iOS14下YBImageBrowser显示图片黑屏

问题

更新iOS14后发现原来使用的YBImageBrowser浏览图片出现黑屏，使用YYImage显示图片也出现了相同的黑屏问题。

黑屏问题

原因⚠️：iOS 14系统调用方法- (void)displayLayer:(CALayer *)layer，YYAnimatedImageView没有正确处理。

解决

方式一

-(void)displayLayer:(CALayer *)layer {
    UIImage *currentFrame = _curFrame;
    if (!currentFrame) {
        currentFrame = self.image;
    }
    if (currentFrame) {
        layer.contentsScale = currentFrame.scale;
        layer.contents = (__bridge id)currentFrame.CGImage;
    }
}

方式二

- (void)displayLayer:(CALayer *)layer {
    if (_curFrame) {
        layer.contents = (__bridge id)_curFrame.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];
        }
    }
}

方式三

pod 'YYImage', :git => 'https://github.com/QiuYeHong90/YYImage.git'

方式四

#import "YYAnimatedImageView+Extension.h"

@implementation YYAnimatedImageView (Extension)

+(void)load
{
    // hook：钩子函数
    Method method1 = class_getInstanceMethod(self, @selector(displayLayer:));
    
    Method method2 = class_getInstanceMethod(self, @selector(dx_displayLayer:));
    method_exchangeImplementations(method1, method2);
}

-(void)dx_displayLayer:(CALayer *)layer {
    
    if ([UIImageView instancesRespondToSelector:@selector(displayLayer:)]) {
        [super displayLayer:layer];
    }
    
}