ios - 设置导航栏背景图片

Question

这是我的代码:

let logo = UIImage(named: "navigationbar")
self.navigationController!.navigationBar.setBackgroundImage(logo!.resizableImage(withCapInsets: UIEdgeInsets(top: 0,left: 0, bottom: 0 ,right: 0), resizingMode: .stretch), for: .default)

但不起作用。这是错误代码。

Thread 1: Fatal error: Unexpectedly found nil while unwrapping an Optional value

Answer 1

试试这段代码，看看你的代码在哪里崩溃了……它的起点……然后解决你的代码中 nil 的那部分……navigationController或 Image是零

if let logo = UIImage(named: "navigationbar") {
    if let navigation = self.navigationController {

       navigation.navigationBar.setBackgroundImage(logo!.resizableImage(withCapInsets: UIEdgeInsets(top: 0,left: 0, bottom: 0 ,right: 0), resizingMode: .stretch), for: .default)
      }else {
        print("Navigation cotroller not found and its nil")
      }
} else {
   print("problem wiyh image file")
}