3.5. API Behavioral Compatibility

Device implementations:

  • [C-0-9] MUST ensure that API behavioral compatibility is applied for all installed apps unless they are restricted as described in Section 3.5.1.
  • [C-0-10] MUST NOT implement the whitelisting approach that ensures API behavioral compatibility only for apps that are selected by device implementers.

The behaviors of each of the API types (managed, soft, native, and web) must be consistent with the preferred implementation of the upstream Android Open Source Project. Some specific areas of compatibility are:

  • [C-0-1] Devices MUST NOT change the behavior or semantics of a standard intent.
  • [C-0-2] Devices MUST NOT alter the lifecycle or lifecycle semantics of a particular type of system component (such as Service, Activity, ContentProvider, etc.).
  • [C-0-3] Devices MUST NOT change the semantics of a standard permission.
  • Devices MUST NOT alter the limitations enforced on background applications. More specifically, for background apps:
    • [C-0-4] they MUST stop executing callbacks that are registered by the app to receive outputs from the GnssMeasurement and GnssNavigationMessage.
    • [C-0-5] they MUST rate-limit the frequency of updates that are provided to the app through the LocationManager API class or the WifiManager.startScan() method.
    • [C-0-6] if the app is targeting API level 25 or higher, they MUST NOT allow to register broadcast receivers for the implicit broadcasts of standard Android intents in the app's manifest, unless the broadcast intent requires a "signature" or "signatureOrSystem" protectionLevel permission or are on the exemption list .
    • [C-0-7] if the app is targeting API level 25 or higher, they MUST stop the app‘s background services, just as if the app had called the services’stopSelf() method, unless the app is placed on a temporary whitelist to handle a task that's visible to the user.
    • [C-0-8] if the app is targeting API level 25 or higher, they MUST release the wakelocks the app holds.
  • [C-0-9] Devices MUST return the following security providers as the first seven array values from the Security.getProviders() method, in the given order and with the given names (as returned by Provider.getName()) and classes, unless the app has modified the list via insertProviderAt() or removeProvider(). Devices MAY return additional providers after the specified list of providers below.
    1. AndroidNSSP - android.security.net.config.NetworkSecurityConfigProvider
    2. AndroidOpenSSL - com.android.org.conscrypt.OpenSSLProvider
    3. CertPathProvider - sun.security.provider.CertPathProvider
    4. AndroidKeyStoreBCWorkaround - android.security.keystore.AndroidKeyStoreBCWorkaroundProvider
    5. BC - com.android.org.bouncycastle.jce.provider.BouncyCastleProvider
    6. HarmonyJSSE - com.android.org.conscrypt.JSSEProvider
    7. AndroidKeyStore - android.security.keystore.AndroidKeyStoreProvider

The above list is not comprehensive. The Compatibility Test Suite (CTS) tests significant portions of the platform for behavioral compatibility, but not all. It is the responsibility of the implementer to ensure behavioral compatibility with the Android Open Source Project. For this reason, device implementers SHOULD use the source code available via the Android Open Source Project where possible, rather than re-implement significant parts of the system.

3.5.1. Application Restriction

If device implementations implement a proprietary mechanism to restrict apps and that mechanism is more restrictive than the Rare App Standby Bucket, they:

  • [C-1-1] MUST provide user affordance where the user can see the list of restricted apps.
  • [C-1-2] MUST provide user affordance to turn on / off the restrictions on each app.
  • [C-1-3] MUST not automatically apply restrictions without evidence of poor system health behavior, but MAY apply the restrictions on apps upon detection of poor system health behavior like stuck wakelocks, long running services, and other criteria. The criteria MAY be determined by device implementers but MUST be related to the app’s impact on the system health. Other criteria that are not purely related to the system health, such as the app’s lack of popularity in the market, MUST NOT be used as criteria.
  • [C-1-4] MUST not automatically apply app restrictions for apps when a user has turned off app restrictions manually, and MAY suggest the user to apply app restrictions.
  • [C-1-5] MUST inform users if app restrictions are applied to an app automatically. Such information MUST be provided within 24 hours of when the restrictions are applied.
  • [C-1-6] MUST return true for ActivityManager.isBackgroundRestricted() when the restricted app calls this API.
  • [C-1-7] MUST NOT restrict the top foreground app that is explicitly used by the user.
  • [C-1-8] MUST suspend restrictions on an app that becomes the top foreground application when the user explicitly starts to use the app that used to be restricted.
  • [C-1-9] MUST report all app restriction events via UsageStats. If device implementations extend the app restrictions that are implemented in AOSP, MUST follow the implementation described in this document.