ACTION_SEND: Incorrect mime sent to WhatsApp resulting in missing Thumbnails

Question

My App manages a few videos and photos downloaded from a IoT device. It downloads videos & photos from these devices and places them in the Apps external Downloads directory (retrieved with context.getExternalFilesDir(Environment.DIRECTORY_DOWNLOADS)).

The App offers a sharing feature, which utilizes the ACTION_SEND intent to export a file to another application.

I have observed different behavior with my App, based on the phones Android OS version. My test is simple: Share the same file (a single photo) to 3 different Apps: 1) WhatsApp, 2) Gmail 3) InShot.

On Android 7.0, the App behavior is incomplete:

1. WhatsApp: Can not show image thumbnail, the file is sent as a "document".
2. Gmail: No problems, the file is sent passed over to Gmail correctly, including a thumbnail
3. InShot: Can not retrieve the file and shows a error message.

On Android 8.0, everything works as expected.

1. WhatsApp: Shows the video or photo editor, then copies the file correctly.
2. Gmail: No problem, as above.
3. InShot: No problem, file can be imported.

Code

The App is using a FileProvider to export the files as it's the standard on Android now.

Support library version is 27.1.0.

The relevant code parts looks like this:

AndroidManifest.xml

Nothing special, just the default config and a link to the paths.xml. applicationId and filesAuthority placeholders are correctly replaced.

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

paths.xml

<?xml version="1.0" encoding="utf-8"?>
<paths>
    <external-files-path
        name="Download"
        path="Download"/>
</paths>

createSharingIntent(context: Context, videos: List<Video>): Intent

var hasVideos = false
var hasImages = false

var items = emptyArray<ClipData.Item>()
var contentTypes = emptyArray<String>()

// Create ClipData items & contentTypes which help to further specify the Intent contents.
for (video in videos) {
    items += ClipData.Item(FileProvider.getUriForFile(context, BuildConfig.FILES_AUTHORITY, File(video.path)))
    contentTypes += (if (video.isJpg) IMAGE_JPG else MediaFormat.MIMETYPE_VIDEO_AVC)

    if (video.isJpg) {
        hasImages = true
    } else {
        hasVideos = true
    }
}

// Build the Intent
val intent: Intent

val intentType = when {
    hasImages && hasVideos -> "*/*"
    hasImages -> IMAGE_JPG
    else -> MediaFormat.MIMETYPE_VIDEO_AVC
}

intent = if (items.size > 1) {
    Intent().setAction(Intent.ACTION_SEND_MULTIPLE)
            .setType(intentType)
            .putParcelableArrayListExtra(Intent.EXTRA_STREAM, ArrayList(items.map { it.uri }))
} else {
    Intent().setAction(Intent.ACTION_SEND)
            .setDataAndTypeAndNormalize(items[0].uri, intentType)
            .putExtra(Intent.EXTRA_STREAM, items[0].uri)
}

intent.flags = Intent.FLAG_GRANT_READ_URI_PERMISSION.or(Intent.FLAG_GRANT_WRITE_URI_PERMISSION)

// Specify more detail in ClipData - which might be helpful for 
val clipData = ClipData("Export", contentTypes, items[0])
for (i in 1 until items.size) {
    clipData.addItem(items[i])
}
intent.clipData = clipData

return intent

take intent and send

Intent intent = createSharingIntent(activity, videos)
Intent chooser = Intent.createChooser(intent, activity.getString(R.string.share_files));
activity.startActivity(chooser);

What is missing to create the same behavior - and most importantly - ensure WhatsApp and other apps can see the image properly, like Gmail?

Answer 1

This question was resolved by ensuring the filename is passed along in lowercase.

Some Android phones did trip over this while others didn't.