1page.title=Setting Up File Sharing 2trainingnavtop=true 3@jd:body 4 5 6<div id="tb-wrapper"> 7<div id="tb"> 8 9<!-- table of contents --> 10<h2>This lesson teaches you to</h2> 11<ol> 12 <li><a href="#DefineProvider">Specify the FileProvider</a></li> 13 <li><a href="#DefineMetaData">Specify Sharable Directories</a></li> 14</ol> 15 16<h2>You should also read</h2> 17<ul> 18 <li><a href="{@docRoot}guide/topics/data/data-storage.html">Storage Options</a></li> 19 <li><a href="{@docRoot}training/basics/data-storage/files.html">Saving Files</a> 20</ul> 21 22</div> 23</div> 24 25<p> 26 To securely offer a file from your app to another app, you need to configure your app to offer 27 a secure handle to the file, in the form of a content URI. The Android 28 {@link android.support.v4.content.FileProvider} component generates content URIs for 29 files, based on specifications you provide in XML. This lesson shows you how to add the default 30 implementation of {@link android.support.v4.content.FileProvider} to your app, and how to 31 specify the files you want to offer to other apps. 32</p> 33 34<p class="note"> 35 <strong>Note:</strong> The {@link android.support.v4.content.FileProvider} class is part of the 36 <a href="{@docRoot}tools/support-library/features.html#v4">v4 Support Library</a>. For information 37 about including this library in your application, see 38 <a href="{@docRoot}tools/support-library/setup.html">Support Library Setup</a>. 39</p> 40 41<h2 id="DefineProvider">Specify the FileProvider</h2> 42<p> 43 Defining a {@link android.support.v4.content.FileProvider} for your app requires an entry in 44 your manifest. This entry specifies the authority to use in generating content URIs, as well as 45 the name of an XML file that specifies the directories your app can share. 46</p> 47<p> 48 The following snippet shows you how to add to your manifest the 49 <code><a href="{@docRoot}guide/topics/manifest/provider-element.html" 50 ><provider></a></code> element that specifies the 51 {@link android.support.v4.content.FileProvider} class, the authority, and the 52 XML file name: 53</p> 54<pre> 55<manifest xmlns:android="http://schemas.android.com/apk/res/android" 56 package="com.example.myapp"> 57 <application 58 ...> 59 <provider 60 android:name="android.support.v4.content.FileProvider" 61 android:authorities="com.example.myapp.fileprovider" 62 android:grantUriPermissions="true" 63 android:exported="false"> 64 <meta-data 65 android:name="android.support.FILE_PROVIDER_PATHS" 66 android:resource="@xml/filepaths" /> 67 </provider> 68 ... 69 </application> 70</manifest></pre> 71<p> 72 In this example, the <code><a href="{@docRoot}guide/topics/manifest/provider-element.html#auth" 73 >android:authorities</a></code> attribute specifies the URI authority 74 that you want to use for content URIs generated by the 75 {@link android.support.v4.content.FileProvider}. 76 In the example, the authority is <code>com.example.myapp.fileprovider</code>. For your own 77 app, specify an authority consisting of the app's 78 <code><a href="{@docRoot}guide/topics/manifest/manifest-element.html#package" 79 >android:package</a></code> value with the string "fileprovider" appended to it. To learn more 80 about the authority value, see the topic 81 <a href="{@docRoot}guide/topics/providers/content-provider-basics.html#ContentURIs" 82 >Content URIs</a> and the documentation for the 83 <code><a href="{@docRoot}guide/topics/manifest/provider-element.html#auth" 84 >android:authorities</a></code> attribute. 85</p> 86<p> 87 The <code><a href="{@docRoot}guide/topics/manifest/meta-data-element.html" 88 ><meta-data></a></code> child element of the 89 <code><a href="{@docRoot}guide/topics/manifest/provider-element.html" 90 ><provider></a></code> points to an XML file that specifies the directories you want to 91 share. The <code>android:resource</code> attribute is the path and name of the file, without 92 the <code>.xml</code> extension.The contents of this file are described in the next section. 93</p> 94<h2 id="DefineMetaData">Specify Sharable Directories</h2> 95<p> 96 Once you have added the {@link android.support.v4.content.FileProvider} to your app manifest, 97 you need to specify the directories that contain the files you want to share. To specify the 98 directories, start by creating the file <code>filepaths.xml</code> in the <code>res/xml/</code> 99 subdirectory of your project. In this file, specify the directories by adding an XML element for 100 each directory. The following snippet shows you an example of the contents of 101 <code>res/xml/filepaths.xml</code>. The snippet also demonstrates how to share a subdirectory 102 of the <code>files/</code> directory in your internal storage area: 103</p> 104<pre> 105<paths> 106 <files-path path="images/" name="myimages" /> 107</paths></pre> 108<p> 109 In this example, the <code><files-path></code> tag shares directories within the 110 <code>files/</code> directory of your app's internal storage. The <code>path</code> attribute 111 shares the <code>images/</code> subdirectory of <code>files/</code>. The <code>name</code> 112 attribute tells the {@link android.support.v4.content.FileProvider} to add the path segment 113 <code>myimages</code> to content URIs for files in the <code>files/images/</code> subdirectory. 114</p> 115<p> 116 The <code><paths></code> element can have multiple children, each specifying a different 117 directory to share. In addition to the <code><files-path></code> element, you can 118 use the <code><external-path></code> element to share directories in external storage, and 119 the <code><cache-path></code> element to share directories in your internal cache 120 directory. To learn more about the child elements that specify shared directories, see the 121 {@link android.support.v4.content.FileProvider} reference documentation. 122</p> 123<p class="note"> 124 <strong>Note:</strong> The XML file is the only way you can specify the directories you want to 125 share; you can't programmatically add a directory. 126</p> 127<p> 128 You now have a complete specification of a {@link android.support.v4.content.FileProvider} 129 that generates content URIs for files in the <code>files/</code> directory of your app's 130 internal storage or for files in subdirectories of <code>files/</code>. When your app generates 131 a content URI for a file, it contains the authority specified in the 132 <code><a href="{@docRoot}guide/topics/manifest/provider-element.html" 133 ><provider></a></code> element (<code>com.example.myapp.fileprovider</code>), 134 the path <code>myimages/</code>, and the name of the file. 135</p> 136<p> 137 For example, if you define a {@link android.support.v4.content.FileProvider} according to the 138 snippets in this lesson, and you request a content URI for the file 139 <code>default_image.jpg</code>, {@link android.support.v4.content.FileProvider} returns the 140 following URI: 141</p> 142<pre> 143content://com.example.myapp.fileprovider/myimages/default_image.jpg</pre> 144 145
