xcode iphone球动画

Question

我想要做的是每十秒钟在屏幕外创建一个球，创建它时移动到屏幕中心。我怎样才能做到这一点？

Answer 1

在您的视图控制器设置了一个UIImageView属性为你的球，contruct球并确保它的起始位置远离creen的可视区域，然后使用一个NSTimer它将触发每十秒这卡拉斯一方法将屏幕上的球移动到中心。

-(void)viewDidLoad{ 
    NSTimer *ballTimer = [NSTimer timerWithTimeInterval:10.0 
               target:self 
               selector:@selector(moveBall) 
               userInfo:nil 
               repeats:YES]; 

    [[NSRunLoop mainRunLoop] addTimer:ballTimer forMode:NSRunLoopCommonModes]; 

    myBall = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"MyBallImageFile.png"]]; 
    myBall.center = CGPointMake(320/2, [self randNumBetween:-50:-100]); 
    [self.view addSubview:myBall]; 
} 

-(void)moveBall{ 
    myBall.center = CGPointMake(320/2, [self randNumBetween:-50:-100]); 
    [UIView animateWithDuration:5.0 animations:^{ 
     myBall.center = CGPointMake(320/2, 480/2); 
    }]; 
} 

---------- ------------编辑

- (CGFloat)randNumBetween:(CGFloat) min :(CGFloat) max{ 
    CGFloat difference = max - min; 
    return (((CGFloat) rand()/(CGFloat)RAND_MAX) * difference) + min; 
} 

Answer 2

- (void)viewDidLoad { 
    [super viewDidLoad]; 

    myBallImage = [[UIImage imageNamed:@"ball.png"] retain]; 
    myTimer = [NSTimer scheduledTimerWithTimeInterval:10.0 target:self selector:@selector(addBallToScreen) userInfo:nil repeats:YES]; 
} 
- (void)viewDidUnload { 
    [myBallImage release]; 
    [myTimer invalidate]; 
} 

- (void)addBallToScreen { 
    //Create the imageView 
    UIImageView *imageView = [[UIImageView alloc] initWithImage:myBallImage]; 
    imageView.transform = CGAffineTransformMakeTranslation(1000, 1000); 
    [self.view addSubview:imageView]; 
    [imageView release]; 

    //Animate the image view 
    [UIView beginAnimations:nil context:nil]; 
    imageView.transform = CGAffineTransformMakeTranslation(50, 50); 
    [UIView commitAnimations]; 
}