ProgressDialog实现

package com.example.progressbar;import java.io.IOException;import android.os.Bundle;import android.app.Activity;import android.app.ProgressDialog;import android.view.Menu;import android.view.View;import android.widget.Button;public class MainActivity extends Activity {    private Button btn;    private ProgressDialog pg;@Overrideprotected void onCreate(Bundle savedInstanceState){super.onCreate(savedInstanceState);setContentView(R.layout.main);btn=(Button)findViewById(R.id.b1);btn.setOnClickListener(new Button.OnClickListener(){public void onClick(View view){final CharSequence Body="Please wait for a moment";final CharSequence Title="Progress Bar";pg=ProgressDialog.show(MainActivity.this, Title, Body);new Thread(){public void run(){try{sleep(3000);}catch(Exception e){e.printStackTrace();}finally{pg.dismiss();}}}.start();}});}@Overridepublic 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;}}