當(dāng)系統(tǒng)升級到iOS11及以上版本時，我們會發(fā)現(xiàn)原先設(shè)置在searchBar中間的placeholder和圖片會往左邊移（沒任何設(shè)置的效果）,在這里小編附上了解決的辦法，希望大家能夠得到參考。
效果如下圖：

如何實現(xiàn)

1.加入searchBar控件

小編在這里用的是storyboard,若與小編一樣是用storyboard或者XIB的,記得千萬要設(shè)置placeholder。

2.設(shè)置searchBar

在這里可以根據(jù)自己的需要設(shè)置一下searchBar樣式

//        searchBar的外觀設(shè)置
        searchBar.layer.masksToBounds = true;
        searchBar.layer.cornerRadius = searchBar.frame.size.height / 2;
        searchBar.layer.borderWidth = 1;
        searchBar.contentMode = .center;
        searchBar.layer.borderColor = UIColor.init(red: 197/255.0, green: 199/255.0, blue: 200/255.0, alpha: 1).cgColor;
//        searchBar彈出的鍵盤類型設(shè)置
        searchBar.returnKeyType = UIReturnKeyType.done;

3.searchBar中textField的設(shè)置

//        searchBar中的textField設(shè)置
        let searchField = searchBar.value(forKey: "_searchField") as! UITextField;
        searchField.setValue(UIFont.systemFont(ofSize: 10), forKeyPath: "_placeholderLabel.font");
        searchField.setValue(UIColor.init(red: 70/255.0, green: 70/255.0, blue: 70/255.0, alpha: 1), forKeyPath: "_placeholderLabel.textColor");

4.獲取系統(tǒng)版本號

//    當(dāng)前IOS系統(tǒng)版本
    var currentVersion: Int!
------------------------------
//        獲取系統(tǒng)版本號
        let sysVersion = UIDevice.current.systemVersion
        currentVersion = Int(sysVersion.components(separatedBy: ".").first!)

5.根據(jù)系統(tǒng)版本號判斷操作

let space = 50;//搜索框圖片加上圖片和字體之間的距離
----------------------------------------
//        判斷是不是大于IOS 11
        if currentVersion! < 11 {
            searchField.attributedPlaceholder = NSAttributedString.init(string: "SEARCH", attributes: [NSAttributedStringKey.baselineOffset:-2]);
        }else
        {
//            searchBar中textField的placeholder的寬度可以獲取
//            let label = UILabel.init()
//            label.text = "SEARCH"
//            label.font = UIFont.systemFont(ofSize: 10)
//            label.sizeToFit()
//            print(label.frame.width)
//            獲取當(dāng)前屏幕寬度
            self.view.frame.size.width = UIScreen.main.bounds.size.width
//            重新布局
            self.view.layoutSubviews()
//            計算偏移量:偏移量 =（searchBar的寬度-label寬度-搜索框圖片加上圖片和字體之間的寬度）/ 2
            searchBar.setPositionAdjustment(UIOffsetMake((searchBar.frame.size.width - 40.5 - 50 ) / 2 , 0), for: UISearchBarIcon.search)
        }

6.在searchBar的代理中進(jìn)行判斷

func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String) {
//        輸入時需要進(jìn)行的操作
    }
    func searchBarShouldBeginEditing(_ searchBar: UISearchBar) -> Bool {
        if currentVersion >= 11 {
            self.searchBar.setPositionAdjustment(UIOffset.zero, for: UISearchBarIcon.search)
        }
        return true
    }
    func searchBarShouldEndEditing(_ searchBar: UISearchBar) -> Bool {
        if currentVersion >= 11 {
            searchBar.setPositionAdjustment(UIOffsetMake((searchBar.frame.size.width - 40.5 - 50 ) / 2 , 0), for: UISearchBarIcon.search)
        }
        return true
    }
    func searchBarSearchButtonClicked(_ searchBar: UISearchBar) {
//        輸入完成時，點擊按鈕需要進(jìn)行的操作
        searchBar.resignFirstResponder()
    }

7.最后，加上點擊空白處關(guān)閉鍵盤就完成了

//        使鍵盤點擊空白處關(guān)閉
        let tap = UITapGestureRecognizer.init(target: self, action: #selector(viewTapped(tap:)));
        tap.cancelsTouchesInView = false;
        self.view.addGestureRecognizer(tap);
    }
    @objc func viewTapped(tap: UITapGestureRecognizer) {
        searchBar.resignFirstResponder()
    }

最后，希望這篇文章對各位看官們有所幫助。Demo下載地址：Demo，對支持小編的看官們表示感謝。