- (UIImageView *)bgView {
    if (_bgView == nil) {
        _bgView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, self.width, self.height)];
        _bgView.image = [UIImage imageNamed:@"背景"];
        _bgView.contentMode = UIViewContentModeScaleAspectFill;
        _bgView.layer.cornerRadius = 4;
        _bgView.clipsToBounds = YES;
    }
    return _bgView;
}