164检测屏幕中动画的状态

效果如下：

ViewController.h

1 #import <UIKit/UIKit.h>
2 
3 @interface ViewController : UIViewController
4 @property (strong, nonatomic) UIImageView *imgVAnimation;
5 
6 @end

ViewController.m

 1 #import "ViewController.h"
 2 
 3 @interface ViewController ()
 4 - (void)layoutUI;
 5 - (void)startAnimation;
 6 - (void)animationWillStart:(NSString *)animationID context:(void *)context;
 7 - (void)animationDidStop:(NSString *)animationID finished:(NSNumber *)finished context:(void *)context;
 8 @end
 9 
10 @implementation ViewController
11 
12 - (void)viewDidLoad {
13     [super viewDidLoad];
14     
15     [self layoutUI];
16 }
17 
18 - (void)didReceiveMemoryWarning {
19     [super didReceiveMemoryWarning];
20     // Dispose of any resources that can be recreated.
21 }
22 
23 - (void)layoutUI {
24     self.view.backgroundColor = [UIColor blackColor];
25     
26     _imgVAnimation = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"ImageForAnimation"]];
27     _imgVAnimation.center = CGPointMake(self.view.center.x, 100);
28     [self.view addSubview:_imgVAnimation];
29 }
30 
31 - (void)viewWillAppear:(BOOL)animated {
32     [super viewWillAppear:animated];
33     
34     [self startAnimation];
35 }
36 
37 - (void)startAnimation {
38     _imgVAnimation.center = CGPointMake(self.view.center.x, 100);
39     _imgVAnimation.alpha = 1.0;
40     _imgVAnimation.transform = CGAffineTransformIdentity;
41     
42     [UIView beginAnimations:nil context:NULL];
43     [UIView setAnimationCurve:UIViewAnimationCurveEaseInOut]; //设置动画弧度；默认值为UIViewAnimationCurveEaseInOut
44     [UIView setAnimationDuration:2.0];
45     [UIView setAnimationRepeatCount:1.0]; //设置动画播放重复次数；默认值为0，表示不循环只执行一次（区别于UIImageView.animationRepeatCount=0为无限循环）
46     [UIView setAnimationRepeatAutoreverses:YES]; //设置自动倒退，即动画回放；默认值为NO，只在动画起码执行一次的情况下有效
47     [UIView setAnimationDelegate:self];
48     [UIView setAnimationWillStartSelector:@selector(animationWillStart:context:)]; //设置动画将开始时执行委托方法；在设置好委托前提下，默认就是绑定animationWillStart:context:
49     [UIView setAnimationDidStopSelector:@selector(animationDidStop:finished:context:)]; //设置动画结束后执行委托方法；在设置好委托前提下，默认就是绑定animationDidStop:finished:context:
50     
51     _imgVAnimation.center = CGPointMake(self.view.center.x, 300);
52     _imgVAnimation.alpha = 0.2;
53     //设置放大和旋转
54     CGAffineTransform transformScale = CGAffineTransformScale(CGAffineTransformIdentity, 3, 3);
55     CGAffineTransform transformRotate = CGAffineTransformRotate(CGAffineTransformIdentity, M_PI); //M_PI表示180度
56     _imgVAnimation.transform = CGAffineTransformConcat(transformScale, transformRotate);
57     
58     [UIView commitAnimations];
59 }
60 
61 - (void)animationWillStart:(NSString *)animationID context:(void *)context {
62     static BOOL isFirstTime = YES;
63     if (isFirstTime) {
64         UIAlertView *alertVAnimation = [[UIAlertView alloc] initWithTitle:@"提示信息"
65                                                                   message:@"开始动画了"
66                                                                  delegate:nil
67                                                         cancelButtonTitle:nil
68                                                         otherButtonTitles:@"确定", nil];
69         [alertVAnimation show];
70         
71         isFirstTime = NO;
72     }
73 }
74 
75 - (void)animationDidStop:(NSString *)animationID finished:(NSNumber *)finished context:(void *)context {
76     //如果动画正常结束时（非强制取消），就再次开始动画
77     if ([finished boolValue]) {
78         [self startAnimation];
79     }
80 }
81 
82 @end