getProfileConnectionState
之前检查用户是否已授予权限。
<uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />
OpenJDK 17 更新
Android 14 continues the work of refreshing Android's core libraries to align with the features in the latest OpenJDK LTS releases, including both library updates and Java 17 language support for app and platform developers.
A few of these changes can affect app compatibility:
- Changes to regular expressions: Invalid group references are now
disallowed to more closely follow the semantics of OpenJDK. You might see
new cases where an
IllegalArgumentException
is thrown by thejava.util.regex.Matcher
class, so make sure to test your app for areas that use regular expressions. To enable or disable this change while testing, toggle theDISALLOW_INVALID_GROUP_REFERENCE
flag using the compatibility framework tools. - UUID handling: The
java.util.UUID.fromString()
method now does more strict checks when validating the input argument, so you might see anIllegalArgumentException
during deserialization. To enable or disable this change while testing, toggle theENABLE_STRICT_VALIDATION
flag using the compatibility framework tools. - ProGuard issues: In some cases, the addition of the
java.lang.ClassValue
class causes an issue if you try to shrink, obfuscate, and optimize your app using ProGuard. The problem originates with a Kotlin library that changes runtime behaviour based on whetherClass.forName("java.lang.ClassValue")
returns a class or not. If your app was developed against an older version of the runtime without thejava.lang.ClassValue
class available, then these optimizations might remove thecomputeValue
method from classes derived fromjava.lang.ClassValue
.
JobScheduler 增强回调和网络行为
自引入以来,JobScheduler 会预期您的应用在几秒内从 onStartJob
或 onStopJob
返回。在 Android 14 之前,如果作业运行时间太长,则会静默停止并失败。如果您的应用以 Android 14(API 级别 34)或更高版本为目标平台且在主线程上超出了授权的时间,应用会触发 ANR,并显示错误消息“对 onStartJob
没有响应”或“对 onStopJob
没有响应”。请考虑迁移到 WorkManager,该版本可支持异步处理,或将所有繁重工作迁移到后台线程。
JobScheduler
还引入了,如果使用 setRequiredNetworkType
或 setRequiredNetwork
约束条件,则需要声明 ACCESS_NETWORK_STATE
权限。如果应用在调度作业时未声明 ACCESS_NETWORK_STATE
权限,并且以 Android 14 或更高版本为目标平台,则会导致 SecurityException
。
隐私权
拥有部分照片和视频的访问权限
Android 14 引入了所选照片访问权限,可让用户授权应用访问其媒体库中的特定图片和视频,而不是授予对指定类型的所有媒体的访问权限。
仅当您的应用以 Android 14(API 级别 34)或更高版本为目标平台时,才会启用此变更。如果您还没有使用照片选择器,建议您在应用中实现该选择器,以便在选择图片和视频时提供一致的体验,同时还可以加强用户隐私保护,而无需请求任何存储权限。
如果您使用存储权限维护自己的图库选择器,并且需要完全控制您的实现,请调整您的实现,以使用新的 READ_MEDIA_VISUAL_USER_SELECTED
权限。如果您的应用不使用新权限,系统会在兼容模式下运行应用。
用户体验
安全的全屏 intent 通知
With Android 11 (API level 30), it was possible for any app to use
Notification.Builder.setFullScreenIntent
to send full-screen
intents while the phone is locked. You could auto-grant this on app install by
declaring USE_FULL_SCREEN_INTENT
permission in the
AndroidManifest.
Full-screen intent notifications are designed for extremely high-priority
notifications demanding the user's immediate attention, such as an incoming
phone call or alarm clock settings configured by the user. For apps targeting
Android 14 (API level 34) or higher, apps that are allowed to use this
permission are limited to those that provide calling and alarms only. The Google
Play Store revokes default USE_FULL_SCREEN_INTENT
permissions for any apps
that don't fit this profile. The deadline for these policy changes is May 31,
2024.
This permission remains enabled for apps installed on the phone before the user updates to Android 14. Users can turn this permission on and off.
You can use the new API
NotificationManager.canUseFullScreenIntent
to check if your app
has the permission; if not, your app can use the new intent
ACTION_MANAGE_APP_USE_FULL_SCREEN_INTENT
to launch the settings
page where users can grant the permission.
安全性
对隐式 intent 和待处理 intent 的限制
对于以 Android 14(API 级别 34)或更高版本为目标平台的应用,Android 会通过以下方式限制应用向内部应用组件发送隐式 intent:
- 隐式 intent 只能传送到导出的组件。应用必须使用显式 intent 传送到未导出的组件,或将该组件标记为已导出。
- 如果应用通过未指定组件或软件包的 intent 创建可变待处理 intent,系统会抛出异常。
这些变更可防止恶意应用拦截意在供应用内部组件使用的隐式 intent。
例如,下面是可以在应用的清单文件中声明的 intent 过滤器:
<activity
android:name=".AppActivity"
android:exported="false">
<intent-filter>
<action android:name="com.example.action.APP_ACTION" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
如果应用尝试使用隐式 intent 启动此 activity,则系统会抛出异常:
Kotlin
// Throws an exception when targeting Android 14. context.startActivity(Intent("com.example.action.APP_ACTION"))
Java
// Throws an exception when targeting Android 14. context.startActivity(new Intent("com.example.action.APP_ACTION"));
如需启动非导出的 activity,应用应改用显式 intent:
Kotlin
// This makes the intent explicit. val explicitIntent = Intent("com.example.action.APP_ACTION") explicitIntent.apply { package = context.packageName } context.startActivity(explicitIntent)
Java
// This makes the intent explicit. Intent explicitIntent = new Intent("com.example.action.APP_ACTION") explicitIntent.setPackage(context.getPackageName()); context.startActivity(explicitIntent);
在运行时注册的广播接收器必须指定导出行为
Apps and services that target Android 14 (API level 34) or higher and use
context-registered receivers are required to specify a flag
to indicate whether or not the receiver should be exported to all other apps on
the device: either RECEIVER_EXPORTED
or RECEIVER_NOT_EXPORTED
, respectively.
This requirement helps protect apps from security vulnerabilities by leveraging
the features for these receivers introduced in Android 13.
Exception for receivers that receive only system broadcasts
If your app is registering a receiver only for
system broadcasts through Context#registerReceiver
methods, such as Context#registerReceiver()
, then it
shouldn't specify a flag when registering the receiver.
更安全的动态代码加载
If your app targets Android 14 (API level 34) or higher and uses Dynamic Code Loading (DCL), all dynamically-loaded files must be marked as read-only. Otherwise, the system throws an exception. 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.
If you must dynamically load code, use the following approach to set the dynamically-loaded file (such as a DEX, JAR, or APK file) as read-only as soon as the file is opened and before any content is written:
Kotlin
val jar = File("DYNAMICALLY_LOADED_FILE.jar") val os = FileOutputStream(jar) os.use { // Set the file to read-only first to prevent race conditions jar.setReadOnly() // Then write the actual file content } val cl = PathClassLoader(jar, parentClassLoader)
Java
File jar = new File("DYNAMICALLY_LOADED_FILE.jar"); try (FileOutputStream os = new FileOutputStream(jar)) { // Set the file to read-only first to prevent race conditions jar.setReadOnly(); // Then write the actual file content } catch (IOException e) { ... } PathClassLoader cl = new PathClassLoader(jar, parentClassLoader);
Handle dynamically-loaded files that already exist
To prevent exceptions from being thrown for existing dynamically-loaded files, we recommend deleting and recreating the files before you try to dynamically load them again in your app. As you recreate the files, follow the preceding guidance for marking the files read-only at write time. Alternatively, you can re-label the existing files as read-only, but in this case, we strongly recommend that you verify the integrity of the files first (for example, by checking the file's signature against a trusted value), to help protect your app from malicious actions.
针对从后台启动 activity 的其他限制
对于以 Android 14(API 级别 34)或更高版本为目标平台的应用,系统会进一步限制允许应用何时从后台启动 activity:
- 当应用使用
PendingIntent#send()
或类似方法发送PendingIntent
时,如果它想要授予自己的后台 activity 启动待处理 intent 的启动特权,则必须选择启用。如需选择启用,应用应通过setPendingIntentBackgroundActivityStartMode(MODE_BACKGROUND_ACTIVITY_START_ALLOWED)
传递ActivityOptions
软件包。 - 现在,当可见应用使用
bindService()
方法绑定另一个后台应用的服务时,如果可见应用想要授予自己的后台 activity 对绑定服务的启动特权,则必须选择启用。如需选择启用,应用应在调用bindService()
方法时包含BIND_ALLOW_ACTIVITY_STARTS
标志。
这些变更扩展了一组现有限制,以防止恶意应用滥用 API 以在后台启动干扰性活动,从而保护用户。
压缩路径遍历
对于以 Android 14(API 级别 34)或更高版本为目标平台的应用,Android 会通过以下方式防止 Zip 路径遍历漏洞:如果 zip 文件条目名称包含“..”或以“/”开头,则 ZipInputStream.getNextEntry()
会抛出 ZipException
。ZipFile(String)
应用可以通过调用 dalvik.system.ZipPathValidator.clearCallback()
选择停用此验证。
每个 MediaProjection 拍摄会话均需要征得用户同意
For apps targeting Android 14 (API level 34) or higher, a SecurityException
is
thrown by MediaProjection#createVirtualDisplay
in either of the following
scenarios:
- Your app caches the
Intent
that is returned fromMediaProjectionManager#createScreenCaptureIntent
, and passes it multiple times toMediaProjectionManager#getMediaProjection
. - Your app invokes
MediaProjection#createVirtualDisplay
multiple times on the sameMediaProjection
instance.
Your app must ask the user to give consent before each capture session. A single
capture session is a single invocation on
MediaProjection#createVirtualDisplay
, and each MediaProjection
instance must
be used only once.
Handle configuration changes
If your app needs to invoke MediaProjection#createVirtualDisplay
to handle
configuration changes (such as the screen orientation or screen size changing),
you can follow these steps to update the VirtualDisplay
for the existing
MediaProjection
instance:
- Invoke
VirtualDisplay#resize
with the new width and height. - Provide a new
Surface
with the new width and height toVirtualDisplay#setSurface
.
Register a callback
Your app should register a callback to handle cases where the user doesn't grant
consent to continue a capture session. To do this, implement
Callback#onStop
and have your app release any related resources (such as
the VirtualDisplay
and Surface
).
If your app doesn't register this callback,
MediaProjection#createVirtualDisplay
throws an IllegalStateException
when your app invokes it.
更新后的非 SDK 限制
Android 14 includes updated lists of restricted non-SDK interfaces based on collaboration with Android developers and the latest internal testing. Whenever possible, we make sure that public alternatives are available before we restrict non-SDK interfaces.
If your app does not target Android 14, some of these changes might not immediately affect you. However, while you can currently use some non-SDK interfaces (depending on your app's target API level), using any non-SDK method or field always carries a high risk of breaking your app.
If you are unsure if your app uses non-SDK interfaces, you can test your app to find out. If your app relies on non-SDK interfaces, you should begin planning a migration to SDK alternatives. Nevertheless, we understand that some apps have valid use cases for using non-SDK interfaces. If you cannot find an alternative to using a non-SDK interface for a feature in your app, you should request a new public API.
如需详细了解此 Android 版本中的变更,请参阅 Android 14 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。