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author | Trevor Johns <trevorjohns@google.com> | 2013-12-30 19:52:21 +0000 |
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committer | Android Git Automerger <android-git-automerger@android.com> | 2013-12-30 19:52:21 +0000 |
commit | ac91e153f659aaa6b52e744ee4e57e0a2f272ab5 (patch) | |
tree | 84cfcdbd64f196485cd8fda3bbc72fe144f6f1e8 /common | |
parent | de2f30c598a3685b11d6f663ba305550182dc30b (diff) | |
parent | 0b49cffeb519e9b652ed086b919e61e30bd79f80 (diff) | |
download | android-ac91e153f659aaa6b52e744ee4e57e0a2f272ab5.tar.gz |
am 0b49cffe: am a57f444c: Add AssetProvider to common dirctory
* commit '0b49cffeb519e9b652ed086b919e61e30bd79f80':
Add AssetProvider to common dirctory
Diffstat (limited to 'common')
-rw-r--r-- | common/src/java/com/example/android/common/assetprovider/AssetProvider.java | 140 |
1 files changed, 140 insertions, 0 deletions
diff --git a/common/src/java/com/example/android/common/assetprovider/AssetProvider.java b/common/src/java/com/example/android/common/assetprovider/AssetProvider.java new file mode 100644 index 00000000..f6c0f613 --- /dev/null +++ b/common/src/java/com/example/android/common/assetprovider/AssetProvider.java @@ -0,0 +1,140 @@ +/* +* 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.common.assetprovider; + +import android.content.ContentProvider; +import android.content.ContentValues; +import android.content.Context; +import android.content.res.AssetFileDescriptor; +import android.content.res.AssetManager; +import android.database.Cursor; +import android.net.Uri; + +import java.io.FileNotFoundException; +import java.io.IOException; + +import static java.net.URLConnection.guessContentTypeFromName; + +/** + * Generic content provider, which makes any files available in this app's "assets" directory + * available publicly. + * + * <p>To use, add the following to your AndroidManifest.xml: + * + * <code><pre> + * <provider + * android:name=".AssetProvider" + * android:authorities="[YOUR CONTENT PROVIDER DOMAIN HERE]" + * android:exported="true"/> + * </pre></code> + */ +public class AssetProvider extends ContentProvider { + AssetManager mAssets; + + @Override + public boolean onCreate() { + Context ctx = getContext(); + if (ctx == null) { + // Context not available. Give up. + return false; + } + mAssets = ctx.getAssets(); + return true; + } + + @Override + public String getType(Uri uri){ + // Returns the MIME type for the selected URI, in conformance with the ContentProvider + // interface. Looks up the file indicated by /res/assets/{uri.path}, and returns the MIME + // type for that file as guessed by the URLConnection class. + + // Setup + String path = uri.getPath(); + + // Check if file exists + if (!fileExists(path)) { + return null; + } + + // Determine MIME-type based on filename + return guessContentTypeFromName(uri.toString()); + } + + + @Override + public AssetFileDescriptor openAssetFile (Uri uri, String mode) + throws FileNotFoundException, SecurityException { + // ContentProvider interface for opening a file descriptor by URI. This content provider + // maps all URIs to the contents of the APK's assets folder, so a file handle to + // /res/assets/{uri.path} will be returned. + + // Security check. This content provider only supports read-only access. (Also, the contents + // of an APKs assets folder are immutable, so read-write access doesn't make sense here.) + if (!"r".equals(mode)) { + throw new SecurityException("Only read-only access is supported, mode must be [r]"); + } + + // Open asset from within APK and return file descriptor + String path = uri.getPath(); + try { + return mAssets.openFd(path); + } catch (IOException e) { + throw new FileNotFoundException(); + } + } + + /** + * Check if file exists inside APK assets. + * + * @param path Fully qualified path to file. + * @return true if exists, false otherwise. + */ + private boolean fileExists(String path) { + try { + // Check to see if file can be opened. If so, file exists. + mAssets.openFd(path).close(); + return true; + } catch (IOException e) { + // Unable to open file descriptor for specified path; file doesn't exist. + return false; + } + } + + // Required/unused ContentProvider methods below. + @Override + public Cursor query(Uri uri, String[] projection, String selection, + String[] selectionArgs, String sortOrder) { + // Note: It might be worth implementing support for querying + // android.provider.OpenableColumns here in the future. + throw new RuntimeException("Operation not supported"); + } + + @Override + public Uri insert(Uri uri, ContentValues contentValues) { + throw new RuntimeException("Operation not supported"); + } + + @Override + public int delete(Uri uri, String selection, String[] selectionArgs) { + throw new RuntimeException("Operation not supported"); + } + + @Override + public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) { + throw new RuntimeException("Operation not supported"); + } +} |