iOS UIActivityIndicatorView的简单使用

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{    self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];    // Override point for customization after application launch.    self.window.backgroundColor = [UIColor grayColor];        UIActivityIndicatorView *activityView=[[UIActivityIndicatorView alloc]initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];    activityView.frame=CGRectMake(60, 130, 200, 200);//其大小不变//    activityView.center=CGPointMake(160, 230);    [activityView startAnimating];        [self.window addSubview:activityView];    [activityView release];        [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(updateInfo:) userInfo:activityView repeats:NO];    //设置通知栏的ActivityIndicator     [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:YES];        [self.window makeKeyAndVisible];    return YES;}-(void)updateInfo:(NSTimer *)timer{    [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:NO];    //获取    UIActivityIndicatorView *activityView=[timer userInfo];    //停止    [activityView stopAnimating];    //从父视图移除//    [activityView removeFromSuperview];    }