ios swift：在导航栏中设置返回按钮图像
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swift: setting back button image in nav bar
提问by fuiiii
I'm trying to set the back button image in nav bar in my controller, here's my code in viewDidLoad():
我正在尝试在控制器的导航栏中设置后退按钮图像，这是我在 viewDidLoad() 中的代码：
var backImg: UIImage? = UIImage(named: "back_btn.png")
println(backImg)
if var back_img = backImg {
println("GET IT")
println(back_img)
println(UIControlState.Normal)
println(UIBarMetrics.Default)
self.navigationController.navigationBar.backItem.backBarButtonItem.setBackButtonBackgroundImage(back_img, forState: UIControlState.Normal, barMetrics: UIBarMetrics.Default)
}
I tried to put them to viewWillLoad, but getting the same error
我试图把它们放到 viewWillLoad，但得到同样的错误
Console with error message:
带有错误消息的控制台：
<UIImage: 0x7ff37bd85750>
GET IT
<UIImage: 0x7ff37bd85750>
VSC14UIControlState (has 1 child)
(Enum Value)
fatal error: unexpectedly found nil while unwrapping an Optional value
I don't know which part went wrong. Seems like the back_img is not nil, but I got error saying it's nil
不知道是哪个环节出了问题。似乎 back_img 不是 nil，但我收到错误说它是 nil
Thanks!
谢谢！
回答by Shahid Aslam
In Swift 3.0 +put below code in appdelegatedidFinishLaunchingWithOptionsmethod, it will work perfectly
在Swift 3.0 +将下面的代码放入appdelegatedidFinishLaunchingWithOptions方法中，它将完美运行
let backImage = UIImage(named: "BackNavigation")?.withRenderingMode(.alwaysOriginal)
UINavigationBar.appearance().backIndicatorImage = backImage
UINavigationBar.appearance().backIndicatorTransitionMaskImage = backImage
UIBarButtonItem.appearance().setBackButtonTitlePositionAdjustment(UIOffsetMake(0, -80.0), for: .default)
Or for Swift 4.0 +
或者Swift 4.0 +
let backImage = UIImage(named: "back-icon").withRenderingMode(.alwaysOriginal)
UINavigationBar.appearance().backIndicatorImage = backImage
UINavigationBar.appearance().backIndicatorTransitionMaskImage = backImage
UIBarButtonItem.appearance().setBackButtonTitlePositionAdjustment(UIOffset(horizontal: 0, vertical: -80.0), for: .default)
The last line will remove the title of Navigation Back Buttonif you don't want to remove title then just remove last line
最后一行将删除标题，Navigation Back Button如果您不想删除标题，则只需删除最后一行
回答by Jaro
If you want to change the back button in every controller you can add this to app delegate in didFinishLaunchingWithOptions
如果您想更改每个控制器中的后退按钮，您可以将其添加到 didFinishLaunchingWithOptions 中的应用程序委托中
let backImg: UIImage = UIImage(named: "back_button")!
UIBarButtonItem.appearance().setBackButtonBackgroundImage(backImg, forState: .Normal, barMetrics: .Default)
回答by fuiiii
I have figured out by looking into sample code. 1) Create a bar button item in storyboard. 2) Link that button to controller using IBOutlet 3) Add image to the button
我已经通过查看示例代码弄清楚了。1）在故事板中创建一个条形按钮项。2) 使用 IBOutlet 将该按钮链接到控制器 3) 将图像添加到按钮
var backImg: UIImage = UIImage(named: "back_btn")
backBtn.setBackgroundImage(backImg, forState: .Normal, barMetrics: .Default)
PS: image should be added to Images.xcassets folder, see sample code, UICatalog, for details.
PS：图片需要添加到Images.xcassets文件夹中，详见示例代码UICatalog。
回答by Mantas Laurinavi?ius
self.navigationController?.navigationBar.backIndicatorImage = UIImage(named: "back-icon")
self.navigationController?.navigationBar.backIndicatorTransitionMaskImage = UIImage(named: "back-icon")
回答by Mehul
//Here is the perfect solution To Set back button with Image and Action in default Navigation Bar
//这是在默认导航栏中设置带有图像和操作的后退按钮的完美解决方案
First add UIBarButton in Navigation bar
首先在导航栏中添加 UIBarButton
Then Go to property in File inspector in storyboard and add space to hide back button title text
然后转到故事板文件检查器中的属性并添加空间以隐藏后退按钮标题文本
Set image in Ui Bar button image
在 Ui Bar 按钮图像中设置图像
/Write on click action method/
/写入点击动作方法/
To enable swipe to pop (back to previous controller), write two line code in ViewDidLoad method
要启用滑动弹出（回到上一个控制器），请在 ViewDidLoad 方法中编写两行代码
And you will get perfect Back Button with Swipe to back animation
你会得到完美的后退按钮和滑动到后退动画
//Note:- To disable back button previous viewcontroller title , add one space in title text in back button in storyboard file inspector
//注意：-要禁用后退按钮上一个视图控制器标题，请在故事板文件检查器的后退按钮的标题文本中添加一个空格
回答by zevij
alternative way: click on the navigation controller in storyboard (not the navigation controller in the UIViewController itself). Then, in the attributes section on the RHS you'll see back image and back mask. Set back image and you're done.
替代方法：单击情节提要中的导航控制器（而不是 UIViewController 本身中的导航控制器）。然后，在 RHS 的属性部分，您将看到背面图像和背面蒙版。设置回图像，你就完成了。
回答by Abhishek Jain
Swift 4+ version
斯威夫特 4+ 版本
let backImage = UIImage(named: "back-icon").withRenderingMode(.alwaysOriginal)
UINavigationBar.appearance().backIndicatorImage = backImage
UINavigationBar.appearance().backIndicatorTransitionMaskImage = backImage
UIBarButtonItem.appearance().setBackButtonTitlePositionAdjustment(UIOffset(horizontal: 0, vertical: -80.0), for: .default)
