Android&Handler2

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" 
    android:orientation="vertical">

    <TextView
        android:id="@+id/myTextView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />
    <ProgressBar
        android:id="@+id/bar"
        android:layout_width="200dp"
        android:layout_height="40dp"
        style="?android:attr/progressBarStyleHorizontal"
        android:visibility="gone"
        android:max="100"
        android:layout_gravity="center_vertical"
        />
    <Button
        android:id="@+id/startButton"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Start"
        />
    <Button
        android:id="@+id/endButton"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="End"
        />"
</LinearLayout>

package com.example.handleactivity;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ProgressBar;

public class MainActivity extends Activity {

    private Button startButton = null;
    private Button endButton = null;
    private ProgressBar bar = null;
    private MyHandler myHandler = new MyHandler();
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        startButton = (Button)findViewById(R.id.startButton);
        endButton = (Button)findViewById(R.id.endButton);
        bar = (ProgressBar)findViewById(R.id.bar);
        
        startButton.setOnClickListener(new OnClickListener(){

            @Override
            public void onClick(View arg0) {
                // TODO Auto-generated method stub
                bar.setVisibility(View.VISIBLE);
                myHandler.post(myThread);
            }
            
        });
        
        endButton.setOnClickListener(new OnClickListener(){

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                myHandler.removeCallbacks(myThread);
            }
            
        });
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
    
    class MyHandler extends Handler{

        public void handleMessage(Message msg) {
            // TODO Auto-generated method stub
            super.handleMessage(msg);
            bar.setProgress(msg.arg1);
            this.post(myThread);
        }
        
    }
    Runnable myThread = new Runnable(){
        private int count = 0;
        @Override
        public void run() {
            // TODO Auto-generated method stub
            if(count<100){
                count += 10;
            Message msg = myHandler.obtainMessage();
            msg.arg1 = count;
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            myHandler.sendMessage(msg);
            }
            else{
                myHandler.removeCallbacks(this);
            }
        }
        
        
    };
    
}