Android 11 上的 FileProvider 共享文件

Question

I'm facing a weird issue. I'm running on Samsung Galaxy S20FE Android 11. I want to open a PDF file from my app so as I've searched around I need to use a fileProvider. This is how I declared it in the manifest:

<provider
        android:name="android.support.v4.content.FileProvider"
        android:authorities="${applicationId}.provider"
        android:exported="false"
        android:grantUriPermissions="true">
        <meta-data
            android:name="android.support.FILE_PROVIDER_PATHS"
            android:resource="@xml/file_paths" />
    </provider>

This is the XML file:

<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
<root-path name="root" path="/storage/" />
</paths>

The file is located inside the app's directory but on SD and not in internal storage of the device. I'm calling the function to open PDF file:

File file = new File(pdfpath);
Uri path = FileProvider.getUriForFile(this, "package.myapp.provider", file);
        Intent intent = new Intent(Intent.ACTION_VIEW);
        intent.setDataAndType(path, "application/pdf");
        intent.setFlags(Intent.FLAG_ACTIVITY_NO_HISTORY | Intent.FLAG_GRANT_READ_URI_PERMISSION);

        try {
            startActivity(intent);
        }
        catch (ActivityNotFoundException e) {
            Toast.makeText(MainActivity.this,
                    "No Application Available to View PDF",
                    Toast.LENGTH_SHORT).show();
        }
    }

According to anywhere I've searched I don't see what I'm missing. I also tried something for older version that should give UriPermissions to all needed packages:

List<ResolveInfo> resInfoList = context.getPackageManager().queryIntentActivities(intent,
PackageManager.MATCH_DEFAULT_ONLY);


for (ResolveInfo resolveInfo : resInfoList) {
    String packageName = resolveInfo.activityInfo.packageName;
    context.grantUriPermission(packageName, uri, Intent.FLAG_GRANT_WRITE_URI_PERMISSION | 
         Intent.FLAG_GRANT_READ_URI_PERMISSION);
}

But no matter what I try, I always end up with the same exception:

2021-05-25 18:04:03.556 8873-8907/package.myapp E/DatabaseUtils: Writing exception to parcel
java.lang.SecurityException: Permission Denial: writing android.support.v4.content.FileProvider uri content://package.myapp.provider/root/0A18-B25A/Android/Data/package.myapp/gis/pdf/dragunov.pdf from pid=13365, uid=10104 requires the provider be exported, or grantUriPermission()

I don't understand why I'm getting permission denied. Also, I've tried setting the XML property to export the FileProvider but I ended up with getting an exception about that the provider can not be exported due to security so I decided not to try and go in that direction.

Any help would be appreciated.

Answer 1

<root-path name="root" path="/storage/" />

You cannot use root-path anymore on an Android 11 device.

Think it was not even possible since Android Q.

So FileProvider cannot serve from removable media now adays.

Use your own ContentProvider to do so.