1、如何创建一个bundle：

iOS 如何把图片资源打包成bundle文件及遇到的坑

2、把图片资源，xib打包进bundle以后，如何使用？

2.1、加载本地的bundle

+ (NSBundle *)bundle {
    static NSBundle *bundle = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        bundle = [NSBundle bundleWithPath:[[NSBundle bundleForClass:[self class]] pathForResource:@"ZLYKit" ofType:@"bundle"]];
    });
    return bundle;
}

2.2、获取bundle里面的图片资源

+ (UIImage *)imageNamed:(NSString *)name {
    UIImage *image = [UIImage imageNamed:name inBundle:self.bundle compatibleWithTraitCollection:nil];
    return image;
}

+ (UIImage *)imageNamed:(NSString *)name type:(NSString *)type {
    if (name.length == 0) return nil;
    int scale = (int)UIScreen.mainScreen.scale;
    if (scale < 2) scale = 2;
    else if (scale > 3) scale = 3;
    NSString *n = [NSString stringWithFormat:@"%@@%dx", name, scale];
    UIImage *image = [UIImage imageWithContentsOfFile:[self.bundle pathForResource:n ofType:type]];
    if (!image) image = [UIImage imageWithContentsOfFile:[self.bundle pathForResource:name ofType:type]];
    return image;
}

[self.leftImageView sd_setImageWithURL:[NSURL URLWithString:fileModel.courseImageUrl] placeholderImage:[ZLYUtilities imageNamed:@"place_holder_home_lesson"]];

2.3、获取bundle里面的xib资源

[_tableView registerNib:[UINib nibWithNibName:@"LYChatRoomImageTableViewCell" bundle:[ZLYUtilities bundle]] forCellReuseIdentifier:imageID];