Modifiche del comportamento: tutte le app

La piattaforma Android 14 include modifiche del comportamento che potrebbero interessare la tua app. Le seguenti modifiche del comportamento si applicano a tutte le app quando vengono eseguite su Android 14, indipendentemente da targetSdkVersion. Devi testare l'app e poi modificarla in base alle esigenze per supportarle correttamente, ove applicabile.

Assicurati di esaminare anche l'elenco delle modifiche del comportamento che interessano solo le app che hanno come target Android 14.

Funzionalità di base

La programmazione di sveglie esatte è negata per impostazione predefinita

精确的闹钟适用于用户指定的通知，或是在确切时间需要执行的操作。从 Android 14 开始，系统不再向以 Android 13 及更高版本为目标平台的大多数新安装应用预先授予 SCHEDULE_EXACT_ALARM 权限，该权限默认处于拒绝状态。

详细了解安排精确闹钟的权限变化。

Le trasmissioni registrate al contesto vengono messe in coda mentre le app vengono memorizzate nella cache

On Android 14, the system can place context-registered broadcasts in a queue while the app is in the cached state. This is similar to the queuing behavior that Android 12 (API level 31) introduced for async binder transactions. Manifest-declared broadcasts aren't queued, and apps are removed from the cached state for broadcast delivery.

When the app leaves the cached state, such as returning to the foreground, the system delivers any queued broadcasts. Multiple instances of certain broadcasts might be merged into one broadcast. Depending on other factors, such as system health, apps might be removed from the cached state, and any previously queued broadcasts are delivered.

Le app possono terminare solo i propri processi in background

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.

La MTU è impostata su 517 per il primo client GATT che richiede una MTU

Starting from Android 14, the Android Bluetooth stack more strictly adheres to Version 5.2 of the Bluetooth Core Specification and requests the BLE ATT MTU to 517 bytes when the first GATT client requests an MTU using the BluetoothGatt#requestMtu(int) API, and disregards all subsequent MTU requests on that ACL connection.

Note: This change doesn't have an impact unless the peripheral device isn't handling the MTU negotiation properly and accepting any MTU size even if it doesn't support it. In such cases, it could cause issues when your app sends large amounts of data from Android 14 devices.

To address this change and make your app more robust, consider the following options:

• Your peripheral device should respond to the Android device's MTU request with a reasonable value that can be accommodated by the peripheral. The final negotiated value will be a minimum of the Android requested value and the remote provided value (for example, min(517, remoteMtu))
  • Implementing this fix could require a firmware update for peripheral
• Alternatively, limit your GATT characteristic writes based on the minimum between the known supported value of your peripheral and the received MTU change
  • A reminder that you should reduce 5 bytes from the supported size for the headers
  • For example: arrayMaxLength = min(SUPPORTED_MTU, GATT_MAX_ATTR_LEN(517)) - 5

Nuovo motivo per cui un'app può essere inserita nel bucket in standby limitato

Android 14 introduce un nuovo motivo per cui un'app può essere inserita nel bucket in standby con restrizioni. I job dell'app attivano più volte errori ANR a causa di timeout dei metodi onStartJob, onStopJob o onBind. (consulta JobScheduler rafforza il comportamento di callback e rete per le modifiche a onStartJob e onStopJob.)

Nota: consulta la sezione relativa alla gestione dell'alimentazione per scoprire gli effetti sull'app se viene inserita nel bucket con restrizioni. L'app viene spostata nuovamente nel bucket attivo quando l'utente avvia l'app in primo piano, come nelle versioni precedenti di Android.

Per monitorare se l'app è entrata o meno nel bucket in standby limitato, ti consigliamo di eseguire il logging con l'API UsageStatsManager.getAppStandbyBucket() durante l'esecuzione del job o UsageStatsManager.queryEventsForSelf() all'avvio dell'app.

Mlock limitato a 64 kB

在 Android 14（API 级别 34）及更高版本中，平台将可使用 mlock() 锁定的最大内存减少为每个进程 64 KB。在以前的版本中，每个进程的大小上限为 64 MB。此限制可促进跨应用和系统更好地管理内存。为了提高各设备之间的一致性，Android 14 针对兼容设备上的新 mlock() 限制添加了新的 CTS 测试。

Il sistema applica l'utilizzo delle risorse delle app memorizzate nella cache

By design, an app's process is in a cached state when it's moved to the background and no other app process components are running. Such an app process is subject to being killed due to system memory pressure. Any work that Activity instances perform after the onStop() method has been called and returned, while in this state, is unreliable and strongly discouraged.

Android 14 introduces consistency and enforcement to this design. Shortly after an app process enters a cached state, background work is disallowed, until a process component re-enters an active state of the lifecycle.

Apps that use typical framework-supported lifecycle APIs – such as services, JobScheduler, and Jetpack WorkManager – shouldn't be impacted by these changes.

Esperienza utente

Modifiche all'esperienza degli utenti relativa alle notifiche non ignorabili

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
• Media notifications
• The default Search Selector package

Le informazioni sulla sicurezza dei dati sono più visibili

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。

Accessibilità

Ridimensionamento dei caratteri non lineari al 200%

从 Android 14 开始，系统支持字体放大高达 200%，为弱视用户提供了符合网络内容无障碍指南 (WCAG) 的其他无障碍功能选项。

如果您已使用放大像素 (sp) 单位来定义文本大小，这项更改可能不会对您的应用产生太大影响。不过，您应在启用最大字号 (200%) 的情况下执行界面测试，确保应用能够在不影响易用性的情况下适应较大的字号。

Sicurezza

Livello API target minimo installabile

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

I nomi dei pacchetti del proprietario dei media potrebbero essere oscurati

媒体库支持查询 OWNER_PACKAGE_NAME 列，该列表示存储特定媒体文件的应用。从 Android 14 开始，除非满足以下条件之一，否则系统会隐去此值：

• 存储媒体文件的应用有一个软件包名称始终对其他应用可见。

• 查询媒体库的应用会请求 QUERY_ALL_PACKAGES 权限。

  注意：使用 QUERY_ALL_PACKAGES 权限需遵守 Google Play 政策。

详细了解 Android 如何出于隐私保护目的而过滤软件包可见性。