I want childview of a layout to change in auto with the mediaplayer currentposition

I have created a viewflipper vf1 having 9 childview.

onclick method of button B5 create a thread which update the value of mediaplayercurrent position. I want to change child view of a linear layout in auto with the current postion of the mediaplayer, but if statement is not working.

B5.setOnClickListener(new View.OnClickListener(){         
    public void onClick(View v){            

        if(B5.isChecked()){         


     new Thread(new Runnable() {

             public void run() {
                 while(mediaPlayer!=null&&j<mediaPlayer.getDuration()){
                     try {
                         Thread.sleep(1000);
                         j= mediaPlayer.getCurrentPosition();


                         if((j>2000)&&开发者_如何学编程;(j<43000))
                        {vf1.setDisplayedChild(4);}
                    if((j>43000)&&(j<72000))
                        {vf1.setDisplayedChild(1);}
                    if((j>72000)&&(j<101000))
                    {vf1.setDisplayedChild(2);}
                    if((j>101000)&&(j<130000))
                    {vf1.setDisplayedChild(3);}
                    if((j>130000)&&(j<160000))
                    {vf1.setDisplayedChild(4);}
                    if((j>160000)&&(j<189000))
                    {vf1.setDisplayedChild(5);}
                    if((j>189000)&&(j<220000))
                    {vf1.setDisplayedChild(6);}
                    if((j>220000)&&(j<251000))
                    {vf1.setDisplayedChild(7);}
                    if((j>251000)&&(j<280000))
                    {vf1.setDisplayedChild(8);}
                    if((j>280000))
                    {vf1.setDisplayedChild(0);} 


                     } catch (InterruptedException e) {
                         return;
                     } catch (Exception e){
                         return ;
                     }            

                 }
             }
           }).start();



        }




        }});

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i got the clue, i did it by using main runonUIthread