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CloudMediaProvider  |  Android Developers

 2 years ago
source link: https://developer.android.com/reference/android/provider/CloudMediaProvider
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CloudMediaProvider

public abstract class CloudMediaProvider

extends ContentProvider

Base class for a cloud media provider. A cloud media provider offers read-only access to durable media files, specifically photos and videos stored on a local disk, or files in a cloud storage service. To create a cloud media provider, extend this class, implement the abstract methods, and add it to your manifest like this:

<manifest>
    ...
    <application>
        ...
        <provider
            android:name="com.example.MyCloudProvider"
            android:authorities="com.example.mycloudprovider"
            android:exported="true"
            android:permission="com.android.providers.media.permission.MANAGE_CLOUD_MEDIA_PROVIDERS"
            <intent-filter>
                <action android:name="android.content.action.CLOUD_MEDIA_PROVIDER" />
            </intent-filter>
        </provider>
        ...
    </application>
</manifest>

When defining your provider, you must protect it with the CloudMediaProviderContract#MANAGE_CLOUD_MEDIA_PROVIDERS_PERMISSION, which is a permission only the system can obtain, trying to define an unprotected CloudMediaProvider will result in a SecurityException.

Applications cannot use a cloud media provider directly; they must go through MediaStore#ACTION_PICK_IMAGES which requires a user to actively navigate and select media items. When a user selects a media item through that UI, the system issues narrow URI permission grants to the requesting application.

Media items

A media item must be an openable stream (with a specific MIME type). Media items can belong to zero or more albums. Albums cannot contain other albums.

Each item under a provider is uniquely referenced by its media or album id, which must not change without changing the provider version as returned by onGetMediaInfo(Bundle).

Summary

Inherited constants

From interface android.content.ComponentCallbacks2

Public constructors

CloudMediaProvider()

Public methods

final void attachInfo(Context context, ProviderInfo info)

Implementation is provided by the parent class.

final Bundle call(String method, String arg, Bundle extras)

Implementation is provided by the parent class.

final Uri canonicalize(Uri uri)

Implementation is provided by the parent class.

final int delete(Uri uri, String selection, String[] selectionArgs)

Implementation is provided by the parent class.

final String getType(Uri uri)

Implementation is provided by the parent class.

final Uri insert(Uri uri, ContentValues values)

Implementation is provided by the parent class.

Bundle onGetAccountInfo(Bundle extras)

Returns account related information for the media collection.

abstract Bundle onGetMediaInfo(Bundle extras)

Returns metadata about the media collection itself.

abstract ParcelFileDescriptor onOpenMedia(String mediaId, CancellationSignal signal)

Returns the full size media item identified by mediaId.

abstract AssetFileDescriptor onOpenThumbnail(String mediaId, Point size, CancellationSignal signal)

Returns a thumbnail of size for a media item identified by mediaId.

Cursor onQueryAlbums(Bundle extras)

Returns a cursor representing all album items in the media collection optionally filtered by extras and sorted in reverse chronological order of CloudMediaProviderContract.AlbumColumns#DATE_TAKEN_MS, i.e.

abstract Cursor onQueryDeletedMedia(Bundle extras)

Returns a Cursor representing all deleted media items in the entire media collection within the current provider version as returned by onGetMediaInfo(Bundle).

abstract Cursor onQueryMedia(String mediaId)

Returns a Cursor to a single media item containing the columns representing the media item identified by the CloudMediaProviderContract.MediaColumns#ID with mediaId.

abstract Cursor onQueryMedia(Bundle extras)

Returns a cursor representing all media items in the media collection optionally filtered by extras and sorted in reverse chronological order of CloudMediaProviderContract.MediaColumns#DATE_TAKEN_MS, i.e.

final ParcelFileDescriptor openFile(Uri uri, String mode, CancellationSignal signal)

Implementation is provided by the parent class.

final ParcelFileDescriptor openFile(Uri uri, String mode)

Implementation is provided by the parent class.

final AssetFileDescriptor openTypedAssetFile(Uri uri, String mimeTypeFilter, Bundle opts)

Implementation is provided by the parent class.

final AssetFileDescriptor openTypedAssetFile(Uri uri, String mimeTypeFilter, Bundle opts, CancellationSignal signal)

Implementation is provided by the parent class.

final Cursor query(Uri uri, String[] projection, Bundle queryArgs, CancellationSignal cancellationSignal)

Implementation is provided by the parent class.

final Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder)

Implementation is provided by the parent class.

final Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder, CancellationSignal cancellationSignal)

Implementation is provided by the parent class.

final int update(Uri uri, ContentValues values, String selection, String[] selectionArgs)

Implementation is provided by the parent class.

Public constructors

CloudMediaProvider

public CloudMediaProvider ()

Public methods

attachInfo

public final void attachInfo (Context context, 
                ProviderInfo info)

Implementation is provided by the parent class. Cannot be overridden.

Parameters context Context: This value cannot be null. info ProviderInfo: This value cannot be null. 
public final Bundle call (String method, 
                String arg, 
                Bundle extras)

Implementation is provided by the parent class. Cannot be overridden.

Parameters method String: This value cannot be null. arg String: This value may be null. extras Bundle: This value may be null.
Returns Bundle This value cannot be null.

canonicalize

public final Uri canonicalize (Uri uri)

Implementation is provided by the parent class. Throws by default, and cannot be overridden.

Parameters uri Uri: This value cannot be null.
Returns Uri This value cannot be null.

delete

public final int delete (Uri uri, 
                String selection, 
                String[] selectionArgs)

Implementation is provided by the parent class. Throws by default, and cannot be overridden.

Parameters uri Uri: This value cannot be null. selection String: This value may be null. selectionArgs String: This value may be null.
Returns int The number of rows affected.

getType

public final String getType (Uri uri)

Implementation is provided by the parent class. Throws by default, and cannot be overridden.

Parameters uri Uri: This value cannot be null.
Returns String This value cannot be null.

insert

public final Uri insert (Uri uri, 
                ContentValues values)

Implementation is provided by the parent class. Throws by default, and cannot be overridden.

Parameters uri Uri: This value cannot be null. values ContentValues: This value cannot be null.
Returns Uri This value cannot be null.

onGetAccountInfo

public Bundle onGetAccountInfo (Bundle extras)

Returns account related information for the media collection.

This is useful for the OS to populate a settings page with account information and allow users configure their media collection account.

onGetMediaInfo

public abstract Bundle onGetMediaInfo (Bundle extras)

Returns metadata about the media collection itself.

This is useful for the OS to determine if its cache of media items in the collection is still valid and if a full or incremental sync is required with onQueryMedia(Bundle).

This method might be called by the OS frequently and is performance critical, hence it should avoid long running operations.

If the provider handled any filters in extras, it must add the key to the ContentResolver#EXTRA_HONORED_ARGS as part of the returned Bundle.

Parameters extras Bundle: containing keys to filter result:

This value may be null.

onOpenMedia

public abstract ParcelFileDescriptor onOpenMedia (String mediaId, 
                CancellationSignal signal)

Returns the full size media item identified by mediaId.

If you block while downloading content, you should periodically check CancellationSignal#isCanceled() to abort abandoned open requests.

Parameters mediaId String: the media item to return This value cannot be null. signal CancellationSignal: used by the OS to signal if the request should be cancelled This value may be null.

Returns ParcelFileDescriptor read-only file descriptor for accessing the media file

This value cannot be null.

onOpenThumbnail

public abstract AssetFileDescriptor onOpenThumbnail (String mediaId, 
                Point size, 
                CancellationSignal signal)

Returns a thumbnail of size for a media item identified by mediaId.

This is expected to be a much lower resolution version than the item returned by onOpenMedia(String, CancellationSignal).

If you block while downloading content, you should periodically check CancellationSignal#isCanceled() to abort abandoned open requests.

Parameters mediaId String: the media item to return This value cannot be null. size Point: the dimensions of the thumbnail to return. The returned file descriptor doesn't have to match the size precisely because the OS will adjust the dimensions before usage. Implementations can return close approximations especially if the approximation is already locally on the device and doesn't require downloading from the cloud. This value cannot be null. signal CancellationSignal: used by the OS to signal if the request should be cancelled This value may be null.

Returns AssetFileDescriptor read-only file descriptor for accessing the thumbnail for the media file

This value cannot be null.

onQueryAlbums

public Cursor onQueryAlbums (Bundle extras)

Returns a cursor representing all album items in the media collection optionally filtered by extras and sorted in reverse chronological order of CloudMediaProviderContract.AlbumColumns#DATE_TAKEN_MS, i.e. most recent items first.

If the provider handled any filters in extras, it must add the key to the ContentResolver#EXTRA_HONORED_ARGS as part of the returned Cursor#setExtras Bundle.

Returns Cursor cursor representing album items containing all CloudMediaProviderContract.AlbumColumns columns This value cannot be null.

onQueryDeletedMedia

public abstract Cursor onQueryDeletedMedia (Bundle extras)

Returns a Cursor representing all deleted media items in the entire media collection within the current provider version as returned by onGetMediaInfo(Bundle). These items can be optionally filtered by extras.

If the provider handled any filters in extras, it must add the key to the ContentResolver#EXTRA_HONORED_ARGS as part of the returned Cursor#setExtras Bundle.

Returns Cursor cursor representing deleted media items containing just the CloudMediaProviderContract.MediaColumns#ID column This value cannot be null.

onQueryMedia

public abstract Cursor onQueryMedia (String mediaId)

Returns a Cursor to a single media item containing the columns representing the media item identified by the CloudMediaProviderContract.MediaColumns#ID with mediaId.

Parameters mediaId String: the media item to return This value cannot be null.
Returns Cursor cursor representing single media item containing all CloudMediaProviderContract.MediaColumns This value cannot be null.

onQueryMedia

public abstract Cursor onQueryMedia (Bundle extras)

Returns a cursor representing all media items in the media collection optionally filtered by extras and sorted in reverse chronological order of CloudMediaProviderContract.MediaColumns#DATE_TAKEN_MS, i.e. most recent items first.

If the cloud media provider handled any filters in extras, it must add the key to the ContentResolver#EXTRA_HONORED_ARGS as part of the returned Cursor#setExtras Bundle.

Returns Cursor cursor representing media items containing all CloudMediaProviderContract.MediaColumns columns This value cannot be null.

openFile

public final ParcelFileDescriptor openFile (Uri uri, 
                String mode, 
                CancellationSignal signal)

Implementation is provided by the parent class. Cannot be overridden.

Parameters uri Uri: This value cannot be null. mode String: This value cannot be null. signal CancellationSignal: This value may be null.
Returns ParcelFileDescriptor This value cannot be null.

openFile

public final ParcelFileDescriptor openFile (Uri uri, 
                String mode)

Implementation is provided by the parent class. Cannot be overridden.

Parameters uri Uri: This value cannot be null. mode String: This value cannot be null.
Returns ParcelFileDescriptor This value cannot be null.

openTypedAssetFile

public final AssetFileDescriptor openTypedAssetFile (Uri uri, 
                String mimeTypeFilter, 
                Bundle opts)

Implementation is provided by the parent class. Cannot be overridden.

Parameters uri Uri: This value cannot be null. mimeTypeFilter String: This value cannot be null. opts Bundle: This value may be null.
Returns AssetFileDescriptor This value cannot be null.

openTypedAssetFile

public final AssetFileDescriptor openTypedAssetFile (Uri uri, 
                String mimeTypeFilter, 
                Bundle opts, 
                CancellationSignal signal)

Implementation is provided by the parent class. Cannot be overridden.

Parameters uri Uri: This value cannot be null. mimeTypeFilter String: This value cannot be null. opts Bundle: This value may be null. signal CancellationSignal: This value may be null.
Returns AssetFileDescriptor This value cannot be null.

query

public final Cursor query (Uri uri, 
                String[] projection, 
                Bundle queryArgs, 
                CancellationSignal cancellationSignal)

Implementation is provided by the parent class. Cannot be overridden.

Parameters uri Uri: This value cannot be null. projection String: This value may be null. queryArgs Bundle: This value may be null. cancellationSignal CancellationSignal: This value may be null.
Returns Cursor This value cannot be null.

query

public final Cursor query (Uri uri, 
                String[] projection, 
                String selection, 
                String[] selectionArgs, 
                String sortOrder)

Implementation is provided by the parent class. Throws by default, and cannot be overridden.

Parameters uri Uri: This value cannot be null. projection String: This value may be null. selection String: This value may be null. selectionArgs String: This value may be null. sortOrder String: This value may be null.
Returns Cursor This value cannot be null.

query

public final Cursor query (Uri uri, 
                String[] projection, 
                String selection, 
                String[] selectionArgs, 
                String sortOrder, 
                CancellationSignal cancellationSignal)

Implementation is provided by the parent class. Throws by default, and cannot be overridden.

Parameters uri Uri: This value cannot be null. projection String: This value may be null. selection String: This value may be null. selectionArgs String: This value may be null. sortOrder String: This value may be null. cancellationSignal CancellationSignal: This value may be null.
Returns Cursor This value cannot be null.

update

public final int update (Uri uri, 
                ContentValues values, 
                String selection, 
                String[] selectionArgs)

Implementation is provided by the parent class. Throws by default, and cannot be overridden.

Parameters uri Uri: This value cannot be null. values ContentValues: This value cannot be null. selection String: This value may be null. selectionArgs String: This value may be null.
Returns int the number of rows affected.

report

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