實現(xiàn)代碼

self.activityIndicatorView=[[UIActivityIndicatorView alloc]initWithFrame:CGRectMake(0, 0, 100, 100)];
    self.activityIndicatorView.center=self.view.center;
//設(shè)置樣式
    [self.activityIndicatorView setActivityIndicatorViewStyle:UIActivityIndicatorViewStyleGray];
    [self.activityIndicatorView setActivityIndicatorViewStyle:UIActivityIndicatorViewStyleWhiteLarge];
    [self.activityIndicatorView setBackgroundColor:[UIColor lightGrayColor]];
    [self.view addSubview:self.activityIndicatorView];
//開始動畫
    [self.activityIndicatorView startAnimating];

關(guān)于style的設(shè)置，有三種白色和灰色，這兩種的尺寸都是20*20，白色大圖是37*37:

typedef NS_ENUM(NSInteger, UIActivityIndicatorViewStyle) {
    UIActivityIndicatorViewStyleWhiteLarge,
    UIActivityIndicatorViewStyleWhite,
    UIActivityIndicatorViewStyleGray,
};

關(guān)閉動畫

dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(5* NSEC_PER_SEC)), dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0),^{
        [self.activityIndicatorView stopAnimating];
    });