Android 进度条

<RelativeLayout 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="com.example.test12.MainActivity" >

   <Button 
       android:layout_width="wrap_content"
       android:layout_height="wrap_content"
       android:text="Button1"
       android:onClick="btn1Onclick"/>

</RelativeLayout>

package com.example.test12;

import android.support.v7.app.ActionBarActivity;
import android.app.ProgressDialog;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;

public class MainActivity extends ActionBarActivity {
	private final static  int Msg_PROGRESS=0x001;
	private final static  int Msg_FINISH=0x002;
	private ProgressDialog dlg;
	private Handler handler=new Handler(){
		public void handleMessage(Message msg) {
			switch (msg.what) {
			case Msg_PROGRESS:
				int progress=msg.arg1;
				dlg.setProgress(progress);
				break;
			case Msg_FINISH:
				dlg.dismiss();
				break;
			}
		};
	};
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		dlg=new ProgressDialog(this);
		dlg.setIcon(R.drawable.ic_launcher);
		dlg.setMessage("这是一个进度条");
		dlg.setTitle("进度条");
		dlg.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
	}

	public void btn1Onclick(View view){
		dlg.show();
		new Thread(){
			@Override
			public void run() {
				for(int i=0;i<100;i++){
					Message msg=handler.obtainMessage();
					msg.what=Msg_PROGRESS;
					msg.arg1=i;
					handler.sendMessage(msg);
					try {
						Thread.sleep(100);
					} catch (InterruptedException e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					}
					
				}
				handler.sendEmptyMessage(Msg_FINISH);
			}
		}.start();
	}
}