StorageProvider / src / com.example.android.storageprovider /

MyCloudProvider.java

1
/*
2
 * Copyright (C) 2013 The Android Open Source Project
3
 *
4
 * Licensed under the Apache License, Version 2.0 (the "License");
5
 * you may not use this file except in compliance with the License.
6
 * You may obtain a copy of the License at
7
 *
8
 *      http://www.apache.org/licenses/LICENSE-2.0
9
 *
10
 * Unless required by applicable law or agreed to in writing, software
11
 * distributed under the License is distributed on an "AS IS" BASIS,
12
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13
 * See the License for the specific language governing permissions and
14
 * limitations under the License.
15
 */
16
 
17
 
18
package com.example.android.storageprovider;
19
 
20
import android.content.Context;
21
import android.content.SharedPreferences;
22
import android.content.res.AssetFileDescriptor;
23
import android.content.res.TypedArray;
24
import android.database.Cursor;
25
import android.database.MatrixCursor;
26
import android.graphics.Point;
27
import android.os.CancellationSignal;
28
import android.os.Handler;
29
import android.os.ParcelFileDescriptor;
30
import android.provider.DocumentsContract.Document;
31
import android.provider.DocumentsContract.Root;
32
import android.provider.DocumentsProvider;
33
import android.webkit.MimeTypeMap;
34
 
35
import com.example.android.common.logger.Log;
36
 
37
import java.io.ByteArrayOutputStream;
38
import java.io.File;
39
import java.io.FileNotFoundException;
40
import java.io.FileOutputStream;
41
import java.io.IOException;
42
import java.io.InputStream;
43
import java.util.Collections;
44
import java.util.Comparator;
45
import java.util.HashSet;
46
import java.util.LinkedList;
47
import java.util.PriorityQueue;
48
import java.util.Set;
49
 
50
/**
51
 * Manages documents and exposes them to the Android system for sharing.
52
 */
53
public class MyCloudProvider extends DocumentsProvider {
54
    private static final String TAG = MyCloudProvider.class.getSimpleName();
55
 
56
    // Use these as the default columns to return information about a root if no specific
57
    // columns are requested in a query.
58
    private static final String[] DEFAULT_ROOT_PROJECTION = new String[]{
59
            Root.COLUMN_ROOT_ID,
60
            Root.COLUMN_MIME_TYPES,
61
            Root.COLUMN_FLAGS,
62
            Root.COLUMN_ICON,
63
            Root.COLUMN_TITLE,
64
            Root.COLUMN_SUMMARY,
65
            Root.COLUMN_DOCUMENT_ID,
66
            Root.COLUMN_AVAILABLE_BYTES
67
    };
68
 
69
    // Use these as the default columns to return information about a document if no specific
70
    // columns are requested in a query.
71
    private static final String[] DEFAULT_DOCUMENT_PROJECTION = new String[]{
72
            Document.COLUMN_DOCUMENT_ID,
73
            Document.COLUMN_MIME_TYPE,
74
            Document.COLUMN_DISPLAY_NAME,
75
            Document.COLUMN_LAST_MODIFIED,
76
            Document.COLUMN_FLAGS,
77
            Document.COLUMN_SIZE
78
    };
79
 
80
    // No official policy on how many to return, but make sure you do limit the number of recent
81
    // and search results.
82
    private static final int MAX_SEARCH_RESULTS = 20;
83
    private static final int MAX_LAST_MODIFIED = 5;
84
 
85
    private static final String ROOT = "root";
86
 
87
    // A file object at the root of the file hierarchy.  Depending on your implementation, the root
88
    // does not need to be an existing file system directory.  For example, a tag-based document
89
    // provider might return a directory containing all tags, represented as child directories.
90
    private File mBaseDir;
91
 
92
    @Override
93
    public boolean onCreate() {
94
        Log.v(TAG, "onCreate");
95
 
96
        mBaseDir = getContext().getFilesDir();
97
 
98
        writeDummyFilesToStorage();
99
 
100
        return true;
101
    }
102
 
104
    @Override
105
    public Cursor queryRoots(String[] projection) throws FileNotFoundException {
106
        Log.v(TAG, "queryRoots");
107
 
108
        // Create a cursor with either the requested fields, or the default projection.  This
109
        // cursor is returned to the Android system picker UI and used to display all roots from
110
        // this provider.
111
        final MatrixCursor result = new MatrixCursor(resolveRootProjection(projection));
112
 
113
        // If user is not logged in, return an empty root cursor.  This removes our provider from
114
        // the list entirely.
115
        if (!isUserLoggedIn()) {
116
            return result;
117
        }
118
 
119
        // It's possible to have multiple roots (e.g. for multiple accounts in the same app) -
120
        // just add multiple cursor rows.
121
        // Construct one row for a root called "MyCloud".
122
        final MatrixCursor.RowBuilder row = result.newRow();
123
 
124
        row.add(Root.COLUMN_ROOT_ID, ROOT);
125
        row.add(Root.COLUMN_SUMMARY, getContext().getString(R.string.root_summary));
126
 
127
        // FLAG_SUPPORTS_CREATE means at least one directory under the root supports creating
128
        // documents.  FLAG_SUPPORTS_RECENTS means your application's most recently used
129
        // documents will show up in the "Recents" category.  FLAG_SUPPORTS_SEARCH allows users
130
        // to search all documents the application shares.
131
        row.add(Root.COLUMN_FLAGS, Root.FLAG_SUPPORTS_CREATE |
132
                Root.FLAG_SUPPORTS_RECENTS |
133
                Root.FLAG_SUPPORTS_SEARCH);
134
 
135
        // COLUMN_TITLE is the root title (e.g. what will be displayed to identify your provider).
136
        row.add(Root.COLUMN_TITLE, getContext().getString(R.string.app_name));
137
 
138
        // This document id must be unique within this provider and consistent across time.  The
139
        // system picker UI may save it and refer to it later.
140
        row.add(Root.COLUMN_DOCUMENT_ID, getDocIdForFile(mBaseDir));
141
 
142
        // The child MIME types are used to filter the roots and only present to the user roots
143
        // that contain the desired type somewhere in their file hierarchy.
144
        row.add(Root.COLUMN_MIME_TYPES, getChildMimeTypes(mBaseDir));
145
        row.add(Root.COLUMN_AVAILABLE_BYTES, mBaseDir.getFreeSpace());
146
        row.add(Root.COLUMN_ICON, R.drawable.ic_launcher);
147
 
148
        return result;
149
    }
151
 
153
    @Override
154
    public Cursor queryRecentDocuments(String rootId, String[] projection)
155
            throws FileNotFoundException {
156
        Log.v(TAG, "queryRecentDocuments");
157
 
158
        // This example implementation walks a local file structure to find the most recently
159
        // modified files.  Other implementations might include making a network call to query a
160
        // server.
161
 
162
        // Create a cursor with the requested projection, or the default projection.
163
        final MatrixCursor result = new MatrixCursor(resolveDocumentProjection(projection));
164
 
165
        final File parent = getFileForDocId(rootId);
166
 
167
        // Create a queue to store the most recent documents, which orders by last modified.
168
        PriorityQueue<File> lastModifiedFiles = new PriorityQueue<File>(5, new Comparator<File>() {
169
            public int compare(File i, File j) {
170
                return Long.compare(i.lastModified(), j.lastModified());
171
            }
172
        });
173
 
174
        // Iterate through all files and directories in the file structure under the root.  If
175
        // the file is more recent than the least recently modified, add it to the queue,
176
        // limiting the number of results.
177
        final LinkedList<File> pending = new LinkedList<File>();
178
 
179
        // Start by adding the parent to the list of files to be processed
180
        pending.add(parent);
181
 
182
        // Do while we still have unexamined files
183
        while (!pending.isEmpty()) {
184
            // Take a file from the list of unprocessed files
185
            final File file = pending.removeFirst();
186
            if (file.isDirectory()) {
187
                // If it's a directory, add all its children to the unprocessed list
188
                Collections.addAll(pending, file.listFiles());
189
            } else {
190
                // If it's a file, add it to the ordered queue.
191
                lastModifiedFiles.add(file);
192
            }
193
        }
194
 
195
        // Add the most recent files to the cursor, not exceeding the max number of results.
196
        for (int i = 0; i < Math.min(MAX_LAST_MODIFIED + 1, lastModifiedFiles.size()); i++) {
197
            final File file = lastModifiedFiles.remove();
198
            includeFile(result, null, file);
199
        }
200
        return result;
201
    }
203
 
205
    @Override
206
    public Cursor querySearchDocuments(String rootId, String query, String[] projection)
207
            throws FileNotFoundException {
208
        Log.v(TAG, "querySearchDocuments");
209
 
210
        // Create a cursor with the requested projection, or the default projection.
211
        final MatrixCursor result = new MatrixCursor(resolveDocumentProjection(projection));
212
        final File parent = getFileForDocId(rootId);
213
 
214
        // This example implementation searches file names for the query and doesn't rank search
215
        // results, so we can stop as soon as we find a sufficient number of matches.  Other
216
        // implementations might use other data about files, rather than the file name, to
217
        // produce a match; it might also require a network call to query a remote server.
218
 
219
        // Iterate through all files in the file structure under the root until we reach the
220
        // desired number of matches.
221
        final LinkedList<File> pending = new LinkedList<File>();
222
 
223
        // Start by adding the parent to the list of files to be processed
224
        pending.add(parent);
225
 
226
        // Do while we still have unexamined files, and fewer than the max search results
227
        while (!pending.isEmpty() && result.getCount() < MAX_SEARCH_RESULTS) {
228
            // Take a file from the list of unprocessed files
229
            final File file = pending.removeFirst();
230
            if (file.isDirectory()) {
231
                // If it's a directory, add all its children to the unprocessed list
232
                Collections.addAll(pending, file.listFiles());
233
            } else {
234
                // If it's a file and it matches, add it to the result cursor.
235
                if (file.getName().toLowerCase().contains(query)) {
236
                    includeFile(result, null, file);
237
                }
238
            }
239
        }
240
        return result;
241
    }
243
 
245
    @Override
246
    public AssetFileDescriptor openDocumentThumbnail(String documentId, Point sizeHint,
247
                                                     CancellationSignal signal)
248
            throws FileNotFoundException {
249
        Log.v(TAG, "openDocumentThumbnail");
250
 
251
        final File file = getFileForDocId(documentId);
252
        final ParcelFileDescriptor pfd =
253
                ParcelFileDescriptor.open(file, ParcelFileDescriptor.MODE_READ_ONLY);
254
        return new AssetFileDescriptor(pfd, 0, AssetFileDescriptor.UNKNOWN_LENGTH);
255
    }
257
 
259
    @Override
260
    public Cursor queryDocument(String documentId, String[] projection)
261
            throws FileNotFoundException {
262
        Log.v(TAG, "queryDocument");
263
 
264
        // Create a cursor with the requested projection, or the default projection.
265
        final MatrixCursor result = new MatrixCursor(resolveDocumentProjection(projection));
266
        includeFile(result, documentId, null);
267
        return result;
268
    }
270
 
272
    @Override
273
    public Cursor queryChildDocuments(String parentDocumentId, String[] projection,
274
                                      String sortOrder) throws FileNotFoundException {
275
        Log.v(TAG, "queryChildDocuments, parentDocumentId: " +
276
                parentDocumentId +
277
                " sortOrder: " +
278
                sortOrder);
279
 
280
        final MatrixCursor result = new MatrixCursor(resolveDocumentProjection(projection));
281
        final File parent = getFileForDocId(parentDocumentId);
282
        for (File file : parent.listFiles()) {
283
            includeFile(result, null, file);
284
        }
285
        return result;
286
    }
288
 
289
 
291
    @Override
292
    public ParcelFileDescriptor openDocument(final String documentId, final String mode,
293
                                             CancellationSignal signal)
294
            throws FileNotFoundException {
295
        Log.v(TAG, "openDocument, mode: " + mode);
296
        // It's OK to do network operations in this method to download the document, as long as you
297
        // periodically check the CancellationSignal.  If you have an extremely large file to
298
        // transfer from the network, a better solution may be pipes or sockets
299
        // (see ParcelFileDescriptor for helper methods).
300
 
301
        final File file = getFileForDocId(documentId);
302
        final int accessMode = ParcelFileDescriptor.parseMode(mode);
303
 
304
        final boolean isWrite = (mode.indexOf('w') != -1);
305
        if (isWrite) {
306
            // Attach a close listener if the document is opened in write mode.
307
            try {
308
                Handler handler = new Handler(getContext().getMainLooper());
309
                return ParcelFileDescriptor.open(file, accessMode, handler,
310
                        new ParcelFileDescriptor.OnCloseListener() {
311
                    @Override
312
                    public void onClose(IOException e) {
313
 
314
                        // Update the file with the cloud server.  The client is done writing.
315
                        Log.i(TAG, "A file with id " + documentId + " has been closed!  Time to " +
316
                                "update the server.");
317
                    }
318
 
319
                });
320
            } catch (IOException e) {
321
                throw new FileNotFoundException("Failed to open document with id " + documentId +
322
                        " and mode " + mode);
323
            }
324
        } else {
325
            return ParcelFileDescriptor.open(file, accessMode);
326
        }
327
    }
329
 
330
 
332
    @Override
333
    public String createDocument(String documentId, String mimeType, String displayName)
334
            throws FileNotFoundException {
335
        Log.v(TAG, "createDocument");
336
 
337
        File parent = getFileForDocId(documentId);
338
        File file = new File(parent.getPath(), displayName);
339
        try {
340
            file.createNewFile();
341
            file.setWritable(true);
342
            file.setReadable(true);
343
        } catch (IOException e) {
344
            throw new FileNotFoundException("Failed to create document with name " +
345
                    displayName +" and documentId " + documentId);
346
        }
347
        return getDocIdForFile(file);
348
    }
350
 
352
    @Override
353
    public void deleteDocument(String documentId) throws FileNotFoundException {
354
        Log.v(TAG, "deleteDocument");
355
        File file = getFileForDocId(documentId);
356
        if (file.delete()) {
357
            Log.i(TAG, "Deleted file with id " + documentId);
358
        } else {
359
            throw new FileNotFoundException("Failed to delete document with id " + documentId);
360
        }
361
    }
363
 
364
 
365
    @Override
366
    public String getDocumentType(String documentId) throws FileNotFoundException {
367
        File file = getFileForDocId(documentId);
368
        return getTypeForFile(file);
369
    }
370
 
371
    /**
372
     * @param projection the requested root column projection
373
     * @return either the requested root column projection, or the default projection if the
374
     * requested projection is null.
375
     */
376
    private static String[] resolveRootProjection(String[] projection) {
377
        return projection != null ? projection : DEFAULT_ROOT_PROJECTION;
378
    }
379
 
380
    private static String[] resolveDocumentProjection(String[] projection) {
381
        return projection != null ? projection : DEFAULT_DOCUMENT_PROJECTION;
382
    }
383
 
384
    /**
385
     * Get a file's MIME type
386
     *
387
     * @param file the File object whose type we want
388
     * @return the MIME type of the file
389
     */
390
    private static String getTypeForFile(File file) {
391
        if (file.isDirectory()) {
392
            return Document.MIME_TYPE_DIR;
393
        } else {
394
            return getTypeForName(file.getName());
395
        }
396
    }
397
 
398
    /**
399
     * Get the MIME data type of a document, given its filename.
400
     *
401
     * @param name the filename of the document
402
     * @return the MIME data type of a document
403
     */
404
    private static String getTypeForName(String name) {
405
        final int lastDot = name.lastIndexOf('.');
406
        if (lastDot >= 0) {
407
            final String extension = name.substring(lastDot + 1);
408
            final String mime = MimeTypeMap.getSingleton().getMimeTypeFromExtension(extension);
409
            if (mime != null) {
410
                return mime;
411
            }
412
        }
413
        return "application/octet-stream";
414
    }
415
 
416
    /**
417
     * Gets a string of unique MIME data types a directory supports, separated by newlines.  This
418
     * should not change.
419
     *
420
     * @param parent the File for the parent directory
421
     * @return a string of the unique MIME data types the parent directory supports
422
     */
423
    private String getChildMimeTypes(File parent) {
424
        Set<String> mimeTypes = new HashSet<String>();
425
        mimeTypes.add("image/*");
426
        mimeTypes.add("text/*");
427
        mimeTypes.add("application/vnd.openxmlformats-officedocument.wordprocessingml.document");
428
 
429
        // Flatten the list into a string and insert newlines between the MIME type strings.
430
        StringBuilder mimeTypesString = new StringBuilder();
431
        for (String mimeType : mimeTypes) {
432
            mimeTypesString.append(mimeType).append("\n");
433
        }
434
 
435
        return mimeTypesString.toString();
436
    }
437
 
438
    /**
439
     * Get the document ID given a File.  The document id must be consistent across time.  Other
440
     * applications may save the ID and use it to reference documents later.
441
     * <p/>
442
     * This implementation is specific to this demo.  It assumes only one root and is built
443
     * directly from the file structure.  However, it is possible for a document to be a child of
444
     * multiple directories (for example "android" and "images"), in which case the file must have
445
     * the same consistent, unique document ID in both cases.
446
     *
447
     * @param file the File whose document ID you want
448
     * @return the corresponding document ID
449
     */
450
    private String getDocIdForFile(File file) {
451
        String path = file.getAbsolutePath();
452
 
453
        // Start at first char of path under root
454
        final String rootPath = mBaseDir.getPath();
455
        if (rootPath.equals(path)) {
456
            path = "";
457
        } else if (rootPath.endsWith("/")) {
458
            path = path.substring(rootPath.length());
459
        } else {
460
            path = path.substring(rootPath.length() + 1);
461
        }
462
 
463
        return "root" + ':' + path;
464
    }
465
 
466
    /**
467
     * Add a representation of a file to a cursor.
468
     *
469
     * @param result the cursor to modify
470
     * @param docId  the document ID representing the desired file (may be null if given file)
471
     * @param file   the File object representing the desired file (may be null if given docID)
472
     * @throws java.io.FileNotFoundException
473
     */
474
    private void includeFile(MatrixCursor result, String docId, File file)
475
            throws FileNotFoundException {
476
        if (docId == null) {
477
            docId = getDocIdForFile(file);
478
        } else {
479
            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
486
            // thumbnail to be displayed for each image.
487
            //            flags |= Document.FLAG_DIR_PREFERS_GRID;
488
 
489
            // Add FLAG_DIR_SUPPORTS_CREATE if the file is a writable directory.
490
            if (file.isDirectory() && file.canWrite()) {
491
                flags |= Document.FLAG_DIR_SUPPORTS_CREATE;
492
            }
493
        } else if (file.canWrite()) {
494
            // If the file is writable set FLAG_SUPPORTS_WRITE and
495
            // FLAG_SUPPORTS_DELETE
496
            flags |= Document.FLAG_SUPPORTS_WRITE;
497
            flags |= Document.FLAG_SUPPORTS_DELETE;
498
        }
499
 
500
        final String displayName = file.getName();
501
        final String mimeType = getTypeForFile(file);
502
 
503
        if (mimeType.startsWith("image/")) {
504
            // Allow the image to be represented by a thumbnail rather than an icon
505
            flags |= Document.FLAG_SUPPORTS_THUMBNAIL;
506
        }
507
 
508
        final MatrixCursor.RowBuilder row = result.newRow();
509
        row.add(Document.COLUMN_DOCUMENT_ID, docId);
510
        row.add(Document.COLUMN_DISPLAY_NAME, displayName);
511
        row.add(Document.COLUMN_SIZE, file.length());
512
        row.add(Document.COLUMN_MIME_TYPE, mimeType);
513
        row.add(Document.COLUMN_LAST_MODIFIED, file.lastModified());
514
        row.add(Document.COLUMN_FLAGS, flags);
515
 
516
        // Add a custom icon
517
        row.add(Document.COLUMN_ICON, R.drawable.ic_launcher);
518
    }
519
 
520
    /**
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
 
546
    /**
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) {
558
            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
    }
619
 
620
 
621
}