Can't open a file which has a question mark in its name

Question

In my Android app, users can download files. The app modify the downloaded file right after the download completes. However, whenever the downloaded file's name includes a question mark somewhere in it, the downloaded file cannot be reached and thus cannot be modified. Related code is as follows:

String pathToFile = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS) + "/" + document.getTitle();

// Example pathToFile: /storage/emulated/0/Download/Recording ? 20171227.mp3
File downloadedFile = new File(pathToFile);

if (!downloadedFile.exists()) {
    // Always gets here if filename includes at least one '?'
}

I try adding "file://" prefix to pathToFile, converting pathToFile to Uri or URI, but nothing worked. It always says file doesn't exist. Any help is appreciated.

ADDITIONAL INFO: The document filename is retrieved from the internet and I save the document using the same filename. I can see the file with same filename in the Downloads folder, however, I cannot open it programmatically.

Are you downloading this file yourself? If so, why not create it using a safe filename, one without spaces and odd punctuation? — CommonsWare, Feb 20 '18 at 14:16
Yeah, I do the download in the app itself. The DownloadManager manages to download and save it, so I did't want to impose any restriction. — Mehmed, Feb 20 '18 at 14:17
https://stackoverflow.com/questions/2679699/what-characters-allowed-in-file-names-on-android — GriffeyDog, Feb 20 '18 at 14:18
@GriffeyDog, I checked the link before but it confused me since there is no single solution. — Mehmed, Feb 20 '18 at 14:30
@Mehmed `?` is not generally supported in filenames, so you need to sanitize the filenames so they don't include `?`s. — GriffeyDog, Feb 20 '18 at 14:33
OK, I will, thanks. Do you know the minimal reserved/forbidden character set for providing safeness? — Mehmed, Feb 20 '18 at 14:57

score 1 · Accepted Answer · answered Feb 24 '18 at 20:08

1

As recommended by commentators, I replace #, % and ? with empty string. The following characters don't cause a problem: !@$^&*()[]{}|

answered Feb 24 '18 at 20:08

Mehmed

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Can't open a file which has a question mark in its name

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