iOS 给tabbar 设置背景色

给tabbarController添加一个UIImageView

#pragma mark - lazy load

- (UIImageView *)backgroundImgView
{
    if (!_backgroundImgView) {
        _backgroundImgView = [[UIImageView alloc] init];
    }
    return _backgroundImgView;
}

   
        [self.tabBar insertSubview:self.backgroundImgView atIndex:0];
        self.backgroundImgView.frame = self.tabBar.bounds;
 }