Add FileProvider.java (103998f0f71ce45147449044f57a6ba2618225a9)
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Adrian Ulrich
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714
src/android/support/v4/content/FileProvider.java
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714
src/android/support/v4/content/FileProvider.java
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/*
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* Copyright (C) 2013 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package android.support.v4.content;
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import static org.xmlpull.v1.XmlPullParser.END_DOCUMENT;
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import static org.xmlpull.v1.XmlPullParser.START_TAG;
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import android.content.ContentProvider;
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import android.content.ContentValues;
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import android.content.Context;
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import android.content.Intent;
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import android.content.pm.PackageManager;
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import android.content.pm.ProviderInfo;
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import android.content.res.XmlResourceParser;
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import android.database.Cursor;
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import android.database.MatrixCursor;
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import android.net.Uri;
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import android.os.Environment;
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import android.os.ParcelFileDescriptor;
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import android.provider.OpenableColumns;
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import android.text.TextUtils;
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import android.webkit.MimeTypeMap;
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import org.xmlpull.v1.XmlPullParserException;
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import java.io.File;
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import java.io.FileNotFoundException;
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import java.io.IOException;
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import java.util.HashMap;
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import java.util.Map;
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/**
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* FileProvider is a special subclass of {@link ContentProvider} that facilitates secure sharing
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* of files associated with an app by creating a <code>content://</code> {@link Uri} for a file
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* instead of a <code>file:///</code> {@link Uri}.
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* <p>
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* A content URI allows you to grant read and write access using
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* temporary access permissions. When you create an {@link Intent} containing
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* a content URI, in order to send the content URI
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* to a client app, you can also call {@link Intent#setFlags(int) Intent.setFlags()} to add
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* permissions. These permissions are available to the client app for as long as the stack for
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* a receiving {@link android.app.Activity} is active. For an {@link Intent} going to a
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* {@link android.app.Service}, the permissions are available as long as the
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* {@link android.app.Service} is running.
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* <p>
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* In comparison, to control access to a <code>file:///</code> {@link Uri} you have to modify the
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* file system permissions of the underlying file. The permissions you provide become available to
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* <em>any</em> app, and remain in effect until you change them. This level of access is
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* fundamentally insecure.
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* <p>
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* The increased level of file access security offered by a content URI
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* makes FileProvider a key part of Android's security infrastructure.
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* <p>
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* This overview of FileProvider includes the following topics:
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* </p>
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* <ol>
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* <li><a href="#ProviderDefinition">Defining a FileProvider</a></li>
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* <li><a href="#SpecifyFiles">Specifying Available Files</a></li>
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* <li><a href="#GetUri">Retrieving the Content URI for a File</li>
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* <li><a href="#Permissions">Granting Temporary Permissions to a URI</a></li>
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* <li><a href="#ServeUri">Serving a Content URI to Another App</a></li>
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* </ol>
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* <h3 id="ProviderDefinition">Defining a FileProvider</h3>
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* <p>
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* Since the default functionality of FileProvider includes content URI generation for files, you
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* don't need to define a subclass in code. Instead, you can include a FileProvider in your app
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* by specifying it entirely in XML. To specify the FileProvider component itself, add a
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* <code><a href="{@docRoot}guide/topics/manifest/provider-element.html"><provider></a></code>
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* element to your app manifest. Set the <code>android:name</code> attribute to
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* <code>android.support.v4.content.FileProvider</code>. Set the <code>android:authorities</code>
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* attribute to a URI authority based on a domain you control; for example, if you control the
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* domain <code>mydomain.com</code> you should use the authority
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* <code>com.mydomain.fileprovider</code>. Set the <code>android:exported</code> attribute to
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* <code>false</code>; the FileProvider does not need to be public. Set the
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* <a href="{@docRoot}guide/topics/manifest/provider-element.html#gprmsn"
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* >android:grantUriPermissions</a> attribute to <code>true</code>, to allow you
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* to grant temporary access to files. For example:
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* <pre class="prettyprint">
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*<manifest>
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* ...
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* <application>
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* ...
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* <provider
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* android:name="android.support.v4.content.FileProvider"
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* android:authorities="com.mydomain.fileprovider"
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* android:exported="false"
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* android:grantUriPermissions="true">
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* ...
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* </provider>
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* ...
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* </application>
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*</manifest></pre>
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* <p>
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* If you want to override any of the default behavior of FileProvider methods, extend
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* the FileProvider class and use the fully-qualified class name in the <code>android:name</code>
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* attribute of the <code><provider></code> element.
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* <h3 id="SpecifyFiles">Specifying Available Files</h3>
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* A FileProvider can only generate a content URI for files in directories that you specify
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* beforehand. To specify a directory, specify the its storage area and path in XML, using child
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* elements of the <code><paths></code> element.
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* For example, the following <code>paths</code> element tells FileProvider that you intend to
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* request content URIs for the <code>images/</code> subdirectory of your private file area.
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* <pre class="prettyprint">
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*<paths xmlns:android="http://schemas.android.com/apk/res/android">
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* <files-path name="my_images" path="images/"/>
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* ...
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*</paths>
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*</pre>
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* <p>
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* The <code><paths></code> element must contain one or more of the following child elements:
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* </p>
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* <dl>
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* <dt>
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* <pre class="prettyprint">
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*<files-path name="<i>name</i>" path="<i>path</i>" />
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*</pre>
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* </dt>
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* <dd>
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* Represents files in the <code>files/</code> subdirectory of your app's internal storage
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* area. This subdirectory is the same as the value returned by {@link Context#getFilesDir()
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* Context.getFilesDir()}.
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* <dt>
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* <pre class="prettyprint">
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*<external-path name="<i>name</i>" path="<i>path</i>" />
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*</pre>
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* </dt>
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* <dd>
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* Represents files in the root of your app's external storage area. The path
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* {@link Context#getExternalFilesDir(String) Context.getExternalFilesDir()} returns the
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* <code>files/</code> subdirectory of this this root.
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* </dd>
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* <dt>
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* <pre>
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*<cache-path name="<i>name</i>" path="<i>path</i>" />
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*</pre>
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* <dt>
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* <dd>
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* Represents files in the cache subdirectory of your app's internal storage area. The root path
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* of this subdirectory is the same as the value returned by {@link Context#getCacheDir()
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* getCacheDir()}.
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* </dd>
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* </dl>
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* <p>
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* These child elements all use the same attributes:
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* </p>
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* <dl>
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* <dt>
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* <code>name="<i>name</i>"</code>
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* </dt>
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* <dd>
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* A URI path segment. To enforce security, this value hides the name of the subdirectory
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* you're sharing. The subdirectory name for this value is contained in the
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* <code>path</code> attribute.
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* </dd>
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* <dt>
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* <code>path="<i>path</i>"</code>
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* </dt>
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* <dd>
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* The subdirectory you're sharing. While the <code>name</code> attribute is a URI path
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* segment, the <code>path</code> value is an actual subdirectory name. Notice that the
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* value refers to a <b>subdirectory</b>, not an individual file or files. You can't
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* share a single file by its file name, nor can you specify a subset of files using
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* wildcards.
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* </dd>
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* </dl>
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* <p>
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* You must specify a child element of <code><paths></code> for each directory that contains
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* files for which you want content URIs. For example, these XML elements specify two directories:
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* <pre class="prettyprint">
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*<paths xmlns:android="http://schemas.android.com/apk/res/android">
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* <files-path name="my_images" path="images/"/>
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* <files-path name="my_docs" path="docs/"/>
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*</paths>
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*</pre>
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* <p>
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* Put the <code><paths></code> element and its children in an XML file in your project.
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* For example, you can add them to a new file called <code>res/xml/file_paths.xml</code>.
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* To link this file to the FileProvider, add a
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* <a href="{@docRoot}guide/topics/manifest/meta-data-element.html"><meta-data></a> element
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* as a child of the <code><provider></code> element that defines the FileProvider. Set the
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* <code><meta-data></code> element's "android:name" attribute to
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* <code>android.support.FILE_PROVIDER_PATHS</code>. Set the element's "android:resource" attribute
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* to <code>@xml/file_paths</code> (notice that you don't specify the <code>.xml</code>
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* extension). For example:
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* <pre class="prettyprint">
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*<provider
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* android:name="android.support.v4.content.FileProvider"
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* android:authorities="com.mydomain.fileprovider"
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* android:exported="false"
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* android:grantUriPermissions="true">
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* <meta-data
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* android:name="android.support.FILE_PROVIDER_PATHS"
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* android:resource="@xml/file_paths" />
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*</provider>
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*</pre>
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* <h3 id="GetUri">Generating the Content URI for a File</h3>
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* <p>
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* To share a file with another app using a content URI, your app has to generate the content URI.
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* To generate the content URI, create a new {@link File} for the file, then pass the {@link File}
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* to {@link #getUriForFile(Context, String, File) getUriForFile()}. You can send the content URI
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* returned by {@link #getUriForFile(Context, String, File) getUriForFile()} to another app in an
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* {@link android.content.Intent}. The client app that receives the content URI can open the file
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* and access its contents by calling
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* {@link android.content.ContentResolver#openFileDescriptor(Uri, String)
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* ContentResolver.openFileDescriptor} to get a {@link ParcelFileDescriptor}.
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* <p>
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* For example, suppose your app is offering files to other apps with a FileProvider that has the
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* authority <code>com.mydomain.fileprovider</code>. To get a content URI for the file
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* <code>default_image.jpg</code> in the <code>images/</code> subdirectory of your internal storage
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* add the following code:
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* <pre class="prettyprint">
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*File imagePath = new File(Context.getFilesDir(), "images");
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*File newFile = new File(imagePath, "default_image.jpg");
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*Uri contentUri = getUriForFile(getContext(), "com.mydomain.fileprovider", newFile);
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*</pre>
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* As a result of the previous snippet,
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* {@link #getUriForFile(Context, String, File) getUriForFile()} returns the content URI
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* <code>content://com.mydomain.fileprovider/my_images/default_image.jpg</code>.
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* <h3 id="Permissions">Granting Temporary Permissions to a URI</h3>
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* To grant an access permission to a content URI returned from
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* {@link #getUriForFile(Context, String, File) getUriForFile()}, do one of the following:
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* <ul>
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* <li>
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* Call the method
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* {@link Context#grantUriPermission(String, Uri, int)
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* Context.grantUriPermission(package, Uri, mode_flags)} for the <code>content://</code>
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* {@link Uri}, using the desired mode flags. This grants temporary access permission for the
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* content URI to the specified package, according to the value of the
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* the <code>mode_flags</code> parameter, which you can set to
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* {@link Intent#FLAG_GRANT_READ_URI_PERMISSION}, {@link Intent#FLAG_GRANT_WRITE_URI_PERMISSION}
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* or both. The permission remains in effect until you revoke it by calling
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* {@link Context#revokeUriPermission(Uri, int) revokeUriPermission()} or until the device
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* reboots.
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* </li>
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* <li>
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* Put the content URI in an {@link Intent} by calling {@link Intent#setData(Uri) setData()}.
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* </li>
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* <li>
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* Next, call the method {@link Intent#setFlags(int) Intent.setFlags()} with either
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* {@link Intent#FLAG_GRANT_READ_URI_PERMISSION} or
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* {@link Intent#FLAG_GRANT_WRITE_URI_PERMISSION} or both.
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* </li>
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* <li>
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* Finally, send the {@link Intent} to
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* another app. Most often, you do this by calling
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* {@link android.app.Activity#setResult(int, android.content.Intent) setResult()}.
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* <p>
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* Permissions granted in an {@link Intent} remain in effect while the stack of the receiving
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* {@link android.app.Activity} is active. When the stack finishes, the permissions are
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* automatically removed. Permissions granted to one {@link android.app.Activity} in a client
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* app are automatically extended to other components of that app.
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* </p>
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* </li>
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* </ul>
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* <h3 id="ServeUri">Serving a Content URI to Another App</h3>
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* <p>
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* There are a variety of ways to serve the content URI for a file to a client app. One common way
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* is for the client app to start your app by calling
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* {@link android.app.Activity#startActivityForResult(Intent, int, Bundle) startActivityResult()},
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* which sends an {@link Intent} to your app to start an {@link android.app.Activity} in your app.
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* In response, your app can immediately return a content URI to the client app or present a user
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* interface that allows the user to pick a file. In the latter case, once the user picks the file
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* your app can return its content URI. In both cases, your app returns the content URI in an
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* {@link Intent} sent via {@link android.app.Activity#setResult(int, Intent) setResult()}.
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* </p>
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* <p>
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* You can also put the content URI in a {@link android.content.ClipData} object and then add the
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* object to an {@link Intent} you send to a client app. To do this, call
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* {@link Intent#setClipData(ClipData) Intent.setClipData()}. When you use this approach, you can
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* add multiple {@link android.content.ClipData} objects to the {@link Intent}, each with its own
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* content URI. When you call {@link Intent#setFlags(int) Intent.setFlags()} on the {@link Intent}
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* to set temporary access permissions, the same permissions are applied to all of the content
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* URIs.
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* </p>
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* <p class="note">
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* <strong>Note:</strong> The {@link Intent#setClipData(ClipData) Intent.setClipData()} method is
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* only available in platform version 16 (Android 4.1) and later. If you want to maintain
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* compatibility with previous versions, you should send one content URI at a time in the
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* {@link Intent}. Set the action to {@link Intent#ACTION_SEND} and put the URI in data by calling
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* {@link Intent#setData setData()}.
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* </p>
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* <h3 id="">More Information</h3>
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* <p>
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* To learn more about FileProvider, see the Android training class
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* <a href="{@docRoot}training/secure-uri/index.html">Sharing Files Securely with URIs</a>.
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* </p>
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*/
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public class FileProvider extends ContentProvider {
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private static final String[] COLUMNS = {
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OpenableColumns.DISPLAY_NAME, OpenableColumns.SIZE };
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private static final String
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META_DATA_FILE_PROVIDER_PATHS = "android.support.FILE_PROVIDER_PATHS";
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private static final String TAG_ROOT_PATH = "root-path";
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private static final String TAG_FILES_PATH = "files-path";
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private static final String TAG_CACHE_PATH = "cache-path";
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private static final String TAG_EXTERNAL = "external-path";
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private static final String ATTR_NAME = "name";
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private static final String ATTR_PATH = "path";
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private static final File DEVICE_ROOT = new File("/");
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// @GuardedBy("sCache")
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private static HashMap<String, PathStrategy> sCache = new HashMap<String, PathStrategy>();
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private PathStrategy mStrategy;
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/**
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* The default FileProvider implementation does not need to be initialized. If you want to
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* override this method, you must provide your own subclass of FileProvider.
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*/
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@Override
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public boolean onCreate() {
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return true;
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}
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/**
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* After the FileProvider is instantiated, this method is called to provide the system with
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* information about the provider.
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*
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* @param context A {@link Context} for the current component.
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* @param info A {@link ProviderInfo} for the new provider.
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*/
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@Override
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public void attachInfo(Context context, ProviderInfo info) {
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super.attachInfo(context, info);
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// Sanity check our security
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if (info.exported) {
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throw new SecurityException("Provider must not be exported");
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}
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if (!info.grantUriPermissions) {
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throw new SecurityException("Provider must grant uri permissions");
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}
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mStrategy = getPathStrategy(context, info.authority);
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}
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/**
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* Return a content URI for a given {@link File}. Specific temporary
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* permissions for the content URI can be set with
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* {@link Context#grantUriPermission(String, Uri, int)}, or added
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* to an {@link Intent} by calling {@link Intent#setData(Uri) setData()} and then
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* {@link Intent#setFlags(int) setFlags()}; in both cases, the applicable flags are
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* {@link Intent#FLAG_GRANT_READ_URI_PERMISSION} and
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* {@link Intent#FLAG_GRANT_WRITE_URI_PERMISSION}. A FileProvider can only return a
|
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* <code>content</code> {@link Uri} for file paths defined in their <code><paths></code>
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* meta-data element. See the Class Overview for more information.
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*
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* @param context A {@link Context} for the current component.
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* @param authority The authority of a {@link FileProvider} defined in a
|
||||
* {@code <provider>} element in your app's manifest.
|
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* @param file A {@link File} pointing to the filename for which you want a
|
||||
* <code>content</code> {@link Uri}.
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* @return A content URI for the file.
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* @throws IllegalArgumentException When the given {@link File} is outside
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* the paths supported by the provider.
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*/
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public static Uri getUriForFile(Context context, String authority, File file) {
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final PathStrategy strategy = getPathStrategy(context, authority);
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return strategy.getUriForFile(file);
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}
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/**
|
||||
* Use a content URI returned by
|
||||
* {@link #getUriForFile(Context, String, File) getUriForFile()} to get information about a file
|
||||
* managed by the FileProvider.
|
||||
* FileProvider reports the column names defined in {@link android.provider.OpenableColumns}:
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||||
* <ul>
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||||
* <li>{@link android.provider.OpenableColumns#DISPLAY_NAME}</li>
|
||||
* <li>{@link android.provider.OpenableColumns#SIZE}</li>
|
||||
* </ul>
|
||||
* For more information, see
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||||
* {@link ContentProvider#query(Uri, String[], String, String[], String)
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* ContentProvider.query()}.
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*
|
||||
* @param uri A content URI returned by {@link #getUriForFile}.
|
||||
* @param projection The list of columns to put into the {@link Cursor}. If null all columns are
|
||||
* included.
|
||||
* @param selection Selection criteria to apply. If null then all data that matches the content
|
||||
* URI is returned.
|
||||
* @param selectionArgs An array of {@link java.lang.String}, containing arguments to bind to
|
||||
* the <i>selection</i> parameter. The <i>query</i> method scans <i>selection</i> from left to
|
||||
* right and iterates through <i>selectionArgs</i>, replacing the current "?" character in
|
||||
* <i>selection</i> with the value at the current position in <i>selectionArgs</i>. The
|
||||
* values are bound to <i>selection</i> as {@link java.lang.String} values.
|
||||
* @param sortOrder A {@link java.lang.String} containing the column name(s) on which to sort
|
||||
* the resulting {@link Cursor}.
|
||||
* @return A {@link Cursor} containing the results of the query.
|
||||
*
|
||||
*/
|
||||
@Override
|
||||
public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,
|
||||
String sortOrder) {
|
||||
// ContentProvider has already checked granted permissions
|
||||
final File file = mStrategy.getFileForUri(uri);
|
||||
if (projection == null) {
|
||||
projection = COLUMNS;
|
||||
}
|
||||
String[] cols = new String[projection.length];
|
||||
Object[] values = new Object[projection.length];
|
||||
int i = 0;
|
||||
for (String col : projection) {
|
||||
if (OpenableColumns.DISPLAY_NAME.equals(col)) {
|
||||
cols[i] = OpenableColumns.DISPLAY_NAME;
|
||||
values[i++] = file.getName();
|
||||
} else if (OpenableColumns.SIZE.equals(col)) {
|
||||
cols[i] = OpenableColumns.SIZE;
|
||||
values[i++] = file.length();
|
||||
}
|
||||
}
|
||||
cols = copyOf(cols, i);
|
||||
values = copyOf(values, i);
|
||||
final MatrixCursor cursor = new MatrixCursor(cols, 1);
|
||||
cursor.addRow(values);
|
||||
return cursor;
|
||||
}
|
||||
/**
|
||||
* Returns the MIME type of a content URI returned by
|
||||
* {@link #getUriForFile(Context, String, File) getUriForFile()}.
|
||||
*
|
||||
* @param uri A content URI returned by
|
||||
* {@link #getUriForFile(Context, String, File) getUriForFile()}.
|
||||
* @return If the associated file has an extension, the MIME type associated with that
|
||||
* extension; otherwise <code>application/octet-stream</code>.
|
||||
*/
|
||||
@Override
|
||||
public String getType(Uri uri) {
|
||||
// ContentProvider has already checked granted permissions
|
||||
final File file = mStrategy.getFileForUri(uri);
|
||||
final int lastDot = file.getName().lastIndexOf('.');
|
||||
if (lastDot >= 0) {
|
||||
final String extension = file.getName().substring(lastDot + 1);
|
||||
final String mime = MimeTypeMap.getSingleton().getMimeTypeFromExtension(extension);
|
||||
if (mime != null) {
|
||||
return mime;
|
||||
}
|
||||
}
|
||||
return "application/octet-stream";
|
||||
}
|
||||
/**
|
||||
* By default, this method throws an {@link java.lang.UnsupportedOperationException}. You must
|
||||
* subclass FileProvider if you want to provide different functionality.
|
||||
*/
|
||||
@Override
|
||||
public Uri insert(Uri uri, ContentValues values) {
|
||||
throw new UnsupportedOperationException("No external inserts");
|
||||
}
|
||||
/**
|
||||
* By default, this method throws an {@link java.lang.UnsupportedOperationException}. You must
|
||||
* subclass FileProvider if you want to provide different functionality.
|
||||
*/
|
||||
@Override
|
||||
public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
|
||||
throw new UnsupportedOperationException("No external updates");
|
||||
}
|
||||
/**
|
||||
* Deletes the file associated with the specified content URI, as
|
||||
* returned by {@link #getUriForFile(Context, String, File) getUriForFile()}. Notice that this
|
||||
* method does <b>not</b> throw an {@link java.io.IOException}; you must check its return value.
|
||||
*
|
||||
* @param uri A content URI for a file, as returned by
|
||||
* {@link #getUriForFile(Context, String, File) getUriForFile()}.
|
||||
* @param selection Ignored. Set to {@code null}.
|
||||
* @param selectionArgs Ignored. Set to {@code null}.
|
||||
* @return 1 if the delete succeeds; otherwise, 0.
|
||||
*/
|
||||
@Override
|
||||
public int delete(Uri uri, String selection, String[] selectionArgs) {
|
||||
// ContentProvider has already checked granted permissions
|
||||
final File file = mStrategy.getFileForUri(uri);
|
||||
return file.delete() ? 1 : 0;
|
||||
}
|
||||
/**
|
||||
* By default, FileProvider automatically returns the
|
||||
* {@link ParcelFileDescriptor} for a file associated with a <code>content://</code>
|
||||
* {@link Uri}. To get the {@link ParcelFileDescriptor}, call
|
||||
* {@link android.content.ContentResolver#openFileDescriptor(Uri, String)
|
||||
* ContentResolver.openFileDescriptor}.
|
||||
*
|
||||
* To override this method, you must provide your own subclass of FileProvider.
|
||||
*
|
||||
* @param uri A content URI associated with a file, as returned by
|
||||
* {@link #getUriForFile(Context, String, File) getUriForFile()}.
|
||||
* @param mode Access mode for the file. May be "r" for read-only access, "rw" for read and
|
||||
* write access, or "rwt" for read and write access that truncates any existing file.
|
||||
* @return A new {@link ParcelFileDescriptor} with which you can access the file.
|
||||
*/
|
||||
@Override
|
||||
public ParcelFileDescriptor openFile(Uri uri, String mode) throws FileNotFoundException {
|
||||
// ContentProvider has already checked granted permissions
|
||||
final File file = mStrategy.getFileForUri(uri);
|
||||
final int fileMode = modeToMode(mode);
|
||||
return ParcelFileDescriptor.open(file, fileMode);
|
||||
}
|
||||
/**
|
||||
* Return {@link PathStrategy} for given authority, either by parsing or
|
||||
* returning from cache.
|
||||
*/
|
||||
private static PathStrategy getPathStrategy(Context context, String authority) {
|
||||
PathStrategy strat;
|
||||
synchronized (sCache) {
|
||||
strat = sCache.get(authority);
|
||||
if (strat == null) {
|
||||
try {
|
||||
strat = parsePathStrategy(context, authority);
|
||||
} catch (IOException e) {
|
||||
throw new IllegalArgumentException(
|
||||
"Failed to parse " + META_DATA_FILE_PROVIDER_PATHS + " meta-data", e);
|
||||
} catch (XmlPullParserException e) {
|
||||
throw new IllegalArgumentException(
|
||||
"Failed to parse " + META_DATA_FILE_PROVIDER_PATHS + " meta-data", e);
|
||||
}
|
||||
sCache.put(authority, strat);
|
||||
}
|
||||
}
|
||||
return strat;
|
||||
}
|
||||
/**
|
||||
* Parse and return {@link PathStrategy} for given authority as defined in
|
||||
* {@link #META_DATA_FILE_PROVIDER_PATHS} {@code <meta-data>}.
|
||||
*
|
||||
* @see #getPathStrategy(Context, String)
|
||||
*/
|
||||
private static PathStrategy parsePathStrategy(Context context, String authority)
|
||||
throws IOException, XmlPullParserException {
|
||||
final SimplePathStrategy strat = new SimplePathStrategy(authority);
|
||||
final ProviderInfo info = context.getPackageManager()
|
||||
.resolveContentProvider(authority, PackageManager.GET_META_DATA);
|
||||
final XmlResourceParser in = info.loadXmlMetaData(
|
||||
context.getPackageManager(), META_DATA_FILE_PROVIDER_PATHS);
|
||||
if (in == null) {
|
||||
throw new IllegalArgumentException(
|
||||
"Missing " + META_DATA_FILE_PROVIDER_PATHS + " meta-data");
|
||||
}
|
||||
int type;
|
||||
while ((type = in.next()) != END_DOCUMENT) {
|
||||
if (type == START_TAG) {
|
||||
final String tag = in.getName();
|
||||
final String name = in.getAttributeValue(null, ATTR_NAME);
|
||||
String path = in.getAttributeValue(null, ATTR_PATH);
|
||||
File target = null;
|
||||
if (TAG_ROOT_PATH.equals(tag)) {
|
||||
target = buildPath(DEVICE_ROOT, path);
|
||||
} else if (TAG_FILES_PATH.equals(tag)) {
|
||||
target = buildPath(context.getFilesDir(), path);
|
||||
} else if (TAG_CACHE_PATH.equals(tag)) {
|
||||
target = buildPath(context.getCacheDir(), path);
|
||||
} else if (TAG_EXTERNAL.equals(tag)) {
|
||||
target = buildPath(Environment.getExternalStorageDirectory(), path);
|
||||
}
|
||||
if (target != null) {
|
||||
strat.addRoot(name, target);
|
||||
}
|
||||
}
|
||||
}
|
||||
return strat;
|
||||
}
|
||||
/**
|
||||
* Strategy for mapping between {@link File} and {@link Uri}.
|
||||
* <p>
|
||||
* Strategies must be symmetric so that mapping a {@link File} to a
|
||||
* {@link Uri} and then back to a {@link File} points at the original
|
||||
* target.
|
||||
* <p>
|
||||
* Strategies must remain consistent across app launches, and not rely on
|
||||
* dynamic state. This ensures that any generated {@link Uri} can still be
|
||||
* resolved if your process is killed and later restarted.
|
||||
*
|
||||
* @see SimplePathStrategy
|
||||
*/
|
||||
interface PathStrategy {
|
||||
/**
|
||||
* Return a {@link Uri} that represents the given {@link File}.
|
||||
*/
|
||||
public Uri getUriForFile(File file);
|
||||
/**
|
||||
* Return a {@link File} that represents the given {@link Uri}.
|
||||
*/
|
||||
public File getFileForUri(Uri uri);
|
||||
}
|
||||
/**
|
||||
* Strategy that provides access to files living under a narrow whitelist of
|
||||
* filesystem roots. It will throw {@link SecurityException} if callers try
|
||||
* accessing files outside the configured roots.
|
||||
* <p>
|
||||
* For example, if configured with
|
||||
* {@code addRoot("myfiles", context.getFilesDir())}, then
|
||||
* {@code context.getFileStreamPath("foo.txt")} would map to
|
||||
* {@code content://myauthority/myfiles/foo.txt}.
|
||||
*/
|
||||
static class SimplePathStrategy implements PathStrategy {
|
||||
private final String mAuthority;
|
||||
private final HashMap<String, File> mRoots = new HashMap<String, File>();
|
||||
public SimplePathStrategy(String authority) {
|
||||
mAuthority = authority;
|
||||
}
|
||||
/**
|
||||
* Add a mapping from a name to a filesystem root. The provider only offers
|
||||
* access to files that live under configured roots.
|
||||
*/
|
||||
public void addRoot(String name, File root) {
|
||||
if (TextUtils.isEmpty(name)) {
|
||||
throw new IllegalArgumentException("Name must not be empty");
|
||||
}
|
||||
try {
|
||||
// Resolve to canonical path to keep path checking fast
|
||||
root = root.getCanonicalFile();
|
||||
} catch (IOException e) {
|
||||
throw new IllegalArgumentException(
|
||||
"Failed to resolve canonical path for " + root, e);
|
||||
}
|
||||
mRoots.put(name, root);
|
||||
}
|
||||
@Override
|
||||
public Uri getUriForFile(File file) {
|
||||
String path;
|
||||
try {
|
||||
path = file.getCanonicalPath();
|
||||
} catch (IOException e) {
|
||||
throw new IllegalArgumentException("Failed to resolve canonical path for " + file);
|
||||
}
|
||||
// Find the most-specific root path
|
||||
Map.Entry<String, File> mostSpecific = null;
|
||||
for (Map.Entry<String, File> root : mRoots.entrySet()) {
|
||||
final String rootPath = root.getValue().getPath();
|
||||
if (path.startsWith(rootPath) && (mostSpecific == null
|
||||
|| rootPath.length() > mostSpecific.getValue().getPath().length())) {
|
||||
mostSpecific = root;
|
||||
}
|
||||
}
|
||||
if (mostSpecific == null) {
|
||||
throw new IllegalArgumentException(
|
||||
"Failed to find configured root that contains " + path);
|
||||
}
|
||||
// Start at first char of path under root
|
||||
final String rootPath = mostSpecific.getValue().getPath();
|
||||
if (rootPath.endsWith("/")) {
|
||||
path = path.substring(rootPath.length());
|
||||
} else {
|
||||
path = path.substring(rootPath.length() + 1);
|
||||
}
|
||||
// Encode the tag and path separately
|
||||
path = Uri.encode(mostSpecific.getKey()) + '/' + Uri.encode(path, "/");
|
||||
return new Uri.Builder().scheme("content")
|
||||
.authority(mAuthority).encodedPath(path).build();
|
||||
}
|
||||
@Override
|
||||
public File getFileForUri(Uri uri) {
|
||||
String path = uri.getEncodedPath();
|
||||
final int splitIndex = path.indexOf('/', 1);
|
||||
final String tag = Uri.decode(path.substring(1, splitIndex));
|
||||
path = Uri.decode(path.substring(splitIndex + 1));
|
||||
final File root = mRoots.get(tag);
|
||||
if (root == null) {
|
||||
throw new IllegalArgumentException("Unable to find configured root for " + uri);
|
||||
}
|
||||
File file = new File(root, path);
|
||||
try {
|
||||
file = file.getCanonicalFile();
|
||||
} catch (IOException e) {
|
||||
throw new IllegalArgumentException("Failed to resolve canonical path for " + file);
|
||||
}
|
||||
if (!file.getPath().startsWith(root.getPath())) {
|
||||
throw new SecurityException("Resolved path jumped beyond configured root");
|
||||
}
|
||||
return file;
|
||||
}
|
||||
}
|
||||
/**
|
||||
* Copied from ContentResolver.java
|
||||
*/
|
||||
private static int modeToMode(String mode) {
|
||||
int modeBits;
|
||||
if ("r".equals(mode)) {
|
||||
modeBits = ParcelFileDescriptor.MODE_READ_ONLY;
|
||||
} else if ("w".equals(mode) || "wt".equals(mode)) {
|
||||
modeBits = ParcelFileDescriptor.MODE_WRITE_ONLY
|
||||
| ParcelFileDescriptor.MODE_CREATE
|
||||
| ParcelFileDescriptor.MODE_TRUNCATE;
|
||||
} else if ("wa".equals(mode)) {
|
||||
modeBits = ParcelFileDescriptor.MODE_WRITE_ONLY
|
||||
| ParcelFileDescriptor.MODE_CREATE
|
||||
| ParcelFileDescriptor.MODE_APPEND;
|
||||
} else if ("rw".equals(mode)) {
|
||||
modeBits = ParcelFileDescriptor.MODE_READ_WRITE
|
||||
| ParcelFileDescriptor.MODE_CREATE;
|
||||
} else if ("rwt".equals(mode)) {
|
||||
modeBits = ParcelFileDescriptor.MODE_READ_WRITE
|
||||
| ParcelFileDescriptor.MODE_CREATE
|
||||
| ParcelFileDescriptor.MODE_TRUNCATE;
|
||||
} else {
|
||||
throw new IllegalArgumentException("Invalid mode: " + mode);
|
||||
}
|
||||
return modeBits;
|
||||
}
|
||||
private static File buildPath(File base, String... segments) {
|
||||
File cur = base;
|
||||
for (String segment : segments) {
|
||||
if (segment != null) {
|
||||
cur = new File(cur, segment);
|
||||
}
|
||||
}
|
||||
return cur;
|
||||
}
|
||||
private static String[] copyOf(String[] original, int newLength) {
|
||||
final String[] result = new String[newLength];
|
||||
System.arraycopy(original, 0, result, 0, newLength);
|
||||
return result;
|
||||
}
|
||||
private static Object[] copyOf(Object[] original, int newLength) {
|
||||
final Object[] result = new Object[newLength];
|
||||
System.arraycopy(original, 0, result, 0, newLength);
|
||||
return result;
|
||||
}
|
||||
}
|
||||
Loading…
x
Reference in New Issue
Block a user