DataApi

public interface DataApi

Exposes an API for components to read or write {@linkplain DataItem data items} and {@linkplain Asset assets}.

A DataItem is synchronized across all devices in an Android Wear network. It is possible to set data items while not connected to any nodes. Those data items will be synchronized when the nodes eventually come online.

Data items are private to the application that created them, and are only accessible by that application on other nodes. They should generally be small in size, relying on {@linkplain Asset assets} for the transfer of larger, more persistent data objects such as images.

DataItem URI format

Each data item is identified by a URI, accessible with getUri(), that indicates the item's creator and path. Fully specified URIs follow the following format: 
wear://<node_id>/<path>
where <node_id> is the node ID of the wearable node that created the data item, and <path> is an application-defined path. This means that given a data item's URI, calling getHost() will return the creator's node ID.

Some methods, such as getDataItems(GoogleApiClient, Uri) and addListener(GoogleApiClient, DataListener, Uri, int), support wildcard node IDs to match data items with the same path or path prefix created by multiple nodes. A wildcard data item URI has the following format: 

wear://*/<path>
See method documentation for details.

Concurrency

Concurrent modification of data items from different nodes may result in inconsistent results. It is recommended that apps are built with some concept of ownership of data items. Two common patterns are:
  • Creator owns data items: Data items may be updated only by the original creator node.
  • Producer-consumer: One node is responsible for creating a data item, and a second node is responsible for deleting it, once it has been processed. Data items should have unique IDs when using this pattern, and data items should not be modified once created.

Nested Class Summary

interface DataApi.DataItemResult Contains a single data item. 
interface DataApi.DataListener Used with addListener(GoogleApiClient, DataApi.DataListener) to receive data events. 
interface DataApi.DeleteDataItemsResult Contains the number of deleted items. 
@interface DataApi.FilterType  
interface DataApi.GetFdForAssetResult Contains a file descriptor for the requested asset. 

Constant Summary

String ACTION_DATA_CHANGED Data changed action for use in manifest-based listener filters.
int FILTER_LITERAL Filter type for getDataItems(GoogleApiClient, Uri, int), deleteDataItems(GoogleApiClient, Uri, int): addListener(GoogleApiClient, DataListener, Uri, int): if this filter is set, the given URI will be taken as a literal path, and the operation will apply to the matching item only.
int FILTER_PREFIX Filter type for getDataItems(GoogleApiClient, Uri, int), deleteDataItems(GoogleApiClient, Uri, int): addListener(GoogleApiClient, DataListener, Uri, int): if this filter is set, the given URI will be taken as a path prefix, and the operation will apply to all matching items.

Public Method Summary

abstract PendingResult<Status>
addListener(GoogleApiClient client, DataApi.DataListener listener)
Registers a listener to receive data item changed and deleted events.
abstract PendingResult<Status>
addListener(GoogleApiClient client, DataApi.DataListener listener, Uri uri, int filterType)
Registers a listener to receive data item changed and deleted events.
abstract PendingResult<DataApi.DeleteDataItemsResult>
deleteDataItems(GoogleApiClient client, Uri uri, int filterType)
Removes all specified data items from the Android Wear network.
abstract PendingResult<DataApi.DeleteDataItemsResult>
deleteDataItems(GoogleApiClient client, Uri uri)
Removes all specified data items from the Android Wear network.
abstract PendingResult<DataApi.DataItemResult>
getDataItem(GoogleApiClient client, Uri uri)
Retrieves a single DataItem from the Android Wear network.
abstract PendingResult<DataItemBuffer>
getDataItems(GoogleApiClient client, Uri uri, int filterType)
Retrieves all data items matching the provided URI and filter type, from the Android Wear network.
abstract PendingResult<DataItemBuffer>
getDataItems(GoogleApiClient client)
Retrieves all data items from the Android Wear network.
abstract PendingResult<DataItemBuffer>
getDataItems(GoogleApiClient client, Uri uri)
Retrieves all data items matching the provided URI, from the Android Wear network.
abstract PendingResult<DataApi.GetFdForAssetResult>
getFdForAsset(GoogleApiClient client, Asset asset)
Retrieves a ParcelFileDescriptor pointing at the bytes of an asset.
abstract PendingResult<DataApi.GetFdForAssetResult>
getFdForAsset(GoogleApiClient client, DataItemAsset asset)
Retrieves a ParcelFileDescriptor pointing at the bytes of an asset.
abstract PendingResult<DataApi.DataItemResult>
putDataItem(GoogleApiClient client, PutDataRequest request)
Adds a DataItem to the Android Wear network.
abstract PendingResult<Status>
removeListener(GoogleApiClient client, DataApi.DataListener listener)
Removes a data listener which was previously added through addListener(GoogleApiClient, DataListener).

Constants

public static final String ACTION_DATA_CHANGED

Data changed action for use in manifest-based listener filters.

See Also
Constant Value: "com.google.android.gms.wearable.DATA_CHANGED"

public static final int FILTER_LITERAL

Filter type for getDataItems(GoogleApiClient, Uri, int), deleteDataItems(GoogleApiClient, Uri, int): addListener(GoogleApiClient, DataListener, Uri, int): if this filter is set, the given URI will be taken as a literal path, and the operation will apply to the matching item only.

Constant Value: 0

public static final int FILTER_PREFIX

Filter type for getDataItems(GoogleApiClient, Uri, int), deleteDataItems(GoogleApiClient, Uri, int): addListener(GoogleApiClient, DataListener, Uri, int): if this filter is set, the given URI will be taken as a path prefix, and the operation will apply to all matching items.

Constant Value: 1

Public Methods

public abstract PendingResult<Status> addListener (GoogleApiClient client, DataApi.DataListener listener)

Registers a listener to receive data item changed and deleted events. This call should be balanced with a call to removeListener(GoogleApiClient, DataListener), to avoid leaking resources.

Listener events will be called on the main thread, or the handler specified on client when it was built (using setHandler(Handler)).

public abstract PendingResult<Status> addListener (GoogleApiClient client, DataApi.DataListener listener, Uri uri, int filterType)

Registers a listener to receive data item changed and deleted events. This call should be balanced with a call to removeListener(GoogleApiClient, DataListener), to avoid leaking resources.

uri and filterType can be used to filter the data item changes sent to the listener. For example, if uri and filterType create a path prefix filter, then only items matching that prefix will be notified. The uri follows the rules of the <data> element of <intent-filter>. The path is ignored if a URI host is not specified. The host should be an Android Wear node ID, or * to match any node. i.e, you should use: 

wear://*/<path>
or 
wear://<nodeId>/<path>

Listener events will be called on the main thread, or the handler specified on client when it was built (using setHandler(Handler)).

public abstract PendingResult<DataApi.DeleteDataItemsResult> deleteDataItems (GoogleApiClient client, Uri uri, int filterType)

Removes all specified data items from the Android Wear network.

If uri is fully specified, this method will delete at most one data item. If uri contains a wildcard host, multiple data items may be deleted, since different nodes may create data items with the same path. See DataApi for details of the URI format.

The filterType parameter changes the interpretation of uri. For example, if uri represents a path prefix, all items matching that prefix will be deleted.

public abstract PendingResult<DataApi.DeleteDataItemsResult> deleteDataItems (GoogleApiClient client, Uri uri)

Removes all specified data items from the Android Wear network.

If uri is fully specified, this method will delete at most one data item. If uri contains a wildcard host, multiple data items may be deleted, since different nodes may create data items with the same path. See DataApi for details of the URI format.

public abstract PendingResult<DataApi.DataItemResult> getDataItem (GoogleApiClient client, Uri uri)

Retrieves a single DataItem from the Android Wear network. A fully qualified URI must be specified. The URI's host must be the ID of the node that created the item.

See DataApi for details of the URI format.

public abstract PendingResult<DataItemBuffer> getDataItems (GoogleApiClient client, Uri uri, int filterType)

Retrieves all data items matching the provided URI and filter type, from the Android Wear network.

The URI must contain a path. If uri is fully specified, at most one data item will be returned. If uri contains a wildcard host, multiple data items may be returned, since different nodes may create data items with the same path. See DataApi for details of the URI format.

Callers must call release() on the returned buffer when finished processing results.

The filterType parameter changes the interpretation of uri. For example, if uri represents a path prefix, all items matching that prefix will be returned.

public abstract PendingResult<DataItemBuffer> getDataItems (GoogleApiClient client)

Retrieves all data items from the Android Wear network.

Callers must call release() on the returned buffer when finished processing results.

public abstract PendingResult<DataItemBuffer> getDataItems (GoogleApiClient client, Uri uri)

Retrieves all data items matching the provided URI, from the Android Wear network.

The URI must contain a path. If uri is fully specified, at most one data item will be returned. If uri contains a wildcard host, multiple data items may be returned, since different nodes may create data items with the same path. See DataApi for details of the URI format.

Callers must call release() on the returned buffer when finished processing results.

public abstract PendingResult<DataApi.GetFdForAssetResult> getFdForAsset (GoogleApiClient client, Asset asset)

Retrieves a ParcelFileDescriptor pointing at the bytes of an asset. Only assets previously stored in a DataItem may be retrieved.

public abstract PendingResult<DataApi.GetFdForAssetResult> getFdForAsset (GoogleApiClient client, DataItemAsset asset)

Retrieves a ParcelFileDescriptor pointing at the bytes of an asset. Only assets previously stored in a DataItem may be retrieved.

public abstract PendingResult<DataApi.DataItemResult> putDataItem (GoogleApiClient client, PutDataRequest request)

Adds a DataItem to the Android Wear network. The updated item is synchronized across all devices.

public abstract PendingResult<Status> removeListener (GoogleApiClient client, DataApi.DataListener listener)

Removes a data listener which was previously added through addListener(GoogleApiClient, DataListener).