IOS实现自定义透明背景的tabbar

```//  UIImageView *imageView = [[UIImageView alloc]initWithFrame:CGRectMake(0, 0, kScreenW, tabBarHeight + 5)];//  [imageView setImage:[self createImageWithColor:[UIColor clearColor]]];//  [imageView setContentMode:UIViewContentModeScaleToFill];//  [self.tabBar insertSubview:imageView atIndex:0];  //覆盖原生Tabbar的上横线//  [[UITabBar appearance] setShadowImage:[self createImageWithColor:[UIColor clearColor]]];//背景图片为透明色//  [[UITabBar appearance] setBackgroundImage:[self createImageWithColor:[UIColor clearColor]]];  self.tabBar.backgroundColor = [UIColor clearColor];//设置为半透明  self.tabBarController.tabBar.translucent = YES;``````-(UIImage*) createImageWithColor:(UIColor*) color{  CGRect rect=CGRectMake(0.0f, 0.0f, 1.0f, 1.0f);  UIGraphicsBeginImageContext(rect.size);  CGContextRef context = UIGraphicsGetCurrentContext();  CGContextSetFillColorWithColor(context, [color CGColor]);  CGContextFillRect(context, rect);  UIImage *theImage = UIGraphicsGetImageFromCurrentImageContext();  UIGraphicsEndImageContext();  return theImage;}```