UIActivityIndicatorView的应用

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 {

intwidth=32,height=32;CGRect frame = CGRectMake(100,200,110,70) ;//[parent frame]; //[[UIScreen mainScreen] applicationFrame];intx = frame.size.width;inty = frame.size.height;frame = CGRectMake((x -width) /2, (y -height) /2,width,height);UIActivityIndicatorView* progressInd = [[UIActivityIndicatorView alloc]initWithFrame:frame];[progressInd startAnimating];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) ;//[parent frame];UIView*theView = [[UIViewalloc] initWithFrame:frame];theView.backgroundColor= [UIColorblackColor];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.view viewWithTag:9999] removeFromSuperview];

}

另一种实现

UIActivityIndicatorView *activityView = [[[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge] autorelease];

activityView.frame = CGRectMake(139.0f-18.0f, 50.0f, 37.0f, 37.0f);

[self.loadingView addSubview:activityView];

[activityView startAnimating];

activityView.center = self.loadingView.center;

[activityView stopAnimating];