Java tutorial
//package com.java2s; /* * Copyright (C) 2007-2008 OpenIntents.org * * 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. */ import android.annotation.SuppressLint; import android.content.ContentUris; import android.content.Context; import android.database.Cursor; import android.database.DatabaseUtils; import android.net.Uri; import android.os.Build; import android.os.Environment; import android.provider.DocumentsContract; import android.provider.MediaStore; import android.util.Log; import java.io.File; public class Main { /** * TAG for log messages. */ static final String TAG = "FileUtils"; private static final boolean DEBUG = false; /** * Convert Uri into File, if possible. * * @return file A local file that the Uri was pointing to, or null if the * Uri is unsupported or pointed to a remote resource. * @author paulburke * @see #getPath(Context, Uri) */ public static File getFile(Context context, Uri uri) { if (uri != null) { String path = getPath(context, uri); if (path != null && isLocal(path)) { return new File(path); } } return null; } /** * Get a file path from a Uri. This will get the the path for Storage Access * Framework Documents, as well as the _data field for the MediaStore and * other file-based ContentProviders.<br> * <br> * Callers should check whether the path is local before assuming it * represents a local file. * * @param context The context. * @param uri The Uri to query. * @author paulburke * @see #isLocal(String) * @see #getFile(Context, Uri) */ @SuppressLint("NewApi") public static String getPath(final Context context, final Uri uri) { if (DEBUG) Log.d(TAG + " File -", "Authority: " + uri.getAuthority() + ", Fragment: " + uri.getFragment() + ", Port: " + uri.getPort() + ", Query: " + uri.getQuery() + ", Scheme: " + uri.getScheme() + ", Host: " + uri.getHost() + ", Segments: " + uri.getPathSegments().toString()); final boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT; // DocumentProvider if (isKitKat && DocumentsContract.isDocumentUri(context, uri)) { if (isExternalStorageDocument(uri)) { final String docId = DocumentsContract.getDocumentId(uri); final String[] split = docId.split(":"); final String type = split[0]; if ("primary".equalsIgnoreCase(type)) { return Environment.getExternalStorageDirectory() + "/" + split[1]; } // TODO handle non-primary volumes } // DownloadsProvider else if (isDownloadsDocument(uri)) { final String id = DocumentsContract.getDocumentId(uri); final Uri contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads/public_downloads"), Long.valueOf(id)); return getDataColumn(context, contentUri, null, null); } // MediaProvider else if (isMediaDocument(uri)) { final String docId = DocumentsContract.getDocumentId(uri); final String[] split = docId.split(":"); final String type = split[0]; Uri contentUri = null; if ("image".equals(type)) { contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI; } else if ("video".equals(type)) { contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI; } else if ("audio".equals(type)) { contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI; } final String selection = "_id=?"; final String[] selectionArgs = new String[] { split[1] }; return getDataColumn(context, contentUri, selection, selectionArgs); } } // MediaStore (and general) else if ("content".equalsIgnoreCase(uri.getScheme())) { // Return the remote address if (isGooglePhotosUri(uri)) return uri.getLastPathSegment(); return getDataColumn(context, uri, null, null); } // File else if ("file".equalsIgnoreCase(uri.getScheme())) { return uri.getPath(); } return null; } /** * @return Whether the URI is a local one. */ public static boolean isLocal(String url) { if (url != null && !url.startsWith("http://") && !url.startsWith("https://")) { return true; } return false; } /** * @param uri The Uri to check. * @return Whether the Uri authority is ExternalStorageProvider. * @author paulburke */ public static boolean isExternalStorageDocument(Uri uri) { return "com.android.externalstorage.documents".equals(uri.getAuthority()); } /** * @param uri The Uri to check. * @return Whether the Uri authority is DownloadsProvider. * @author paulburke */ public static boolean isDownloadsDocument(Uri uri) { return "com.android.providers.downloads.documents".equals(uri.getAuthority()); } /** * Get the value of the data column for this Uri. This is useful for * MediaStore Uris, and other file-based ContentProviders. * * @param context The context. * @param uri The Uri to query. * @param selection (Optional) Filter used in the query. * @param selectionArgs (Optional) Selection arguments used in the query. * @return The value of the _data column, which is typically a file path. * @author paulburke */ public static String getDataColumn(Context context, Uri uri, String selection, String[] selectionArgs) { Cursor cursor = null; final String column = "_data"; final String[] projection = { column }; try { cursor = context.getContentResolver().query(uri, projection, selection, selectionArgs, null); if (cursor != null && cursor.moveToFirst()) { if (DEBUG) DatabaseUtils.dumpCursor(cursor); final int column_index = cursor.getColumnIndexOrThrow(column); return cursor.getString(column_index); } } catch (IllegalArgumentException ex) { Log.i(TAG, "getDataColumn: _data", ex); } finally { if (cursor != null) cursor.close(); } return null; } /** * @param uri The Uri to check. * @return Whether the Uri authority is MediaProvider. * @author paulburke */ public static boolean isMediaDocument(Uri uri) { return "com.android.providers.media.documents".equals(uri.getAuthority()); } /** * @param uri The Uri to check. * @return Whether the Uri authority is Google Photos. */ public static boolean isGooglePhotosUri(Uri uri) { return "com.google.android.apps.photos.content".equals(uri.getAuthority()); } }