/*
* Copyright (C) 2013 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.example.android.storageprovider;
import android.content.Context;
import android.content.SharedPreferences;
import android.content.res.AssetFileDescriptor;
import android.content.res.TypedArray;
import android.database.Cursor;
import android.database.MatrixCursor;
import android.graphics.Point;
import android.os.CancellationSignal;
import android.os.Handler;
import android.os.ParcelFileDescriptor;
import android.provider.DocumentsContract.Document;
import android.provider.DocumentsContract.Root;
import android.provider.DocumentsProvider;
import android.webkit.MimeTypeMap;
import com.example.android.common.logger.Log;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.PriorityQueue;
import java.util.Set;
/**
* Manages documents and exposes them to the Android system for sharing.
*/
public class MyCloudProvider extends DocumentsProvider {
private static final String TAG = MyCloudProvider.class.getSimpleName();
// Use these as the default columns to return information about a root if no specific
// columns are requested in a query.
private static final String[] DEFAULT_ROOT_PROJECTION = new String[]{
Root.COLUMN_ROOT_ID,
Root.COLUMN_MIME_TYPES,
Root.COLUMN_FLAGS,
Root.COLUMN_ICON,
Root.COLUMN_TITLE,
Root.COLUMN_SUMMARY,
Root.COLUMN_DOCUMENT_ID,
Root.COLUMN_AVAILABLE_BYTES
};
// Use these as the default columns to return information about a document if no specific
// columns are requested in a query.
private static final String[] DEFAULT_DOCUMENT_PROJECTION = new String[]{
Document.COLUMN_DOCUMENT_ID,
Document.COLUMN_MIME_TYPE,
Document.COLUMN_DISPLAY_NAME,
Document.COLUMN_LAST_MODIFIED,
Document.COLUMN_FLAGS,
Document.COLUMN_SIZE
};
// No official policy on how many to return, but make sure you do limit the number of recent
// and search results.
private static final int MAX_SEARCH_RESULTS = 20;
private static final int MAX_LAST_MODIFIED = 5;
private static final String ROOT = "root";
// A file object at the root of the file hierarchy. Depending on your implementation, the root
// does not need to be an existing file system directory. For example, a tag-based document
// provider might return a directory containing all tags, represented as child directories.
private File mBaseDir;
@Override
public boolean onCreate() {
Log.v(TAG, "onCreate");
mBaseDir = getContext().getFilesDir();
writeDummyFilesToStorage();
return true;
}
// BEGIN_INCLUDE(query_roots)
@Override
public Cursor queryRoots(String[] projection) throws FileNotFoundException {
Log.v(TAG, "queryRoots");
// Create a cursor with either the requested fields, or the default projection. This
// cursor is returned to the Android system picker UI and used to display all roots from
// this provider.
final MatrixCursor result = new MatrixCursor(resolveRootProjection(projection));
// If user is not logged in, return an empty root cursor. This removes our provider from
// the list entirely.
if (!isUserLoggedIn()) {
return result;
}
// It's possible to have multiple roots (e.g. for multiple accounts in the same app) -
// just add multiple cursor rows.
// Construct one row for a root called "MyCloud".
final MatrixCursor.RowBuilder row = result.newRow();
row.add(Root.COLUMN_ROOT_ID, ROOT);
row.add(Root.COLUMN_SUMMARY, getContext().getString(R.string.root_summary));
// FLAG_SUPPORTS_CREATE means at least one directory under the root supports creating
// documents. FLAG_SUPPORTS_RECENTS means your application's most recently used
// documents will show up in the "Recents" category. FLAG_SUPPORTS_SEARCH allows users
// to search all documents the application shares.
row.add(Root.COLUMN_FLAGS, Root.FLAG_SUPPORTS_CREATE |
Root.FLAG_SUPPORTS_RECENTS |
Root.FLAG_SUPPORTS_SEARCH);
// COLUMN_TITLE is the root title (e.g. what will be displayed to identify your provider).
row.add(Root.COLUMN_TITLE, getContext().getString(R.string.app_name));
// This document id must be unique within this provider and consistent across time. The
// system picker UI may save it and refer to it later.
row.add(Root.COLUMN_DOCUMENT_ID, getDocIdForFile(mBaseDir));
// The child MIME types are used to filter the roots and only present to the user roots
// that contain the desired type somewhere in their file hierarchy.
row.add(Root.COLUMN_MIME_TYPES, getChildMimeTypes(mBaseDir));
row.add(Root.COLUMN_AVAILABLE_BYTES, mBaseDir.getFreeSpace());
row.add(Root.COLUMN_ICON, R.drawable.ic_launcher);
return result;
}
// END_INCLUDE(query_roots)
// BEGIN_INCLUDE(query_recent_documents)
@Override
public Cursor queryRecentDocuments(String rootId, String[] projection)
throws FileNotFoundException {
Log.v(TAG, "queryRecentDocuments");
// This example implementation walks a local file structure to find the most recently
// modified files. Other implementations might include making a network call to query a
// server.
// Create a cursor with the requested projection, or the default projection.
final MatrixCursor result = new MatrixCursor(resolveDocumentProjection(projection));
final File parent = getFileForDocId(rootId);
// Create a queue to store the most recent documents, which orders by last modified.
PriorityQueue<File> lastModifiedFiles = new PriorityQueue<File>(5, new Comparator<File>() {
public int compare(File i, File j) {
return Long.compare(i.lastModified(), j.lastModified());
}
});
// Iterate through all files and directories in the file structure under the root. If
// the file is more recent than the least recently modified, add it to the queue,
// limiting the number of results.
final LinkedList<File> pending = new LinkedList<File>();
// Start by adding the parent to the list of files to be processed
pending.add(parent);
// Do while we still have unexamined files
while (!pending.isEmpty()) {
// Take a file from the list of unprocessed files
final File file = pending.removeFirst();
if (file.isDirectory()) {
// If it's a directory, add all its children to the unprocessed list
Collections.addAll(pending, file.listFiles());
} else {
// If it's a file, add it to the ordered queue.
lastModifiedFiles.add(file);
}
}
// Add the most recent files to the cursor, not exceeding the max number of results.
for (int i = 0; i < Math.min(MAX_LAST_MODIFIED + 1, lastModifiedFiles.size()); i++) {
final File file = lastModifiedFiles.remove();
includeFile(result, null, file);
}
return result;
}
// END_INCLUDE(query_recent_documents)
// BEGIN_INCLUDE(query_search_documents)
@Override
public Cursor querySearchDocuments(String rootId, String query, String[] projection)
throws FileNotFoundException {
Log.v(TAG, "querySearchDocuments");
// Create a cursor with the requested projection, or the default projection.
final MatrixCursor result = new MatrixCursor(resolveDocumentProjection(projection));
final File parent = getFileForDocId(rootId);
// This example implementation searches file names for the query and doesn't rank search
// results, so we can stop as soon as we find a sufficient number of matches. Other
// implementations might use other data about files, rather than the file name, to
// produce a match; it might also require a network call to query a remote server.
// Iterate through all files in the file structure under the root until we reach the
// desired number of matches.
final LinkedList<File> pending = new LinkedList<File>();
// Start by adding the parent to the list of files to be processed
pending.add(parent);
// Do while we still have unexamined files, and fewer than the max search results
while (!pending.isEmpty() && result.getCount() < MAX_SEARCH_RESULTS) {
// Take a file from the list of unprocessed files
final File file = pending.removeFirst();
if (file.isDirectory()) {
// If it's a directory, add all its children to the unprocessed list
Collections.addAll(pending, file.listFiles());
} else {
// If it's a file and it matches, add it to the result cursor.
if (file.getName().toLowerCase().contains(query)) {
includeFile(result, null, file);
}
}
}
return result;
}
// END_INCLUDE(query_search_documents)
// BEGIN_INCLUDE(open_document_thumbnail)
@Override
public AssetFileDescriptor openDocumentThumbnail(String documentId, Point sizeHint,
CancellationSignal signal)
throws FileNotFoundException {
Log.v(TAG, "openDocumentThumbnail");
final File file = getFileForDocId(documentId);
final ParcelFileDescriptor pfd =
ParcelFileDescriptor.open(file, ParcelFileDescriptor.MODE_READ_ONLY);
return new AssetFileDescriptor(pfd, 0, AssetFileDescriptor.UNKNOWN_LENGTH);
}
// END_INCLUDE(open_document_thumbnail)
// BEGIN_INCLUDE(query_document)
@Override
public Cursor queryDocument(String documentId, String[] projection)
throws FileNotFoundException {
Log.v(TAG, "queryDocument");
// Create a cursor with the requested projection, or the default projection.
final MatrixCursor result = new MatrixCursor(resolveDocumentProjection(projection));
includeFile(result, documentId, null);
return result;
}
// END_INCLUDE(query_document)
// BEGIN_INCLUDE(query_child_documents)
@Override
public Cursor queryChildDocuments(String parentDocumentId, String[] projection,
String sortOrder) throws FileNotFoundException {
Log.v(TAG, "queryChildDocuments, parentDocumentId: " +
parentDocumentId +
" sortOrder: " +
sortOrder);
final MatrixCursor result = new MatrixCursor(resolveDocumentProjection(projection));
final File parent = getFileForDocId(parentDocumentId);
for (File file : parent.listFiles()) {
includeFile(result, null, file);
}
return result;
}
// END_INCLUDE(query_child_documents)
// BEGIN_INCLUDE(open_document)
@Override
public ParcelFileDescriptor openDocument(final String documentId, final String mode,
CancellationSignal signal)
throws FileNotFoundException {
Log.v(TAG, "openDocument, mode: " + mode);
// It's OK to do network operations in this method to download the document, as long as you
// periodically check the CancellationSignal. If you have an extremely large file to
// transfer from the network, a better solution may be pipes or sockets
// (see ParcelFileDescriptor for helper methods).
final File file = getFileForDocId(documentId);
final int accessMode = ParcelFileDescriptor.parseMode(mode);
final boolean isWrite = (mode.indexOf('w') != -1);
if (isWrite) {
// Attach a close listener if the document is opened in write mode.
try {
Handler handler = new Handler(getContext().getMainLooper());
return ParcelFileDescriptor.open(file, accessMode, handler,
new ParcelFileDescriptor.OnCloseListener() {
@Override
public void onClose(IOException e) {
// Update the file with the cloud server. The client is done writing.
Log.i(TAG, "A file with id " + documentId + " has been closed! Time to " +
"update the server.");
}
});
} catch (IOException e) {
throw new FileNotFoundException("Failed to open document with id " + documentId +
" and mode " + mode);
}
} else {
return ParcelFileDescriptor.open(file, accessMode);
}
}
// END_INCLUDE(open_document)
// BEGIN_INCLUDE(create_document)
@Override
public String createDocument(String documentId, String mimeType, String displayName)
throws FileNotFoundException {
Log.v(TAG, "createDocument");
File parent = getFileForDocId(documentId);
File file = new File(parent.getPath(), displayName);
try {
file.createNewFile();
file.setWritable(true);
file.setReadable(true);
} catch (IOException e) {
throw new FileNotFoundException("Failed to create document with name " +
displayName +" and documentId " + documentId);
}
return getDocIdForFile(file);
}
// END_INCLUDE(create_document)
// BEGIN_INCLUDE(delete_document)
@Override
public void deleteDocument(String documentId) throws FileNotFoundException {
Log.v(TAG, "deleteDocument");
File file = getFileForDocId(documentId);
if (file.delete()) {
Log.i(TAG, "Deleted file with id " + documentId);
} else {
throw new FileNotFoundException("Failed to delete document with id " + documentId);
}
}
// END_INCLUDE(delete_document)
@Override
public String getDocumentType(String documentId) throws FileNotFoundException {
File file = getFileForDocId(documentId);
return getTypeForFile(file);
}
/**
* @param projection the requested root column projection
* @return either the requested root column projection, or the default projection if the
* requested projection is null.
*/
private static String[] resolveRootProjection(String[] projection) {
return projection != null ? projection : DEFAULT_ROOT_PROJECTION;
}
private static String[] resolveDocumentProjection(String[] projection) {
return projection != null ? projection : DEFAULT_DOCUMENT_PROJECTION;
}
/**
* Get a file's MIME type
*
* @param file the File object whose type we want
* @return the MIME type of the file
*/
private static String getTypeForFile(File file) {
if (file.isDirectory()) {
return Document.MIME_TYPE_DIR;
} else {
return getTypeForName(file.getName());
}
}
/**
* Get the MIME data type of a document, given its filename.
*
* @param name the filename of the document
* @return the MIME data type of a document
*/
private static String getTypeForName(String name) {
final int lastDot = name.lastIndexOf('.');
if (lastDot >= 0) {
final String extension = name.substring(lastDot + 1);
final String mime = MimeTypeMap.getSingleton().getMimeTypeFromExtension(extension);
if (mime != null) {
return mime;
}
}
return "application/octet-stream";
}
/**
* Gets a string of unique MIME data types a directory supports, separated by newlines. This
* should not change.
*
* @param parent the File for the parent directory
* @return a string of the unique MIME data types the parent directory supports
*/
private String getChildMimeTypes(File parent) {
Set<String> mimeTypes = new HashSet<String>();
mimeTypes.add("image/*");
mimeTypes.add("text/*");
mimeTypes.add("application/vnd.openxmlformats-officedocument.wordprocessingml.document");
// Flatten the list into a string and insert newlines between the MIME type strings.
StringBuilder mimeTypesString = new StringBuilder();
for (String mimeType : mimeTypes) {
mimeTypesString.append(mimeType).append("\n");
}
return mimeTypesString.toString();
}
/**
* Get the document ID given a File. The document id must be consistent across time. Other
* applications may save the ID and use it to reference documents later.
* <p/>
* This implementation is specific to this demo. It assumes only one root and is built
* directly from the file structure. However, it is possible for a document to be a child of
* multiple directories (for example "android" and "images"), in which case the file must have
* the same consistent, unique document ID in both cases.
*
* @param file the File whose document ID you want
* @return the corresponding document ID
*/
private String getDocIdForFile(File file) {
String path = file.getAbsolutePath();
// Start at first char of path under root
final String rootPath = mBaseDir.getPath();
if (rootPath.equals(path)) {
path = "";
} else if (rootPath.endsWith("/")) {
path = path.substring(rootPath.length());
} else {
path = path.substring(rootPath.length() + 1);
}
return "root" + ':' + path;
}
/**
* Add a representation of a file to a cursor.
*
* @param result the cursor to modify
* @param docId the document ID representing the desired file (may be null if given file)
* @param file the File object representing the desired file (may be null if given docID)
* @throws java.io.FileNotFoundException
*/
private void includeFile(MatrixCursor result, String docId, File file)
throws FileNotFoundException {
if (docId == null) {
docId = getDocIdForFile(file);
} else {
file = getFileForDocId(docId);
}
int flags = 0;
if (file.isDirectory()) {
// Request the folder to lay out as a grid rather than a list. This also allows a larger
// thumbnail to be displayed for each image.
// flags |= Document.FLAG_DIR_PREFERS_GRID;
// Add FLAG_DIR_SUPPORTS_CREATE if the file is a writable directory.
if (file.isDirectory() && file.canWrite()) {
flags |= Document.FLAG_DIR_SUPPORTS_CREATE;
}
} else if (file.canWrite()) {
// If the file is writable set FLAG_SUPPORTS_WRITE and
// FLAG_SUPPORTS_DELETE
flags |= Document.FLAG_SUPPORTS_WRITE;
flags |= Document.FLAG_SUPPORTS_DELETE;
}
final String displayName = file.getName();
final String mimeType = getTypeForFile(file);
if (mimeType.startsWith("image/")) {
// Allow the image to be represented by a thumbnail rather than an icon
flags |= Document.FLAG_SUPPORTS_THUMBNAIL;
}
final MatrixCursor.RowBuilder row = result.newRow();
row.add(Document.COLUMN_DOCUMENT_ID, docId);
row.add(Document.COLUMN_DISPLAY_NAME, displayName);
row.add(Document.COLUMN_SIZE, file.length());
row.add(Document.COLUMN_MIME_TYPE, mimeType);
row.add(Document.COLUMN_LAST_MODIFIED, file.lastModified());
row.add(Document.COLUMN_FLAGS, flags);
// Add a custom icon
row.add(Document.COLUMN_ICON, R.drawable.ic_launcher);
}
/**
* Translate your custom URI scheme into a File object.
*
* @param docId the document ID representing the desired file
* @return a File represented by the given document ID
* @throws java.io.FileNotFoundException
*/
private File getFileForDocId(String docId) throws FileNotFoundException {
File target = mBaseDir;
if (docId.equals(ROOT)) {
return target;
}
final int splitIndex = docId.indexOf(':', 1);
if (splitIndex < 0) {
throw new FileNotFoundException("Missing root for " + docId);
} else {
final String path = docId.substring(splitIndex + 1);
target = new File(target, path);
if (!target.exists()) {
throw new FileNotFoundException("Missing file for " + docId + " at " + target);
}
return target;
}
}
/**
* Preload sample files packaged in the apk into the internal storage directory. This is a
* dummy function specific to this demo. The MyCloud mock cloud service doesn't actually
* have a backend, so it simulates by reading content from the device's internal storage.
*/
private void writeDummyFilesToStorage() {
if (mBaseDir.list().length > 0) {
return;
}
int[] imageResIds = getResourceIdArray(R.array.image_res_ids);
for (int resId : imageResIds) {
writeFileToInternalStorage(resId, ".jpeg");
}
int[] textResIds = getResourceIdArray(R.array.text_res_ids);
for (int resId : textResIds) {
writeFileToInternalStorage(resId, ".txt");
}
int[] docxResIds = getResourceIdArray(R.array.docx_res_ids);
for (int resId : docxResIds) {
writeFileToInternalStorage(resId, ".docx");
}
}
/**
* Write a file to internal storage. Used to set up our dummy "cloud server".
*
* @param resId the resource ID of the file to write to internal storage
* @param extension the file extension (ex. .png, .mp3)
*/
private void writeFileToInternalStorage(int resId, String extension) {
InputStream ins = getContext().getResources().openRawResource(resId);
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
int size;
byte[] buffer = new byte[1024];
try {
while ((size = ins.read(buffer, 0, 1024)) >= 0) {
outputStream.write(buffer, 0, size);
}
ins.close();
buffer = outputStream.toByteArray();
String filename = getContext().getResources().getResourceEntryName(resId) + extension;
FileOutputStream fos = getContext().openFileOutput(filename, Context.MODE_PRIVATE);
fos.write(buffer);
fos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
private int[] getResourceIdArray(int arrayResId) {
TypedArray ar = getContext().getResources().obtainTypedArray(arrayResId);
int len = ar.length();
int[] resIds = new int[len];
for (int i = 0; i < len; i++) {
resIds[i] = ar.getResourceId(i, 0);
}
ar.recycle();
return resIds;
}
/**
* Dummy function to determine whether the user is logged in.
*/
private boolean isUserLoggedIn() {
final SharedPreferences sharedPreferences =
getContext().getSharedPreferences(getContext().getString(R.string.app_name),
Context.MODE_PRIVATE);
return sharedPreferences.getBoolean(getContext().getString(R.string.key_logged_in), false);
}
}