쓰레드를 사용해야대는데 어디부분에다가 사용해야할지 잘모르겠습니다..

아시는분들 있으면..저에게 도움을..ㅠㅠ

public class Test extends Activity {
 WebView webView;
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.main);

  
 
  webView.getSettings().setJavaScriptEnabled(true);
  webView.loadUrl("이부분은 지웠습니다.);
  webView.requestFocus();
  webView.setWebViewClient(new Callback());
 }

 private class Callback extends WebViewClient{
  private void downloadFile(String fileUrl){
   URL myFileUrl = null;
   Log.e("sdsd", "sdsd");
   try {
    myFileUrl = new URL("fileUrl);
    
   } catch (MalformedURLException e) {
    e.printStackTrace();
   }
   try {
    HttpURLConnection conn = (HttpURLConnection) myFileUrl.openConnection();
    conn.setDoInput(true);
    conn.connect();
    InputStream is = conn.getInputStream();
    
    String mPath = "sdcard/testt.apk";
    FileOutputStream fos;
    File f= new File(mPath);
    if(f.createNewFile()){
     fos = new FileOutputStream(mPath);
     int read;
     while((read= is.read())!=-1){
      fos.write(read);
     }
     fos.close();
    }
   } catch (IOException e) {
   e.printStackTrace();
   }
   Toast.makeText(getApplicationContext(), "download complete", 0).show();
   //안드로이드 패키지 매니저를 통해 다운 받은 apk 파일을 처리하도록 한다.
   
   Intent intent = new Intent(Intent.ACTION_VIEW);
            intent.setDataAndType(Uri.fromFile(new File(Environment.getExternalStorageDirectory() + "/download/" + "Gygtest.apk")), "application/vnd.android.package-archive");
          startActivity(intent);
  }

  @Override
  public boolean shouldOverrideUrlLoading(WebView view, String url) {
   downloadFile(url);
   return super.shouldOverrideUrlLoading(view, url);
  }
  
 }
}