In Android 11 and later, the Quick Access Device Controls feature
lets the user quickly view and control external devices such as lights,
thermostats, and cameras from a user affordance within three interactions from a
default launcher. The device OEM chooses what launcher they use. Device
aggregators—for example, Google Home—and third-party vendor apps can
provide devices for display in this space. This page shows you how to surface
device controls in this space and link them to your control app.
To add this support, create and declare a
ControlsProviderService
. Create the
controls your app supports based on predefined control types, and then create
publishers for these controls.
User interface
Devices are displayed under
Device controls
as templated widgets. Five
device control widgets are available, as shown in the following figure:
Toggle
|
Toggle with slider
|
Range (can't be toggled on or off)
|
Stateless toggle
|
Temperature panel (closed)
|
Figure 2.
Collection of templated widgets.
Touching & holding a widget takes you to the app for deeper control. You can
customize the icon and color on each widget, but for the best user experience,
use the default icon and color if the default set matches the device.
Create the service
This section shows how to create the
ControlsProviderService
.
This service tells the Android system UI that your app contains device controls
that must be surfaced in the
Device controls
area of the Android UI.
The
ControlsProviderService
API assumes familiarity with reactive streams, as
defined in the
Reactive Streams GitHub
project
and implemented in the
Java 9 Flow
interfaces
.
The API is built around the following concepts:
- Publisher:
your application is the publisher.
- Subscriber:
the system UI is the subscriber and it can request a number
of controls from the publisher.
- Subscription:
the timeframe during which the publisher can send updates
to the System UI. Either the publisher or the subscriber can close this
window.
Declare the service
Your app must declare a service—such as
MyCustomControlService
—in
its app manifest.
The service must include an intent filter for
ControlsProviderService
. This
filter lets applications contribute controls to the system UI.
You also need a
label
that is displayed in the controls in the system UI.
The following example shows how to declare a service:
<service
android:name="MyCustomControlService"
android:label="My Custom Controls"
android:permission="android.permission.BIND_CONTROLS"
android:exported="true"
>
<intent-filter>
<action android:name="android.service.controls.ControlsProviderService" />
</intent-filter>
</service>
Next, create a new Kotlin file named
MyCustomControlService.kt
and make it
extend
ControlsProviderService()
:
Kotlin
class MyCustomControlService : ControlsProviderService() {
...
}
Java
public class MyCustomJavaControlService extends ControlsProviderService {
...
}
Select the correct control type
The API provides builder methods to create the controls. To populate the
builder, determine the device you want to control and how the user interacts
with it. Perform the following steps:
- Pick the type of device the control represents. The
DeviceTypes
class is an
enumeration of all supported devices. The type is used to determine the
icons and colors for the device in the UI.
- Determine the user-facing name, device location—for example,
kitchen—and other UI textual elements associated with the control.
- Pick the best template to support user interaction. Controls are assigned a
ControlTemplate
from the application. This template directly shows the control state to the
user as well as the available input methods—that is, the
ControlAction
.
The following table outlines some of the available templates and the actions
they support:
Template
|
Action
|
Description
|
ControlTemplate.getNoTemplateObject()
|
None
|
The application might use this to convey information about the control,
but the user can't interact with it.
|
ToggleTemplate
|
BooleanAction
|
Represents a control that can be switched between enabled and disabled
states. The
BooleanAction
object contains a field that changes
to represent the requested new state when the user taps the control.
|
RangeTemplate
|
FloatAction
|
Represents a slider widget with specified min, max, and step values. When
the user interacts with the slider, send a new
FloatAction
object back to the application with the updated value.
|
ToggleRangeTemplate
|
BooleanAction
,
FloatAction
|
This template is a combination of the
ToggleTemplate
and
RangeTemplate
. It supports touch events as well as a slider,
such as to control dimmable lights.
|
TemperatureControlTemplate
|
ModeAction
,
BooleanAction
,
FloatAction
|
In addition to encapsulating the preceding actions, this template lets
the user set a mode, such as heat, cool, heat/cool, eco, or off.
|
StatelessTemplate
|
CommandAction
|
Used to indicate a control that provides touch capability but whose state
can't be determined, such as an IR television remote. You can use this
template to define a routine or macro, which is an aggregation of control
and state changes.
|
With this information, you can create the control:
For example, to control a smart light bulb and a thermostat, add the following
constants to your
MyCustomControlService
:
Kotlin
private const val LIGHT_ID = 1234
private const val LIGHT_TITLE = "My fancy light"
private const val LIGHT_TYPE = DeviceTypes.TYPE_LIGHT
private const val THERMOSTAT_ID = 5678
private const val THERMOSTAT_TITLE = "My fancy thermostat"
private const val THERMOSTAT_TYPE = DeviceTypes.TYPE_THERMOSTAT
class MyCustomControlService : ControlsProviderService() {
...
}
Java
public class MyCustomJavaControlService extends ControlsProviderService {
private final int LIGHT_ID = 1337;
private final String LIGHT_TITLE = "My fancy light";
private final int LIGHT_TYPE = DeviceTypes.TYPE_LIGHT;
private final int THERMOSTAT_ID = 1338;
private final String THERMOSTAT_TITLE = "My fancy thermostat";
private final int THERMOSTAT_TYPE = DeviceTypes.TYPE_THERMOSTAT;
...
}
Create publishers for the controls
After you create the control, it needs a publisher. The publisher informs the
system UI of the existence of the control. The
ControlsProviderService
class
has two publisher methods that you must override in your application code:
createPublisherForAllAvailable()
: creates a
Publisher
for all the controls available in your app. Use
Control.StatelessBuilder()
to build
Control
objects for this publisher.
createPublisherFor()
: creates a
Publisher
for a list of given controls,
as identified by their string identifiers. Use
Control.StatefulBuilder
to
build these
Control
objects, since the publisher must assign a state to
each control.
Create the publisher
When your app first publishes controls to the system UI, the app doesn't know
the state of each control. Getting the state can be a time-consuming operation
involving many hops in the device-provider's network. Use the
createPublisherForAllAvailable()
method to advertise the available controls to the system. This method uses the
Control.StatelessBuilder
builder class, since the state of each control is
unknown.
Once the controls appear in the Android UI , the user can select favorite
controls.
To use Kotlin coroutines to create a
ControlsProviderService
, add a new
dependency to your
build.gradle
:
Groovy
dependencies {
????implementation "org.jetbrains.kotlinx:kotlinx-coroutines-jdk9:1.6.4"
}
Kotlin
dependencies {
????implementation("org.jetbrains.kotlinx:kotlinx-coroutines-jdk9:1.6.4")
}
Once you sync your Gradle files, add the following snippet to your
Service
to
implement
createPublisherForAllAvailable()
:
Kotlin
class MyCustomControlService : ControlsProviderService() {
override fun createPublisherForAllAvailable(): Flow.Publisher
=
flowPublish {
send(createStatelessControl(LIGHT_ID, LIGHT_TITLE, LIGHT_TYPE))
send(createStatelessControl(THERMOSTAT_ID, THERMOSTAT_TITLE, THERMOSTAT_TYPE))
}
private fun createStatelessControl(id: Int, title: String, type: Int): Control {
val intent = Intent(this, MainActivity::class.java)
.putExtra(EXTRA_MESSAGE, title)
.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
val action = PendingIntent.getActivity(
this,
id,
intent,
PendingIntent.FLAG_UPDATE_CURRENT or PendingIntent.FLAG_IMMUTABLE
)
return Control.StatelessBuilder(id.toString(), action)
.setTitle(title)
.setDeviceType(type)
.build()
}
override fun createPublisherFor(controlIds: List
): Flow.Publisher
{
TODO()
}
override fun performControlAction(
controlId: String,
action: ControlAction,
consumer: Consumer
) {
TODO()
}
}
Java
public class MyCustomJavaControlService extends ControlsProviderService {
private final int LIGHT_ID = 1337;
private final String LIGHT_TITLE = "My fancy light";
private final int LIGHT_TYPE = DeviceTypes.TYPE_LIGHT;
private final int THERMOSTAT_ID = 1338;
private final String THERMOSTAT_TITLE = "My fancy thermostat";
private final int THERMOSTAT_TYPE = DeviceTypes.TYPE_THERMOSTAT;
private boolean toggleState = false;
private float rangeState = 18f;
private final Map
> controlFlows = new HashMap
<>();
@NonNull
@Override
public Flow.Publisher
createPublisherForAllAvailable() {
List
controls = new ArrayList
<>();
controls.add(createStatelessControl(LIGHT_ID, LIGHT_TITLE, LIGHT_TYPE));
controls.add(createStatelessControl(THERMOSTAT_ID, THERMOSTAT_TITLE, THERMOSTAT_TYPE));
return FlowAdapters.toFlowPublisher(Flowable.fromIterable(controls));
}
@NonNull
@Override
public Flow.Publisher
createPublisherFor(@NonNull List
controlIds) {
ReplayProcessor
updatePublisher = ReplayProcessor.create();
controlIds.forEach(control -> {
controlFlows.put(control, updatePublisher);
updatePublisher.onNext(createLight());
updatePublisher.onNext(createThermostat());
});
return FlowAdapters.toFlowPublisher(updatePublisher);
}
}
Swipe down the system menu and locate the
Device controls
button, shown in
figure 4:
Tapping
Device controls
navigates to a second screen where you can select
your app. Once you select your app, you see how the previous snippet creates a
custom system menu showing your new controls, as shown in figure 5:
Now, implement the
createPublisherFor()
method, adding the following to your
Service
:
Kotlin
private val job = SupervisorJob()
private val scope = CoroutineScope(Dispatchers.IO + job)
private val controlFlows = mutableMapOf
>()
private var toggleState = false
private var rangeState = 18f
override fun createPublisherFor(controlIds: List
): Flow.Publisher
{
val flow = MutableSharedFlow
(replay = 2, extraBufferCapacity = 2)
controlIds.forEach { controlFlows[it] = flow }
scope.launch {
delay(1000) // Retrieving the toggle state.
flow.tryEmit(createLight())
delay(1000) // Retrieving the range state.
flow.tryEmit(createThermostat())
}
return flow.asPublisher()
}
private fun createLight() = createStatefulControl(
LIGHT_ID,
LIGHT_TITLE,
LIGHT_TYPE,
toggleState,
ToggleTemplate(
LIGHT_ID.toString(),
ControlButton(
toggleState,
toggleState.toString().uppercase(Locale.getDefault())
)
)
)
private fun createThermostat() = createStatefulControl(
THERMOSTAT_ID,
THERMOSTAT_TITLE,
THERMOSTAT_TYPE,
rangeState,
RangeTemplate(
THERMOSTAT_ID.toString(),
15f,
25f,
rangeState,
0.1f,
"%1.1f"
)
)
private fun
createStatefulControl(id: Int, title: String, type: Int, state: T, template: ControlTemplate): Control {
val intent = Intent(this, MainActivity::class.java)
.putExtra(EXTRA_MESSAGE, "$title $state")
.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
val action = PendingIntent.getActivity(
this,
id,
intent,
PendingIntent.FLAG_UPDATE_CURRENT or PendingIntent.FLAG_IMMUTABLE
)
return Control.StatefulBuilder(id.toString(), action)
.setTitle(title)
.setDeviceType(type)
.setStatus(Control.STATUS_OK)
.setControlTemplate(template)
.build()
}
override fun onDestroy() {
super.onDestroy()
job.cancel()
}
Java
@NonNull
@Override
public Flow.Publisher
createPublisherFor(@NonNull List
controlIds) {
ReplayProcessor
updatePublisher = ReplayProcessor.create();
controlIds.forEach(control -> {
controlFlows.put(control, updatePublisher);
updatePublisher.onNext(createLight());
updatePublisher.onNext(createThermostat());
});
return FlowAdapters.toFlowPublisher(updatePublisher);
}
private Control createStatelessControl(int id, String title, int type) {
Intent intent = new Intent(this, MainActivity.class)
.putExtra(EXTRA_MESSAGE, title)
.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
PendingIntent action = PendingIntent.getActivity(
this,
id,
intent,
PendingIntent.FLAG_UPDATE_CURRENT | PendingIntent.FLAG_IMMUTABLE
);
return new Control.StatelessBuilder(id + "", action)
.setTitle(title)
.setDeviceType(type)
.build();
}
private Control createLight() {
return createStatefulControl(
LIGHT_ID,
LIGHT_TITLE,
LIGHT_TYPE,
toggleState,
new ToggleTemplate(
LIGHT_ID + "",
new ControlButton(
toggleState,
String.valueOf(toggleState).toUpperCase(Locale.getDefault())
)
)
);
}
private Control createThermostat() {
return createStatefulControl(
THERMOSTAT_ID,
THERMOSTAT_TITLE,
THERMOSTAT_TYPE,
rangeState,
new RangeTemplate(
THERMOSTAT_ID + "",
15f,
25f,
rangeState,
0.1f,
"%1.1f"
)
);
}
private
Control createStatefulControl(int id, String title, int type, T state, ControlTemplate template) {
Intent intent = new Intent(this, MainActivity.class)
.putExtra(EXTRA_MESSAGE, "$title $state")
.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
PendingIntent action = PendingIntent.getActivity(
this,
id,
intent,
PendingIntent.FLAG_UPDATE_CURRENT | PendingIntent.FLAG_IMMUTABLE
);
return new Control.StatefulBuilder(id + "", action)
.setTitle(title)
.setDeviceType(type)
.setStatus(Control.STATUS_OK)
.setControlTemplate(template)
.build();
}
In this example, the
createPublisherFor()
method contains a fake
implementation of what your app must do: communicate with your device to
retrieve its status, and emit that status to the system.
The
createPublisherFor()
method uses Kotlin coroutines and flows to satisfy
the required Reactive Streams API by doing the following:
- Creates a
Flow
.
- Waits for one second.
- Creates and emits the state of the smart light.
- Waits for another second.
- Creates and emits the state of the thermostat.
Handle actions
The
performControlAction()
method signals when the user interacts with a
published control. The type of
ControlAction
sent determines the action.
Perform the appropriate action for the given control and then update the state
of the device in the Android UI.
To complete the example, add the following to your
Service
:
Kotlin
override fun performControlAction(
controlId: String,
action: ControlAction,
consumer: Consumer
) {
controlFlows[controlId]?.let { flow ->
when (controlId) {
LIGHT_ID.toString() -> {
consumer.accept(ControlAction.RESPONSE_OK)
if (action is BooleanAction) toggleState = action.newState
flow.tryEmit(createLight())
}
THERMOSTAT_ID.toString() -> {
consumer.accept(ControlAction.RESPONSE_OK)
if (action is FloatAction) rangeState = action.newValue
flow.tryEmit(createThermostat())
}
else -> consumer.accept(ControlAction.RESPONSE_FAIL)
}
} ?: consumer.accept(ControlAction.RESPONSE_FAIL)
}
Java
@Override
public void performControlAction(@NonNull String controlId, @NonNull ControlAction action, @NonNull Consumer
consumer) {
ReplayProcessor
processor = controlFlows.get(controlId);
if (processor == null) return;
if (controlId.equals(LIGHT_ID + "")) {
consumer.accept(ControlAction.RESPONSE_OK);
if (action instanceof BooleanAction) toggleState = ((BooleanAction) action).getNewState();
processor.onNext(createLight());
}
if (controlId.equals(THERMOSTAT_ID + "")) {
consumer.accept(ControlAction.RESPONSE_OK);
if (action instanceof FloatAction) rangeState = ((FloatAction) action).getNewValue()
processor.onNext(createThermostat());
}
}
Run the app, access the
Device controls
menu, and see your light and
thermostat controls.