問題

更新iOS14后發現原來使用的YBImageBrowser瀏覽圖片出現黑屏，使用YYImage顯示圖片也出現了相同的黑屏問題。

黑屏問題

原因??：iOS 14系統調用方法- (void)displayLayer:(CALayer *)layer，YYAnimatedImageView沒有正確處理。

解決

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：鉤子函數
    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];
    }
    
}