Can't write to sdcard even with permissions set and external storage in MEDIA_MOUNTED state

Question

While trying to write file to sdcard I get java.io.FileNotFoundException: /filename (Read-only file system) exception. Sadly none of the many solutions posted h

Answer 1

Try this:

File file = new File(filePath);
File parent = file.getParentFile();
if (!parent.exists() && !parent.mkdirs()) {
      return;
}

file = new File(Helpers.StripExtension(filePath) + ".blk");
OutputStream fos = new FileOutputStream(file);
fos.write(digest.getBytes());
fos.close();

Answer 2

Great, I've had the exact same problem some time ago. Path delimiter (or whatever it's called) is missing.

File file = new File(Environment.getExternalStorageDirectory() + "test_file.blk");

didn't work, but

File file = new File(Environment.getExternalStorageDirectory() + "/test_file.blk");

performed well

Also:

FileWriter f = new FileWriter(Environment.getExternalStorageDirectory().getPath()+ "/foobar");
f.append("stuff");
f.close();

Works fine etc.
I think exceptions said it's readonly, because root filesystem is readonly indeed.

NOTE:
java.io.FileNotFoundException: /foobar (Read-only file system) means we are writing to the system root
java.io.FileNotFoundException: /mnt/sdcard/foobar (Read-only file system) means sdcard root (I didn't get this exception it's just an example)

tl;dr wrong path

Answer 3

Try this:

File file = new File(Helpers.StripExtension(filePath) + ".blk");
file.createNewFile();
FileOutputStream fos = new FileOutputStream(file);
fos.write(digest.getBytes());
fos.close();

and if that doesn't work, I think you may have a problem when reading from the original file (digest.getBytes()). Post a little more code on this and we can go from there

Edit:

If it is not letting you write to the selected directory, try testing with a path like this:

File file = new File(Environment.getExternalStorageDirectory() + "test_file.blk");

It should work fine and you probably just don't have write permissions to the directory you are using.