IOS---UIActivityIndicatorView

1.在.h文件里面声明

#import <UIKit/UIKit.h>

@interface ViewController :
UIViewController
{

UIActivityIndicatorView * activityView;

}
- (IBAction)onClicked:(id)sender;

@end

2.在.m文件里面实现

#import "ViewController.h"

@interface
ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {

[super
viewDidLoad];

// Do any additional setup after loading the view, typically from a nib.

activityView=[[UIActivityIndicatorView
alloc] initWithFrame:CGRectMake(50,
50,
30, 30)];

[activityView
setCenter:CGPointMake(160,
140)];

[activityView
setActivityIndicatorViewStyle:UIActivityIndicatorViewStyleGray];

[self.view
addSubview:activityView];

[activityView
startAnimating];

}

- (void)didReceiveMemoryWarning {

[super
didReceiveMemoryWarning];

// Dispose of any resources that can be recreated.
}

- (IBAction)onClicked:(id)sender {

[activityView
stopAnimating];
}

@end
startAnimating 开启方法

stopAnimating停止方法