Saturday, January 27, 2018

Content resolver returns wrong size

By Hường Hana 1:30 PM , Leave a Comment

I am picking an image from the gallery and querying its size via ContentResolver API, it returns 29kb.

However when I check the file via adb using ls -al it is 44kb

here is how I query the size of the image:

    private fun getFileInfo(contentResolver: ContentResolver, fileUri: Uri): Pair<String, Long>? {     val projection = arrayOf(MediaStore.MediaColumns.DISPLAY_NAME, MediaStore.MediaColumns.SIZE)     val metaCursor = contentResolver.query(fileUri, projection, null, null, null)         metaCursor?.use {             if (it.moveToFirst()) {                 val displayNameIndex = it.getColumnIndex(MediaStore.MediaColumns.DISPLAY_NAME)                 val sizeIndex = it.getColumnIndex(MediaStore.MediaColumns.SIZE)                 return Pair(it.getString(displayNameIndex), it.getLong(sizeIndex))             }     }     return null }

I am using an Oreo Emulator. I have also checked via emulator's tools, file browser shows as 29kb on the other hand file details shows 45kb. What is going on?

Here are the images from file browser:

Summary

Details

Another side note, above situation can be reproducible every time when using camera app on emulator with Android 26-Oreo emulator, however it is fine with emulator Android 25-Nougat.

I have checked, new Document API also returns 29kb

1 Answers

Answers 1

Android 8.0 (Oreo) introduced the 'SDCardFS' filesystem, which replaced 'FUSE' on the /sdcard partition.

it is possible that this new filesystem has a large cluster size and is therefore not able to allocate exactly 29kb, but instead the smallest block larger than 29kb, which in your case is 44.*kb.

The difference between ls -al and file details is probably caused by different rounding.

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