UIActivityIndicatorView的使用

UIActivityIndicatorView 解释：菊花进度条

@property (weak, nonatomic) IBOutlet UIActivityIndicatorView *chrysanthemum;

- (void)viewDidLoad {
//首先隐藏，待有相应时再显示
[self.chrysanthemum setHidden:YES];
}
//我们假设点击按钮1时出现进度条，开始转圈圈，点击按钮2时停止进度条
//按钮1
- (IBAction)onClickPictureChange:(id)sender
{
//显示
[self.chrysanthemum setHidden:NO];
//开始旋转动画
[self.chrysanthemum  startAnimating];
}
//按钮2
- (IBAction)stopAnimating:(id)sender
{
//停止旋转动画
[self.chrysanthemum  stopAnimating];
}