Xcode 图像旋转 toValue 和 fromValue

Question

我想在按下按钮时将图像旋转 190 度。这是可行的，但是当我再次按下按钮时，动画需要从上次结束的地方开始，而不是从 0 开始。所以每次我按下按钮时，动画都需要旋转 190 度。

每次它都从 0 开始，因为我的 fromValue 设置为 0。

有人知道我如何使 fromValue 从我的图像结束处开始。我的代码在下面。

- (IBAction)buttonPressed
{ 
    CABasicAnimation *imageRotation = [CABasicAnimation animationWithKeyPath:@"transform.rotation"];

    imageRotation.fromValue = [NSNumber numberWithFloat:0];
    imageRotation.toValue = [NSNumber numberWithFloat:((190*M_PI)/ -180)];

    imageRotation.duration = 1.5;
    imageRotation.repeatCount = 1;

    imageRotation.removedOnCompletion = NO;
    imageRotation.autoreverses=NO;
    imageRotation.fillMode = kCAFillModeForwards;

    [image.layer addAnimation:imageRotation forKey:@"imageRotation"];
}

Answer 1

感谢您的回答，但这就是我的做法。希望人们可以使用这个：D

我的 .h 文件看起来像这样：

#import <UIKit/UIKit.h>
#import <QuartzCore/QuartzCore.h>

@interface testViewController : UIViewController {
   IBOutlet UIImageView *image;
   NSObject *lastValue;
}

- (IBAction)buttonPressed;

@property(nonatomic, retain) IBOutlet NSObject *lastValue;

@end

我的 .m 文件看起来像这样：

@synthesize lastValue;

- (void)viewAnimation0 
{
   CABasicAnimation *imageRotation = [CABasicAnimation animationWithKeyPath:@"transform.rotation"];

   imageRotation.fromValue = lastValue;
   imageRotation.toValue = [NSNumber numberWithFloat:((30*M_PI)/ -180)];
   lastValue = imageRotation.toValue;

   imageRotation.duration = 1.5;
   imageRotation.repeatCount = 1;

   imageRotation.removedOnCompletion = NO;
   imageRotation.autoreverses=NO;
   imageRotation.fillMode = kCAFillModeForwards;

   [image.layer addAnimation:imageRotation forKey:@"imageRotation"];
}

- (void)viewAnimation1 
{
   CABasicAnimation *imageRotation = [CABasicAnimation animationWithKeyPath:@"transform.rotation"];

   imageRotation.fromValue = lastValue;
   imageRotation.toValue = [NSNumber numberWithFloat:((60*M_PI)/ -180)];
   lastValue = imageRotation.toValue;

   imageRotation.duration = 1.5;
   imageRotation.repeatCount = 1;

   imageRotation.removedOnCompletion = NO;
   imageRotation.autoreverses=NO;
   imageRotation.fillMode = kCAFillModeForwards;

   [image.layer addAnimation:imageRotation forKey:@"imageRotation"];
}

- (void)viewAnimation2 
{
   CABasicAnimation *imageRotation = [CABasicAnimation animationWithKeyPath:@"transform.rotation"];

   imageRotation.fromValue = lastValue;
   imageRotation.toValue = [NSNumber numberWithFloat:((90*M_PI)/ -180)];
   lastValue = imageRotation.toValue;

   imageRotation.duration = 1.5;
   imageRotation.repeatCount = 1;

   imageRotation.removedOnCompletion = NO;
   imageRotation.autoreverses=NO;
   imageRotation.fillMode = kCAFillModeForwards;

   [image.layer addAnimation:imageRotation forKey:@"imageRotation"];
}

- (IBAction)buttonPressed 
{
   static int counter = 0;
   switch (++counter) {

    case 1:
        [self viewAnimation1];
        break;

    case 2:
        [self viewAnimation2];
        break;

    default:
        [self viewAnimation0];
        counter = 0;
        break;
   }
   //    animateButton.enabled = NO;
} 

Answer 2

您需要做两件事：您需要实际设置图层的旋转（而不是设置removedOnCompletion = NO），并且您不需要设置fromValue。

- (IBAction)buttonPressed
{
    CABasicAnimation *imageRotation = [CABasicAnimation animationWithKeyPath:@"transform.rotation"];

    imageRotation.toValue = [NSNumber numberWithFloat:((190*M_PI)/ -180)];

    imageRotation.duration = 1.5;
    imageRotation.repeatCount = 1;

    [image.layer setValue:imageRotation.toValue forKey:imageRotation.keyPath];
    [image.layer addAnimation:imageRotation forKey:@"imageRotation"];
}

观看 WWDC 2011 中的核心动画要点视频来了解为什么您需要设置图层的属性而不是设置removedOnCompletion = NO。