Swift 获取第一响应者以及监听改变TextFiled边框颜色

前言

项目为实现监听用户是否在某个TextFiled输入然后改变边框颜色，这里就需要或者到当前的响应者。

效果图：

一、Swift代码

extension UIView {
    var firstResponder: UIView? {
        guard !isFirstResponder else { return self }

        for subview in subviews {
            if let firstResponder = subview.firstResponder {
                return firstResponder
            }
        }
        return nil
    }
}

二、OC代码

@implementation UIView (FindFirstResponder)
- (id)findFirstResponder
{
    if (self.isFirstResponder) {
        return self;
    }
    for (UIView *subView in self.view.subviews) {
        if ([subView isFirstResponder]) {
            return subView;
        }
    }
    return nil;
}

或者

UIWindow *keyWindow = [[UIApplication sharedApplication] keyWindow];  
UIView *firstResponder = [keyWindow performSelector:@selector(firstResponder)]; 

三、效果代码

class ViewController: UIViewController {

    var textFielddd: UITextField?
    var textFieldcc: UITextField?
    
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        
        let textField = UITextField(frame: CGRect(x:20, y:100, width:self.view.bounds.width - 40, height:30))
        textField.borderStyle = UITextField.BorderStyle.none
        textField.layer.borderWidth = 1.0
        textField.layer.cornerRadius = 8
        textField.layer.borderColor = UIColor.black.cgColor
        textFielddd = textField
        view.addSubview(textField)
        
        
        let textField1 = UITextField(frame: CGRect(x:20, y:150, width:self.view.bounds.width - 40, height:30))

        textField1.borderStyle = UITextField.BorderStyle.none
        textField1.layer.borderWidth = 1.0
        textField1.layer.cornerRadius = 8
        textField1.layer.borderColor = UIColor.black.cgColor
        textFieldcc = textField1
        view.addSubview(textField1)
        
        //键盘弹起
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow(aNotification:)), name: UIResponder.keyboardWillChangeFrameNotification, object: nil)
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHied(aNotification:)), name: UIResponder.keyboardWillHideNotification, object: nil)
    }

    //监听键盘弹出
    @objc func keyboardWillShow(aNotification: NSNotification) {
        
        if let firstResponder = view.window?.firstResponder {
            if firstResponder == textFielddd {
                print("打印一下当前响应者：ss--------")
                textFielddd?.layer.borderColor = UIColor.red.cgColor
                textFieldcc?.layer.borderColor = UIColor.black.cgColor
            }else if firstResponder == textFieldcc {
                print("打印一下当前响应者：tttt--------")
                textFielddd?.layer.borderColor = UIColor.black.cgColor
                textFieldcc?.layer.borderColor = UIColor.red.cgColor
            }
        }
    }
    //监听键盘收回
    @objc func keyboardWillHied(aNotification: NSNotification){
        textFielddd?.layer.borderColor = UIColor.black.cgColor
        textFieldcc?.layer.borderColor = UIColor.black.cgColor
    }
    
    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        self.view.endEditing(true)
    }
}

extension UIView {
    var firstResponder: UIView? {
        guard !isFirstResponder else { return self }

        for subview in subviews {
            if let firstResponder = subview.firstResponder {
                return firstResponder
            }
        }
        return nil
    }
}

END.

代码007普通

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