xcode iphone球動畫

Question

我想要做的是每十秒鐘在屏幕外創建一個球，創建它時移動到屏幕中心。我怎樣才能做到這一點？

Answer 1

在您的視圖控制器設置了一個UIImageView屬性爲你的球，contruct球並確保它的起始位置遠離creen的可視區域，然後使用一個NSTimer它將觸發每十秒這卡拉斯一方法將屏幕上的球移動到中心。

-(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); 
    }]; 
} 

---------- ------------編輯

- (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]; 
}