iOS中动画理解

 1     UIImageView *imageView1 = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"page1.png"]];
 2     imageView1.backgroundColor = [UIColor redColor];
 3     imageView1.frame = CGRectMake(0, 0, 100, 200);
 4     [self.view addSubview:imageView1];
 5     
 6     [UIImageView beginAnimations:@"test" context:nil];
 7     [UIImageView setAnimationDuration:1];
 8     
 9     imageView1.image = [UIImage imageNamed:@"page2"];
10     imageView1.backgroundColor = [UIColor yellowColor];
11     imageView1.frame = CGRectMake(100, 200, 100, 200);
12     imageView1.alpha = 0.5;
13     [UIImageView commitAnimations];

 1     UIImageView * imageView2 = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"page2.png"]];
 2     imageView2.frame = CGRectMake(0, 0, 100, 200);
 3     [self.view addSubview:imageView2];
 4     [UIImageView animateWithDuration:1.0f delay:1.0f options:UIViewAnimationOptionAllowAnimatedContent animations:^{
 5         imageView2.image = [UIImage imageNamed:@"page1"];
 6         imageView2.frame = CGRectMake(100, 200, 100, 200);
 7         imageView2.alpha = 0.1f;
 8     } completion:^(BOOL finished) {         //动画结束的时候在的位置;
 9         imageView2.frame = CGRectMake(100, 0, 100, 200);
10         imageView2.alpha = 1.0f;
11     }];