如何使用iPhone SDK无限旋转360度图像？

Question

我想使用iPhone SDK将图像无限旋转360度吗？

如何才能做到这一点？

谢谢！

Answer 1

-(void)startAnimationWithRevolutions:(float)revPerSecond forTime:(float)time
{
    spinWheel.userInteractionEnabled = FALSE;
    float totalRevolutions = revPerSecond * time;
    [CATransaction begin];
    [CATransaction setValue:[NSNumber numberWithFloat:time] forKey:kCATransactionAnimationDuration];

    CABasicAnimation* spinAnimation = [CABasicAnimation
                                       animationWithKeyPath:@"transform.rotation"];
    CGAffineTransform transform = spinWheel.transform;
    float fromAngle = atan2(transform.b, transform.a);
    float toAngle = fromAngle + (totalRevolutions*4*M_PI);
    spinAnimation.fromValue = [NSNumber numberWithFloat:fromAngle];
    spinAnimation.toValue = [NSNumber numberWithFloat:toAngle];
    spinAnimation.repeatCount = 0;
    spinAnimation.removedOnCompletion = NO;
    spinAnimation.delegate = self;
    spinAnimation.timingFunction = [CAMediaTimingFunction functionWithName:
                                    kCAMediaTimingFunctionEaseOut];
    [spinWheel.layer addAnimation:spinAnimation forKey:@"spinAnimation"];
    [CATransaction commit];
}

尝试使用它，它起作用。

Answer 2

假设您正在UIImageView中显示图像，则可以旋转视图的局部坐标系（请参阅此处 ），并使用NSTimer定期增加旋转（请参见此处 ）。

（我会为此使用OpenGL，但这只是个人喜好，可能对您的情况有些过分。）