An AutofillService is a service used to automatically fill the contents of the screen on behalf of a given user - for more information about autofill, read Autofill Framework.
This service can be implemented to interact between Telecom and its implementor for making outgoing call with optional redirection/cancellation purposes.
This service can be implemented by the default dialer (see TelecomManager#getDefaultDialerPackage()) or a third party app to allow or disallow incoming calls before they are shown to a user.
If the default SMS app has a service that extends this class, the system always tries to bind it so that the process is always running, which allows the app to have a persistent connection to the server.
An abstract service that should be implemented by any apps which either:
Can make phone calls (VoIP or otherwise) and want those calls to be integrated into the built-in phone app. Referred to as a system managedConnectionService.
Are a standalone calling app and don't want their calls to be integrated into the built-in phone app. Referred to as a self managedConnectionService.
Once implemented, the needs to take the following steps so that Telecom will bind to it:
Base class for services that are started by ODP on a call to OnDevicePersonalizationManager#execute(ComponentName, PersistableBundle, java.util.concurrent.Executor, OutcomeReceiver) and run in an isolated process.
OffHostApduService is a convenience Service class that can be extended to describe one or more NFC applications that are residing off-host, for example on an embedded secure element or a UICC.
Dynamically specifies the summary (subtitle) and enabled status of a preference injected into the list of app settings displayed by the system settings app
Top-level service of the current global voice interactor, which is providing support for hotwording, the back-end of a android.app.VoiceInteractor, etc.
InputMethodService provides a standard implementation of an InputMethod, which final implementations can derive from and customize.
A Service is an application component representing either an application's desire to perform a longer-running operation while not interacting with the user or to supply functionality for other applications to use. Each service class must have a corresponding <service> declaration in its package's AndroidManifest.xml. Services can be started with Context.startService() and android.content.Context#bindService.
Note that services, like other application objects, run in the main thread of their hosting process. This means that, if your service is going to do any CPU intensive (such as MP3 playback) or blocking (such as networking) operations, it should spawn its own thread in which to do that work. More information on this can be found in Processes and Threads. The androidx.core.app.JobIntentService class is available as a standard implementation of Service that has its own thread where it schedules its work to be done.
Most confusion about the Service class actually revolves around what it is not:
A Service is not a separate process. The Service object itself does not imply it is running in its own process; unless otherwise specified, it runs in the same process as the application it is part of.
A Service is not a thread. It is not a means itself to do work off of the main thread (to avoid Application Not Responding errors).
Thus a Service itself is actually very simple, providing two main features:
A facility for the application to tell the system about something it wants to be doing in the background (even when the user is not directly interacting with the application). This corresponds to calls to Context.startService(), which ask the system to schedule work for the service, to be run until the service or someone else explicitly stop it.
A facility for an application to expose some of its functionality to other applications. This corresponds to calls to android.content.Context#bindService, which allows a long-standing connection to be made to the service in order to interact with it.
When a Service component is actually created, for either of these reasons, all that the system actually does is instantiate the component and call its onCreate and any other appropriate callbacks on the main thread. It is up to the Service to implement these with the appropriate behavior, such as creating a secondary thread in which it does its work.
Note that because Service itself is so simple, you can make your interaction with it as simple or complicated as you want: from treating it as a local Java object that you make direct method calls on (as illustrated by Local Service Sample), to providing a full remoteable interface using AIDL.
Service Lifecycle
There are two reasons that a service can be run by the system. If someone calls Context.startService() then the system will retrieve the service (creating it and calling its onCreate method if needed) and then call its onStartCommand method with the arguments supplied by the client. The service will at this point continue running until Context.stopService() or stopSelf() is called. Note that multiple calls to Context.startService() do not nest (though they do result in multiple corresponding calls to onStartCommand()), so no matter how many times it is started a service will be stopped once Context.stopService() or stopSelf() is called; however, services can use their stopSelf(int) method to ensure the service is not stopped until started intents have been processed.
For started services, there are two additional major modes of operation they can decide to run in, depending on the value they return from onStartCommand(): START_STICKY is used for services that are explicitly started and stopped as needed, while START_NOT_STICKY or START_REDELIVER_INTENT are used for services that should only remain running while processing any commands sent to them. See the linked documentation for more detail on the semantics.
Clients can also use android.content.Context#bindService to obtain a persistent connection to a service. This likewise creates the service if it is not already running (calling onCreate while doing so), but does not call onStartCommand(). The client will receive the android.os.IBinder object that the service returns from its onBind method, allowing the client to then make calls back to the service. The service will remain running as long as the connection is established (whether or not the client retains a reference on the service's IBinder). Usually the IBinder returned is for a complex interface that has been written in aidl.
A service can be both started and have connections bound to it. In such a case, the system will keep the service running as long as either it is started or there are one or more connections to it with the Context.BIND_AUTO_CREATE flag. Once neither of these situations hold, the service's onDestroy method is called and the service is effectively terminated. All cleanup (stopping threads, unregistering receivers) should be complete upon returning from onDestroy().
Permissions
Global access to a service can be enforced when it is declared in its manifest's <service> tag. By doing so, other applications will need to declare a corresponding <uses-permission> element in their own manifest to be able to start, stop, or bind to the service.
In addition, a service can protect individual IPC calls into it with permissions, by calling the checkCallingPermission method before executing the implementation of that call.
See the Security and Permissions document for more information on permissions and security in general.
Process Lifecycle
The Android system will attempt to keep the process hosting a service around as long as the service has been started or has clients bound to it. When running low on memory and needing to kill existing processes, the priority of a process hosting the service will be the higher of the following possibilities:
If the service is currently executing code in its onCreate(), onStartCommand(), or onDestroy() methods, then the hosting process will be a foreground process to ensure this code can execute without being killed.
If the service has been started, then its hosting process is considered to be less important than any processes that are currently visible to the user on-screen, but more important than any process not visible. Because only a few processes are generally visible to the user, this means that the service should not be killed except in low memory conditions. However, since the user is not directly aware of a background service, in that state it is considered a valid candidate to kill, and you should be prepared for this to happen. In particular, long-running services will be increasingly likely to kill and are guaranteed to be killed (and restarted if appropriate) if they remain started long enough.
A started service can use the startForeground(int,android.app.Notification) API to put the service in a foreground state, where the system considers it to be something the user is actively aware of and thus not a candidate for killing when low on memory. (It is still theoretically possible for the service to be killed under extreme memory pressure from the current foreground application, but in practice this should not be a concern.)
Note this means that most of the time your service is running, it may be killed by the system if it is under heavy memory pressure. If this happens, the system will later try to restart the service. An important consequence of this is that if you implement onStartCommand() to schedule work to be done asynchronously or in another thread, then you may want to use START_FLAG_REDELIVERY to have the system re-deliver an Intent for you so that it does not get lost if your service is killed while processing it.
Other application components running in the same process as the service (such as an android.app.Activity) can, of course, increase the importance of the overall process beyond just the importance of the service itself.
Local Service Sample
One of the most common uses of a Service is as a secondary component running alongside other parts of an application, in the same process as the rest of the components. All components of an .apk run in the same process unless explicitly stated otherwise, so this is a typical situation.
When used in this way, by assuming the components are in the same process, you can greatly simplify the interaction between them: clients of the service can simply cast the IBinder they receive from it to a concrete class published by the service.
An example of this use of a Service is shown here. First is the Service itself, publishing a custom class when bound:
With that done, one can now write client code that directly accesses the running service, such as:
Remote Messenger Service Sample
If you need to be able to write a Service that can perform complicated communication with clients in remote processes (beyond simply the use of Context.startService to send commands to it), then you can use the android.os.Messenger class instead of writing full AIDL files.
An example of a Service that uses Messenger as its client interface is shown here. First is the Service itself, publishing a Messenger to an internal Handler when bound:
If we want to make this service run in a remote process (instead of the standard one for its .apk), we can use android:process in its manifest tag to specify one:
Note that the name "remote" chosen here is arbitrary, and you can use other names if you want additional processes. The ':' prefix appends the name to your package's standard process name.
With that done, clients can now bind to the service and send messages to it. Note that this allows clients to register with it to receive messages back as well:
This flag is set in onStartCommand if the Intent is a re-delivery of a previously delivered intent, because the service had previously returned START_REDELIVER_INTENT but had been killed before calling stopSelf(int) for that Intent.
Constant to return from onStartCommand: if this service's process is killed while it is started (after returning from onStartCommand), and there are no new start intents to deliver to it, then take the service out of the started state and don't recreate until a future explicit call to Context.startService(Intent).
Constant to return from onStartCommand: if this service's process is killed while it is started (after returning from onStartCommand), then it will be scheduled for a restart and the last delivered Intent re-delivered to it again via onStartCommand.
Constant to return from onStartCommand: if this service's process is killed while it is started (after returning from onStartCommand), then leave it in the started state but don't retain this delivered intent.
Constant to return from onStartCommand: compatibility version of START_STICKY that does not guarantee that onStartCommand will be called again after being killed.
Flag for #bindService: indicates that the client application binding to this service considers the service to be more important than the app itself. When set, the platform will try to have the out of memory killer kill the app before it kills the service it is bound to, though this is not guaranteed to be the case.
Flag for #bindService: If binding from an activity, allow the target service's process importance to be raised based on whether the activity is visible to the user, regardless whether another flag is used to reduce the amount that the client process's overall importance is used to impact it.
Flag for #bindService: If binding from an app that is visible, the bound service is allowed to start an activity from background. This was the default behavior before SDK version android.os.Build.VERSION_CODES#UPSIDE_DOWN_CAKE. Since then, the default behavior changed to disallow the bound service to start a background activity even if the app bound to it is in foreground, unless this flag is specified when binding.
Flag for #bindService: allow the process hosting the bound service to go through its normal memory management. It will be treated more like a running service, allowing the system to (temporarily) expunge the process if low on memory or for some other whim it may have, and being more aggressive about making it a candidate to be killed (and restarted) if running for a long time.
Flag for #bindService: automatically create the service as long as the binding exists. Note that while this will create the service, its android.app.Service#onStartCommand method will still only be called due to an explicit call to startService. Even without that, though, this still provides you with access to the service object while the service is created.
Note that prior to android.os.Build.VERSION_CODES#ICE_CREAM_SANDWICH, not supplying this flag would also impact how important the system consider's the target service's process to be. When set, the only way for it to be raised was by binding from a service in which case it will only be important when that activity is in the foreground. Now to achieve this behavior you must explicitly supply the new flag BIND_ADJUST_WITH_ACTIVITY. For compatibility, old applications that don't specify BIND_AUTO_CREATE will automatically have the flags BIND_WAIVE_PRIORITY and BIND_ADJUST_WITH_ACTIVITY set for them in order to achieve the same result.
Flag for #bindService: include debugging help for mismatched calls to unbind. When this flag is set, the callstack of the following unbindService call is retained, to be printed if a later incorrect unbind call is made. Note that doing this requires retaining information about the binding that was made for the lifetime of the app, resulting in a leak -- this should only be used for debugging.
Flag for #bindService: The service being bound is an isolated, external service. This binds the service into the calling application's package, rather than the package in which the service is declared.
When using this flag, the code for the service being bound will execute under the calling application's package name and user ID. Because the service must be an isolated process, it will not have direct access to the application's data, though. The purpose of this flag is to allow applications to provide services that are attributed to the app using the service, rather than the application providing the service.
Flag for #bindService: this service is very important to the client, so should be brought to the foreground process level when the client is. Normally a process can only be raised to the visibility level by a client, even if that client is in the foreground.
Flag for #bindService: If binding from an app that has specific capabilities due to its foreground state such as an activity or foreground service, then this flag will allow the bound app to get the same capabilities, as long as it has the required permissions as well. If binding from a top app and its target SDK version is at or above android.os.Build.VERSION_CODES#R, the app needs to explicitly use BIND_INCLUDE_CAPABILITIES flag to pass all capabilities to the service so the other app can have while-in-use access such as location, camera, microphone from background. If binding from a top app and its target SDK version is below android.os.Build.VERSION_CODES#R, BIND_INCLUDE_CAPABILITIES is implicit.
Flag for #bindService: don't allow this binding to raise the target service's process to the foreground scheduling priority. It will still be raised to at least the same memory priority as the client (so that its process will not be killable in any situation where the client is not killable), but for CPU scheduling purposes it may be left in the background. This only has an impact in the situation where the binding client is a foreground process and the target service is in a background process.
Flag for #bindService: If binding from an app that is visible or user-perceptible, lower the target service's importance to below the perceptible level. This allows the system to (temporarily) expunge the bound process from memory to make room for more important user-perceptible processes.
Flag for #bindIsolatedService: Bind the service into a shared isolated process, but only with other isolated services from the same package that declare the same process name.
Specifying this flag allows multiple isolated services defined in the same package to be running in a single shared isolated process. This shared isolated process must be specified since this flag will not work with the default application process.
This flag is different from BIND_SHARED_ISOLATED_PROCESS since it only allows binding services from the same package in the same shared isolated process. This also means the shared package isolated process is global, and not scoped to each potential calling app.
The shared isolated process instance is identified by the "android:process" attribute defined by the service. This flag cannot be used without this attribute set.
Flag for #bindIsolatedService: Bind the service into a shared isolated process. Specifying this flag allows multiple isolated services to be running in a single shared isolated process. The shared isolated process instance is identified by the instanceName parameter in bindIsolatedService(android.content.Intent,int,java.lang.String,java.util.concurrent.Executor,android.content.ServiceConnection). Subsequent calls to #bindIsolatedService with the same instanceName will cause the isolated service to be co-located in the same shared isolated process. Note that the shared isolated process is scoped to the calling app; once created, only the calling app can bind additional isolated services into the shared process. However, the services themselves can come from different APKs and therefore different vendors. Only services that set the android.R.attr#allowSharedIsolatedProcess attribute to true are allowed to be bound into a shared isolated process.
Flag for #bindService: don't impact the scheduling or memory management priority of the target service's hosting process. Allows the service's process to be managed on the background LRU list just like a regular application process in the background.
Use with getSystemService(java.lang.String) to retrieve a for performing network connectivity diagnostics as well as receiving network connectivity information from the system.
Flag for use with createPackageContext: ignore any security restrictions on the Context being requested, allowing it to always be loaded. For use with CONTEXT_INCLUDE_CODE to allow code to be loaded into a process even when it isn't safe to do so. Use with extreme care!
Flag for use with createPackageContext: include the application code with the context. This means loading code into the caller's process, so that getClassLoader() can be used to instantiate the application's classes. Setting this flags imposes security restrictions on what application context you can access; if the requested application can not be safely loaded into your process, java.lang.SecurityException will be thrown. If this flag is not set, there will be no restrictions on the packages that can be loaded, but getClassLoader will always return the default system class loader.
Flag for use with createPackageContext: a restricted context may disable specific features. For instance, a View associated with a restricted context would ignore particular XML attributes.
SharedPreference loading flag: when set, the file on disk will be checked for modification even if the shared preferences instance is already loaded in this process. This behavior is sometimes desired in cases where the application has multiple processes, all writing to the same SharedPreferences file. Generally there are better forms of communication between processes, though.
This was the legacy (but undocumented) behavior in and before Gingerbread (Android 2.3) and this flag is implied when targeting such releases. For applications targeting SDK versions greater than Android 2.3, this flag must be explicitly set if desired.
File creation mode: the default mode, where the created file can only be accessed by the calling application (or all applications sharing the same user ID).
Flag for #registerReceiver: The receiver can receive broadcasts from other Apps. Has the same behavior as marking a statically registered receiver with "exported=true"
Flag for #registerReceiver: The receiver cannot receive broadcasts from other Apps. Has the same behavior as marking a statically registered receiver with "exported=false"
Use with getSystemService(java.lang.String) to retrieve a for access to USB devices (as a USB host) and for controlling this device's behavior as a USB device.
Level for onTrimMemory(int): the process has gone on to the LRU list. This is a good opportunity to clean up resources that can efficiently and quickly be re-built if the user returns to the app.
Level for onTrimMemory(int): the process is around the middle of the background LRU list; freeing memory can help the system keep other processes running later in the list for better overall performance.
Level for onTrimMemory(int): the process is not an expendable background process, but the device is running extremely low on memory and is about to not be able to keep any background processes running. Your running process should free up as many non-critical resources as it can to allow that memory to be used elsewhere. The next thing that will happen after this is onLowMemory() called to report that nothing at all can be kept in the background, a situation that can start to notably impact the user.
Level for onTrimMemory(int): the process is not an expendable background process, but the device is running low on memory. Your running process should free up unneeded resources to allow that memory to be used elsewhere.
Level for onTrimMemory(int): the process is not an expendable background process, but the device is running moderately low on memory. Your running process may want to release some unneeded resources for use elsewhere.
Level for onTrimMemory(int): the process had been showing a user interface, and is no longer doing so. Large allocations with the UI should be released at this point to allow memory to be better managed.
Called by the system every time a client explicitly starts the service by calling android.content.Context#startService, providing the arguments it supplied and a unique integer token representing the start request.
If your service is started (running through Context#startService(Intent)), then also make this service run in the foreground, supplying the ongoing notification to be shown to the user while in this state.
Determine whether the calling process of an IPC or you has been granted permission to access a list of URIs. This is the same as checkCallingUriPermission, except it grants your own permissions if you are not currently processing an IPC. Use with care!
Determine whether a particular process and uid has been granted permission to access a list of URIs. This only checks for permissions that have been explicitly granted -- if the given process/uid has more general access to the URI's content provider then this check will always fail. Note: On SDK Version android.os.Build.VERSION_CODES#S, calling this method from a secondary-user's context will incorrectly return PackageManager#PERMISSION_DENIED for all {code uris}.
Return a new Context object for the current Context but attribute to a different tag. In complex apps attribution tagging can be used to distinguish between separate logical parts.
Returns a new Context object from the current context but with device association given by the deviceId. Each call to this method returns a new instance of a context object. Context objects are not shared; however, common state (such as the ClassLoader and other resources for the same configuration) can be shared, so the Context itself is lightweight.
Applications that run on virtual devices may use this method to access the default device capabilities and functionality (by passing Context#DEVICE_ID_DEFAULT. Similarly, applications running on the default device may access the functionality of virtual devices.
Note that the newly created instance will be associated with the same display as the parent Context, regardless of the device ID passed here.
The window context is created with the appropriate Configuration for the area of the display that the windows created with it can occupy; it must be used when inflating views, such that they can be inflated with proper Resources. Below is a sample code to add an application overlay window on the primary display:
...
final DisplayManager dm = anyContext.getSystemService(DisplayManager.class);
final Display primaryDisplay = dm.getDisplay(DEFAULT_DISPLAY);
final Context windowContext = anyContext.createDisplayContext(primaryDisplay)
.createWindowContext(TYPE_APPLICATION_OVERLAY, null);
final View overlayView = Inflater.from(windowContext).inflate(someLayoutXml, null);
// WindowManager.LayoutParams initialization
...
// The types used in addView and createWindowContext must match.
mParams.type = TYPE_APPLICATION_OVERLAY;
...
windowContext.getSystemService(WindowManager.class).addView(overlayView, mParams);
This context's configuration and resources are adjusted to an area of the display where the windows with provided type will be added. Note that all windows associated with the same context will have an affinity and can only be moved together between different displays or areas on a display. If there is a need to add different window types, or non-associated windows, separate Contexts should be used.
Creating a window context is an expensive operation. Misuse of this API may lead to a huge performance drop. The best practice is to use the same window context when possible. An approach is to create one window context with specific window type and display and use it everywhere it's needed.
Below is sample code to attach an existing token to a window context:
final DisplayManager dm = anyContext.getSystemService(DisplayManager.class);
final Display primaryDisplay = dm.getDisplay(DEFAULT_DISPLAY);
final Context windowContext = anyContext.createWindowContext(primaryDisplay,
TYPE_APPLICATION, null);
// Get an existing token.
final IBinder existingToken = activity.getWindow().getAttributes().token;
// The types used in addView() and createWindowContext() must match.
final WindowManager.LayoutParams params = new WindowManager.LayoutParams(TYPE_APPLICATION);
params.token = existingToken;
// After WindowManager#addView(), the server side will extract the provided token from
// LayoutParams#token (existingToken in the sample code), and switch to propagate
// configuration changes from the node associated with the provided token.
windowContext.getSystemService(WindowManager.class).addView(overlayView, mParams);
Note that using android.app.Application or android.app.Service context for UI-related queries may result in layout or continuity issues on devices with variable screen sizes (e.g. foldables) or in multi-window modes, since these non-UI contexts may not reflect the Configuration changes for the visual container.
If neither you nor the calling process of an IPC you are handling has been granted a particular permission, throw a SecurityException. This is the same as enforceCallingPermission, except it grants your own permissions if you are not currently processing an IPC. Use with care!
Returns absolute path to application-specific directory on the primary shared/external storage device where the application can place cache files it owns. These files are internal to the application, and not typically visible to the user as media.
This is like getCacheDir() in that these files will be deleted when the application is uninstalled, however there are some important differences:
The platform does not always monitor the space available in shared storage, and thus may not automatically delete these files. Apps should always manage the maximum space used in this location. Currently the only time files here will be deleted by the platform is when running on android.os.Build.VERSION_CODES#JELLY_BEAN_MR1 or later and Environment#isExternalStorageEmulated(File) returns true.
Shared storage may not always be available, since removable media can be ejected by the user. Media state can be checked using Environment#getExternalStorageState(File).
If a shared storage device is emulated (as determined by Environment#isExternalStorageEmulated(File)), its contents are backed by a private user data partition, which means there is little benefit to storing data here instead of the private directory returned by getCacheDir().
On devices with multiple users (as described by UserManager), each user has their own isolated shared storage. Applications only have access to the shared storage for the user they're running as.
The returned path may change over time if different shared storage media is inserted, so only relative paths should be persisted.
Returns the absolute path to the directory on the primary shared/external storage device where the application can place persistent files it owns. These files are internal to the applications, and not typically visible to the user as media.
This is like getFilesDir() in that these files will be deleted when the application is uninstalled, however there are some important differences:
Shared storage may not always be available, since removable media can be ejected by the user. Media state can be checked using Environment#getExternalStorageState(File).
If a shared storage device is emulated (as determined by Environment#isExternalStorageEmulated(File)), its contents are backed by a private user data partition, which means there is little benefit to storing data here instead of the private directories returned by getFilesDir(), etc.
On devices with multiple users (as described by UserManager), each user has their own isolated shared storage. Applications only have access to the shared storage for the user they're running as.
The returned path may change over time if different shared storage media is inserted, so only relative paths should be persisted.
Here is an example of typical code to manipulate a file in an application's shared storage:
If you supply a non-null type to this function, the returned file will be a path to a sub-directory of the given type. Though these files are not automatically scanned by the media scanner, you can explicitly add them to the media database with MediaScannerConnection.scanFile. Note that this is not the same as Environment.getExternalStoragePublicDirectory(), which provides directories of media shared by all applications. The directories returned here are owned by the application, and their contents will be removed when the application is uninstalled. Unlike Environment.getExternalStoragePublicDirectory(), the directory returned here will be automatically created for you.
Here is an example of typical code to manipulate a picture in an application's shared storage and add it to the media database:
Add a new ComponentCallbacks to the base application of the Context, which will be called at the same times as the ComponentCallbacks methods of activities and other components are called. Note that you must be sure to use unregisterComponentCallbacks when appropriate in the future; this will not be removed for you.
Register a BroadcastReceiver to be run in the main activity thread. The receiver will be called with any broadcast Intent that matches filter, in the main application thread.
The system may broadcast Intents that are "sticky" -- these stay around after the broadcast has finished, to be sent to any later registrations. If your IntentFilter matches one of these sticky Intents, that Intent will be returned by this function and sent to your receiver as if it had just been broadcast.
There may be multiple sticky Intents that match filter, in which case each of these will be sent to receiver. In this case, only one of these can be returned directly by the function; which of these that is returned is arbitrarily decided by the system.
If you know the Intent your are registering for is sticky, you can supply null for your receiver. In this case, no receiver is registered -- the function simply returns the sticky Intent that matches filter. In the case of multiple matches, the same rules as described above apply.
As of android.os.Build.VERSION_CODES#ICE_CREAM_SANDWICH, receivers registered with this method will correctly respect the Intent#setPackage(String) specified for an Intent being broadcast. Prior to that, it would be ignored and delivered to all matching registered receivers. Be careful if using this for security.
Note: this method cannot be called from a BroadcastReceiver component; that is, from a BroadcastReceiver that is declared in an application's manifest. It is okay, however, to call this method from another BroadcastReceiver that has itself been registered at run time with #registerReceiver, since the lifetime of such a registered BroadcastReceiver is tied to the object that registered it.
Register to receive intent broadcasts, with the receiver optionally being exposed to Instant Apps. See registerReceiver(android.content.BroadcastReceiver,android.content.IntentFilter) for more information. By default Instant Apps cannot interact with receivers in other applications, this allows you to expose a receiver that Instant Apps can interact with.
As of android.os.Build.VERSION_CODES#ICE_CREAM_SANDWICH, receivers registered with this method will correctly respect the Intent#setPackage(String) specified for an Intent being broadcast. Prior to that, it would be ignored and delivered to all matching registered receivers. Be careful if using this for security.
Register to receive intent broadcasts, to run in the context of scheduler. See registerReceiver(android.content.BroadcastReceiver,android.content.IntentFilter) for more information. This allows you to enforce permissions on who can broadcast intents to your receiver, or have the receiver run in a different thread than the main application thread.
As of android.os.Build.VERSION_CODES#ICE_CREAM_SANDWICH, receivers registered with this method will correctly respect the Intent#setPackage(String) specified for an Intent being broadcast. Prior to that, it would be ignored and delivered to all matching registered receivers. Be careful if using this for security.
As of android.os.Build.VERSION_CODES#ICE_CREAM_SANDWICH, receivers registered with this method will correctly respect the Intent#setPackage(String) specified for an Intent being broadcast. Prior to that, it would be ignored and delivered to all matching registered receivers. Be careful if using this for security.
Triggers the revocation of one or more permissions for the calling package. A package is only able to revoke runtime permissions. If a permission is not currently granted, it is ignored and will not get revoked (even if later granted by the user). Ultimately, you should never make assumptions about a permission status as users may grant or revoke them at any time.
Background permissions which have no corresponding foreground permission still granted once the revocation is effective will also be revoked.
The revocation happens asynchronously and kills all processes running in the calling UID. It will be triggered once it is safe to do so. In particular, it will not be triggered as long as the package remains in the foreground, or has any active manifest components (e.g. when another app is accessing a content provider in the package).
If you want to revoke the permissions right away, you could call System.exit() in Handler.postDelayed with a delay to allow completion of async IPC, But System.exit() could affect other apps that are accessing your app at the moment. For example, apps accessing a content provider in your app will all crash.
Note that the settings UI shows a permission group as granted as long as at least one permission in the group is granted. If you want the user to observe the revocation in the settings, you should revoke every permission in the target group. To learn the current list of permissions in a group, you may use PackageManager#getGroupOfPlatformPermission(String, Executor, Consumer) and PackageManager#getPlatformPermissionsForGroup(String, Executor, Consumer). This list of permissions may evolve over time, so it is recommended to check whether it contains any permission you wish to retain before trying to revoke an entire group.
Broadcast the given intent to all interested BroadcastReceivers, allowing an optional required permission to be enforced. This call is asynchronous; it returns immediately, and you will continue executing while the receivers are run. No results are propagated from receivers and receivers can not abort the broadcast. If you want to allow receivers to propagate results or abort the broadcast, you must send an ordered broadcast using sendOrderedBroadcast(android.content.Intent,java.lang.String).
Broadcast the given intent to all interested BroadcastReceivers, allowing an optional required permission to be enforced. This call is asynchronous; it returns immediately, and you will continue executing while the receivers are run. No results are propagated from receivers and receivers can not abort the broadcast. If you want to allow receivers to propagate results or abort the broadcast, you must send an ordered broadcast using sendOrderedBroadcast(android.content.Intent,java.lang.String).
Broadcast the given intent to all interested BroadcastReceivers, delivering them one at a time to allow more preferred receivers to consume the broadcast before it is delivered to less preferred receivers. This call is asynchronous; it returns immediately, and you will continue executing while the receivers are run.
Broadcast the given intent to all interested BroadcastReceivers, delivering them one at a time to allow more preferred receivers to consume the broadcast before it is delivered to less preferred receivers. This call is asynchronous; it returns immediately, and you will continue executing while the receivers are run.
Version of #sendStickyBroadcast that allows you to receive data back from the broadcast. This is accomplished by supplying your own BroadcastReceiver when calling, which will be treated as a final receiver at the end of the broadcast -- its BroadcastReceiver#onReceive method will be called with the result values collected from the other receivers. The broadcast will be serialized in the same way as calling sendOrderedBroadcast(android.content.Intent,java.lang.String).
Like sendBroadcast(android.content.Intent), this method is asynchronous; it will return before resultReceiver.onReceive() is called. Note that the sticky data stored is only the data you initially supply to the broadcast, not the result of any changes made by the receivers.
Launch multiple new activities. This is generally the same as calling startActivity(android.content.Intent) for the first Intent in the array, that activity during its creation calling startActivity(android.content.Intent) for the second entry, etc. Note that unlike that approach, generally none of the activities except the last in the array will be created at this point, but rather will be created when the user first visits them (due to pressing back from the activity on top).
This method throws ActivityNotFoundException if there was no Activity found for any given Intent. In this case the state of the activity stack is undefined (some Intents in the list may be on it, some not), so you probably want to avoid such situations.
Launch a new activity. You will not receive any information about when the activity exits.
Note that if this method is being called from outside of an android.app.Activity Context, then the Intent must include the Intent#FLAG_ACTIVITY_NEW_TASK launch flag. This is because, without being started from an existing Activity, there is no existing task in which to place the new activity and thus it needs to be placed in its own separate task.
This method throws ActivityNotFoundException if there was no Activity found to run the given Intent.
Similar to startService(android.content.Intent), but with an implicit promise that the Service will call startForeground(int, android.app.Notification) once it begins running. The service is given an amount of time comparable to the ANR interval to do this, otherwise the system will automatically crash the process, in which case an internal exception ForegroundServiceDidNotStartInTimeException is logged on logcat on devices running SDK Version android.os.Build.VERSION_CODES#S or later. On older Android versions, an internal exception RemoteServiceException is logged instead, with a corresponding message.
Unlike the ordinary startService(android.content.Intent), this method can be used at any time, regardless of whether the app hosting the service is in a foreground state.
Start executing an android.app.Instrumentation class. The given Instrumentation component will be run by killing its target application (if currently running), starting the target process, instantiating the instrumentation component, and then letting it drive the application.
This function is not synchronous -- it returns as soon as the instrumentation has started and while it is running.
Instrumentation is normally only allowed to run against a package that is either unsigned or signed with a signature that the the instrumentation package is also signed with (ensuring the target trusts the instrumentation).
Like startActivity(android.content.Intent,android.os.Bundle), but taking a IntentSender to start. If the IntentSender is for an activity, that activity will be started as if you had called the regular startActivity(android.content.Intent) here; otherwise, its associated action will be executed (such as sending a broadcast) as if you had called android.content.IntentSender#sendIntent on it.
Request that a given application service be started. The Intent should either contain the complete class name of a specific service implementation to start, or a specific package name to target. If the Intent is less specified, it logs a warning about this. In this case any of the multiple matching services may be used. If this service is not already running, it will be instantiated and started (creating a process for it if needed); if it is running then it remains running.
Every call to this method will result in a corresponding call to the target service's android.app.Service#onStartCommand method, with the intent given here. This provides a convenient way to submit jobs to a service without having to bind and call on to its interface.
Using startService() overrides the default service lifetime that is managed by #bindService: it requires the service to remain running until stopService is called, regardless of whether any clients are connected to it. Note that calls to startService() do not nest: no matter how many times you call startService(), a single call to stopService will stop it.
The system attempts to keep running services around as much as possible. The only time they should be stopped is if the current foreground application is using so many resources that the service needs to be killed. If any errors happen in the service's process, it will automatically be restarted.
This function will throw SecurityException if you do not have permission to start the given service.
Note: Each call to startService() results in significant work done by the system to manage service lifecycle surrounding the processing of the intent, which can take multiple milliseconds of CPU time. Due to this cost, startService() should not be used for frequent intent delivery to a service, and only for scheduling significant work. Use #bindService for high frequency calls.
Returns a localized formatted string from the application's package's default string table, substituting the format arguments as defined in java.util.Formatter and java.lang.String#format.
Note: System services obtained via this API may be closely associated with the Context in which they are obtained from. In general, do not share the service objects between various different contexts (Activities, Applications, Services, Providers, etc.)
Triggers the asynchronous revocation of a runtime permission. If the permission is not currently granted, nothing happens (even if later granted by the user).
Broadcast the given intent to all interested BroadcastReceivers, allowing an array of required permissions to be enforced. This call is asynchronous; it returns immediately, and you will continue executing while the receivers are run. No results are propagated from receivers and receivers can not abort the broadcast. If you want to allow receivers to propagate results or abort the broadcast, you must send an ordered broadcast using sendOrderedBroadcast(android.content.Intent,java.lang.String).
Called by the system when the device configuration changes while your component is running. Note that, unlike activities, other components are never restarted when a configuration changes: they must always deal with the results of the change, such as by re-retrieving resources.
At the time that this function has been called, your Resources object will have been updated to return resource values matching the new configuration.
This is called when the overall system is running low on memory, and actively running processes should trim their memory usage. While the exact point at which this will be called is not defined, generally it will happen when all background process have been killed. That is, before reaching the point of killing processes hosting service and foreground UI that we would like to avoid killing.
This flag is set in onStartCommand if the Intent is a re-delivery of a previously delivered intent, because the service had previously returned START_REDELIVER_INTENT but had been killed before calling stopSelf(int) for that Intent.
Constant to return from onStartCommand: if this service's process is killed while it is started (after returning from onStartCommand), and there are no new start intents to deliver to it, then take the service out of the started state and don't recreate until a future explicit call to Context.startService(Intent). The service will not receive a onStartCommand(android.content.Intent,int,int) call with a null Intent because it will not be restarted if there are no pending Intents to deliver.
This mode makes sense for things that want to do some work as a result of being started, but can be stopped when under memory pressure and will explicit start themselves again later to do more work. An example of such a service would be one that polls for data from a server: it could schedule an alarm to poll every N minutes by having the alarm start its service. When its onStartCommand is called from the alarm, it schedules a new alarm for N minutes later, and spawns a thread to do its networking. If its process is killed while doing that check, the service will not be restarted until the alarm goes off.
Constant to return from onStartCommand: if this service's process is killed while it is started (after returning from onStartCommand), then it will be scheduled for a restart and the last delivered Intent re-delivered to it again via onStartCommand. This Intent will remain scheduled for redelivery until the service calls stopSelf(int) with the start ID provided to onStartCommand. The service will not receive a onStartCommand(android.content.Intent,int,int) call with a null Intent because it will only be restarted if it is not finished processing all Intents sent to it (and any such pending events will be delivered at the point of restart).
Constant to return from onStartCommand: if this service's process is killed while it is started (after returning from onStartCommand), then leave it in the started state but don't retain this delivered intent. Later the system will try to re-create the service. Because it is in the started state, it will guarantee to call onStartCommand after creating the new service instance; if there are not any pending start commands to be delivered to the service, it will be called with a null intent object, so you must take care to check for this.
This mode makes sense for things that will be explicitly started and stopped to run for arbitrary periods of time, such as a service performing background music playback.
Since Android version Build.VERSION_CODES#S, apps targeting Build.VERSION_CODES#S or above are disallowed to start a foreground service from the background, but the restriction doesn't impact restarts of a sticky foreground service. However, when apps start a sticky foreground service from the background, the same restriction still applies.
Constant to return from onStartCommand: compatibility version of START_STICKY that does not guarantee that onStartCommand will be called again after being killed.
Selector for stopForeground(int): if set, the notification previously supplied to #startForeground will be detached from the service's lifecycle. The notification will remain shown even after the service is stopped and destroyed.
Return the communication channel to the service. May return null if clients can not bind to the service. The returned android.os.IBinder is usually for a complex interface that has been described using aidl.
Note that unlike other application components, calls on to the IBinder interface returned here may not happen on the main thread of the process. More information about the main thread can be found in Processes and Threads.
Parameters
intent
Intent!: The Intent that was used to bind to this service, as given to android.content.Context#bindService. Note that any extras that were included with the Intent at that point will not be seen here.
Called by the system to notify a Service that it is no longer used and is being removed. The service should clean up any resources it holds (threads, registered receivers, etc) at this point. Upon return, there will be no more calls in to this Service object and it is effectively dead. Do not call this method directly.
Called when new clients have connected to the service, after it had previously been notified that all had disconnected in its onUnbind. This will only be called if the implementation of onUnbind was overridden to return true.
Parameters
intent
Intent!: The Intent that was used to bind to this service, as given to android.content.Context#bindService. Note that any extras that were included with the Intent at that point will not be seen here.
openfun onStartCommand( intent:Intent!, flags:Int, startId:Int ): Int
Called by the system every time a client explicitly starts the service by calling android.content.Context#startService, providing the arguments it supplied and a unique integer token representing the start request. Do not call this method directly.
Note that the system calls this on your service's main thread. A service's main thread is the same thread where UI operations take place for Activities running in the same process. You should always avoid stalling the main thread's event loop. When doing long-running operations, network calls, or heavy disk I/O, you should kick off a new thread, or use android.os.AsyncTask.
This is called if the service is currently running and the user has removed a task that comes from the service's application. If you have set ServiceInfo.FLAG_STOP_WITH_TASK then you will not receive this callback; instead, the service will simply be stopped.
Parameters
rootIntent
Intent!: The original root Intent that was used to launch the task that is being removed.
If the foreground service of type ServiceInfo#FOREGROUND_SERVICE_TYPE_SHORT_SERVICE doesn't finish even after it's timed out, the app will be declared an ANR after a short grace period of several seconds.
openfun onTimeout( startId:Int, fgsType:Int ): Unit
Callback called when a particular foreground service type has timed out.
This callback is meant to give the app a small grace period of a few seconds to finish the foreground service of the associated type - if it fails to do so, the app will crash.
The specific time limit for each type (if one exists) is mentioned in the documentation for that foreground service type. See dataSync for example.
Note: time limits are restricted to a rolling 24-hour window - for example, if a foreground service type has a time limit of 6 hours, that time counter begins as soon as the foreground service starts. This time limit will only be reset once every 24 hours or if the app comes into the foreground state.
Called when all clients have disconnected from a particular interface published by the service. The default implementation does nothing and returns false.
Parameters
intent
Intent!: The Intent that was used to bind to this service, as given to android.content.Context#bindService. Note that any extras that were included with the Intent at that point will not be seen here.
If your service is started (running through Context#startService(Intent)), then also make this service run in the foreground, supplying the ongoing notification to be shown to the user while in this state. By default started services are background, meaning that their process won't be given foreground CPU scheduling (unless something else in that process is foreground) and, if the system needs to kill them to reclaim more memory (such as to display a large page in a web browser), they can be killed without too much harm. You use #startForeground if killing your service would be disruptive to the user, such as if your service is performing background music playback, so the user would notice if their music stopped playing.
Note that calling this method does not put the service in the started state itself, even though the name sounds like it. You must always call startService(android.content.Intent) first to tell the system it should keep the service running, and then use this method to tell it to keep it running harder.
If the app targeting API is android.os.Build.VERSION_CODES#S or later, and the service is restricted from becoming foreground service due to background restriction.
If the app targeting API is android.os.Build.VERSION_CODES#S or later, and the service is restricted from becoming foreground service due to background restriction.
fun stopForeground(notificationBehavior:Int): Unit
Remove this service from foreground state, allowing it to be killed if more memory is needed. This does not stop the service from running (for that you use stopSelf() or related methods), just takes it out of the foreground state.
If STOP_FOREGROUND_REMOVE is supplied, the service's associated notification will be cancelled immediately.
If STOP_FOREGROUND_DETACH is supplied, the service's association with the notification will be severed. If the notification had not yet been shown, due to foreground-service notification deferral policy, it is immediately posted when stopForeground(STOP_FOREGROUND_DETACH) is called. In all cases, the notification remains shown even after this service is stopped fully and destroyed.
If zero is passed as the argument, the result will be the legacy behavior as defined prior to Android L: the notification will remain posted until the service is fully stopped, at which time it will automatically be cancelled.
Stop the service if the most recent time it was started was startId. This is the same as calling android.content.Context#stopService for this particular service but allows you to safely avoid stopping if there is a start request from a client that you haven't yet seen in onStart.
Be careful about ordering of your calls to this function.. If you call this function with the most-recently received ID before you have called it for previously received IDs, the service will be immediately stopped anyway. If you may end up processing IDs out of order (such as by dispatching them on separate threads), then you are responsible for stopping them in the same order you received them.
Parameters
startId
Int: The most recent start identifier received in onStart.
Print the Service's state into the given stream. This gets invoked if you run "adb shell dumpsys activity service <yourservicename>" (note that for this command to work, the service must be running, and you must specify a fully-qualified service name). This is distinct from "dumpsys <servicename>", which only works for named system services and which invokes the IBinder#dump method on the IBinder interface registered with ServiceManager.
Parameters
fd
FileDescriptor!: The raw file descriptor that the dump is being sent to.
writer
PrintWriter!: The PrintWriter to which you should dump your state. This will be closed for you after you return.
args
Array<String!>!: additional arguments to the dump request.
Content and code samples on this page are subject to the licenses described in the Content License. Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.
