行为变更：所有应用

Android 14 平台包含一些行为变更，这些变更可能会影响您的应用。以下行为变更将影响在 Android 14 上运行的所有应用，无论采用哪种 targetSdkVersion 都不例外。您应该测试您的应用，然后根据需要进行修改，以适当地支持这些变更。

此外，请务必查看仅影响以 Android 14 为目标平台的应用的行为变更列表。

核心功能

默认拒绝设定精确的闹钟

Exact alarms are meant for user-intentioned notifications, or for actions that need to happen at a precise time. Starting in Android 14, the SCHEDULE_EXACT_ALARM permission is no longer being pre-granted to most newly installed apps targeting Android 13 and higher—the permission is denied by default.

Learn more about the changes to the permission for scheduling exact alarms.

当应用进入缓存时，上下文注册的广播将加入队列

在 Android 14 中，当应用处于缓存状态时，系统可能会将上下文注册的广播放入队列中。这与 Android 12（API 级别 31）为异步 binder 事务引入的队列行为类似。在清单中声明的广播不会加入队列，并且应用会从缓存状态中移除以进行广播传递。

当应用离开缓存状态（例如返回前台）时，系统会传递所有已加入队列的广播。某些广播的多个实例可以合并为一个广播。

应用只能终止自己的后台进程

Starting in Android 14, when your app calls killBackgroundProcesses(), the API can kill only the background processes of your own app.

If you pass in the package name of another app, this method has no effect on that app's background processes, and the following message appears in Logcat:

Invalid packageName: com.example.anotherapp

Your app shouldn't use the killBackgroundProcesses() API or otherwise attempt to influence the process lifecycle of other apps, even on older OS versions. Android is designed to keep cached apps in the background and kill them automatically when the system needs memory. If your app kills other apps unnecessarily, it can reduce system performance and increase battery consumption by requiring full restarts of those apps later, which takes significantly more resources than resuming an existing cached app.

Note: It isn't possible for a 3rd-party application to improve the memory, power, or thermal behavior of an Android device. You should ensure that your app is compliant with Google Play's policy regarding misleading claims.

安全

最低可安装的目标 API 级别

Starting with Android 14, apps with a targetSdkVersion lower than 23 can't be installed. Requiring apps to meet these minimum target API level requirements improves security and privacy for users.

Malware often targets older API levels in order to bypass security and privacy protections that have been introduced in newer Android versions. For example, some malware apps use a targetSdkVersion of 22 to avoid being subjected to the runtime permission model introduced in 2015 by Android 6.0 Marshmallow (API level 23). This Android 14 change makes it harder for malware to avoid security and privacy improvements. Attempting to install an app targeting a lower API level will result in an installation failure, with the following message appearing in Logcat:

INSTALL_FAILED_DEPRECATED_SDK_VERSION: App package must target at least SDK version 23, but found 7

On devices upgrading to Android 14, any apps with a targetSdkVersion lower than 23 will remain installed.

If you need to test an app targeting an older API level, use the following ADB command:

adb install --bypass-low-target-sdk-block FILENAME.apk

媒体所有者软件包名称可能会隐去

The media store supports queries for the OWNER_PACKAGE_NAME column, which indicates the app that stored a particular media file. Starting in Android 14, this value is redacted unless at least one of the following conditions is true:

• The app that stored the media file has a package name that is always visible to other apps.

• The app that queries the media store requests the QUERY_ALL_PACKAGES permission.

  Caution: Use of the QUERY_ALL_PACKAGES permission is subject to Google Play Policy.

Learn more about how Android filters package visibility for privacy purposes.

用户体验

授予对照片和视频的部分访问权限

Note: If your app already uses the photo picker, you don't need to take any action to support this change.

On Android 14, the user can grant partial access to their photos and videos when an app requests any visual media permissions that were introduced in Android 13 (API level 33): READ_MEDIA_IMAGES or READ_MEDIA_VIDEO.

The new dialog shows the following permission choices:

• Select photos and videos: New in Android 14. The user selects the specific photos and videos that they want to make available to your app.
• Allow all: The user grants full-library access to all photos and videos on the device.
• Don't allow: The user denies all access.

To handle this change more gracefully in your app, consider declaring the new READ_MEDIA_VISUAL_USER_SELECTED permission. Learn more about how to support the case where the user grants partial permission to their media library.

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. Starting with Android 14, apps 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. These changes are landing at the end of 2023.

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.

关于不可关闭通知用户体验方式的变更

If your app shows non-dismissable foreground notifications to users, Android 14 has changed the behavior to allow users to dismiss such notifications.

This change applies to apps that prevent users from dismissing foreground notifications by setting Notification.FLAG_ONGOING_EVENT through Notification.Builder#setOngoing(true) or NotificationCompat.Builder#setOngoing(true). The behavior of FLAG_ONGOING_EVENT has changed to make such notifications actually dismissable by the user.

These kinds of notifications are still non-dismissable in the following conditions:

• When the phone is locked
• If the user selects a Clear all notification action (which helps with accidental dismissals)

Also, this new behavior doesn't apply to notifications in the following use cases:

• CallStyle notifications
• Device policy controller (DPC) and supporting packages for enterprise

数据安全信息更显眼

为了加强用户隐私保护，Android 14 增加了系统显示您在 Play 管理中心表单中声明的信息的位置数量。目前，用户可以在 Google Play 中的应用详情的数据安全部分查看此信息。

我们建议您查看应用的位置数据分享政策，并花一点时间对应用的 Google Play“数据安全”部分进行任何适用的更新。

如需了解详情，请参阅有关如何在 Android 14 上以更显眼的方式显示数据安全信息的指南。

无障碍

非线性字体放大至 200%

Starting in Android 14, the system supports font scaling up to 200%, providing low-vision users with additional accessibility options that align with Web Content Accessibility Guidelines (WCAG).

If you already use scaled pixels (sp) units to define text sizing, then this change probably won't have a high impact on your app. However, you should perform UI testing with the maximum font size enabled (200%) to ensure that your app can accommodate larger font sizes without impacting usability.