DocumentsProvider
public
abstract
class
DocumentsProvider
extends ContentProvider
java.lang.Object | ||
↳ | android.content.ContentProvider | |
↳ | android.provider.DocumentsProvider |
Base class for a document provider. A document provider offers read and write access to durable files, such as files stored on a local disk, or files in a cloud storage service. To create a document 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:grantUriPermissions="true" android:permission="android.permission.MANAGE_DOCUMENTS" android:enabled="@bool/isAtLeastKitKat"> <intent-filter> <action android:name="android.content.action.DOCUMENTS_PROVIDER" /> </intent-filter> </provider> ... </application> </manifest>
When defining your provider, you must protect it with
Manifest.permission.MANAGE_DOCUMENTS
, which is a permission
only the system can obtain. Applications cannot use a documents provider
directly; they must go through Intent#ACTION_OPEN_DOCUMENT
or
Intent#ACTION_CREATE_DOCUMENT
which requires a user to actively
navigate and select documents. When a user selects documents through that UI,
the system issues narrow URI permission grants to the requesting application.
Documents
A document can be either an openable stream (with a specific MIME type), or a
directory containing additional documents (with the
Document#MIME_TYPE_DIR
MIME type). Each directory represents the top
of a subtree containing zero or more documents, which can recursively contain
even more documents and directories.
Each document can have different capabilities, as described by
Document#COLUMN_FLAGS
. For example, if a document can be represented
as a thumbnail, your provider can set
Document#FLAG_SUPPORTS_THUMBNAIL
and implement
openDocumentThumbnail(java.lang.String, android.graphics.Point, android.os.CancellationSignal)
to return
that thumbnail.
Each document under a provider is uniquely referenced by its
Document#COLUMN_DOCUMENT_ID
, which must not change once returned. A
single document can be included in multiple directories when responding to
queryChildDocuments(java.lang.String, java.lang.String[], java.lang.String)
. For example, a
provider might surface a single photo in multiple locations: once in a
directory of geographic locations, and again in a directory of dates.
Roots
All documents are surfaced through one or more "roots." Each root represents
the top of a document tree that a user can navigate. For example, a root
could represent an account or a physical storage device. Similar to
documents, each root can have capabilities expressed through
Root#COLUMN_FLAGS
.
Summary
Inherited constants |
---|
Public constructors | |
---|---|
DocumentsProvider()
|
Public methods | |
---|---|
void
|
attachInfo(Context context, ProviderInfo info)
Implementation is provided by the parent class. |
Bundle
|
call(String method, String arg, Bundle extras)
Implementation is provided by the parent class. |
Uri
|
canonicalize(Uri uri)
Implementation is provided by the parent class. |
String
|
copyDocument(String sourceDocumentId, String targetParentDocumentId)
Copy the requested document or a document tree. |
String
|
createDocument(String parentDocumentId, String mimeType, String displayName)
Create a new document and return its newly generated
|
IntentSender
|
createWebLinkIntent(String documentId, Bundle options)
Creates an intent sender for a web link, if the document is web linkable. |
final
int
|
delete(Uri uri, String selection, String[] selectionArgs)
Implementation is provided by the parent class. |
void
|
deleteDocument(String documentId)
Delete the requested document. |
void
|
ejectRoot(String rootId)
Ejects the root. |
DocumentsContract.Path
|
findDocumentPath(String parentDocumentId, String childDocumentId)
Finds the canonical path for the requested document. |
Bundle
|
getDocumentMetadata(String documentId)
Returns metadata associated with the document. |
String[]
|
getDocumentStreamTypes(String documentId, String mimeTypeFilter)
Return a list of streamable MIME types matching the filter, which can be passed to
|
String
|
getDocumentType(String documentId)
Return concrete MIME type of the requested document. |
String[]
|
getStreamTypes(Uri uri, String mimeTypeFilter)
Called by a client to determine the types of data streams that this content provider support for the given URI. |
final
String
|
getType(Uri uri)
Implementation is provided by the parent class. |
final
String
|
getTypeAnonymous(Uri uri)
An unrestricted version of getType, which does not reveal sensitive information |
final
Uri
|
insert(Uri uri, ContentValues values)
Implementation is provided by the parent class. |
boolean
|
isChildDocument(String parentDocumentId, String documentId)
Test if a document is descendant (child, grandchild, etc) from the given parent. |
String
|
moveDocument(String sourceDocumentId, String sourceParentDocumentId, String targetParentDocumentId)
Move the requested document or a document tree. |
final
AssetFileDescriptor
|
openAssetFile(Uri uri, String mode, CancellationSignal signal)
Implementation is provided by the parent class. |
final
AssetFileDescriptor
|
openAssetFile(Uri uri, String mode)
Implementation is provided by the parent class. |
abstract
ParcelFileDescriptor
|
openDocument(String documentId, String mode, CancellationSignal signal)
Open and return the requested document. |
AssetFileDescriptor
|
openDocumentThumbnail(String documentId, Point sizeHint, CancellationSignal signal)
Open and return a thumbnail of the requested document. |
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. |
AssetFileDescriptor
|
openTypedDocument(String documentId, String mimeTypeFilter, Bundle opts, CancellationSignal signal)
Open and return the document in a format matching the specified MIME type filter. |
final
Cursor
|
query(Uri uri, String[] projection, Bundle queryArgs, CancellationSignal cancellationSignal)
Implementation is provided by the parent class. |
Cursor
|
query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder, CancellationSignal cancellationSignal)
WARNING: Sub-classes should not override this method. |
final
Cursor
|
query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder)
Implement this to handle query requests from clients. |
Cursor
|
queryChildDocuments(String parentDocumentId, String[] projection, Bundle queryArgs)
Override this method to return the children documents contained in the requested directory. |
abstract
Cursor
|
queryChildDocuments(String parentDocumentId, String[] projection, String sortOrder)
Return the children documents contained in the requested directory. |
abstract
Cursor
|
queryDocument(String documentId, String[] projection)
Return metadata for the single requested document. |
Cursor
|
queryRecentDocuments(String rootId, String[] projection, Bundle queryArgs, CancellationSignal signal)
Return recently modified documents under the requested root. |
Cursor
|
queryRecentDocuments(String rootId, String[] projection)
Return recently modified documents under the requested root. |
abstract
Cursor
|
queryRoots(String[] projection)
Return all roots currently provided. |
Cursor
|
querySearchDocuments(String rootId, String[] projection, Bundle queryArgs)
Return documents that match the given query under the requested root. |
Cursor
|
querySearchDocuments(String rootId, String query, String[] projection)
Return documents that match the given query under the requested root. |
void
|
removeDocument(String documentId, String parentDocumentId)
Removes the requested document or a document tree. |
String
|
renameDocument(String documentId, String displayName)
Rename an existing document. |
final
void
|
revokeDocumentPermission(String documentId)
Revoke any active permission grants for the given
|
final
int
|
update(Uri uri, ContentValues values, String selection, String[] selectionArgs)
Implementation is provided by the parent class. |
Inherited methods | |
---|---|
Public constructors
DocumentsProvider
public DocumentsProvider ()
Public methods
attachInfo
public void attachInfo (Context context, ProviderInfo info)
Implementation is provided by the parent class.
Parameters | |
---|---|
context |
Context : The context this provider is running in |
info |
ProviderInfo : Registered information about this content provider |
call
public Bundle call (String method, String arg, Bundle extras)
Implementation is provided by the parent class. Can be overridden to
provide additional functionality, but subclasses must always
call the superclass. If the superclass returns null
, the subclass
may implement custom behavior.
If you override this method you must call through to the
superclass implementation.
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 may be null . |
canonicalize
public Uri canonicalize (Uri uri)
Implementation is provided by the parent class. Can be overridden to
provide additional functionality, but subclasses must always
call the superclass. If the superclass returns null
, the subclass
may implement custom behavior.
This is typically used to resolve a subtree URI into a concrete document
reference, issuing a narrower single-document URI permission grant along
the way.
If you override this method you must call through to the
superclass implementation.
Parameters | |
---|---|
uri |
Uri : The Uri to canonicalize.
This value cannot be null . |
Returns | |
---|---|
Uri |
Return the canonical representation of url, or null if canonicalization of that Uri is not supported. |
copyDocument
public String copyDocument (String sourceDocumentId, String targetParentDocumentId)
Copy the requested document or a document tree.
Copies a document including all child documents to another location within
the same document provider. Upon completion returns the document id of
the copied document at the target destination. null
must never
be returned.
Parameters | |
---|---|
sourceDocumentId |
String : the document to copy. |
targetParentDocumentId |
String : the target document to be copied into as a child. |
Returns | |
---|---|
String |
Throws | |
---|---|
AuthenticationRequiredException |
If authentication is required from the user (such as login credentials), but it is not guaranteed that the client will handle this properly. |
FileNotFoundException |
createDocument
public String createDocument (String parentDocumentId, String mimeType, String displayName)
Create a new document and return its newly generated
Document#COLUMN_DOCUMENT_ID
. You must allocate a new
Document#COLUMN_DOCUMENT_ID
to represent the document, which must
not change once returned.
Parameters | |
---|---|
parentDocumentId |
String : the parent directory to create the new document
under. |
mimeType |
String : the concrete MIME type associated with the new document.
If the MIME type is not supported, the provider must throw. |
displayName |
String : the display name of the new document. The provider may
alter this name to meet any internal constraints, such as
avoiding conflicting names. |
Returns | |
---|---|
String |
Throws | |
---|---|
AuthenticationRequiredException |
If authentication is required from the user (such as login credentials), but it is not guaranteed that the client will handle this properly. |
FileNotFoundException |
createWebLinkIntent
public IntentSender createWebLinkIntent (String documentId, Bundle options)
Creates an intent sender for a web link, if the document is web linkable.
AuthenticationRequiredException
can be thrown if user does not have
sufficient permission for the linked document. Before any new permissions
are granted for the linked document, a visible UI must be shown, so the
user can explicitly confirm whether the permission grants are expected.
The user must be able to cancel the operation.
Options passed as an argument may include a list of recipients, such as email addresses. The provider should reflect these options if possible, but it's acceptable to ignore them. In either case, confirmation UI must be shown before any new permission grants are granted.
It is all right to generate a web link without granting new permissions, if opening the link would result in a page for requesting permission access. If it's impossible then the operation must fail by throwing an exception.
Parameters | |
---|---|
documentId |
String : the document to create a web link intent for. |
options |
Bundle : additional information, such as list of recipients. Optional.
This value may be null . |
Returns | |
---|---|
IntentSender |
Throws | |
---|---|
AuthenticationRequiredException |
If authentication is required from the user (such as login credentials), but it is not guaranteed that the client will handle this properly. |
FileNotFoundException |
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 : The full URI to query, including a row ID (if a specific
record is requested).
This value cannot be null . |
selection |
String : An optional restriction to apply to rows when deleting.
This value may be null . |
selectionArgs |
String : This value may be null . |
Returns | |
---|---|
int |
The number of rows affected. |
See also:
deleteDocument
public void deleteDocument (String documentId)
Delete the requested document.
Upon returning, any URI permission grants for the given document will be
revoked. If additional documents were deleted as a side effect of this
call (such as documents inside a directory) the implementor is
responsible for revoking those permissions using
revokeDocumentPermission(java.lang.String)
.
Parameters | |
---|---|
documentId |
String : the document to delete. |
Throws | |
---|---|
AuthenticationRequiredException |
If authentication is required from the user (such as login credentials), but it is not guaranteed that the client will handle this properly. |
FileNotFoundException |
ejectRoot
public void ejectRoot (String rootId)
Ejects the root. Throws IllegalStateException
if ejection failed.
Parameters | |
---|---|
rootId |
String : the root to be ejected. |
findDocumentPath
public DocumentsContract.Path findDocumentPath (String parentDocumentId, String childDocumentId)
Finds the canonical path for the requested document. The path must start from the parent document if parentDocumentId is not null or the root document if parentDocumentId is null. If there are more than one path to this document, return the most typical one. Include both the parent document or root document and the requested document in the returned path.
This API assumes that document ID has enough info to infer the root. Different roots should use different document ID to refer to the same document.
Parameters | |
---|---|
parentDocumentId |
String : the document from which the path starts if not null,
or null to indicate a path from the root is requested. |
childDocumentId |
String : the document which path is requested. |
Returns | |
---|---|
DocumentsContract.Path |
the path of the requested document. If parentDocumentId is null returned root ID must not be null. If parentDocumentId is not null returned root ID must be null. |
Throws | |
---|---|
AuthenticationRequiredException |
If authentication is required from the user (such as login credentials), but it is not guaranteed that the client will handle this properly. |
FileNotFoundException |
getDocumentMetadata
public Bundle getDocumentMetadata (String documentId)
Returns metadata associated with the document. The type of metadata returned is specific to the document type. For example the data returned for an image file will likely consist primarily or solely of EXIF metadata.
The returned Bundle
will contain zero or more entries depending
on the type of data supported by the document provider.
- A
DocumentsContract#METADATA_TYPES
containing aString[]
value. The string array identifies the type or types of metadata returned. Each value in the can be used to access aBundle
of data containing that type of data. - An entry each for each type of returned metadata. Each set of metadata is itself represented as a bundle and accessible via a string key naming the type of data.
Parameters | |
---|---|
documentId |
String : get the metadata of the document
This value cannot be null . |
Returns | |
---|---|
Bundle |
a Bundle of Bundles.
This value may be null . |
Throws | |
---|---|
FileNotFoundException |
getDocumentStreamTypes
public String[] getDocumentStreamTypes (String documentId, String mimeTypeFilter)
Return a list of streamable MIME types matching the filter, which can be passed to
openTypedDocument(java.lang.String, java.lang.String, android.os.Bundle, android.os.CancellationSignal)
.
The default implementation returns a MIME type provided by
queryDocument(java.lang.String, java.lang.String[])
as long as it matches the filter and the document
does not have the Document#FLAG_VIRTUAL_DOCUMENT
flag set.
Virtual documents must have at least one streamable format.
Parameters | |
---|---|
documentId |
String |
mimeTypeFilter |
String |
Returns | |
---|---|
String[] |
getDocumentType
public String getDocumentType (String documentId)
Return concrete MIME type of the requested document. Must match the value
of Document#COLUMN_MIME_TYPE
for this document. The default
implementation queries queryDocument(java.lang.String, java.lang.String[])
, so
providers may choose to override this as an optimization.
Parameters | |
---|---|
documentId |
String |
Returns | |
---|---|
String |
Throws | |
---|---|
AuthenticationRequiredException |
If authentication is required from the user (such as login credentials), but it is not guaranteed that the client will handle this properly. |
FileNotFoundException |
getStreamTypes
public String[] getStreamTypes (Uri uri, String mimeTypeFilter)
Called by a client to determine the types of data streams that this content provider support for the given URI.
Overriding this method is deprecated. Override openTypedDocument(String, String, Bundle, CancellationSignal)
instead.
Parameters | |
---|---|
uri |
Uri : The data in the content provider being queried.
This value cannot be null . |
mimeTypeFilter |
String : The type of data the client desires. May be
a pattern, such as */* to retrieve all possible data types.
This value cannot be null . |
Returns | |
---|---|
String[] |
Returns null if there are no possible data streams for the
given mimeTypeFilter. Otherwise returns an array of all available
concrete MIME types. |
See also:
getType
public final String getType (Uri uri)
Implementation is provided by the parent class. Cannot be overridden.
Parameters | |
---|---|
uri |
Uri : the URI to query.
This value cannot be null . |
Returns | |
---|---|
String |
a MIME type string, or null if there is no type. |
See also:
getTypeAnonymous
public final String getTypeAnonymous (Uri uri)
An unrestricted version of getType, which does not reveal sensitive information
Parameters | |
---|---|
uri |
Uri : This value cannot be null . |
Returns | |
---|---|
String |
This value may 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 : The content:// URI of the insertion request.
This value cannot be null . |
values |
ContentValues : A set of column_name/value pairs to add to the database.
This value may be null . |
Returns | |
---|---|
Uri |
The URI for the newly inserted item.
This value may be null . |
See also:
isChildDocument
public boolean isChildDocument (String parentDocumentId, String documentId)
Test if a document is descendant (child, grandchild, etc) from the given
parent. For example, providers must implement this to support
Intent#ACTION_OPEN_DOCUMENT_TREE
. You should avoid making network
requests to keep this request fast.
Parameters | |
---|---|
parentDocumentId |
String : parent to verify against. |
documentId |
String : child to verify. |
Returns | |
---|---|
boolean |
if given document is a descendant of the given parent. |
moveDocument
public String moveDocument (String sourceDocumentId, String sourceParentDocumentId, String targetParentDocumentId)
Move the requested document or a document tree.
Moves a document including all child documents to another location within
the same document provider. Upon completion returns the document id of
the copied document at the target destination. null
must never
be returned.
It's the responsibility of the provider to revoke grants if the document
is no longer accessible using sourceDocumentId
.
Parameters | |
---|---|
sourceDocumentId |
String : the document to move. |
sourceParentDocumentId |
String : the parent of the document to move. |
targetParentDocumentId |
String : the target document to be a new parent of the
source document. |
Returns | |
---|---|
String |
Throws | |
---|---|
AuthenticationRequiredException |
If authentication is required from the user (such as login credentials), but it is not guaranteed that the client will handle this properly. |
FileNotFoundException |
openAssetFile
public final AssetFileDescriptor openAssetFile (Uri uri, String mode, CancellationSignal signal)
Implementation is provided by the parent class. Cannot be overridden.
Parameters | |
---|---|
uri |
Uri : The URI whose file is to be opened.
This value cannot be null . |
mode |
String : The string representation of the file mode. Can be "r", "w", "wt", "wa", "rw"
or "rwt". Please note the exact implementation of these may differ for each
Provider implementation - for example, "w" may or may not truncate.
This value cannot be null . |
signal |
CancellationSignal : A signal to cancel the operation in progress, or
null if none. For example, if you are downloading a
file from the network to service a "rw" mode request, you
should periodically call
CancellationSignal#throwIfCanceled() to check whether
the client has canceled the request and abort the download. |
Returns | |
---|---|
AssetFileDescriptor |
Returns a new AssetFileDescriptor which you can use to access
the file.
This value may be null . |
Throws | |
---|---|
FileNotFoundException |
openAssetFile
public final AssetFileDescriptor openAssetFile (Uri uri, String mode)
Implementation is provided by the parent class. Cannot be overridden.
Parameters | |
---|---|
uri |
Uri : The URI whose file is to be opened.
This value cannot be null . |
mode |
String : The string representation of the file mode. Can be "r", "w", "wt", "wa", "rw"
or "rwt". Please note the exact implementation of these may differ for each
Provider implementation - for example, "w" may or may not truncate.
This value cannot be null . |
Returns | |
---|---|
AssetFileDescriptor |
Returns a new AssetFileDescriptor which you can use to access
the file.
This value may be null . |
Throws | |
---|---|
FileNotFoundException |
openDocument
public abstract ParcelFileDescriptor openDocument (String documentId, String mode, CancellationSignal signal)
Open and return the requested document.
Your provider should return a reliable ParcelFileDescriptor
to
detect when the remote caller has finished reading or writing the
document.
Mode "r" should always be supported. Provider should throw
UnsupportedOperationException
if the passing mode is not supported.
You may return a pipe or socket pair if the mode is exclusively "r" or
"w", but complex modes like "rw" imply a normal file on disk that
supports seeking.
If you block while downloading content, you should periodically check
CancellationSignal#isCanceled()
to abort abandoned open requests.
Parameters | |
---|---|
documentId |
String : the document to return. |
mode |
String : the mode to open with, such as 'r', 'w', or 'rw'. |
signal |
CancellationSignal : used by the caller to signal if the request should be
cancelled. May be null. |
Returns | |
---|---|
ParcelFileDescriptor |
Throws | |
---|---|
AuthenticationRequiredException |
If authentication is required from the user (such as login credentials), but it is not guaranteed that the client will handle this properly. |
FileNotFoundException |
openDocumentThumbnail
public AssetFileDescriptor openDocumentThumbnail (String documentId, Point sizeHint, CancellationSignal signal)
Open and return a thumbnail of the requested document.
A provider should return a thumbnail closely matching the hinted size, attempting to serve from a local cache if possible. A provider should never return images more than double the hinted size.
If you perform expensive operations to download or generate a thumbnail,
you should periodically check CancellationSignal#isCanceled()
to
abort abandoned thumbnail requests.
Parameters | |
---|---|
documentId |
String : the document to return. |
sizeHint |
Point : hint of the optimal thumbnail dimensions. |
signal |
CancellationSignal : used by the caller to signal if the request should be
cancelled. May be null. |
Returns | |
---|---|
AssetFileDescriptor |
Throws | |
---|---|
AuthenticationRequiredException |
If authentication is required from the user (such as login credentials), but it is not guaranteed that the client will handle this properly. |
FileNotFoundException |
openFile
public final ParcelFileDescriptor openFile (Uri uri, String mode, CancellationSignal signal)
Implementation is provided by the parent class. Cannot be overridden.
Parameters | |
---|---|
uri |
Uri : The URI whose file is to be opened.
This value cannot be null . |
mode |
String : The string representation of the file mode. Can be "r", "w", "wt", "wa", "rw"
or "rwt". Please note the exact implementation of these may differ for each
Provider implementation - for example, "w" may or may not truncate.
This value cannot be null . |
signal |
CancellationSignal : A signal to cancel the operation in progress, or
null if none. For example, if you are downloading a
file from the network to service a "rw" mode request, you
should periodically call
CancellationSignal#throwIfCanceled() to check whether
the client has canceled the request and abort the download. |
Returns | |
---|---|
ParcelFileDescriptor |
Returns a new ParcelFileDescriptor which you can use to access
the file.
This value may be null . |
Throws | |
---|---|
FileNotFoundException |
openFile
public final ParcelFileDescriptor openFile (Uri uri, String mode)
Implementation is provided by the parent class. Cannot be overridden.
Parameters | |
---|---|
uri |
Uri : The URI whose file is to be opened.
This value cannot be null . |
mode |
String : The string representation of the file mode. Can be "r", "w", "wt", "wa", "rw"
or "rwt". Please note the exact implementation of these may differ for each
Provider implementation - for example, "w" may or may not truncate.
This value cannot be null . |
Returns | |
---|---|
ParcelFileDescriptor |
Returns a new ParcelFileDescriptor which you can use to access
the file.
This value may be null . |
Throws | |
---|---|
FileNotFoundException |
openTypedAssetFile
public final AssetFileDescriptor openTypedAssetFile (Uri uri, String mimeTypeFilter, Bundle opts)
Implementation is provided by the parent class. Cannot be overridden.
Parameters | |
---|---|
uri |
Uri : The data in the content provider being queried.
This value cannot be null . |
mimeTypeFilter |
String : The type of data the client desires. May be
a pattern, such as */*, if the caller does not have specific type
requirements; in this case the content provider will pick its best
type matching the pattern.
This value cannot be null . |
opts |
Bundle : Additional options from the client. The definitions of
these are specific to the content provider being called.
This value may be null . |
Returns | |
---|---|
AssetFileDescriptor |
Returns a new AssetFileDescriptor from which the client can
read data of the desired type.
This value may be null . |
Throws | |
---|---|
FileNotFoundException |
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 : The data in the content provider being queried.
This value cannot be null . |
mimeTypeFilter |
String : The type of data the client desires. May be
a pattern, such as */*, if the caller does not have specific type
requirements; in this case the content provider will pick its best
type matching the pattern.
This value cannot be null . |
opts |
Bundle : Additional options from the client. The definitions of
these are specific to the content provider being called.
This value may be null . |
signal |
CancellationSignal : A signal to cancel the operation in progress, or
null if none. For example, if you are downloading a
file from the network to service a "rw" mode request, you
should periodically call
CancellationSignal#throwIfCanceled() to check whether
the client has canceled the request and abort the download. |
Returns | |
---|---|
AssetFileDescriptor |
Returns a new AssetFileDescriptor from which the client can
read data of the desired type.
This value may be null . |
Throws | |
---|---|
FileNotFoundException |
openTypedDocument
public AssetFileDescriptor openTypedDocument (String documentId, String mimeTypeFilter, Bundle opts, CancellationSignal signal)
Open and return the document in a format matching the specified MIME type filter.
A provider may perform a conversion if the documents's MIME type is not matching the specified MIME type filter.
Virtual documents must have at least one streamable format.
Parameters | |
---|---|
documentId |
String : the document to return. |
mimeTypeFilter |
String : the MIME type filter for the requested format. May
be *\/*, which matches any MIME type. |
opts |
Bundle : extra options from the client. Specific to the content
provider. |
signal |
CancellationSignal : used by the caller to signal if the request should be
cancelled. May be null. |
Returns | |
---|---|
AssetFileDescriptor |
Throws | |
---|---|
AuthenticationRequiredException |
If authentication is required from the user (such as login credentials), but it is not guaranteed that the client will handle this properly. |
FileNotFoundException |
See also:
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 : The URI to query. This will be the full URI sent by the client.
This value cannot be null . |
projection |
String : The list of columns to put into the cursor.
If null provide a default set of columns. |
queryArgs |
Bundle : A Bundle containing additional information necessary for
the operation. Arguments may include SQL style arguments, such
as ContentResolver#QUERY_ARG_SQL_LIMIT , but note that
the documentation for each individual provider will indicate
which arguments they support.
This value may be null . |
cancellationSignal |
CancellationSignal : A signal to cancel the operation in progress,
or null . |
Returns | |
---|---|
Cursor |
a Cursor or null . |
query
public Cursor query (Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder, CancellationSignal cancellationSignal)
WARNING: Sub-classes should not override this method. This method is non-final solely for the purposes of backwards compatibility.
Parameters | |
---|---|
uri |
Uri : The URI to query. This will be the full URI sent by the client;
if the client is requesting a specific record, the URI will end in a record number
that the implementation should parse and add to a WHERE or HAVING clause, specifying
that _id value.
This value cannot be null . |
projection |
String : The list of columns to put into the cursor. If
null all columns are included. |
selection |
String : A selection criteria to apply when filtering rows.
If null then all rows are included. |
selectionArgs |
String : You may include ?s in selection, which will be replaced by
the values from selectionArgs, in order that they appear in the selection.
The values will be bound as Strings.
This value may be null . |
sortOrder |
String : How the rows in the cursor should be sorted.
If null then the provider is free to define the sort order. |
cancellationSignal |
CancellationSignal : A signal to cancel the operation in progress, or null if none.
If the operation is canceled, then OperationCanceledException will be thrown
when the query is executed. |
Returns | |
---|---|
Cursor |
a Cursor or null . |
query
public final Cursor query (Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder)
Implement this to handle query requests from clients.
Apps targeting Build.VERSION_CODES.O
or higher should override
query(android.net.Uri, java.lang.String[], android.os.Bundle, android.os.CancellationSignal)
and provide a stub
implementation of this method.
This method can be called from multiple threads, as described in Processes and Threads.
Example client call:
// Request a specific record. Cursor managedCursor = managedQuery( ContentUris.withAppendedId(Contacts.People.CONTENT_URI, 2), projection, // Which columns to return. null, // WHERE clause. null, // WHERE clause value substitution People.NAME + " ASC"); // Sort order.Example implementation:
// SQLiteQueryBuilder is a helper class that creates the // proper SQL syntax for us. SQLiteQueryBuilder qBuilder = new SQLiteQueryBuilder(); // Guard against SQL injection attacks qBuilder.setStrict(true); qBuilder.setProjectionMap(MAP_OF_QUERYABLE_COLUMNS); qBuilder.setStrictColumns(true); qBuilder.setStrictGrammar(true); // Set the table we're querying. qBuilder.setTables(DATABASE_TABLE_NAME); // If the query ends in a specific record number, we're // being asked for a specific record, so set the // WHERE clause in our query. if((URI_MATCHER.match(uri)) == SPECIFIC_MESSAGE){ qBuilder.appendWhere("_id=" + uri.getPathLeafId()); } // Make the query. Cursor c = qBuilder.query(mDb, projection, selection, selectionArgs, groupBy, having, sortOrder); c.setNotificationUri(getContext().getContentResolver(), uri); return c;
Parameters | |
---|---|
uri |
Uri : The URI to query. This will be the full URI sent by the client;
if the client is requesting a specific record, the URI will end in a record number
that the implementation should parse and add to a WHERE or HAVING clause, specifying
that _id value.
This value cannot be null . |
projection |
String : The list of columns to put into the cursor. If
null all columns are included. |
selection |
String : A selection criteria to apply when filtering rows.
If null then all rows are included. |
selectionArgs |
String : You may include ?s in selection, which will be replaced by
the values from selectionArgs, in order that they appear in the selection.
The values will be bound as Strings.
This value may be null . |
sortOrder |
String : How the rows in the cursor should be sorted.
If null then the provider is free to define the sort order. |
Returns | |
---|---|
Cursor |
a Cursor or null . |
queryChildDocuments
public Cursor queryChildDocuments (String parentDocumentId, String[] projection, Bundle queryArgs)
Override this method to return the children documents contained in the requested directory. This must return immediate descendants only.
If your provider is cloud-based, and you have data cached
locally, you may return the local data immediately, setting
DocumentsContract#EXTRA_LOADING
on Cursor extras to indicate that
you are still fetching additional data. Then, when the network data is
available, you can send a change notification to trigger a requery and
return the complete contents. To return a Cursor with extras, you need to
extend and override Cursor#getExtras()
.
To support change notifications, you must
Cursor#setNotificationUri(ContentResolver, Uri)
with a relevant
Uri, such as
DocumentsContract#buildChildDocumentsUri(String, String)
. Then
you can call ContentResolver#notifyChange(Uri,
android.database.ContentObserver, boolean)
with that Uri to send change
notifications.
Parameters | |
---|---|
parentDocumentId |
String : the directory to return children for. |
projection |
String : list of Document columns to put into the
cursor. If null all supported columns should be
included. |
queryArgs |
Bundle : Bundle containing sorting information or other
argument useful to the provider. If no sorting
information is available, default sorting
will be used, which may be unordered. See
ContentResolver#QUERY_ARG_SORT_COLUMNS for
details.
This value may be null . |
Returns | |
---|---|
Cursor |
Throws | |
---|---|
AuthenticationRequiredException |
If authentication is required from the user (such as login credentials), but it is not guaranteed that the client will handle this properly. |
FileNotFoundException |
queryChildDocuments
public abstract Cursor queryChildDocuments (String parentDocumentId, String[] projection, String sortOrder)
Return the children documents contained in the requested directory. This must only return immediate descendants, as additional queries will be issued to recursively explore the tree.
Apps targeting Build.VERSION_CODES.O
or higher
should override queryChildDocuments(java.lang.String, java.lang.String[], android.os.Bundle)
.
If your provider is cloud-based, and you have some data cached or pinned
locally, you may return the local data immediately, setting
DocumentsContract#EXTRA_LOADING
on the Cursor to indicate that
you are still fetching additional data. Then, when the network data is
available, you can send a change notification to trigger a requery and
return the complete contents. To return a Cursor with extras, you need to
extend and override Cursor#getExtras()
.
To support change notifications, you must
Cursor#setNotificationUri(ContentResolver, Uri)
with a relevant
Uri, such as
DocumentsContract#buildChildDocumentsUri(String, String)
. Then
you can call ContentResolver#notifyChange(Uri,
android.database.ContentObserver, boolean)
with that Uri to send change
notifications.
Parameters | |
---|---|
parentDocumentId |
String : the directory to return children for. |
projection |
String : list of Document columns to put into the
cursor. If null all supported columns should be
included. |
sortOrder |
String : how to order the rows, formatted as an SQL
ORDER BY clause (excluding the ORDER BY itself).
Passing null will use the default sort order, which
may be unordered. This ordering is a hint that can be used to
prioritize how data is fetched from the network, but UI may
always enforce a specific ordering. |
Returns | |
---|---|
Cursor |
Throws | |
---|---|
AuthenticationRequiredException |
If authentication is required from the user (such as login credentials), but it is not guaranteed that the client will handle this properly. |
FileNotFoundException |
queryDocument
public abstract Cursor queryDocument (String documentId, String[] projection)
Return metadata for the single requested document. You should avoid making network requests to keep this request fast.
Parameters | |
---|---|
documentId |
String : the document to return. |
projection |
String : list of Document columns to put into the
cursor. If null all supported columns should be
included. |
Returns | |
---|---|
Cursor |
Throws | |
---|---|
AuthenticationRequiredException |
If authentication is required from the user (such as login credentials), but it is not guaranteed that the client will handle this properly. |
FileNotFoundException |
queryRecentDocuments
public Cursor queryRecentDocuments (String rootId, String[] projection, Bundle queryArgs, CancellationSignal signal)
Return recently modified documents under the requested root. This will
only be called for roots that advertise
Root#FLAG_SUPPORTS_RECENTS
. The returned documents should be
sorted by Document#COLUMN_LAST_MODIFIED
in descending order of
the most recently modified documents.
If this method is overriden by the concrete DocumentsProvider and
ContentResolver#QUERY_ARG_LIMIT
is specified with a nonnegative
int under queryArgs, the result will be limited by that number and
ContentResolver#QUERY_ARG_LIMIT
will be specified under
ContentResolver#EXTRA_HONORED_ARGS
. Otherwise, a default 64 limit
will be used and no QUERY_ARG* will be specified under
ContentResolver#EXTRA_HONORED_ARGS
.
Recent documents do not support change notifications.
Parameters | |
---|---|
rootId |
String : This value cannot be null . |
projection |
String : list of Document columns to put into the
cursor. If null all supported columns should be
included. |
queryArgs |
Bundle : the extra query arguments.
This value may be null . |
signal |
CancellationSignal : used by the caller to signal if the request should be
cancelled. May be null. |
Returns | |
---|---|
Cursor |
This value may be null . |
Throws | |
---|---|
FileNotFoundException |
See also:
queryRecentDocuments
public Cursor queryRecentDocuments (String rootId, String[] projection)
Return recently modified documents under the requested root. This will
only be called for roots that advertise
Root#FLAG_SUPPORTS_RECENTS
. The returned documents should be
sorted by Document#COLUMN_LAST_MODIFIED
in descending order, and
limited to only return the 64 most recently modified documents.
Recent documents do not support change notifications.
Parameters | |
---|---|
rootId |
String |
projection |
String : list of Document columns to put into the
cursor. If null all supported columns should be
included. |
Returns | |
---|---|
Cursor |
Throws | |
---|---|
FileNotFoundException |
See also:
queryRoots
public abstract Cursor queryRoots (String[] projection)
Return all roots currently provided. To display to users, you must define at least one root. You should avoid making network requests to keep this request fast.
Each root is defined by the metadata columns described in Root
,
including Root#COLUMN_DOCUMENT_ID
which points to a directory
representing a tree of documents to display under that root.
If this set of roots changes, you must call ContentResolver#notifyChange(Uri,
android.database.ContentObserver, boolean)
with
DocumentsContract#buildRootsUri(String)
to notify the system.
Parameters | |
---|---|
projection |
String : list of Root columns to put into the cursor. If
null all supported columns should be included. |
Returns | |
---|---|
Cursor |
Throws | |
---|---|
FileNotFoundException |
querySearchDocuments
public Cursor querySearchDocuments (String rootId, String[] projection, Bundle queryArgs)
Return documents that match the given query under the requested
root. The returned documents should be sorted by relevance in descending
order. How documents are matched against the query string is an
implementation detail left to each provider, but it's suggested that at
least Document#COLUMN_DISPLAY_NAME
be matched in a
case-insensitive fashion.
If your provider is cloud-based, and you have some data cached or pinned
locally, you may return the local data immediately, setting
DocumentsContract#EXTRA_LOADING
on the Cursor to indicate that
you are still fetching additional data. Then, when the network data is
available, you can send a change notification to trigger a requery and
return the complete contents.
To support change notifications, you must
Cursor#setNotificationUri(ContentResolver, Uri)
with a relevant
Uri, such as DocumentsContract#buildSearchDocumentsUri(String,
String, String)
. Then you can call ContentResolver#notifyChange(Uri,
android.database.ContentObserver, boolean)
with that Uri to send change
notifications.
Parameters | |
---|---|
rootId |
String : the root to search under.
This value cannot be null . |
projection |
String : list of Document columns to put into the
cursor. If null all supported columns should be
included. |
queryArgs |
Bundle : the query arguments.
DocumentsContract#QUERY_ARG_EXCLUDE_MEDIA ,
DocumentsContract#QUERY_ARG_DISPLAY_NAME ,
DocumentsContract#QUERY_ARG_MIME_TYPES ,
DocumentsContract#QUERY_ARG_FILE_SIZE_OVER ,
DocumentsContract#QUERY_ARG_LAST_MODIFIED_AFTER .
This value cannot be null . |
Returns | |
---|---|
Cursor |
cursor containing search result. Include
ContentResolver#EXTRA_HONORED_ARGS in Cursor
extras Bundle when any QUERY_ARG_* value was honored
during the preparation of the results.
This value may be null . |
Throws | |
---|---|
FileNotFoundException |
querySearchDocuments
public Cursor querySearchDocuments (String rootId, String query, String[] projection)
Return documents that match the given query under the requested
root. The returned documents should be sorted by relevance in descending
order. How documents are matched against the query string is an
implementation detail left to each provider, but it's suggested that at
least Document#COLUMN_DISPLAY_NAME
be matched in a
case-insensitive fashion.
If your provider is cloud-based, and you have some data cached or pinned
locally, you may return the local data immediately, setting
DocumentsContract#EXTRA_LOADING
on the Cursor to indicate that
you are still fetching additional data. Then, when the network data is
available, you can send a change notification to trigger a requery and
return the complete contents.
To support change notifications, you must
Cursor#setNotificationUri(ContentResolver, Uri)
with a relevant
Uri, such as DocumentsContract#buildSearchDocumentsUri(String,
String, String)
. Then you can call ContentResolver#notifyChange(Uri,
android.database.ContentObserver, boolean)
with that Uri to send change
notifications.
Parameters | |
---|---|
rootId |
String : the root to search under. |
query |
String : string to match documents against. |
projection |
String : list of Document columns to put into the
cursor. If null all supported columns should be
included. |
Returns | |
---|---|
Cursor |
Throws | |
---|---|
AuthenticationRequiredException |
If authentication is required from the user (such as login credentials), but it is not guaranteed that the client will handle this properly. |
FileNotFoundException |
removeDocument
public void removeDocument (String documentId, String parentDocumentId)
Removes the requested document or a document tree.
In contrast to deleteDocument(String)
it requires specifying the parent.
This method is especially useful if the document can be in multiple parents.
It's the responsibility of the provider to revoke grants if the document is removed from the last parent, and effectively the document is deleted.
Parameters | |
---|---|
documentId |
String : the document to remove. |
parentDocumentId |
String : the parent of the document to move. |
Throws | |
---|---|
AuthenticationRequiredException |
If authentication is required from the user (such as login credentials), but it is not guaranteed that the client will handle this properly. |
FileNotFoundException |
renameDocument
public String renameDocument (String documentId, String displayName)
Rename an existing document.
If a different Document#COLUMN_DOCUMENT_ID
must be used to
represent the renamed document, generate and return it. Any outstanding
URI permission grants will be updated to point at the new document. If
the original Document#COLUMN_DOCUMENT_ID
is still valid after the
rename, return null
.
Parameters | |
---|---|
documentId |
String : the document to rename. |
displayName |
String : the updated display name of the document. The provider
may alter this name to meet any internal constraints, such as
avoiding conflicting names. |
Returns | |
---|---|
String |
Throws | |
---|---|
AuthenticationRequiredException |
If authentication is required from the user (such as login credentials), but it is not guaranteed that the client will handle this properly. |
FileNotFoundException |
revokeDocumentPermission
public final void revokeDocumentPermission (String documentId)
Revoke any active permission grants for the given
Document#COLUMN_DOCUMENT_ID
, usually called when a document
becomes invalid. Follows the same semantics as
Context#revokeUriPermission(Uri, int)
.
Parameters | |
---|---|
documentId |
String |
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 : The URI to query. This can potentially have a record ID if
this is an update request for a specific record.
This value cannot be null . |
values |
ContentValues : A set of column_name/value pairs to update in the database.
This value may be null . |
selection |
String : An optional filter to match rows to update.
This value may be null . |
selectionArgs |
String : This value may be null . |
Returns | |
---|---|
int |
the number of rows affected. |