Java tutorial
/* * Created by Angel Leon (@gubatron), Alden Torres (aldenml), Emil Suleymanov (sssemil) * Copyright (c) 2011-2015, FrostWire(R). All rights reserved. * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ package com.frostwire.android.gui; import android.app.Activity; import android.content.ContentResolver; import android.content.Context; import android.content.Intent; import android.net.Uri; import android.os.storage.StorageManager; import android.support.v4.provider.DocumentFile; import com.frostwire.android.R; import com.frostwire.android.gui.util.UIUtils; import com.frostwire.logging.Logger; import java.io.File; import java.lang.reflect.Array; import java.lang.reflect.Method; import java.util.List; /** * @author gubatron * @author aldenml */ public final class StoragePicker { private static final Logger LOG = Logger.getLogger(StoragePicker.class); public static final String ACTION_OPEN_DOCUMENT_TREE = "android.intent.action.OPEN_DOCUMENT_TREE"; public static final int SELECT_FOLDER_REQUEST_CODE = 1267123; private static final String EXTRA_SHOW_ADVANCED = "android.content.extra.SHOW_ADVANCED"; private static final String PRIMARY_VOLUME_NAME = "primary"; private static final String PATH_TREE = "tree"; private StoragePicker() { } public static void show(Activity activity) { Intent intent = new Intent(ACTION_OPEN_DOCUMENT_TREE); intent.putExtra(Intent.EXTRA_LOCAL_ONLY, true); intent.putExtra(EXTRA_SHOW_ADVANCED, true); activity.startActivityForResult(intent, SELECT_FOLDER_REQUEST_CODE); } public static String handle(Context context, int requestCode, int resultCode, Intent data) { String result = null; try { if (resultCode == Activity.RESULT_OK && requestCode == SELECT_FOLDER_REQUEST_CODE) { Uri treeUri = data.getData(); ContentResolver cr = context.getContentResolver(); Method takePersistableUriPermissionM = cr.getClass().getMethod("takePersistableUriPermission", Uri.class, int.class); final int takeFlags = data.getFlags() & (Intent.FLAG_GRANT_READ_URI_PERMISSION | Intent.FLAG_GRANT_WRITE_URI_PERMISSION); takePersistableUriPermissionM.invoke(cr, treeUri, takeFlags); if (treeUri == null) { UIUtils.showShortMessage(context, R.string.storage_picker_treeuri_null); result = null; } else { DocumentFile file = DocumentFile.fromTreeUri(context, treeUri); if (!file.isDirectory()) { UIUtils.showShortMessage(context, R.string.storage_picker_treeuri_not_directory); result = null; } else if (!file.canWrite()) { UIUtils.showShortMessage(context, R.string.storage_picker_treeuri_cant_write); result = null; } else { result = getFullPathFromTreeUri(context, treeUri); } } } } catch (Throwable e) { UIUtils.showShortMessage(context, R.string.storage_picker_treeuri_error); LOG.error("Error handling folder selection", e); result = null; } return result; } private static String getFullPathFromTreeUri(Context ctx, final Uri treeUri) { if (treeUri == null) { return null; } StorageManager mStorageManager = (StorageManager) ctx.getSystemService(Context.STORAGE_SERVICE); String volumePath = getVolumePath(mStorageManager, getVolumeIdFromTreeUri(treeUri)); if (volumePath == null) { return File.separator; } if (volumePath.endsWith(File.separator)) { volumePath = volumePath.substring(0, volumePath.length() - 1); } String documentPath = getDocumentPathFromTreeUri(treeUri); if (documentPath.endsWith(File.separator)) { documentPath = documentPath.substring(0, documentPath.length() - 1); } if (documentPath.length() > 0) { if (documentPath.startsWith(File.separator)) { return volumePath + documentPath; } else { return volumePath + File.separator + documentPath; } } else { return volumePath; } } private static String getVolumePath(StorageManager mStorageManager, final String volumeId) { try { Class<?> storageVolumeClazz = Class.forName("android.os.storage.StorageVolume"); Method getVolumeList = mStorageManager.getClass().getMethod("getVolumeList"); Method getUuid = storageVolumeClazz.getMethod("getUuid"); Method getPath = storageVolumeClazz.getMethod("getPath"); Method isPrimary = storageVolumeClazz.getMethod("isPrimary"); Object result = getVolumeList.invoke(mStorageManager); final int length = Array.getLength(result); for (int i = 0; i < length; i++) { Object storageVolumeElement = Array.get(result, i); String uuid = (String) getUuid.invoke(storageVolumeElement); Boolean primary = (Boolean) isPrimary.invoke(storageVolumeElement); // primary volume? if (primary && PRIMARY_VOLUME_NAME.equals(volumeId)) { return (String) getPath.invoke(storageVolumeElement); } // other volumes? if (uuid != null) { if (uuid.equals(volumeId)) { return (String) getPath.invoke(storageVolumeElement); } } } // not found. return null; } catch (Exception ex) { return null; } } private static String getVolumeIdFromTreeUri(final Uri treeUri) { final String docId = getTreeDocumentId(treeUri); final String[] split = docId.split(":"); if (split.length > 0) { return split[0]; } else { return null; } } private static String getDocumentPathFromTreeUri(final Uri treeUri) { final String docId = getTreeDocumentId(treeUri); final String[] split = docId.split(":"); if ((split.length >= 2) && (split[1] != null)) { return split[1]; } else { return File.separator; } } /** * Extract the via {@link Document#COLUMN_DOCUMENT_ID} from the given URI. */ public static String getTreeDocumentId(Uri documentUri) { final List<String> paths = documentUri.getPathSegments(); if (paths.size() >= 2 && PATH_TREE.equals(paths.get(0))) { return paths.get(1); } throw new IllegalArgumentException("Invalid URI: " + documentUri); } }