Android如何使代码等待一段时间再执行？直接贴程序麻烦高人来看一下。

package com.artifex.mupdfdemo;

import android.app.Activity;

import android.content.Intent;

import android.net.Uri;

import android.os.Bundle;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import com.example.down.HttpDownloader;



public class MainActivity extends Activity {

   private Button mybut=null;

   public void onCreate(Bundle savedInstanceState)

   {

	   super.onCreate(savedInstanceState);

	   setContentView(R.layout.buttonpdf);

	   this.mybut=(Button)super.findViewById(R.id.but);

	   mybut.setOnClickListener(new Show());

	   }

	   

	   public class Show implements OnClickListener{

	   public void onClick(View v)

	   {

		   new Thread()

		   {

		   public void run()

		   {

		   try

		   {

		   HttpDownloader httpDownloader=new HttpDownloader();

		   int result=httpDownloader.download("http://222.26.7.82:8081/PDF/test.pdf","ckpdf/","test.pdf");

		   System.out.println(result);

		   }

		   catch(Exception e)

		   {

		   e.printStackTrace();

		   }

		   }

		   }.start();

		   

		   

		   Uri uri = Uri.parse("file://mnt/sdcard/ckpdf/test.pdf");  

		   Intent intent = new Intent(MainActivity.this,MuPDFActivity.class);  

		   intent.setAction(Intent.ACTION_VIEW);  

		   intent.setData(uri);  

		   startActivity(intent);  }

	   }

}