objective-c - 在 View 的不同位置随机生成动画

Question

您好，我是动画新手，最近才开始玩弄它。我想要显示一个圆圈(圆环)，它从一个小圆环变成一个大圆环，然后消失，然后重新开始这个过程，除了在不同的位置。

为此，我为同一枚戒指制作了 6 种不同尺寸的图像。以下代码是我如何完成的，但我不知道如何重复该过程(也就是它运行该方法但环的位置保持不变，我需要循环随机数生成器但不知道何时检查图像是否已停止)。如果这不是解决此问题的正确方法，请告诉我!附言当它到达最大阶段时，戒指看起来非常丑陋，不知道为什么。

谢谢

-(void) doWork
{

NSInteger number;
NSInteger number2;
NSLog (@"here");

number = (arc4random()%100)+1; 
number2 = (arc4random()%100)+1; 
 NSLog (@" hello numer1: %d", number);
 NSLog (@" hello numer2: %d", number2);

imageView = [[UIImageView alloc] initWithFrame:CGRectMake(number, number2, 135, 135)]; 

imageView.animationImages= [NSArray arrayWithObjects:
                            [UIImage imageNamed:@"smallestRing.png"],
                            [UIImage imageNamed:@"smallRing.png"], 
                            [UIImage imageNamed:@"mediumRing.png"],
                            [UIImage imageNamed:@"large2Ring.png"],
                            [UIImage imageNamed:@"largeRing.png"], nil]; 

imageView.animationDuration= 2.5;
imageView.animationRepeatCount= 0;
imageView.contentMode = UIViewContentModeScaleAspectFit;

[imageView startAnimating];
[self.view addSubview:imageView];

/*[NSTimer scheduledTimerWithTimeInterval:5 target:self selector:@selector(doWork) userInfo:nil repeats:YES];*/

}

Answer 1

如果调整大小(或其他变换，如旋转或过渡)是您唯一需要的动画，您可以使用方法 +animateWithDuration(您可以找到描述 here)

它看起来像:

-(void) doWork
{

NSInteger number;
NSInteger number2;
NSLog (@"here");

number = (arc4random()%100)+1; 
number2 = (arc4random()%100)+1; 
 NSLog (@" hello numer1: %d", number);
 NSLog (@" hello numer2: %d", number2);

imageView = [[UIImageView alloc] initWithFrame:CGRectMake(number, number2, 135, 135)]; 

imageView.image = [UIImage imageNamed:@"largeRing.png"];
[self.view addSubview:imageView];

[self animate:imageView enlarge:YES];
}

-(void) animate:(UIImageView*)imageView enlarge:(BOOL)flag
{
if (flag) 
{
// then animating is starting
// and imageView will appear in random point of view
    int randomX = arc4random()%self.view.frame.size.width;
    int randomY = arc4random()%self.view.frame.size.height;
    imageView.center = CGPointMake(randomX, randomY);
}

double scale = flag ? 2 : 0.5;
[UIView animateWithDuration:5
         animations:^{ imageView.transform = CGAffineTransformMakeScale(scale,scale); }
         completion:^(BOOL finished){ [self animate:imageView: enlarge:!flag]; }];
}