Question

我想按下按钮时将图像旋转190度。这有效，但是当我再次按下按钮时，动画需要从最后结束的地方开始，而不是从0开始。所以每次按下按钮，动画都需要转动190度。

每次从0开始因为我的fromValue被设置为0。

有人知道我如何在我的图像结束时使fromValue开始。我的代码在这里。

- (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，但这是我如何做到的。希望人们可以使用这个：D

我的.h文件如下所示：

#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文件如下所示：

@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"];
}

观看来自WWDC 2011的 Core Animation Essentials 视频，了解您需要设置图层属性的原因，而不是设置removedOnCompletion = NO。

Xcode图像旋转toValue和fromValue

2 个答案: