iOS 14 YYAnimatedImageView加载图片失败的原因主要是：iOS 14下UIKit对 displayLayer:的处理机制有所变化。displayLayer:是CALayerDelegate的代理方法。在iOS 14之前，UIKit在调用这个方法之前就会去渲染UIImageView.image。
而在iOS 14，UIKit则是先去调用代理方法，如果你实现了displayLayer:这个方法，那么UIKit就不会再去渲染了。

解决办法

方法一

- (void)displayLayer:(CALayer *)layer {
    UIImage *currentFrame = _curFrame;
    if (currentFrame) {
        layer.contentsScale = currentFrame.scale;
        layer.contents = (__bridge id)currentFrame.CGImage;
    } else {
        // If we have no animation frames, call super implementation. iOS 14+ UIImageView use this delegate method for rendering.
        if ([UIImageView instancesRespondToSelector:@selector(displayLayer:)]) {
           [super displayLayer:layer];
        }
    }
//    if (_curFrame) {
//        layer.contents = (__bridge id)_curFrame.CGImage;
//    }
}

方法二

#import "YYAnimatedImageView+iOS14.h"

#import <objc/runtime.h>

 

@implementation YYAnimatedImageView (iOS14)

+ (void)load {

    static dispatch_once_t onceToken;

    dispatch_once(&onceToken, ^{

        Method method1;

        Method method2;

        method1 = class_getInstanceMethod([self class], @selector(lz_displayLayer:));

        method2 = class_getInstanceMethod([self class], @selector(displayLayer:));

        method_exchangeImplementations(method1, method2);

    });

}

- (void)lz_displayLayer:(CALayer *)layer {

    Ivar ivar = class_getInstanceVariable(self.class, "_curFrame");

    UIImage *_curFrame = object_getIvar(self, ivar);

    if (_curFrame) {

        layer.contents = (__bridge id)_curFrame.CGImage;

    }else{

        if (@available(iOS 14.0, *)) {

            [super displayLayer:layer];

        }

    }

}

 

@end