file:///storage/emulated/0/***/****.docx exposed beyond app through Intent.getData() error in Xamarin Forms Android

[Sree Sundaram]

I am using the file SaveAndroid.cs as is but when I step through the code on my Android emulator, I get the following error:

 file:///storage/emulated/0/***/****.docx exposed beyond app through Intent.getData()

                    Android.Net.Uri path = Android.Net.Uri.FromFile(file);

                    string extension = Android.Webkit.MimeTypeMap.GetFileExtensionFromUrl(Android.Net.Uri.FromFile(file).ToString());

                    string mimeType = Android.Webkit.MimeTypeMap.Singleton.GetMimeTypeFromExtension(extension);

                    Intent intent = new Intent(Intent.ActionView);

                    intent.SetDataAndType(path, mimeType);

                    Forms.Context.StartActivity(Intent.CreateChooser(intent, "Choose App"));

The exception is thrown on the last line above. In the above code, the mimeType = 

"application/vnd.openxmlformats-officedocument.wordprocessingml.document"

[Suriya Balamurugan]

Hi Sree,

From the given details, we suspect that the reported problem might be due to file:// URI path used for view the generated document.

If your targetSdkVersion >= 24, then we have to use FileProvider class to give access to the particular file or folder to make them accessible for other apps.

To resolve the reported problem, we suggested you to replace file:// URI with content:// URI path in SaveAdnroid.cs

Steps to replace file:// URI with content:// URI:

1. Add a FileProvider <provider> tag in AndroidManifest.xml under <application> tag.

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android" android:versionCode="1" android:versionName="1.0" package="com.companyname.create_word_document">

    <uses-sdk android:minSdkVersion="21" android:targetSdkVersion="30" />

    <application android:label="Create_Word_document.Android" android:theme="@style/MainTheme">

        <provider android:name="androidx.core.content.FileProvider"

             android:authorities="${applicationId}.provider"

             android:exported="false"

             android:grantUriPermissions="true">

            <meta-data android:name="android.support.FILE_PROVIDER_PATHS"

                       android:resource="@xml/provider_paths" />

        </provider>

    </application>

    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

</manifest>

2. Then create a provider_paths.xml file in Resources/xml folder.

<?xml version="1.0" encoding="UTF-8" ?>

<paths xmlns:android="http://schemas.android.com/apk/res/android">

    <external-path name="external_files" path="."/>

</paths>

3. The final step is to change the line of code below in SaveAndroid.cs

//Invoke the created file for viewing

if (file.Exists())

{

    Android.Net.Uri path = Android.Net.Uri.FromFile(file);

    string extension = Android.Webkit.MimeTypeMap.GetFileExtensionFromUrl(Android.Net.Uri.FromFile(file).ToString());

    string mimeType = Android.Webkit.MimeTypeMap.Singleton.GetMimeTypeFromExtension(extension);

    Intent intent = new Intent(Intent.ActionView);

    intent.SetFlags(ActivityFlags.ClearTop | ActivityFlags.NewTask);

    path = FileProvider.GetUriForFile(Android.App.Application.Context, Android.App.Application.Context.PackageName + ".provider", file);

    intent.SetDataAndType(path, mimeType);

    intent.AddFlags(ActivityFlags.GrantReadUriPermission);

    Android.App.Application.Context.StartActivity(intent);

}

Please refer the attached complete sample application.

Could you please try the above solution and let us know whether the reported issue gets resolved?

We will update this code in our documentations and examples also.

Regards,
Suriya Balamurugan.

Attachment: CreateWorddocument_39617366.zip

[Sree Sundaram]

Thank you Suriya. The solution worked for both Word and PowerPoint files.