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The source code is released under:
Apache License
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/* * Copyright (C) 2013 The Android Open Source Project */* www . ja v a2 s . com*/ * 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); } }