Created
February 28, 2018 08:11
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Visibility Toggler UIView Extension
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| // | |
| // VisibilityToggler+UIView.swift | |
| // | |
| private var associatedPropertyHeight: CGFloat = 0 | |
| private var associatedPropertyWidth: CGFloat = 0 | |
| extension UIView { | |
| fileprivate var visibilityConstraintIdentifier: String { return "UIVisibilityGenerated" } | |
| fileprivate var height: CGFloat? { | |
| get { | |
| return objc_getAssociatedObject(self, &associatedPropertyHeight) as? CGFloat | |
| } | |
| set(newValue) { | |
| objc_setAssociatedObject(self, &associatedPropertyHeight, newValue, objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN) | |
| } | |
| } | |
| fileprivate var width: CGFloat? { | |
| get { | |
| return objc_getAssociatedObject(self, &associatedPropertyWidth) as? CGFloat | |
| } | |
| set(newValue) { | |
| objc_setAssociatedObject(self, &associatedPropertyWidth, newValue, objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN) | |
| } | |
| } | |
| func updateConstrainedHeight(_ height: CGFloat) { | |
| if let constraint = getConstraintBy(type: .height) { | |
| constraint.constant = height | |
| } | |
| self.height = height | |
| } | |
| func updateConstrainedWidth(_ width: CGFloat) { | |
| if let constraint = getConstraintBy(type: .width) { | |
| constraint.constant = width | |
| } | |
| self.width = width | |
| } | |
| func zeroHeight(animated: Bool = false) { | |
| if animated { | |
| superview?.layoutIfNeeded() | |
| UIView.animate(withDuration: 0.3, animations: { | |
| self.zeroHeightContraint() | |
| }) | |
| } else { | |
| zeroHeightContraint() | |
| } | |
| } | |
| private func zeroHeightContraint() { | |
| clipsToBounds = true | |
| if let constraint = getConstraintBy(type: .height) { | |
| if constraint.constant > 0 { | |
| self.height = constraint.constant | |
| } | |
| constraint.constant = 0 | |
| superview?.layoutIfNeeded() | |
| } | |
| } | |
| func zeroWidth() { | |
| clipsToBounds = true | |
| if let constraint = getConstraintBy(type: .width) { | |
| if constraint.constant > 0 { | |
| self.width = constraint.constant | |
| } | |
| constraint.constant = 0 | |
| superview?.layoutIfNeeded() | |
| } | |
| } | |
| func restoreHeight(animated: Bool = false) { | |
| if animated { | |
| superview?.layoutIfNeeded() | |
| UIView.animate(withDuration: 0.3, animations: { | |
| self.restoreHeightConstraint() | |
| }) | |
| } else { | |
| restoreHeightConstraint() | |
| } | |
| } | |
| private func restoreHeightConstraint() { | |
| if let constraint = getConstraintBy(type: .height) { | |
| if constraint.constant == 0 { | |
| if self.height != nil { | |
| constraint.constant = self.height! | |
| } else { | |
| constraint.constant = self.frame.height | |
| } | |
| if constraint.identifier == visibilityConstraintIdentifier { | |
| removeConstraint(constraint) | |
| } | |
| superview?.layoutIfNeeded() | |
| } | |
| } | |
| } | |
| func restoreWidth() { | |
| if let constraint = getConstraintBy(type: .width) { | |
| if constraint.constant == 0 { | |
| if self.width != nil { | |
| constraint.constant = self.width! | |
| } else { | |
| constraint.constant = self.frame.width | |
| } | |
| if constraint.identifier == visibilityConstraintIdentifier { | |
| removeConstraint(constraint) | |
| } | |
| superview?.layoutIfNeeded() | |
| } | |
| } | |
| } | |
| func getConstant(type: NSLayoutAttribute) -> CGFloat? { | |
| guard let constraint = getConstraintBy(type: type) else { return nil } | |
| return constraint.constant | |
| } | |
| func isVisible() -> Bool { | |
| if let heightConstraint = getConstraintBy(type: .height, createNewIfNotFound: false) { | |
| return heightConstraint.constant != 0 && isHidden == false | |
| } else if let widthConstraint = getConstraintBy(type: .width, createNewIfNotFound: false) { | |
| return widthConstraint.constant != 0 && isHidden == false | |
| } | |
| return isHidden == false | |
| } | |
| fileprivate func getConstraintBy(type: NSLayoutAttribute, createNewIfNotFound: Bool = true) -> NSLayoutConstraint? { | |
| var returnConstraint: NSLayoutConstraint? = nil | |
| for constraint in self.constraints { | |
| if constraint.firstAttribute == type && type(of: constraint) == NSLayoutConstraint.self { | |
| if returnConstraint == nil { | |
| returnConstraint = constraint | |
| } else { | |
| AppLogWarning("Operating on view with multiple \(type.rawValue) constraints: \(constraint)") | |
| } | |
| } | |
| } | |
| if returnConstraint == nil && createNewIfNotFound { | |
| let newConstraint = NSLayoutConstraint(item: self, attribute: type, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1, constant: 0) | |
| newConstraint.identifier = visibilityConstraintIdentifier | |
| addConstraint(newConstraint) | |
| returnConstraint = newConstraint | |
| } | |
| return returnConstraint | |
| } | |
| } |
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