setReadOnly not working

问题

I am using setReadOnly method to make my app's directory stored on my SD card 'Read-only'. However this method when called is returning 'false' even though I have provided the app with android.permission.WRITE_EXTERNAL_STORAGE permission in the manifest.
Here's my code :

    is.close();
    fos.close();
    Decompress d = new Decompress(productDirectory + "/downloadedfile.zip", productDirectory + "/unzipped/");
    d.unzip();
    File zipfile = new File(productDirectory + "/downloadedfile.zip");
    zipfile.delete();
    productDirectory = new File(Environment.getExternalStorageDirectory().toString() + "/zipfiledemo");
    boolean isWriteLocked = productDirectory.setReadOnly();
    Log.v("Writing access locked",">>>>>>>>>>>>>>>>>>>" + isWriteLocked);

回答1:

You should define permission android.permission.MOUNT_UNMOUNT_FILESYSTEMS in AndroidManifest.xml, it means you can create file and delete file on the SDCard.

来源：https://stackoverflow.com/questions/7160182/setreadonly-not-working