我想在 3 个 ImageView 中背靠背做连续动画我使用了下面的代码，但它只在第一个 ImageView 中显示动画。我调试代码，它会进入方法，但它不会在剩余的中显示任何动画.下面是我的代码

-(void)imageNewsAnimation
{
    [UIView animateWithDuration:0.35f animations:^{
        _imgNews.animationImages=arrnews;
        _imgNews.animationDuration=1;
        _imgNews.animationRepeatCount=1;
        _imgNews.image = [_imgNews.animationImages lastObject];
        [_imgNews startAnimating];

    } completion:^(BOOL finished) {
        [_imgNews stopAnimating];
        [self imageEventAnimation];
    } ];
}

-(void)imageEventAnimation
{
    [UIView animateWithDuration:0.35f delay:0.0 options:UIViewAnimationOptionBeginFromCurrentState animations:^{
        _imgEvents.animationImages=arrEvents;
        _imgEvents.animationDuration=1;
        _imgEvents.animationRepeatCount=1;
        _imgEvents.image = [_imgEvents.animationImages lastObject];
        [_imgEvents startAnimating];


    } completion:^(BOOL finished) {
        [self imageDirectoryAnimation];
    } ];

}
-(void)imageDirectoryAnimation
{
    [UIView animateWithDuration:0.35f animations:^{
        _imgDirectory.animationImages=arrdir;
        _imgDirectory.animationDuration=1;
        _imgDirectory.animationRepeatCount=1;
        _imgDirectory.image = [_imgDirectory.animationImages lastObject];
        [_imgDirectory startAnimating];
    } completion:^(BOOL finished) {
        [self imageInfoAnimation];
    } ];

}

-(void)imageInfoAnimation
{
    [UIView animateWithDuration:0.35f animations:^{
        _imgInfo.animationImages=arrinfo;
        _imgInfo.animationDuration=1;
        _imgInfo.animationRepeatCount=1;
        _imgInfo.image = [_imgInfo.animationImages lastObject];
        [_imgInfo startAnimating];
    } completion:^(BOOL finished) {
        [self imageDirectoryAnimation];
    } ];

}

最佳答案

因为 startAnimating 没有完成处理程序，我会设置如下:

CycleImageView.h

#import <UIKit/UIKit.h>

typedef void (^CycleCompletion)(BOOL finished);

@interface CycleImageView : UIImageView

- (void)startAnimatingWithImages:(NSArray<UIImage *>*)images completion:(CycleCompletion)completion;

@end

CycleImageView.m

#import "CycleImageView.h"

@interface CycleImageView()
@property (nonatomic, copy) CycleCompletion completion;
@end

@implementation CycleImageView

- (void)startAnimatingWithImages:(NSArray<UIImage *>*)images completion:(CycleCompletion)completion {
    self.completion = completion;

    NSMutableArray *imageRefs = [NSMutableArray array];
    for (NSInteger i = 0; i < images.count; i++) {
        [imageRefs addObject:(id)images[i].CGImage];
    }

    CAKeyframeAnimation *animation = [CAKeyframeAnimation animationWithKeyPath:@"contents"];
    animation.delegate = self;
    animation.calculationMode = kCAAnimationDiscrete;
    animation.duration = 1;
    animation.values = imageRefs;
    animation.repeatCount = 1;
    animation.removedOnCompletion = NO;
    animation.fillMode = kCAFillModeForwards;
    [self.layer addAnimation:animation forKey:@"animation"];
}

- (void)animationDidStop:(CAAnimation *)anim finished:(BOOL)flag {
    if (self.completion != nil) {
        self.completion(flag);
        self.completion = nil;
    }
}

@end

使用方法:

使 imgNews、imgEvents、imgDirectory 和 imgInfo 成为 CycleImageView 的所有子类。然后，使用您提供的方法和变量，实现将更改为:

- (void)imageNewsAnimation {
    [_imgNews startAnimatingWithImages:arrnews completion:^(BOOL finished) {
       if (finished) {
           [self imageEventAnimation];
       } 
    }];
}

- (void)imageEventAnimation {
    [_imgEvent startAnimatingWithImages:arrEvents completion:^(BOOL finished) {
       if (finished) {
           [self imageDirectoryAnimation];
       } 
    }];
}

- (void)imageDirectoryAnimation {
    [_imgDirectory startAnimatingWithImages:arrdir completion:^(BOOL finished) {
       if (finished) {
           [self imageInfoAnimation];
       } 
    }];
}

- (void)imageInfoAnimation {
    [_imgInfo startAnimatingWithImages:arrinfo completion:^(BOOL finished) {
       if (finished) {
           // NOTE: Are you intentionally creating this indefinite animation loop?
           [self imageDirectoryAnimation];
       } 
    }];
}

编辑:

创建了一个 gist对于 CycleImageView，也是如此。

关于ios - 动画在 objective-c 中的一个完成后背靠背，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/37020573/