我想在导航栏的左侧快速显示图像。
我尝试添加导航栏按钮项并在那里设置图像。
问题是我必须使用非常小的图像才能使其很好地适应导航栏。但是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。
有没有一种方法可以使用高质量的图像,然后将框架设置为适合导航栏的边界?
我的尝试:
var image = UIImage(named: "Harp.png") image = image?.imageWithRenderingMode(UIImageRenderingMode.AlwaysOriginal) self.navigationItem.leftBarButtonItem = UIBarButtonItem(image: image, style: UIBarButtonItemStyle.Plain, target: nil, action: nil) self.navigationItem.leftBarButtonItem.frame = CGRectMake(0, 0, 53, 31) //image.frame = CGRectMake(0, 0, 53, 31)
我尝试先将框架放在图像上,然后再放在条形按钮项上。但这抛出了一个错误:
没有更多上下文的情况下,表达类型不明确。
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
斯威夫特4
let button = UIButton(type: UIButton.ButtonType.custom) button.setImage(UIImage(named: "getstarted"), for: .normal) button.addTarget(self, action:#selector(callMethod), for: .touchDragInside) button.frame = CGRect(x: 0, y: 0, width: 30, height: 30) let barButton = UIBarButtonItem(customView: button) self.navigationItem.leftBarButtonItems = [barButton]
这是行动
@objc func callMethod() { //do stuff here }