Hey there! Let's tackle this export problem from a user-centric perspective—since your app is for research, users probably want a straightforward, hassle-free way to get their Excel files to desktop without extra hoops. Let's break down your options and the best approach:

First, Let's Address Your Two Initial Ideas #

1. Email Attachment as a Workaround #

You're right—this is a band-aid solution. For users who just need to get the file to their desktop, having to send an email to themselves adds unnecessary steps (open email app, fill in their own address, send, switch to desktop inbox to download). It works, but it's not intuitive or efficient for regular exports. Save this as a secondary option for users who want to share data directly with collaborators, not as the primary export method.

2. Storing to Android's "Documents" Equivalent #

Great question—Android does have a universal, user-friendly Documents folder, and this is absolutely a best practice when done right. Here's what you need to know:

• On Android 10 (API 29) and above, the system uses scoped storage, but you can still save files to the public Documents directory (the same one users see in their file manager's "Documents" tab).
• Even better: Create a dedicated subfolder for your app (e.g., ResearchDataExports) inside the public Documents directory. This way, users don't have to sift through random files—they know exactly where to find your app's exports.

The Optimal Solution: Combine Storage + Guided Access + Flexible Sharing #

The best approach is to make saving to the public Documents folder your primary option, then add quality-of-life features to make it even easier, plus optional sharing for edge cases. Here's how to execute this:

Step 1: Save to a Dedicated Public Documents Subfolder #

Use Android's MediaStore API (for scoped storage compliance) to save your Excel files directly to Documents/[YourAppName]Exports. Example code snippet (simplified):

// Define the file details
val fileName = "ResearchData_${System.currentTimeMillis()}.xlsx"
val mimeType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"

// Create content values for MediaStore
val contentValues = ContentValues().apply {
    put(MediaStore.Documents.Document.COLUMN_DISPLAY_NAME, fileName)
    put(MediaStore.Documents.Document.COLUMN_MIME_TYPE, mimeType)
    // Save to Documents/ResearchDataExports
    put(MediaStore.Documents.Document.COLUMN_RELATIVE_PATH, "${Environment.DIRECTORY_DOCUMENTS}/ResearchDataExports")
}

// Insert the file into MediaStore
val uri = context.contentResolver.insert(
    MediaStore.Documents.getContentUri("external"),
    contentValues
)

// Write your Excel data to the URI
uri?.let {
    context.contentResolver.openOutputStream(it).use { outputStream ->
        // Write your Excel file content here (using libraries like Apache POI or EasyExcel)
    }
}

Step 2: Guide Users to the File #

After saving, don't just leave them guessing:

• Show a clear Toast or snackbar: "File saved to Documents > ResearchDataExports"
• Add an "Open Folder" button in the notification/snackbar that launches the file manager directly to the subfolder (use ACTION_VIEW intent with the folder URI).

Step 3: Add Optional Sharing Features #

For users who prefer to get the file to desktop via cloud or email, add a "Share" button alongside the "Save" option. This can include:

• Email attachment (for direct sharing to others or self)
• Cloud storage apps (Google Drive, OneDrive, Dropbox—users often sync these to their desktop automatically)
• Nearby share (for quick transfer to a nearby computer)

Step 4: Keep Export History in the App #

Add a section in your app that lists all previously exported Excel files. Users can tap to open, re-share, or even re-export the data. This eliminates the need to hunt through the file system if they forget where the file is.

Why This Is Better Than Either Single Option #

• Storing to Documents follows Android's best practices, is compliant with scoped storage, and puts files in a location users already know how to access.
• Guided access removes the "where did my file go?" frustration that plagues many Android apps.
• Flexible sharing covers edge cases where users don't want to navigate the file system, or need to send data to others.

内容的提问来源于stack exchange，提问作者Onkelbummms