Question

Things should be simple, but as most of the time, in Android, aren’t. I need to format the SD card if the user selects the option in my app. Don’t ask me why I need to do this if it’s already in the OS… not practical but it’s a requirement that I need to implement. As you may know, there is an option in Settings \ Storage \ Erase SD Card. I took a look at the froyo source code and it’s something like:

final IMountService service =
         IMountService.Stub.asInterface(ServiceManager.getService("mount"));
        if (service != null) {
            new Thread() {
                public void run() {
                try {
                        service.formatVolume(Environment.getExternalStorageDirectory().toString());
                    } catch (Exception e) {
                        // Intentionally blank - there's nothing we can do here
                    Log.w("MediaFormat", "Unable to invoke IMountService.formatMedia()");
                    }
                }
            }.start();
        } else {
            Log.w("MediaFormat", "Unable to locate IMountService");
        }

It uses android.os.storage.IMountService and android.os.ServiceManager and I don’t seem to have access to it. So, as I see it I could recursively search every file and delete it but that would be “not on my taste”… or I could start the screen from Erase SD card to the user.

Any help is more then welcome, as I am stuck.

Answer 1

I can’t find again the question here on SO, but It had a working solution. So all credit goes to that guy 😉

public void wipeMemoryCard() {
        File deleteMatchingFile = new File(Environment
                .getExternalStorageDirectory().toString());
        try {
            File[] filenames = deleteMatchingFile.listFiles();
            if (filenames != null && filenames.length > 0) {
                for (File tempFile : filenames) {
                    if (tempFile.isDirectory()) {
                        wipeDirectory(tempFile.toString());
                        tempFile.delete();
                    } else {
                        tempFile.delete();
                    }
                }
            } else {
                deleteMatchingFile.delete();
            }
        } catch (Exception e) {
            Utils.log(e.getMessage());
        }
    }

    private static void wipeDirectory(String name) {
        File directoryFile = new File(name);
        File[] filenames = directoryFile.listFiles();
        if (filenames != null && filenames.length > 0) {
            for (File tempFile : filenames) {
                if (tempFile.isDirectory()) {
                    wipeDirectory(tempFile.toString());
                    tempFile.delete();
                } else {
                    tempFile.delete();
                }
            }
        } else {
            directoryFile.delete();
        }
    }