Android：如何在本地写入文件并将其保存到下载中

Question

How do you write files locally and save them to the Downloads App in Android?

Android version: Nougut

The file is not showing in Downloads though. Here's my code:

File file = new File(Environment.getExternalStoragePublicDirectory(
        Environment.DIRECTORY_DOWNLOADS), "foo.txt");

try {
    String exampleString = "bar\nfoo";
    InputStream is = new ByteArrayInputStream(exampleString.getBytes(Charset.forName("UTF-8")));
    OutputStream os = new FileOutputStream(file);
    byte[] data = new byte[is.available()];
    is.read(data);
    os.write(data);
    is.close();
    os.close();
} catch (IOException e) {
    throw new AssertionError(e.toString());
}

MediaScannerConnection.scanFile(
        getContext(),
        new String[]{file.getAbsolutePath()},
        null,
        new MediaScannerConnection.OnScanCompletedListener() {
            @Override
            public void onScanCompleted(String s, Uri uri) {
                Log.d(TAG, "String: "+ s);
                Log.d(TAG, "Uri: "+ uri );
            }
        });

It is logging this in onScanCompleted so it seems like the file should show in Downloads but it doesn't.

D/SignupFragment: String: /storage/emulated/0/Download/foo.txt
D/SignupFragment: Uri: content://media/external/file/84691

I have read the Android docs on saving files

AndroidManifest.xml

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

Answer 1

The standard AOSP Downloads app only shows what DownloadManager downloaded. It does not show files placed in the Downloads/ directory by other means.