与之前的版本一样,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)。
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
前台服务类型是必填项
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。
此方法已要求 BLUETOOTH_CONNECT
权限,但未强制执行。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相应权限。
<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 强化了回调和网络行为
Since its introduction, JobScheduler expects your app to return from
onStartJob
or onStopJob
within a few seconds. Prior to Android 14,
if a job runs too long, the job is stopped and fails silently.
If your app targets Android 14 (API level 34) or higher and
exceeds the granted time on the main thread, the app triggers an ANR
with the error message "No response to onStartJob
" or
"No response to onStopJob
".
This ANR may be a result of 2 scenarios:
1. There is work blocking the main thread, preventing the callbacks onStartJob
or onStopJob
from executing and completing within the expected time limit.
2. The developer is running blocking work within the JobScheduler
callback onStartJob
or onStopJob
, preventing the callback from
completing within the expected time limit.
To address #1, you will need to further debug what is blocking the main thread
when the ANR occurs, you can do this using
ApplicationExitInfo#getTraceInputStream()
to get the tombstone
trace when the ANR occurs. If you're able to manually reproduce the ANR,
you can record a system trace and inspect the trace using either
Android Studio or Perfetto to better understand what is running on
the main thread when the ANR occurs.
Note that this can happen when using JobScheduler API directly
or using the androidx library WorkManager.
To address #2, consider migrating to WorkManager, which provides
support for wrapping any processing in onStartJob
or onStopJob
in an asynchronous thread.
JobScheduler
also introduces a requirement to declare the
ACCESS_NETWORK_STATE
permission if using setRequiredNetworkType
or
setRequiredNetwork
constraint. If your app does not declare the
ACCESS_NETWORK_STATE
permission when scheduling the job and is targeting
Android 14 or higher, it will result in a SecurityException
.
Tiles 发布 API
对于以 Android 14 及更高版本为目标平台的应用,
TileService#startActivityAndCollapse(Intent)
已弃用,现在会抛出
调用时抛出异常。如果您的应用从功能块启动 activity,请使用
TileService#startActivityAndCollapse(PendingIntent)
。
隐私设置
拥有对照片和视频的部分访问权限
Android 14 introduces Selected Photos Access, which allows users to grant apps access to specific images and videos in their library, rather than granting access to all media of a given type.
This change is only enabled if your app targets Android 14 (API level 34) or higher. If you don't use the photo picker yet, we recommend implementing it in your app to provide a consistent experience for selecting images and videos that also enhances user privacy without having to request any storage permissions.
If you maintain your own gallery picker using storage permissions and need to
maintain full control over your implementation, adapt your implementation
to use the new READ_MEDIA_VISUAL_USER_SELECTED
permission. If your app
doesn't use the new permission, the system runs your app in a compatibility
mode.
用户体验
安全的全屏 intent 通知
在 Android 11(API 级别 30)中,任何应用都可以在手机处于锁定状态时使用 Notification.Builder.setFullScreenIntent
发送全屏 intent。您可以通过在 AndroidManifest 中声明 USE_FULL_SCREEN_INTENT
权限,在应用安装时自动授予此权限。
全屏 intent 通知适用于需要用户立即注意的极高优先级通知,例如用户来电或用户配置的闹钟设置。对于以 Android 14(API 级别 34)或更高版本为目标平台的应用,获准使用此权限的应用仅限于提供通话和闹钟的应用。对于不适合此资料的任何应用,Google Play 商店会撤消其默认的 USE_FULL_SCREEN_INTENT
权限。这些政策变更的截止日期为 2024 年 5 月 31 日。
在用户更新到 Android 14 之前,在手机上安装的应用仍拥有此权限。用户可以开启和关闭此权限。
您可以使用新 API NotificationManager.canUseFullScreenIntent
检查应用是否具有该权限;如果没有,应用可以使用新 intent ACTION_MANAGE_APP_USE_FULL_SCREEN_INTENT
启动设置页面,在该页面中,用户可以授予权限。
安全
对隐式 intent 和待处理 intent 的限制
For apps targeting Android 14 (API level 34) or higher, Android restricts apps from sending implicit intents to internal app components in the following ways:
- Implicit intents are only delivered to exported components. Apps must either use an explicit intent to deliver to unexported components, or mark the component as exported.
- If an app creates a mutable pending intent with an intent that doesn't specify a component or package, the system throws an exception.
These changes prevent malicious apps from intercepting implicit intents that are intended for use by an app's internal components.
For example, here is an intent filter that could be declared in your app's manifest file:
<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>
If your app tried to launch this activity using an implicit intent, an
ActivityNotFoundException
exception would be thrown:
Kotlin
// Throws an ActivityNotFoundException exception when targeting Android 14. context.startActivity(Intent("com.example.action.APP_ACTION"))
Java
// Throws an ActivityNotFoundException exception when targeting Android 14. context.startActivity(new Intent("com.example.action.APP_ACTION"));
To launch the non-exported activity, your app should use an explicit intent instead:
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在后台启动 activity 的时间:
- 现在,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。 - 当可见应用绑定了另一个后台应用的服务时
bindService()
方法,可见应用现在必须 如果它想要将自己的后台活动 绑定服务。要选择启用,应用应包含BIND_ALLOW_ACTIVITY_STARTS
标志,在调用bindService()
方法。
这些更改扩大了一组现有限制条件的范围,目的是防止恶意应用滥用 API 以在后台启动干扰性活动,从而保护用户。
压缩路径遍历
For apps targeting Android 14 (API level 34) or higher, Android prevents the Zip
Path Traversal Vulnerability in the following way:
ZipFile(String)
and
ZipInputStream.getNextEntry()
throws a
ZipException
if zip file entry names contain ".." or start
with "/".
Apps can opt-out from this validation by calling
dalvik.system.ZipPathValidator.clearCallback()
.
每次 MediaProjection 捕获会话都需要征得用户同意
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 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 14 为目标平台,其中一些变更可能不会立即对您产生影响。然而,虽然您目前仍可以使用一些非 SDK 接口(具体取决于应用的目标 API 级别),但只要您使用任何非 SDK 方法或字段,终归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,则可以测试您的应用来进行确认。如果您的应用依赖于非 SDK 接口,您应该开始计划迁移到 SDK 替代方案。然而,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某项功能找到使用非 SDK 接口的替代方案,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 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。