Add StorageProvider sample code to browseables.

Change-Id: I353f596e9fc7455781e4c8d7f1972dfcd5739ddb
(cherry picked from commit c921db8d27)

samples/browseable/StorageProvider/AndroidManifest.xml

@@ -0,0 +1,71 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+ Copyright 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.
+-->
+
+
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+          package="com.example.android.storageprovider"
+          android:versionCode="1"
+          android:versionName="1.0">
+
+    <uses-sdk
+        android:minSdkVersion="19"
+        android:targetSdkVersion="19"/>
+
+    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
+    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
+
+    <application
+        android:allowBackup="true"
+        android:label="@string/app_name"
+        android:icon="@drawable/ic_launcher"
+        android:theme="@style/MyAppTheme">
+
+        <activity
+            android:name=".MainActivity"
+            android:uiOptions="splitActionBarWhenNarrow"
+            android:label="@string/app_name">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN"/>
+                <category android:name="android.intent.category.LAUNCHER"/>
+            </intent-filter>
+        </activity>
+
+        <!--BEGIN_INCLUDE(provider_manifest)-->
+        <!--
+        Declare the document provider class MyCloudProvider to the system.  The MANAGE_DOCUMENTS
+        permission belongs only to the Android system, ensuring this provider will never be used
+        directly by another app.  The provider must grant URI permissions in order to expose the
+        specific documents(s) chosen, while not sharing all of its data by default.  It must be
+        exported to be visible outside the application, and it must include a filter with the intent
+        "android.content.action.DOCUMENTS_PROVIDER" in order to be shown in the system document
+        picker UI.
+        -->
+        <provider
+            android:name="com.example.android.storageprovider.MyCloudProvider"
+            android:authorities="com.example.android.storageprovider.documents"
+            android:grantUriPermissions="true"
+            android:exported="true"
+            android:permission="android.permission.MANAGE_DOCUMENTS">
+            <intent-filter>
+                <action android:name="android.content.action.DOCUMENTS_PROVIDER"/>
+            </intent-filter>
+        </provider>
+        <!--END_INCLUDE(provider_manifest)-->
+
+    </application>
+
+</manifest>

samples/browseable/StorageProvider/res/raw/cat_names.txt

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+Top cat names of 2013
+
+1. Angel
+2. Charlie
+3. Mittens
+4. Milkshake
+5. Oreo
+6. Ella
+7. Lily
+8. Ellie
+9. Pepsi
+10. Amber
+11. Molly
+12. Truffles
+13. Peanut
+14. Tiger Lilly
+15. Snowball

samples/browseable/StorageProvider/res/raw/dog_names.txt

@@ -0,0 +1,17 @@
+Top dog names of 2013
+
+1. Gus
+2. Trapper
+3. Finn
+4. Bailey
+5. Cooper
+6. Hawkeye
+7. Wrigley
+8. Boomer
+9. Ace
+10. Butch
+11. Delgado
+12. Evan
+13. Lucky
+14. Otto
+15. Buddy

samples/browseable/StorageProvider/res/values/arrays.xml

@@ -0,0 +1,34 @@
+<!--
+  Copyright 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.
+-->
+
+<resources>
+    <array name="image_res_ids">
+        <item>@raw/android_dinner</item>
+        <item>@raw/android_rose</item>
+        <item>@raw/android_pumpkins_fall</item>
+        <item>@raw/android_computer_back</item>
+        <item>@raw/android_computer_android_studio</item>
+    </array>
+
+    <array name="text_res_ids">
+        <item>@raw/cat_names</item>
+        <item>@raw/dog_names</item>
+    </array>
+
+    <array name="docx_res_ids">
+        <item>@raw/example</item>
+    </array>
+</resources>

samples/browseable/StorageProvider/res/values/strings.xml

@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+Copyright 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.
+-->
+
+
+<resources>
+    <string name="log_in">Log in</string>
+    <string name="log_out">Log out</string>
+    <string name="logged_in_info">You are currently logged in, which means the documents in MyCloud are visible to other applications.</string>
+    <string name="logged_out_info">You are currently logged out, so MyCloud is not visible as a document provider.</string>
+    <string name="root_summary">cloudy with a chance of &#8230;</string>
+    <string name="key_logged_in">logged_in</string>
+</resources>

samples/browseable/StorageProvider/res/values/styles.xml

@@ -0,0 +1,38 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Copyright 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.
+-->
+
+<resources>
+
+    <style name="MyAppTheme" parent="AppTheme">
+        <item name="android:textViewStyle">@style/MyTextViewStyle</item>
+        <item name="android:actionBarStyle">@style/MyActionBarStyle</item>
+        <item name="android:actionMenuTextColor">@android:color/white</item>
+    </style>
+
+    <style name="MyActionBarStyle" parent="android:Widget.Holo.Light.ActionBar.Solid.Inverse">
+        <item name="android:background">#5E2D79</item>
+        <item name="android:backgroundSplit">#5E2D79</item>
+    </style>
+
+    <style name="MyTextViewStyle" parent="android:TextAppearance.Holo.Widget.TextView">
+        <item name="android:textSize">18sp</item>
+        <item name="android:paddingRight">@dimen/margin_medium</item>
+        <item name="android:paddingLeft">@dimen/margin_medium</item>
+        <item name="android:fontFamily">sans-serif-light</item>
+    </style>
+
+</resources>

samples/browseable/StorageProvider/src/com.example.android.storageprovider/MyCloudFragment.java

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+/*
+* Copyright 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.SharedPreferences;
+import android.os.Bundle;
+import android.provider.DocumentsContract;
+import android.support.v4.app.Fragment;
+import android.view.Menu;
+import android.view.MenuItem;
+
+import com.example.android.common.logger.Log;
+
+/**
+ * Toggles the user's login status via a login menu option, and enables/disables the cloud storage
+ * content provider.
+ */
+public class MyCloudFragment extends Fragment {
+
+    private static final String TAG = "MyCloudFragment";
+    private static final String AUTHORITY = "com.example.android.storageprovider.documents";
+    private boolean mLoggedIn = false;
+
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        mLoggedIn = readLoginValue();
+
+        setHasOptionsMenu(true);
+    }
+
+    @Override
+    public void onPrepareOptionsMenu(Menu menu) {
+        super.onPrepareOptionsMenu(menu);
+        MenuItem item = menu.findItem(R.id.action_toggle_login);
+        item.setTitle(mLoggedIn ? R.string.log_out : R.string.log_in);
+    }
+
+    @Override
+    public boolean onOptionsItemSelected(MenuItem item) {
+        if (item.getItemId() == R.id.action_toggle_login) {
+            toggleLogin();
+            item.setTitle(mLoggedIn ? R.string.log_out : R.string.log_in);
+
+            // BEGIN_INCLUDE(notify_change)
+            // Notify the system that the status of our roots has changed.  This will trigger
+            // a call to MyCloudProvider.queryRoots() and force a refresh of the system
+            // picker UI.  It's important to call this or stale results may persist.
+            getActivity().getContentResolver().notifyChange(DocumentsContract.buildRootsUri
+                    (AUTHORITY), null, false);
+            // END_INCLUDE(notify_change)
+        }
+        return true;
+    }
+
+    /**
+     * Dummy function to change the user's authorization status.
+     */
+    private void toggleLogin() {
+        // Replace this with your standard method of authentication to determine if your app
+        // should make the user's documents available.
+        mLoggedIn = !mLoggedIn;
+        writeLoginValue(mLoggedIn);
+        Log.i(TAG, getString(mLoggedIn ? R.string.logged_in_info : R.string.logged_out_info));
+    }
+
+    /**
+     * Dummy function to save whether the user is logged in.
+     */
+    private void writeLoginValue(boolean loggedIn) {
+        final SharedPreferences sharedPreferences =
+                getActivity().getSharedPreferences(getString(R.string.app_name),
+                        getActivity().MODE_PRIVATE);
+        sharedPreferences.edit().putBoolean(getString(R.string.key_logged_in), loggedIn).commit();
+    }
+
+    /**
+     * Dummy function to determine whether the user is logged in.
+     */
+    private boolean readLoginValue() {
+        final SharedPreferences sharedPreferences =
+                getActivity().getSharedPreferences(getString(R.string.app_name),
+                        getActivity().MODE_PRIVATE);
+        return sharedPreferences.getBoolean(getString(R.string.key_logged_in), false);
+    }
+
+}
+
+

samples/browseable/StorageProvider/src/com.example.android.storageprovider/MyCloudProvider.java

@@ -0,0 +1,621 @@
+/*
+ * 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);
+    }
+
+
+}