Android SeekBar ไม่เลี่อนตามเวลาของเพลง ไม่แอคทีฟเวลาเริ่มกดฟังเพลง แต่เลี่อนไปตามเวลาที่ต้องการได้ปกติค่ะ

package com.example.relaxinglife;


import java.io.IOException;

import android.app.Activity;
import android.content.Context;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.os.Handler;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.view.Window;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.SeekBar;
import android.widget.SeekBar.OnSeekBarChangeListener;
import android.widget.TextView;

public class ForestActivity extends Activity implements View.OnClickListener{
	private final Button btn[] = new Button[6];
    private MediaPlayer mPlayer; 
    private Handler handler = new Handler();
	private SeekBar seekBar1;
    TextView txt1;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		
		// Full Screen
		requestWindowFeature(Window.FEATURE_NO_TITLE);
		getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
		WindowManager.LayoutParams.FLAG_FULLSCREEN);
		
		setContentView(R.layout.activity_forest);
		
		// call method ValumnControls()
		ValumnControls();
		
		// Variable
		btn[0] = (Button) findViewById(R.id.button1);	
		btn[1] = (Button) findViewById(R.id.button2);
		btn[2] = (Button) findViewById(R.id.button3);	
		btn[3] = (Button) findViewById(R.id.button4);		
		btn[4] = (Button) findViewById(R.id.button5);	
		btn[5] = (Button) findViewById(R.id.button6);		
		
		for (int i =0; i < btn.length; i++) {
			btn[i].setOnClickListener(this);
		}   	
	               	        
		
	        final Button btn7 = (Button) findViewById(R.id.button7); // Start
	        final Button btn8 = (Button) findViewById(R.id.button8); // Pause
	        final Button btn9 = (Button) findViewById(R.id.button9); // Stop
	        
	        
	        // Start
	        btn7.setOnClickListener(new View.OnClickListener() {
	            public void onClick(View v) {
	            	mPlayer.start();
	            	btn7.setEnabled(false);
	            	btn8.setEnabled(true);
	            	btn9.setEnabled(true);
	            }
	        });
	        
	        // Pause
	        btn8.setOnClickListener(new View.OnClickListener() {
	            public void onClick(View v) {
	            	mPlayer.pause();
	            	btn7.setEnabled(true);
	            	btn8.setEnabled(false);
	            	btn9.setEnabled(false);
	            }
	        });  
	        
	        // Stop
	        btn9.setOnClickListener(new View.OnClickListener() {
	            public void onClick(View v) {
	            	mPlayer.stop();
	            	btn7.setEnabled(true);
	            	btn8.setEnabled(false);
	            	btn9.setEnabled(false);
	            	try {
						mPlayer.prepare();
						mPlayer.seekTo(0);
					} catch (IllegalStateException e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					} catch (IOException e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					}
	            	
	            }
	        }); 
	     
	}
	
	
	public void onClick(View v){
		int resId = 0;
		switch (v.getId()) {
		case R.id.button1 :
			resId = R.raw.peaceful_forest;
			break;
		case R.id.button2 :
			resId = R.raw.theme_of_geffen;
			break;
		case R.id.button3 :
			resId = R.raw.theme_of_payon;
			break;
		case R.id.button4 :
			resId = R.raw.on_the_ground;
			break;
		case R.id.button5 :
			resId = R.raw.plateau;
			break;
		case R.id.button6 :
			resId = R.raw.streamside;
			break;
		}
		
		playSound(resId);
		
	}
	private void playSound(int position) {
	
		if (mPlayer != null) {
			mPlayer.stop();
			mPlayer.release();
		}
		mPlayer = MediaPlayer.create(this,position);
		mPlayer.start();
		
		  // seekBar1 Control media
        seekBar1 = (SeekBar)findViewById(R.id.seekBar1);
        seekBar1.setMax(mPlayer.getDuration());
        seekBar1.setOnTouchListener(new OnTouchListener() {
        	public boolean onTouch(View v, MotionEvent event) {
        		UpdateseekChange(v);
			return false; 
			}   
        	
		});       
		
		}
	
	private void UpdateseekChange(View v){
    	if(mPlayer.isPlaying()){
	    	SeekBar sb = (SeekBar)v;
	    	mPlayer.seekTo(sb.getProgress());
		}
    }
    
	 public void startPlayProgressUpdater() {
	    	seekBar1.setProgress(mPlayer.getCurrentPosition());

			if (mPlayer.isPlaying()) {
				Runnable notification = new Runnable() {
			        public void run() {
			        	startPlayProgressUpdater();
					}
			    };
			    handler.postDelayed(notification, 1000);
	    	}
	    } 
	 
	 @Override
	    protected void onDestroy() {
	   // TODO Auto-generated method stub
	     super.onDestroy();
	     if(mPlayer != null){
	    	 mPlayer.release();  
	     }
	    }

	
	  private void ValumnControls()
	    {
	        try
	        {
	        	SeekBar seekBar2 = (SeekBar)findViewById(R.id.seekBar2);
	        	final AudioManager audioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
	            seekBar2.setMax(audioManager
	                    .getStreamMaxVolume(AudioManager.STREAM_MUSIC));
	            seekBar2.setProgress(audioManager
	                    .getStreamVolume(AudioManager.STREAM_MUSIC));   


	            seekBar2.setOnSeekBarChangeListener(new OnSeekBarChangeListener() 
	            {
	                public void onStopTrackingTouch(SeekBar arg0) 
	                {
	                }

	                public void onStartTrackingTouch(SeekBar arg0) 
	                {
	                }

	                public void onProgressChanged(SeekBar arg0, int progress, boolean arg2) 
	                {
	                    audioManager.setStreamVolume(AudioManager.STREAM_MUSIC,
	                            progress, 0);
	                }
	            });
	        }
	        catch (Exception e) 
	        {
	            e.printStackTrace();
	        }
	    }}