xib拖xib

被拖拽的是CustomView
1、新建
CustomView.h
CustomView.m
CustomView.xib

2、设置
CustomView.xib里file’s owner的Custom Class为 CustomView（不是View的 Custom Class） ，设置其他Xib或StoryBoard里View的 Custom Class为CustomView

3、在 CustomView 重写 - (id)initWithCoder:(NSCoder *)aDecoder

- (id)initWithCoder:(NSCoder *)aDecoder
{
    if (self = [super initWithCoder:aDecoder]) {
        UIView *containerView = [[[UINib nibWithNibName:NSStringFromClass([self class]) bundle:nil] instantiateWithOwner:self options:nil] lastObject];
        CGRect newFrame = CGRectMake(0, 0, self.frame.size.width, self.frame.size.height);
        containerView.frame = newFrame;
        [self addSubview:containerView];
    }
    return self;
}