Question

我在viewDidAppear中有一个动画，如下所示

-(void)viewDidAppear:(BOOL)animated
{
    for (int i = 0; i < 100; i++) {

        p = arc4random_uniform(320)%4+1; //global integer

        CGRect startFrame = CGRectMake(p*50, -50, 50, 50);
        CGRect endFrame   = CGRectMake(p*50, CGRectGetHeight(self.view.bounds) + 50,
                                       50,
                                       50);

        animatedView = [[UIView alloc] initWithFrame:startFrame];
        animatedView.backgroundColor = [UIColor redColor];

        [self.view addSubview:animatedView];

        [UIView animateWithDuration:2.f
                              delay:i * 0.5f
                            options:UIViewAnimationCurveLinear
                         animations:^{
                             animatedView.frame = endFrame;
                         } completion:^(BOOL finished) {
                             [animatedView removeFromSuperview];
                         }];
    }
}

它只是从屏幕顶部创建小方块并移动到底部。我还有一个UIImageView，它由x轴上的加速度计控制。目的不是触及动画对象。就像一场简单的比赛。但是我无法找到如何检测imageView和动画之间的碰撞？

Answer 1

首先，您需要将所有动画视图对象保存在数组中，以检查与图像视图的碰撞。所以你.h文件创建一个NSArray来保存动画视图

NSMutableArray animatedViews;

然后在viewDidLoad中初始化它

animatedViews = [[NSMutableArray alloc] init];

然后更改代码viewWillAppear并添加一行

[self.view addSubview:animatedView];
[animatedViews addObject:animatedView];

然后创建一个检查碰撞的函数，它需要一个参数用于计划的计时器

-(void) checkCollision: (NSTimer *) theTimer{
    for(int i = 0; i < [animatedViews count]; i++) {
        UIView *theView = [animatedViews objectAtIndex:index];
        if (CGRectIntersectsRect(theView.frame, yourImageView.frame) {
           // the image collided
           // stop the timer and do your work here
        }
    }
}

然后在viewWillAppear中添加此行来安排定时器每隔半秒调用一次以调用函数来检查碰撞

[NSTimer scheduledTimerWithTimeInterval: 0.5  
                             target: self  
                           selector: @selector(checkCollision:)  
                           userInfo: nil  
                            repeats: YES];

Answer 2

问题在于此测试：if (CGRectIntersectsRect(theView.frame, yourImageView.frame) 你必须检查视图的presentationLayer：

CGRect movingFrame = [[theImage.layer presentationLayer] frame];
    if (CGRectIntersectsRect(movingFrame, panier.frame)) {           
        // the image collided            
    }

iphone编程：UIImageView和动画的碰撞检测

2 个答案: