设置导航栏透明

iOS 设置导航透明的两种方法

• (void)viewWillAppear:(BOOL)animated{
  [super viewWillAppear:animated];
  [self.navigationController.navigationBar setBackgroundImage:[UIImage new] forBarMetrics:UIBarMetricsDefault];
  //去掉导航栏底部的黑线
  self.navigationController.navigationBar.shadowImage = [UIImage new];
  }
  如果仅设置当前页导航透明，需加入下面方法
• (void)viewWillDisappear:(BOOL)animated{
  [super viewWillDisappear:animated];
  [self.navigationController.navigationBar setBackgroundImage:nil forBarMetrics:UIBarMetricsDefault];
  [self.navigationController.navigationBar setShadowImage:nil];
  }
  需要注意的是：如果返回上一页的操作有动画，则在上一页出现的时候，导航栏的颜色会逐渐变化

方法二

• (void)viewWillAppear:(BOOL)animated{
  [super viewWillAppear:animated];
  [[self.navigationController.navigationBar subviews] objectAtIndex:0].alpha = 0;
  }
  仅设置当前页面
• (void)viewWillDisappear:(BOOL)animated{
  [super viewWillDisappear:animated];
  [[self.navigationController.navigationBar subviews] objectAtIndex:0].alpha = 1;
  }