Question

I’m trying to download a file from within my application. I’ve set a button’s onClickListener to call this method:

private void downloadFile(String fileUrl, File destDir, String fileName) {
    try {
        URL url = new URL(fileUrl);
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        connection.setRequestMethod("GET");
        connection.setDoOutput(true);
        connection.connect();

        if (destDir.isDirectory() && !destDir.exists()) {
            destDir.mkdirs();
        }

        FileOutputStream output = new FileOutputStream(new File(destDir.toString() + "/" + fileName));

        InputStream input = connection.getInputStream();

        byte[] buffer = new byte[1024];
        int byteCount = 0;

        while ((byteCount = input.read(buffer)) != -1) {
             output.write(buffer, 0, byteCount);
        }

        output.close();
        input.close();
    } catch (IOException e) {
        Toast.makeText(this, "Error: " + e.getMessage(), Toast.LENGTH_SHORT).show();
        Log.e("IOException", "Error: " + e.getMessage(), e);
    } finally {
        Toast.makeText(this, "File downloaded: " + fileName, Toast.LENGTH_SHORT).show();
    }
}

I’ve been going through various topics, but neither one seemed to come up with a usable solution. When I use the code specified above, nothing seems to happen.

EDIT: The file will download in the background and show a short toast when finished. The button seems to be “clicked” while downloading, though. Any thoughts on this?

Thanks for your help!

Actually I didn’t need all that code. I just had to use something similar to this:

private void getFile(String url) {
    try {
        Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(url));
        startActivity(intent);
    } catch (ActivityNotFoundException e) {
        Toast.makeText(this, "Error: " + e.getMessage(), Toast.LENGTH_SHORT).show();
        Log.e("ActivityNotFoundException", "Error: " + e.getMessage(), e);
    } catch (NullPointerException e) {
        Toast.makeText(this, "Error: " + e.getMessage(), Toast.LENGTH_SHORT).show();
        Log.e("NullPointerException", "Error: " + e.getMessage(), e);
    }
}

This should also be useful to some people:

private void openFile(File file) {
    try {
        Intent intent = new Intent(Intent.ACTION_VIEW, Uri.fromFile(file));
        intent.addCategory(Intent.CATEGORY_BROWSABLE);
        startActivity(intent);
    } catch (ActivityNotFoundException e) {
        Toast.makeText(this, "Error: " + e.getMessage(), Toast.LENGTH_SHORT).show();
        Log.e("ActivityNotFoundException", "Error: " + e.getMessage(), e);
    } catch (NullPointerException e) {
        Toast.makeText(this, "Error: " + e.getMessage(), Toast.LENGTH_SHORT).show();
        Log.e("NullPointerException", "Error: " + e.getMessage(), e);
    }
}

Answer 1

If nothing happens, you should add some logging to your code.

And you could also show the error to the user, by calling Toast.makeText(context, ex.getMessage(), Toast.LENGTH_SHORT).show()

Better would be to show the root cause message using helper methods like these:

public static String getRootCauseMessage(Throwable ex) {
    ex = getRootCause(ex);
    String message = ex.getLocalizedMessage();
    return message == null ? ex.getClass().getSimpleName() : message;
}

public static Throwable getRootCause(Throwable ex) {
    Throwable cause = ex.getCause();
    return cause == null ? ex : getRootCause(cause);
}