UIActivityIndicatorView的两种形式

用法一：只显示不停旋转的进度滚轮指示器。
//显示进度滚轮指示器
-(void)showWaiting {
 
progressInd=[[UIActivityIndicatorView alloc]initWithActivityIndicatorStyle:
 UIActivityIndicatorViewStyleWhiteLarge];
progressInd.center=CGPointMake(self.view.center.x,240);
[self.navigationController.view addSubview:progressInd];
[progressInd startAnimating];
}
//消除滚动轮指示器
-(void)hideWaiting 
{
[progressInd stopAnimating];
}

用法二：带有半透明背景的进度轮指示器。

 
//显示进度滚轮指示器
-(void)showWaiting:(UIView*)parent
{
 
    int width
= 32,
height = 32;
    
   CGRect frame= CGRectMake(100,200, 110,70)
;//[parent frame]; //[[UIScreenmainScreen] applicationFrame];
    int x
= frame.size.width;
    int y
= frame.size.height;
    
    frame = CGRectMake((x
- width) / 2,
(y - height) / 2,
width, height);
   UIActivityIndicatorView* progressInd =[[UIActivityIndicatorView alloc]initWithFrame:frame];
   [progressIndstartAnimating];
   progressInd.activityIndicatorViewStyle =UIActivityIndicatorViewStyleWhiteLarge;
    
frame = CGRectMake((x
-70)/2,
(y - height) / 2 +
height, 80, 20);
UILabel *waitingLable
=[[UILabel alloc] initWithFrame:frame];
waitingLable.text =@"Loading...";
waitingLable.textColor =[UIColor whiteColor];
waitingLable.font =[UIFont systemFontOfSize:15];
waitingLable.backgroundColor=
[UIColor clearColor];
 
    frame = CGRectMake(100, 200, 110, 70)
;//[parentframe];
    UIView *theView
= [[UIView alloc] initWithFrame:frame];
   theView.backgroundColor =[UIColor blackColor];
    theView.alpha = 0.7;
    
    [theView addSubview:progressInd];
[theView addSubview:waitingLable];
    
   [progressInd release];
[waitingLable release];
    
    [theView setTag:9999];
    [parent addSubview:theView];
    [theView release];
}

//消除滚动轮指示器
-(void)hideWaiting 
{
   [[self.viewviewWithTag:9999]removeFromSuperview];
}