Android 进度条显示在标题栏的实现方法

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="horizontal" android:layout_width="fill_parent" android:layout_height="wrap_content" ><Button android:id="@+id/button1"   android:layout_width="wrap_content"  android:layout_height="wrap_content"  android:text=" 显示"/><Button android:id="@+id/button2"  android:layout_width="wrap_content"  android:layout_height="wrap_content"  android:text="隐藏"/></LinearLayout>

package com.imooc.progressbarr;import android.os.Bundle;import android.app.Activity;import android.view.Menu;import android.view.View;import android.view.View.OnClickListener;import android.view.Window;import android.widget.Button;public class MainActivity extends Activity { private Button btn1; private Button btn2; @Override protected void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  //设置窗口特征：启用显示进度的进度条  requestWindowFeature(Window.FEATURE_PROGRESS);   //设置窗口特征：启用不显示进度的进度条  requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);  setContentView(R.layout.activity_main);  Button btn1=(Button)findViewById(R.id.button1);  Button btn2=(Button)findViewById(R.id.button2);  btn1.setOnClickListener(new OnClickListener(){   @Override   public void onClick(View v) {    // TODO Auto-generated method stub    //显示不带进度的进度条    setProgressBarIndeterminateVisibility(true);    //显示不带进度的进度条    setProgressBarVisibility(true);    //设置进度条的进度    setProgress(4500);   }   });  btn2.setOnClickListener(new OnClickListener(){   @Override   public void onClick(View v) {    // TODO Auto-generated method stub    //隐藏不带进度的进度条    setProgressBarIndeterminateVisibility(false);    //隐藏带进度的进度条    setProgressBarVisibility(false);   }   }); } @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; }}