How to show ProgressBar before GridView when loading

public void onCreate(Bundle savedInstatceState){
    super.onCreate(savedInstatceState);
    setContentView(R.layout.main);

    mContext = this;

    bar = (ProgressBar) findViewById(R.id.progress);
    final GridView grid = (GridView) findViewById(R.id.main);
    grid.setEmptyView(findViewById(R.id.empty));
    layout = (LinearLayout) findViewById(R.id.layout);

    bar.setVisibility(View.VISIBLE);
    layout.setVisibility(View.GONE);


    new Thread(new Runnable(){
        public void run() {
            try{
                List mList = new ArrayList();
                // add items into mList
                grid.setAdapter(new Adapter());
            }
            finally{
                mHandler.sendEmptyMessage(0);
            }
        }
    }).start();

}

final Handler mHandler = new Handler(){
    @Override
    public void handleMessage(Message msg) {
        bar.setVisibility(View.GONE);
        layout.setVisibility(View.VISIBLE);
    }
};