更改 UISearchBar 内 UItextField 中图标的颜色答案

【问题标题】：Changing the color of the icons in a UItextField inside a UISearchBar更改 UISearchBar 内 UItextField 中图标的颜色
【发布时间】：2016-02-29 12:42:01
【问题描述】：

我正在尝试自定义搜索控制器中搜索栏的外观。

设置背景和文本颜色效果很好，但我只是没有找到改变文本字段中图标颜色的方法，特别是放大镜和 x 按钮。

我找到了这个 Objective-C 代码，它应该可以做我想做的事，但我正在努力将它翻译成 Swift：

（编辑：跳到有效的 Swift 3 解决方案的第一个答案。）

UITextField *searchBarTextField = [self.searchDisplayController.searchBar valueForKey:@"_searchField"];

// Magnifying glass icon.
UIImageView *leftImageView = (UIImageView *)searchBarTextField.leftView;
leftImageView.image = [LeftImageView.image imageWithRenderingMode:UIImageRenderingModeAlwaysTemplate];
leftImageView.tintColor = [UIColor whiteColor];

// Clear button
UIButton *clearButton = [searchBarTextField valueForKey:@"_clearButton"];
[clearButton setImage:[clearButton.imageView.image imageWithRenderingMode:UIImageRenderingModeAlwaysTemplate] forState:UIControlStateNormal];
clearButton.tintColor = [UIColor whiteColor];

我尝试翻译成 Swift：

let textField = searchController.searchBar.valueForKey("searchField") as! UITextField
// These two work fine.
textField.backgroundColor = UIColor.blackColor()
textField.textColor = UIColor.blackColor()

var glassIcon = textField.leftView
// This would work.
//glassIcon.hidden = true

// This does not have any effect.
//glassIcon?.tintColor = UIColor.whiteColor()

// My attempt to translate, but it gives an error.
glassIcon.image? = UIImage.imageWithRenderingMode(UIImageRenderingMode.AlwaysTemplate)

 var clearButton = textField.valueForKey("clearButton")!
            clearButton.setImage(clearButton.imageWithRenderingMode(.AlwaysTemplate), forState: .Normal)
// This gives the error: "Cannot assign to property: 'clearButton' is immutable
clearButton.tintColor = UIColor.whiteColor()
  // Sorry for the weird formatting, it glitches here in the editor.

leftView 似乎没有 image 属性。如何像 Objective-C 代码那样访问该属性？另外，如果有更好的方法来实现我想要的，请告诉我。

【问题讨论】：

标签： swift uiimage uitextfield uisearchbar

【解决方案1】：

解决办法如下：

// Text field in search bar.
let textField = searchController.searchBar.value(forKey: "searchField") as! UITextField

let glassIconView = textField.leftView as! UIImageView
glassIconView.image = glassIconView.image?.withRenderingMode(.alwaysTemplate)
glassIconView.tintColor = UIColor.white

let clearButton = textField.valueForKey("clearButton") as! UIButton
clearButton.setImage(clearButton.imageView?.image?.withRenderingMode(.alwaysTemplate), for: .normal)
clearButton.tintColor = UIColor.white

【讨论】：

嗨，使用此代码，如何将其附加到我的搜索栏？
在您的视图控制器中实例化一个搜索控制器：var searchController: UISearchController! 并在您的 viewDidLoad() 中设置它，例如：tableView.tableHeaderView = searchController.searchBar searchController = UISearchController(searchResultsController: nil) searchController.searchResultsUpdater = self searchController.dimsBackgroundDuringPresentation = false searchController.searchBar.delegate = self searchController.searchBar.sizeToFit() searchController.searchBar.barTintColor = UIColor.white
您可以将as! 替换为as?，使代码更安全，没有其他不利影响。

【解决方案2】：

解决办法如下：

extension UITextField{

func setLeftIcon(_ icon: UIImage) {
    
    let padding = 8
    let size = 20
    
    let outerView = UIView(frame: CGRect(x: 0, y: 0, width: size+padding, height: size) )
    let iconView  = UIImageView(frame: CGRect(x: padding, y: 0, width: size, height: size))
    iconView.image = icon.withRenderingMode(.alwaysTemplate)
    iconView.tintColor = UIColor.white
    outerView.addSubview(iconView)
    
    leftView = outerView
    leftViewMode = .always
}
}

【讨论】：