Question

我想在swift的左侧显示一个图像。

＆＃xA;＆＃xA;

我尝试添加导航栏按钮项并在那里设置图像。

＆＃xA;＆＃xA;

问题在于我必须使用非常小的图像才能很好地适应导航栏。但制作如此小的图像会导致像素化，特别是在较大的手机iPhone 6和6 Plus上。

＆＃xA;＆＃xA;

有没有办法使用高质量的图像然后设置框架适合导航栏的范围？

＆＃xA;＆＃xA;

我的尝试：

＆＃xA;＆＃xA;

  var image = UIImage （名为：“Harp.png”）＆＃xA;＆＃xA; image = image？.imageWithRenderingMode（UIImageRenderingMode.AlwaysOriginal）＆＃xA;＆＃xA; self.navigationItem.leftBarButtonItem = UIBarButtonItem（image：image，style： UIBarButtonItemStyle.Plain，target：nil，action：nil）＆＃xA; self.navigationItem.leftBarButtonItem.frame = CGRectMake（0,0,53,31）＆＃xA; // image.frame = CGRectMake（0,0， 53,31）＆＃xA;

＆＃xA;＆＃xA;

我尝试先将帧放在图像上，然后放在条形按钮项上。＆＃xA;但是这个抛出一个错误：

＆＃xA;＆＃xA;

如果没有更多的上下文，表达式的类型是不明确的。

＆＃xA;

Answer 1

试试这个

let button = UIButton(type: UIButtonType.Custom)
button.setImage(UIImage(named: "yourImageName.png"), forState: UIControlState.Normal)
button.addTarget(self, action:Selector("callMethod"), forControlEvents: UIControlEvents.TouchDragInside)
button.frame=CGRectMake(0, 0, 30, 30)
let barButton = UIBarButtonItem(customView: button)
self.navigationItem.leftBarButtonItems = [newBackButton,barButton]

对于Swift 3

let button = UIButton.init(type: .custom)
button.setImage(UIImage.init(named: "yourImageName.png"), for: UIControlState.normal)
button.addTarget(self, action:#selector(ViewController.callMethod), for:.touchUpInside)
button.frame = CGRect.init(x: 0, y: 0, width: 30, height: 30) //CGRectMake(0, 0, 30, 30)
let barButton = UIBarButtonItem.init(customView: button)
            self.navigationItem.leftBarButtonItem = barButton

这是行动

func callMethod() {
//do stuff here
}

Answer 2

使用此代码：

self.navigationItem.leftBarButtonItem = nil

let button = UIButton(type: .custom)
button.setImage(UIImage (named: "ChatTab"), for: .normal)
button.frame = CGRect(x: 0.0, y: 0.0, width: 35.0, height: 35.0)
//button.addTarget(target, action: nil, for: .touchUpInside)
let barButtonItem = UIBarButtonItem(customView: button)

let button2 = UIButton(type: .custom)
button2.setImage(UIImage (named: "ActivityTab"), for: .normal)
button2.frame = CGRect(x: 0.0, y: 0.0, width: 35.0, height: 35.0)
//button.addTarget(target, action: nil, for: .touchUpInside)

let barButtonItem2 = UIBarButtonItem(customView: button2)
self.navigationItem.rightBarButtonItems = [barButtonItem, barButtonItem2]

<强>输出：

Answer 3

根据设备的不同，有一种方法可以使用不同尺寸的图像。它被称为资产目录。您可能已经在项目中拥有一个，或者如果没有，您可以添加一个File > New > File > Resource > Asset Catalogue。

在您的资产目录中，您可以拥有多个＆＃39;图像集＆＃39; （这些将显示在左侧）。使用＆＃39; +＆＃39;添加新的图像集在底部。对于每个图像集，您可以为@ 1x，@ 2x和@ 3x提供不同的图像（例如，不同大小）。

然后，要在代码中使用其中一个图片，只需使用UIImage(named: "name_of_image_set") - 请注意无扩展名。将加载正确的图像，具体取决于设备。

希望这有帮助！

Answer 4

快速4和5：

let imageView = UIImageView(image: UIImage(named: "Harp"))
let buttonItem = UIBarButtonItem(customView: imageView)
self.navigationItem.leftBarButtonItem = buttonItem

Answer 5

使用Swift 5，XCode 11制作带有圆形图像，资产图像或从URL下载的导航栏项。

1）新文件： UIBarButtonItem + RoundedView.swift

import Foundation

class ImageBarButton : UIView {
    var imageView: UIImageView!
    var button: UIButton!

    convenience init(withUrl imageURL: URL? = nil, withImage image: UIImage? = nil, frame: CGRect = CGRect(x: 0, y: 0, width: 40, height: 40)) {
        self.init(frame: frame)

        imageView = UIImageView(frame: frame)
        imageView.backgroundColor = .white
        imageView.layer.cornerRadius = frame.height/2
        imageView.clipsToBounds = true
        imageView.contentMode = .scaleAspectFill
        imageView.clipsToBounds = true
        addSubview(imageView)

        button = UIButton(frame: frame)
        button.backgroundColor = .clear
        button.setTitle("", for: .normal)
        addSubview(button)

        if let url = imageURL { // you can use pods like Nuke or Kingfisher 
         URLSession(configuration: .default).dataTask(with: URL(string: imageUrl)!) {[weak self] (data, response, error) in
          if let data = data , let image = UIImage(data: data) {
              DispatchQueue.main.async {
                self?.imgView.image = image
              }
           }
         }.resume()
        } else if let image = image {
            self.imageView.image = image
        }
    }

    func load()-> UIBarButtonItem {
        return UIBarButtonItem(customView: self)
    }
}

2）添加导航栏项目，可以使用 navigationItem.rightBarButtonItems，navigationItem.leftBarButtonItems ：

private func initalizeNavigationBarItems() {
    let searchBarButtonView = ImageBarButton(withImage: #imageLiteral(resourceName: "greenSearchIcon")) // Assets
    searchBarButtonView.button.addTarget(self, action: #selector(presentSearchViewController), for: .touchUpInside)

    if let user = AccountManager.currentUser, let userProfilePictureURL = user.imageUrl { // API Url
        let profileBarButtonView = ImageBarButton(withUrl: userProfilePictureURL)
        profileBarButtonView.button.addTarget(self, action: #selector(presentMoreViewController), for: .touchUpInside)
        navigationItem.rightBarButtonItems = [searchBarButtonView.load(), profileBarButtonView.load()]
    } else {
        let profileBarButtonView = ImageBarButton(withImage: #imageLiteral(resourceName: "profileIcon"))
        profileBarButtonView.button.addTarget(self, action: #selector(presentMoreViewController), for: .touchUpInside)
        navigationItem.rightBarButtonItems = [searchBarButtonView.load(), profileBarButtonView.load()]
    }
}

@objc func presentMoreViewController(_ sender: Any) {
    // present MoreViewController
}

@objc func presentSearchViewController(_ sender: Any) {
    // present SearchViewController
}

预览

导航栏按钮项目swift的图像

5 个答案: