android - ProgressDialog in a separate thread -

i have procedure extracts data database , populates list. want display progress dialog box while query executed, visually appears after query executed. believe have run progressdialog in separate thread, followed few suggestions , not make work.

so in activity have

private void displayallproductlistview(string sqlstatement) {                 progressdialog dialog =       progressdialog.show(myactivity.context, "loading", "please wait...", true);      //..................      //..................      //execute sql query here      dialog.dismiss();    } 

thanks

1.show process dialog in main thread

2.start new thread (such thread a) process heavy job

3.when done, use handler send message thread main thread, latter dismisses process dialog

code private processdialog pd;

private void startdialog() {   pd = progressdialog.show(mainactivity.this, "title", "loading");         //start new thread process job      new thread(new runnable() {            @override            public void run() {                //heavy job here              //send message main thread              handler.sendemptymessage(0);            }         }).start();  }  handler handler = new handler() {       @override       public void handlemessage(message msg) {         pd.dismiss();      }   };