Android标题栏(titlebar)显示进度条

protected void onCreate(Bundle savedInstanceState) {  
super.onCreate(savedInstanceState);  
requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);//先给Activity注册界面进度条功能  
setContentView(R.layout.main);  
setProgressBarIndeterminateVisibility(true);//在需要显示进度条的时候调用这个方法  
setProgressBarIndeterminateVisibility(false);//在不需要显示进度条的时候调用这个方法