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/*
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* Copyright (C) 2013 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.example.android.storageprovider;
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import android.content.Context;
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import android.content.SharedPreferences;
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import android.content.res.AssetFileDescriptor;
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import android.content.res.TypedArray;
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import android.database.Cursor;
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import android.database.MatrixCursor;
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import android.graphics.Point;
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import android.os.CancellationSignal;
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import android.os.Handler;
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import android.os.ParcelFileDescriptor;
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import android.provider.DocumentsContract.Document;
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import android.provider.DocumentsContract.Root;
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import android.provider.DocumentsProvider;
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import android.webkit.MimeTypeMap;
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import com.example.android.common.logger.Log;
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import java.io.ByteArrayOutputStream;
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import java.io.File;
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import java.io.FileNotFoundException;
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import java.io.FileOutputStream;
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import java.io.IOException;
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import java.io.InputStream;
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import java.util.Collections;
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import java.util.Comparator;
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import java.util.HashSet;
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import java.util.LinkedList;
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import java.util.PriorityQueue;
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import java.util.Set;
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/**
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* Manages documents and exposes them to the Android system for sharing.
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*/
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public class MyCloudProvider extends DocumentsProvider {
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private static final String TAG = MyCloudProvider.class.getSimpleName();
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// Use these as the default columns to return information about a root if no specific
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// columns are requested in a query.
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private static final String[] DEFAULT_ROOT_PROJECTION = new String[]{
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Root.COLUMN_ROOT_ID,
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Root.COLUMN_MIME_TYPES,
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Root.COLUMN_FLAGS,
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Root.COLUMN_ICON,
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Root.COLUMN_TITLE,
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Root.COLUMN_SUMMARY,
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Root.COLUMN_DOCUMENT_ID,
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Root.COLUMN_AVAILABLE_BYTES
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};
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// Use these as the default columns to return information about a document if no specific
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// columns are requested in a query.
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private static final String[] DEFAULT_DOCUMENT_PROJECTION = new String[]{
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Document.COLUMN_DOCUMENT_ID,
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Document.COLUMN_MIME_TYPE,
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Document.COLUMN_DISPLAY_NAME,
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Document.COLUMN_LAST_MODIFIED,
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Document.COLUMN_FLAGS,
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Document.COLUMN_SIZE
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};
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// No official policy on how many to return, but make sure you do limit the number of recent
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// and search results.
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private static final int MAX_SEARCH_RESULTS = 20;
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private static final int MAX_LAST_MODIFIED = 5;
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private static final String ROOT = "root";
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// A file object at the root of the file hierarchy. Depending on your implementation, the root
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// does not need to be an existing file system directory. For example, a tag-based document
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// provider might return a directory containing all tags, represented as child directories.
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private File mBaseDir;
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@Override
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public boolean onCreate() {
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Log.v(TAG, "onCreate");
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mBaseDir = getContext().getFilesDir();
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writeDummyFilesToStorage();
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return true;
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}
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@Override
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public Cursor queryRoots(String[] projection) throws FileNotFoundException {
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Log.v(TAG, "queryRoots");
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// Create a cursor with either the requested fields, or the default projection. This
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// cursor is returned to the Android system picker UI and used to display all roots from
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// this provider.
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final MatrixCursor result = new MatrixCursor(resolveRootProjection(projection));
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// If user is not logged in, return an empty root cursor. This removes our provider from
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// the list entirely.
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if (!isUserLoggedIn()) {
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return result;
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}
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// It's possible to have multiple roots (e.g. for multiple accounts in the same app) -
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// just add multiple cursor rows.
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// Construct one row for a root called "MyCloud".
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final MatrixCursor.RowBuilder row = result.newRow();
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row.add(Root.COLUMN_ROOT_ID, ROOT);
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row.add(Root.COLUMN_SUMMARY, getContext().getString(R.string.root_summary));
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// FLAG_SUPPORTS_CREATE means at least one directory under the root supports creating
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// documents. FLAG_SUPPORTS_RECENTS means your application's most recently used
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// documents will show up in the "Recents" category. FLAG_SUPPORTS_SEARCH allows users
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// to search all documents the application shares.
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row.add(Root.COLUMN_FLAGS, Root.FLAG_SUPPORTS_CREATE |
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Root.FLAG_SUPPORTS_RECENTS |
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Root.FLAG_SUPPORTS_SEARCH);
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// COLUMN_TITLE is the root title (e.g. what will be displayed to identify your provider).
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row.add(Root.COLUMN_TITLE, getContext().getString(R.string.app_name));
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// This document id must be unique within this provider and consistent across time. The
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// system picker UI may save it and refer to it later.
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row.add(Root.COLUMN_DOCUMENT_ID, getDocIdForFile(mBaseDir));
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// The child MIME types are used to filter the roots and only present to the user roots
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// that contain the desired type somewhere in their file hierarchy.
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row.add(Root.COLUMN_MIME_TYPES, getChildMimeTypes(mBaseDir));
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row.add(Root.COLUMN_AVAILABLE_BYTES, mBaseDir.getFreeSpace());
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row.add(Root.COLUMN_ICON, R.drawable.ic_launcher);
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return result;
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}
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@Override
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public Cursor queryRecentDocuments(String rootId, String[] projection)
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throws FileNotFoundException {
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Log.v(TAG, "queryRecentDocuments");
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// This example implementation walks a local file structure to find the most recently
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// modified files. Other implementations might include making a network call to query a
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// server.
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// Create a cursor with the requested projection, or the default projection.
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final MatrixCursor result = new MatrixCursor(resolveDocumentProjection(projection));
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final File parent = getFileForDocId(rootId);
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// Create a queue to store the most recent documents, which orders by last modified.
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PriorityQueue<File> lastModifiedFiles = new PriorityQueue<File>(5, new Comparator<File>() {
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public int compare(File i, File j) {
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return Long.compare(i.lastModified(), j.lastModified());
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}
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});
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// Iterate through all files and directories in the file structure under the root. If
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// the file is more recent than the least recently modified, add it to the queue,
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// limiting the number of results.
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final LinkedList<File> pending = new LinkedList<File>();
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// Start by adding the parent to the list of files to be processed
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pending.add(parent);
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// Do while we still have unexamined files
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while (!pending.isEmpty()) {
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// Take a file from the list of unprocessed files
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final File file = pending.removeFirst();
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if (file.isDirectory()) {
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// If it's a directory, add all its children to the unprocessed list
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Collections.addAll(pending, file.listFiles());
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} else {
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// If it's a file, add it to the ordered queue.
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lastModifiedFiles.add(file);
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}
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}
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// Add the most recent files to the cursor, not exceeding the max number of results.
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for (int i = 0; i < Math.min(MAX_LAST_MODIFIED + 1, lastModifiedFiles.size()); i++) {
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final File file = lastModifiedFiles.remove();
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includeFile(result, null, file);
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}
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return result;
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}
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@Override
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public Cursor querySearchDocuments(String rootId, String query, String[] projection)
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throws FileNotFoundException {
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Log.v(TAG, "querySearchDocuments");
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// Create a cursor with the requested projection, or the default projection.
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final MatrixCursor result = new MatrixCursor(resolveDocumentProjection(projection));
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final File parent = getFileForDocId(rootId);
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// This example implementation searches file names for the query and doesn't rank search
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// results, so we can stop as soon as we find a sufficient number of matches. Other
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// implementations might use other data about files, rather than the file name, to
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// produce a match; it might also require a network call to query a remote server.
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// Iterate through all files in the file structure under the root until we reach the
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// desired number of matches.
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final LinkedList<File> pending = new LinkedList<File>();
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// Start by adding the parent to the list of files to be processed
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pending.add(parent);
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// Do while we still have unexamined files, and fewer than the max search results
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while (!pending.isEmpty() && result.getCount() < MAX_SEARCH_RESULTS) {
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// Take a file from the list of unprocessed files
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final File file = pending.removeFirst();
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if (file.isDirectory()) {
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// If it's a directory, add all its children to the unprocessed list
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Collections.addAll(pending, file.listFiles());
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} else {
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// If it's a file and it matches, add it to the result cursor.
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if (file.getName().toLowerCase().contains(query)) {
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includeFile(result, null, file);
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}
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}
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}
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return result;
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}
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@Override
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public AssetFileDescriptor openDocumentThumbnail(String documentId, Point sizeHint,
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CancellationSignal signal)
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throws FileNotFoundException {
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Log.v(TAG, "openDocumentThumbnail");
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final File file = getFileForDocId(documentId);
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final ParcelFileDescriptor pfd =
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ParcelFileDescriptor.open(file, ParcelFileDescriptor.MODE_READ_ONLY);
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return new AssetFileDescriptor(pfd, 0, AssetFileDescriptor.UNKNOWN_LENGTH);
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}
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@Override
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public Cursor queryDocument(String documentId, String[] projection)
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throws FileNotFoundException {
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Log.v(TAG, "queryDocument");
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// Create a cursor with the requested projection, or the default projection.
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final MatrixCursor result = new MatrixCursor(resolveDocumentProjection(projection));
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includeFile(result, documentId, null);
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return result;
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}
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@Override
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public Cursor queryChildDocuments(String parentDocumentId, String[] projection,
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String sortOrder) throws FileNotFoundException {
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Log.v(TAG, "queryChildDocuments, parentDocumentId: " +
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parentDocumentId +
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" sortOrder: " +
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sortOrder);
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final MatrixCursor result = new MatrixCursor(resolveDocumentProjection(projection));
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final File parent = getFileForDocId(parentDocumentId);
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for (File file : parent.listFiles()) {
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includeFile(result, null, file);
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}
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return result;
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}
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@Override
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public ParcelFileDescriptor openDocument(final String documentId, final String mode,
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CancellationSignal signal)
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throws FileNotFoundException {
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Log.v(TAG, "openDocument, mode: " + mode);
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// It's OK to do network operations in this method to download the document, as long as you
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// periodically check the CancellationSignal. If you have an extremely large file to
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// transfer from the network, a better solution may be pipes or sockets
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// (see ParcelFileDescriptor for helper methods).
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final File file = getFileForDocId(documentId);
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final int accessMode = ParcelFileDescriptor.parseMode(mode);
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final boolean isWrite = (mode.indexOf('w') != -1);
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if (isWrite) {
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// Attach a close listener if the document is opened in write mode.
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try {
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Handler handler = new Handler(getContext().getMainLooper());
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return ParcelFileDescriptor.open(file, accessMode, handler,
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new ParcelFileDescriptor.OnCloseListener() {
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@Override
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public void onClose(IOException e) {
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// Update the file with the cloud server. The client is done writing.
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Log.i(TAG, "A file with id " + documentId + " has been closed! Time to " +
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"update the server.");
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}
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});
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} catch (IOException e) {
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throw new FileNotFoundException("Failed to open document with id " + documentId +
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" and mode " + mode);
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}
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} else {
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return ParcelFileDescriptor.open(file, accessMode);
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}
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}
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@Override
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public String createDocument(String documentId, String mimeType, String displayName)
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throws FileNotFoundException {
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Log.v(TAG, "createDocument");
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File parent = getFileForDocId(documentId);
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File file = new File(parent.getPath(), displayName);
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try {
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file.createNewFile();
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file.setWritable(true);
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file.setReadable(true);
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} catch (IOException e) {
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throw new FileNotFoundException("Failed to create document with name " +
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displayName +" and documentId " + documentId);
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}
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return getDocIdForFile(file);
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}
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@Override
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public void deleteDocument(String documentId) throws FileNotFoundException {
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Log.v(TAG, "deleteDocument");
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File file = getFileForDocId(documentId);
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if (file.delete()) {
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Log.i(TAG, "Deleted file with id " + documentId);
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} else {
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throw new FileNotFoundException("Failed to delete document with id " + documentId);
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}
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}
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@Override
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public String getDocumentType(String documentId) throws FileNotFoundException {
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File file = getFileForDocId(documentId);
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return getTypeForFile(file);
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}
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/**
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* @param projection the requested root column projection
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* @return either the requested root column projection, or the default projection if the
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* requested projection is null.
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*/
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private static String[] resolveRootProjection(String[] projection) {
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return projection != null ? projection : DEFAULT_ROOT_PROJECTION;
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}
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private static String[] resolveDocumentProjection(String[] projection) {
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return projection != null ? projection : DEFAULT_DOCUMENT_PROJECTION;
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}
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/**
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* Get a file's MIME type
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*
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* @param file the File object whose type we want
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* @return the MIME type of the file
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*/
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private static String getTypeForFile(File file) {
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if (file.isDirectory()) {
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return Document.MIME_TYPE_DIR;
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} else {
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return getTypeForName(file.getName());
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}
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}
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/**
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* Get the MIME data type of a document, given its filename.
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*
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* @param name the filename of the document
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* @return the MIME data type of a document
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*/
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private static String getTypeForName(String name) {
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final int lastDot = name.lastIndexOf('.');
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if (lastDot >= 0) {
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final String extension = name.substring(lastDot + 1);
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final String mime = MimeTypeMap.getSingleton().getMimeTypeFromExtension(extension);
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if (mime != null) {
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return mime;
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}
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}
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return "application/octet-stream";
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}
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/**
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* Gets a string of unique MIME data types a directory supports, separated by newlines. This
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* should not change.
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*
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* @param parent the File for the parent directory
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* @return a string of the unique MIME data types the parent directory supports
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*/
423
private String getChildMimeTypes(File parent) {
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Set<String> mimeTypes = new HashSet<String>();
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mimeTypes.add("image/*");
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mimeTypes.add("text/*");
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mimeTypes.add("application/vnd.openxmlformats-officedocument.wordprocessingml.document");
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// Flatten the list into a string and insert newlines between the MIME type strings.
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StringBuilder mimeTypesString = new StringBuilder();
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for (String mimeType : mimeTypes) {
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mimeTypesString.append(mimeType).append("\n");
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}
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return mimeTypesString.toString();
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}
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/**
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* Get the document ID given a File. The document id must be consistent across time. Other
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* applications may save the ID and use it to reference documents later.
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* <p/>
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* This implementation is specific to this demo. It assumes only one root and is built
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* directly from the file structure. However, it is possible for a document to be a child of
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* multiple directories (for example "android" and "images"), in which case the file must have
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* the same consistent, unique document ID in both cases.
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*
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* @param file the File whose document ID you want
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* @return the corresponding document ID
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*/
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private String getDocIdForFile(File file) {
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String path = file.getAbsolutePath();
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// Start at first char of path under root
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final String rootPath = mBaseDir.getPath();
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if (rootPath.equals(path)) {
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path = "";
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} else if (rootPath.endsWith("/")) {
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path = path.substring(rootPath.length());
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} else {
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path = path.substring(rootPath.length() + 1);
461
}
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return "root" + ':' + path;
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}
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/**
467
* Add a representation of a file to a cursor.
468
*
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* @param result the cursor to modify
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* @param docId the document ID representing the desired file (may be null if given file)
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* @param file the File object representing the desired file (may be null if given docID)
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* @throws java.io.FileNotFoundException
473
*/
474
private void includeFile(MatrixCursor result, String docId, File file)
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throws FileNotFoundException {
476
if (docId == null) {
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docId = getDocIdForFile(file);
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} else {
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file = getFileForDocId(docId);
480
}
481
482
int flags = 0;
483
484
if (file.isDirectory()) {
485
// Request the folder to lay out as a grid rather than a list. This also allows a larger
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// thumbnail to be displayed for each image.
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// flags |= Document.FLAG_DIR_PREFERS_GRID;
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// Add FLAG_DIR_SUPPORTS_CREATE if the file is a writable directory.
490
if (file.isDirectory() && file.canWrite()) {
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flags |= Document.FLAG_DIR_SUPPORTS_CREATE;
492
}
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} else if (file.canWrite()) {
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// If the file is writable set FLAG_SUPPORTS_WRITE and
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// FLAG_SUPPORTS_DELETE
496
flags |= Document.FLAG_SUPPORTS_WRITE;
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flags |= Document.FLAG_SUPPORTS_DELETE;
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}
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final String displayName = file.getName();
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final String mimeType = getTypeForFile(file);
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503
if (mimeType.startsWith("image/")) {
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// Allow the image to be represented by a thumbnail rather than an icon
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flags |= Document.FLAG_SUPPORTS_THUMBNAIL;
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}
507
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final MatrixCursor.RowBuilder row = result.newRow();
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row.add(Document.COLUMN_DOCUMENT_ID, docId);
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row.add(Document.COLUMN_DISPLAY_NAME, displayName);
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row.add(Document.COLUMN_SIZE, file.length());
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row.add(Document.COLUMN_MIME_TYPE, mimeType);
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row.add(Document.COLUMN_LAST_MODIFIED, file.lastModified());
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row.add(Document.COLUMN_FLAGS, flags);
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// Add a custom icon
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row.add(Document.COLUMN_ICON, R.drawable.ic_launcher);
518
}
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/**
521
* Translate your custom URI scheme into a File object.
522
*
523
* @param docId the document ID representing the desired file
524
* @return a File represented by the given document ID
525
* @throws java.io.FileNotFoundException
526
*/
527
private File getFileForDocId(String docId) throws FileNotFoundException {
528
File target = mBaseDir;
529
if (docId.equals(ROOT)) {
530
return target;
531
}
532
final int splitIndex = docId.indexOf(':', 1);
533
if (splitIndex < 0) {
534
throw new FileNotFoundException("Missing root for " + docId);
535
} else {
536
final String path = docId.substring(splitIndex + 1);
537
target = new File(target, path);
538
if (!target.exists()) {
539
throw new FileNotFoundException("Missing file for " + docId + " at " + target);
540
}
541
return target;
542
}
543
}
544
545
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/**
547
* Preload sample files packaged in the apk into the internal storage directory. This is a
548
* dummy function specific to this demo. The MyCloud mock cloud service doesn't actually
549
* have a backend, so it simulates by reading content from the device's internal storage.
550
*/
551
private void writeDummyFilesToStorage() {
552
if (mBaseDir.list().length > 0) {
553
return;
554
}
555
556
int[] imageResIds = getResourceIdArray(R.array.image_res_ids);
557
for (int resId : imageResIds) {
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writeFileToInternalStorage(resId, ".jpeg");
559
}
560
561
int[] textResIds = getResourceIdArray(R.array.text_res_ids);
562
for (int resId : textResIds) {
563
writeFileToInternalStorage(resId, ".txt");
564
}
565
566
int[] docxResIds = getResourceIdArray(R.array.docx_res_ids);
567
for (int resId : docxResIds) {
568
writeFileToInternalStorage(resId, ".docx");
569
}
570
}
571
572
/**
573
* Write a file to internal storage. Used to set up our dummy "cloud server".
574
*
575
* @param resId the resource ID of the file to write to internal storage
576
* @param extension the file extension (ex. .png, .mp3)
577
*/
578
private void writeFileToInternalStorage(int resId, String extension) {
579
InputStream ins = getContext().getResources().openRawResource(resId);
580
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
581
int size;
582
byte[] buffer = new byte[1024];
583
try {
584
while ((size = ins.read(buffer, 0, 1024)) >= 0) {
585
outputStream.write(buffer, 0, size);
586
}
587
ins.close();
588
buffer = outputStream.toByteArray();
589
String filename = getContext().getResources().getResourceEntryName(resId) + extension;
590
FileOutputStream fos = getContext().openFileOutput(filename, Context.MODE_PRIVATE);
591
fos.write(buffer);
592
fos.close();
593
594
} catch (IOException e) {
595
e.printStackTrace();
596
}
597
}
598
599
private int[] getResourceIdArray(int arrayResId) {
600
TypedArray ar = getContext().getResources().obtainTypedArray(arrayResId);
601
int len = ar.length();
602
int[] resIds = new int[len];
603
for (int i = 0; i < len; i++) {
604
resIds[i] = ar.getResourceId(i, 0);
605
}
606
ar.recycle();
607
return resIds;
608
}
609
610
/**
611
* Dummy function to determine whether the user is logged in.
612
*/
613
private boolean isUserLoggedIn() {
614
final SharedPreferences sharedPreferences =
615
getContext().getSharedPreferences(getContext().getString(R.string.app_name),
616
Context.MODE_PRIVATE);
617
return sharedPreferences.getBoolean(getContext().getString(R.string.key_logged_in), false);
618
}
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620
621
}