Download Code

Downloader.java

public void download(String url,String path){
        try {
            URL u = new URL(url);
            URLConnection conn = u.openConnection();
            int contentLength = conn.getContentLength();
            DataInputStream stream = new DataInputStream(u.openStream());
            String filePath = Environment.getExternalStorageDirectory().getPath().toString() + "/app.apk";
            File f = new File(filePath);
            DataOutputStream fos = new DataOutputStream(new FileOutputStream(f, false));
            byte data[] = new byte[4096];
            long total = 0;
            int count;
            while ((count = stream.read(data)) != -1) {
                total += count;
                if (contentLength > 0) {
                    Log.e("Downloader","Percent: "+((int) (total * 100 / contentLength)));
                }
                fos.write(data, 0, count);
            }
            fos.flush();
            fos.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

manifest.xml

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