JayachandraA · September 18, 2018 14:34 · Sep 18, 2018
diff --git a/How_to_create_a_stored_property_in_an_swift_extension.swift b/How_to_create_a_stored_property_in_an_swift_extension.swift
@@ -0,0 +1,130 @@
+
+extension UITextField {
+
+    // OPTION - 1
+    struct Instance {
+        static var floating: Bool = false
+    }
+
+
+    var floating: Bool{
+        set{
+            Instance.floating = newValue
+            initializePlaceholder()
+        }
+
+        get{
+            return Instance.floating
+        }
+    }
+
+
+
+    // OPTION - 2
+    struct AssociatedKeys {
+        static var placeholderColor: String = "placeholderColor"
+    }
+
+    var  placeholderColor: UIColor? {
+        set {
+            objc_setAssociatedObject(self, &AssociatedKeys.placeholderColor, newValue, objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN)
+            updatePlaceholderAppearance()
+        }
+
+        get {
+            guard let value = objc_getAssociatedObject(self, &AssociatedKeys.placeholderColor) as? UIColor else { return nil }
+            return value
+        }
+    }
+
+
+    // MARK: - Helper functions
+    func initializePlaceholder(){
+        guard floating == true else {
+            return
+        }
+        if let _ = placeholderLabel(){
+            return
+        }
+
+        addObserver(self, forKeyPath: "placeholder", options: NSKeyValueObservingOptions.new, context: nil)
+        NotificationCenter.default.addObserver(self, selector: #selector(handleKeyboard), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
+
+
+        let label = UILabel(frame: CGRect(origin: CGPoint(x: 5, y: 0), size: bounds.size))
+        label.text = placeholder
+        label.font = font
+        addSubview(label)
+        placeholder = ""
+        let gesture = UITapGestureRecognizer(target: self, action: #selector(animatePlaceholderLabel))
+        label.isUserInteractionEnabled = true
+        label.tag = 765678
+        label.addGestureRecognizer(gesture)
+    }
+
+
+    func placeholderLabel() ->UILabel? {
+        if let label = viewWithTag(765678) as? UILabel{
+            return label
+        }
+        return nil
+    }
+
+    fileprivate  func fontSize() ->CGFloat? {
+        return font?.pointSize
+    }
+
+    fileprivate  func fontName() ->String? {
+        return font?.familyName
+    }
+
+    fileprivate func updatePlaceholder() {
+        guard let label = placeholderLabel() else { return }
+        label.text = placeholder
+        attributedPlaceholder = NSAttributedString(string: placeholder!, attributes: [NSAttributedStringKey.foregroundColor : UIColor.clear])
+    }
+
+    fileprivate func updatePlaceholderAppearance() {
+        guard let label = placeholderLabel() else { return }
+        label.font = self.font
+        label.textColor = placeholderColor
+    }
+
+
+    @objc private func animatePlaceholderLabel() {
+        becomeFirstResponder()
+        guard let label = placeholderLabel() else { return }
+        UIView.animate(withDuration: 0.5, animations: {
+            label.frame = CGRect(origin: CGPoint(x: 5, y: -(self.bounds.size.height * 0.5 + 3)), size: CGSize(width: self.bounds.size.width * 0.5, height: self.bounds.size.height * 0.5))
+        })
+    }
+
+    @objc func handleKeyboard() {
+        if let count = text?.count, count > 0 { return }
+        guard let label = placeholderLabel() else { return }
+        UIView.animate(withDuration: 0.3, animations: {
+            label.frame = CGRect(origin: CGPoint(x: 5, y: 0), size: self.bounds.size)
+            if let name = self.fontName(), let size = self.fontSize(){
+                label.font = UIFont(name: name, size: size)
+            }
+        })
+    }
+
+
+
+    open override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
+        if let path = keyPath, path == "placeholder" {
+            updatePlaceholder()
+        }
+    }
+
+
+    /*
+    // Only override draw() if you perform custom drawing.
+    // An empty implementation adversely affects performance during animation.
+    override func draw(_ rect: CGRect) {
+        // Drawing code
+    }
+    */
+
+}