iOS 13修改启动图未生效

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前言：由于业务要求需要更新应用启动图，拿到新图时分分钟替换完事儿，经测试在iOS 13系统上未生效

问题排查

启动图使用 LaunchScreen.storyboard 的方式，在查阅资料与实践后得出结论：

• 系统会根据LaunchScreen.stroboard的内容生成屏幕快照（@2x和@3x）
• 快照存放在Library/SplashBoard/Snapshots下
• 第次运行时都会生成新的快照图片，根据屏幕倍数显示相应的快照图片
• 在 iOS 13 系统中，更新图片名称、内容，并删除快照图片缓存后，下次启动时启动图才更新

也就是说在 iOS 13 上，更新启动图需要改图片名称、删除快照图片缓存，在下次启动时才生效！！！

解决方案

在 iOS 13 上冷启动时校验缓存图片与当前图片是否一致，若缓存图片不存在或图片不一致则删除快照缓存并更新缓存图片，图片一致时不处理

代码示例

+ (void)cleanSplashBoard {
    float systemVersion = [WM_CURRENT_SYSTEM_VERSION floatValue];
    if (systemVersion >= 13.0 && systemVersion < 14.0) {
        NSString *documentsPath = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES).firstObject;
        NSString *folderPath = [documentsPath stringByAppendingPathComponent:@"Data"];
        NSString *imageCachePath = [folderPath stringByAppendingPathComponent:@"SplashBoard"]; // ~/Documents/Data/SplashBoard
        // 准备
        BOOL isDirectory = YES;
        if (![[NSFileManager defaultManager] fileExistsAtPath:folderPath isDirectory:&isDirectory]) {
            [[NSFileManager defaultManager]  createDirectoryAtPath:folderPath withIntermediateDirectories:YES attributes:nil error:nil];
        }
        NSError *error = nil;
        // 1.获取Images.xcassets中启动图
        UIStoryboard *sb = [UIStoryboard storyboardWithName:@"LaunchScreen" bundle:nil];
        NSAssert(sb != nil, @"未找到 LaunchScreen.storyboard 文件");
        UIViewController *vc = [sb instantiateInitialViewController];
        UIImage *currentImage = nil;
        for (UIView *subview in vc.view.subviews) {
            if ([subview isKindOfClass:[UIImageView class]]) {
                currentImage = ((UIImageView *)subview).image;
                break;
            }
        }
        if (currentImage == nil) {
        NSAssert(currentImage != nil, @"LaunchScreen.storyboard 中缺少 ImageView");
            return;
        }
        NSData *currentData = UIImagePNGRepresentation(currentImage);
        // 2.获取缓存的启动图
        NSData *cachedData = [[NSData alloc] initWithContentsOfFile:imageCachePath];
        if (cachedData && [cachedData isEqualToData:currentData]) {
            return;
        }
        [[NSFileManager defaultManager] removeItemAtPath:[NSHomeDirectory() stringByAppendingString:@"/Library/SplashBoard"] error:nil];
        [currentData writeToFile:imageCachePath atomically:YES];
    }
}