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Commit 672b0521 authored by Janis Danisevskis's avatar Janis Danisevskis
Browse files

Updates training/camera/photobasics.jd with FileProvider details 

As of Android N, passing file:// URIs across package boundaries
throws a FileUriExposedException. This has caused frustration among
app developers trying to use our example as boilerplate code. This
patch replaces the "take picture" example with one that uses
content:// URIs and FileProvider instead.

Bug: 27636012
Change-Id: I9f0b4d9bbcd6b4bfa770dd1e4ad37f321e22195f
parent de5a7afc

docs/html/training/camera/photobasics.jd

+57 −5
Original line number Diff line number Diff line
@@ -175,7 +175,8 @@ attribute:</p> 
</pre>



<p class="note"><strong>Note:</strong> Files you save in the directories provided by

{@link android.content.Context#getExternalFilesDir getExternalFilesDir()} are deleted

{@link android.content.Context#getExternalFilesDir getExternalFilesDir()} or

{@link android.content.Context#getFilesDir getFilesDir()} are deleted

when the user uninstalls your app.</p>



<p>Once you decide the directory for the file, you need to create a
@@ -190,8 +191,7 @@ private File createImageFile() throws IOException { 
    // Create an image file name

    String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());

    String imageFileName = "JPEG_" + timeStamp + "_";

    File storageDir = Environment.getExternalStoragePublicDirectory(

            Environment.DIRECTORY_PICTURES);

    File storageDir = getExternalFilesDir(Environment.DIRECTORY_PICTURES);

    File image = File.createTempFile(

        imageFileName,  /* prefix */

        ".jpg",         /* suffix */
@@ -225,14 +225,66 @@ private void dispatchTakePictureIntent() { 
        }

        // Continue only if the File was successfully created

        if (photoFile != null) {

            takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT,

                    Uri.fromFile(photoFile));

            Uri photoURI = FileProvider.getUriForFile(this,

                                                  "com.example.android.fileprovider",

                                                  photoFile);

            takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, photoURI);

            startActivityForResult(takePictureIntent, REQUEST_TAKE_PHOTO);

        }

    }

}

</pre>



<p class="note"><strong>Note:</strong> We are using {@link

android.support.v4.content.FileProvider#getUriForFile} which returns a <code>content://</code>

URI. For more recent apps targeting Android N and higher, passing a <code>file://</code> URI

across a package boundary causes a {@link android.os.FileUriExposedException

FileUriExposedException}.

Therefore, we now present a more generic way of storing images using a

{@link android.support.v4.content.FileProvider FileProvider}.

</p>



Now, you need to configure the {@link android.support.v4.content.FileProvider

FileProvider}. In your app's manifest, add a provider to your application:



<pre>

&lt;application&gt;

   ...

   &lt;provider

        android:name="android.support.v4.content.FileProvider"

        android:authorities="com.example.android.fileprovider"

        android:exported="false"

        android:grantUriPermissions="true"&gt;

        &lt;meta-data

            android:name="android.support.FILE_PROVIDER_PATHS"

            android:resource="@xml/file_paths"&gt;&lt;/meta-data&gt;

    &lt;/provider&gt;

    ...

&lt;/application&gt;

</pre>



Make sure that the authorities string matches the second argument to {@link

android.support.v4.content.FileProvider#getUriForFile}.

In the meta-data section of the provider definition, you can see that

the provider expects eligible paths to be configured in a dedicated resource file,

<c>res/xml/file_paths.xml</c>. Here is the content required for this particular

example:



<pre>

&lt;?xml version="1.0" encoding="utf-8"?&gt;

&lt;paths xmlns:android="http://schemas.android.com/apk/res/android"&gt;

    &lt;external-path name="my_images" path="Android/data/com.example.package.name/files/Pictures" /&gt;

&lt;/paths&gt;

</pre>



The path component corresponds to the path that is returned by

{@link android.content.Context#getExternalFilesDir getExternalFilesDir()}

when called with {@link android.os.Environment#DIRECTORY_PICTURES

Environment.DIRECTORY_PICTURES}. Make sure that you replace

<code>com.example.package.name</code> with the actual package name of your

app. Also, checkout the documentation of {@link android.support.v4.content.FileProvider} for

an extensive description of path specifiers that you can use besides

<code>external-path</code>.



<h2 id="TaskGallery">Add the Photo to a Gallery</h2>