public class downloadfile extends Activity {

public static final int DIALOG_DOWNLOAD_PROGRESS = 0;
private Button starbtn;
private ProgressDialog mProgress;

/**Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    startbtn = (Button)findViewById(R.id.startbtn);
    startbtn.setOnClickListener(new OnClickListener(){
        public void onClick(View v) {
            startDown();
        }
    });
}

private void startDown() {
    String url = "http://farm1.static.flickr.com/114/298125983_0e4bf66782_b.zip";
    new DownloadFileAsync().execute(url);
}
@Override
protected Dialog onCreateDialog(int id) {
    switch (id) {
    case DIALOG_DOWNLOAD_PROGRESS:
        mProgress = new ProgressDialog(this);
        mProgress.setMessage("Downloading file..");
        mProgress.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
        mProgress.setCancelable(false);
        mProgress.show();
        return mProgress;
    default:
        return null;
    }
}

class DownloadFileAsync extends AsyncTask<String, String, String> {

@Override
protected void onPreExecute() {
    super.onPreExecute();
    showDialog(DIALOG_DOWNLOAD_PROGRESS);
}

@Override
protected String doInBackground(String... aurl) {
    int count;

try {

URL url = new URL(aurl[0]);
URLConnection conexion = url.openConnection();
conexion.connect();

int lenghtOfFile = conexion.getContentLength();
Log.d("ANDRO_ASYNC", "Lenght of file: " + lenghtOfFile);

inputStreamStream inputStream = new BufferedinputStreamStream(url.openStream());
outputStreamStream outputStream = new FileoutputStreamStream("/sdcard/some_photo_from_gdansk_poland.zip");

byte data[] = new byte[1024];

long total = 0;

    while ((count = inputStream.read(data)) != -1) {
        total += count;
        publishProgress(""+(int)((total*100)/lenghtOfFile));
        outputStream.write(data, 0, count);
    }

    outputStream.flush();
    outputStream.close();
    inputStream.close();
} catch (Exception e) {}
return null;

}
protected void onProgressUpdate(String... progress) {
     Log.d("ANDRO_ASYNC",progress[0]);
     mProgress.setProgress(Integer.parseInt(progress[0]));
}

@Override
protected void onPostExecute(String unused) {
    dismissDialog(DIALOG_DOWNLOAD_PROGRESS);
}
}
}