```
public abstract class DataLayerAppHelper

                    
```
Base class on which of the Wear and Phone DataLayerAppHelpers are build.
Provides utility functions for determining installation status and means to install and launch apps as part of the user's journey.

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`public class`	`DataLayerAppHelper.Companion`

Field Summary

Fields
Modifier and Type	Field	Description
`private final Flow<Set<Node>>`	`connectedAndInstalledNodes`

Constructor Summary

Constructors
Constructor	Description
`DataLayerAppHelper(Context context, WearDataLayerRegistry registry)`

Method Summary

Modifier and Type	Method	Description
`abstract Flow<Set<Node>>`	`getConnectedAndInstalledNodes()`	Creates a flow to keep the client updated with the set of connected devices with the app installed.
`final List<AppHelperNodeStatus>`	`connectedNodes()`	Provides a list of connected nodes and the installation status of the app on these nodes.
`abstract AppHelperResultCode`	`installOnNode(String nodeId)`	Launches to the appropriate store on the specified node to allow installation of the app.
`abstract AppHelperResultCode`	`startCompanion(String nodeId)`	Starts the companion that relates to the specified node.
`final AppHelperResultCode`	`startRemoteActivity(String nodeId, ActivityConfig config)`	Launch an activity, which belongs to the same app (same package name), on the specified node.
`final AppHelperResultCode`	`startRemoteOwnApp(String nodeId)`	Launch own app on the specified node.
`final Boolean`	`isAvailable()`	Check whether the data layer is available before use to avoid crashes.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - DataLayerAppHelper
```
DataLayerAppHelper(Context context, WearDataLayerRegistry registry)
```
- Method Detail
  - getConnectedAndInstalledNodes
```
 abstract Flow<Set<Node>> getConnectedAndInstalledNodes()
```
    Creates a flow to keep the client updated with the set of connected devices with the app installed.
    When called from a phone device, multiple watches can be connected to it.
    When called from a watch device, usually only a single phone device will be connected to it.
  - connectedNodes
```
 final List<AppHelperNodeStatus> connectedNodes()
```
    Provides a list of connected nodes and the installation status of the app on these nodes.
  - installOnNode
```
 abstract AppHelperResultCode installOnNode(String nodeId)
```
    Launches to the appropriate store on the specified node to allow installation of the app.
    
    Parameters:
    
    nodeId - The node to launch on.
  - startCompanion
```
@CheckResult() abstract AppHelperResultCode startCompanion(String nodeId)
```
    Starts the companion that relates to the specified node. This will start on the phone, irrespective of whether the specified node is a phone or a watch.
    When called from a watch node, it is required that the same app is installed on the specified node, otherwise a timeout is expected. See AppHelperNodeStatus.appInstallationStatus in order to check the installation status.
    
    Parameters:
    
    nodeId - The node to launch on.
  - startRemoteActivity
```
@CheckResult() final AppHelperResultCode startRemoteActivity(String nodeId, ActivityConfig config)
```
    Launch an activity, which belongs to the same app (same package name), on the specified node.
    Class name should be a fully qualified class name, such as, "com.example.project.SampleActivity".
    This call requires that the same app is installed on the specified node, otherwise a timeout is expected. See AppHelperNodeStatus.appInstallationStatus in order to check the installation status.
  - startRemoteOwnApp
```
@CheckResult() final AppHelperResultCode startRemoteOwnApp(String nodeId)
```
    Launch own app on the specified node.
    This call requires that the same app is installed on the specified node, otherwise a timeout is expected. See AppHelperNodeStatus.appInstallationStatus in order to check the installation status.
  - isAvailable
```
 final Boolean isAvailable()
```
    Check whether the data layer is available before use to avoid crashes.

Class DataLayerAppHelper

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

DataLayerAppHelper

Method Detail

getConnectedAndInstalledNodes

connectedNodes

installOnNode

startCompanion

startRemoteActivity

startRemoteOwnApp

isAvailable