Added Editor component

Material.xcodeproj/project.pbxproj

@@ -173,6 +173,7 @@
 		9D054A6520D175AC00D0528D /* Material+UIButton.swift in Sources */ = {isa = PBXBuildFile; fileRef = 9D054A6320D175AC00D0528D /* Material+UIButton.swift */; };
 		9D054A6620D175AC00D0528D /* Material+UILabel.swift in Sources */ = {isa = PBXBuildFile; fileRef = 9D054A6420D175AC00D0528D /* Material+UILabel.swift */; };
 		9D39A81B20FE8ED100BA8FA1 /* ViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 9D39A81A20FE8ED100BA8FA1 /* ViewController.swift */; };
+		9D9089B92118914500605DC9 /* Editor.swift in Sources */ = {isa = PBXBuildFile; fileRef = 9D9089B82118914500605DC9 /* Editor.swift */; };
 		9DE84D721FF0252600586C8B /* RadioButtonGroup.swift in Sources */ = {isa = PBXBuildFile; fileRef = 9DE84D6F1FF0252500586C8B /* RadioButtonGroup.swift */; };
 		9DE84D731FF0252600586C8B /* BaseButtonGroup.swift in Sources */ = {isa = PBXBuildFile; fileRef = 9DE84D701FF0252500586C8B /* BaseButtonGroup.swift */; };
 		9DE84D741FF0252600586C8B /* CheckButtonGroup.swift in Sources */ = {isa = PBXBuildFile; fileRef = 9DE84D711FF0252500586C8B /* CheckButtonGroup.swift */; };
@@ -294,6 +295,7 @@
 		9D054A6320D175AC00D0528D /* Material+UIButton.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "Material+UIButton.swift"; sourceTree = "<group>"; };
 		9D054A6420D175AC00D0528D /* Material+UILabel.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "Material+UILabel.swift"; sourceTree = "<group>"; };
 		9D39A81A20FE8ED100BA8FA1 /* ViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ViewController.swift; sourceTree = "<group>"; };
+		9D9089B82118914500605DC9 /* Editor.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Editor.swift; sourceTree = "<group>"; };
 		9DE84D6F1FF0252500586C8B /* RadioButtonGroup.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = RadioButtonGroup.swift; sourceTree = "<group>"; };
 		9DE84D701FF0252500586C8B /* BaseButtonGroup.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = BaseButtonGroup.swift; sourceTree = "<group>"; };
 		9DE84D711FF0252500586C8B /* CheckButtonGroup.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = CheckButtonGroup.swift; sourceTree = "<group>"; };
@@ -321,6 +323,7 @@
 				96BCB79C1CB40DC500C806FE /* TextField.swift */,
 				961F18E71CD93E3E008927C5 /* ErrorTextField.swift */,
 				9DF58CED20C098C60098968D /* ErrorTextFieldValidator.swift */,
+				9D9089B82118914500605DC9 /* Editor.swift */,
 			);
 			name = Text;
 			sourceTree = "<group>";
@@ -978,6 +981,7 @@
 				965E811B1DD4D5C800D61E4B /* Switch.swift in Sources */,
 				965E811C1DD4D5C800D61E4B /* TabBar.swift in Sources */,
 				965E811D1DD4D5C800D61E4B /* TableViewCell.swift in Sources */,
+				9D9089B92118914500605DC9 /* Editor.swift in Sources */,
 				965E811E1DD4D5C800D61E4B /* TextField.swift in Sources */,
 				965E811F1DD4D5C800D61E4B /* ErrorTextField.swift in Sources */,
 				965E81211DD4D5C800D61E4B /* TextStorage.swift in Sources */,

Sources/iOS/Editor.swift

+/*
+ * Copyright (C) 2015 - 2018, Daniel Dahan and CosmicMind, Inc. <http://cosmicmind.com>.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *  *  Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ *  *  Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ *  *  Neither the name of CosmicMind nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+import UIKit
+
+public enum EditorPlaceholderAnimation {
+  case `default`
+  case hidden
+}
+
+open class Editor: View {
+  public let textView = TextView()
+  
+  /// A boolean indicating whether the textView is in edit mode.
+  open var isEditing: Bool {
+    return textView.isEditing
+  }
+  
+  /// A boolean indicating whether the text is empty.
+  open var isEmpty: Bool {
+    return textView.isEmpty
+  }
+  
+  /// The placeholder UILabel.
+  @IBInspectable
+  open var placeholderLabel: UILabel {
+    return textView.placeholderLabel
+  }
+  
+  /// A Boolean that indicates if the placeholder label is animated.
+  @IBInspectable
+  open var isPlaceholderAnimated = true
+  
+  /// Set the placeholder animation value.
+  open var placeholderAnimation = EditorPlaceholderAnimation.default {
+    didSet {
+      updatePlaceholderVisibility()
+    }
+  }
+  
+  /// Placeholder normal text color.
+  @IBInspectable
+  open var placeholderNormalColor = Color.darkText.others {
+    didSet {
+      updatePlaceholderLabelColor()
+    }
+  }
+  
+  /// Placeholder active text color.
+  @IBInspectable
+  open var placeholderActiveColor = Color.blue.base {
+    didSet {
+      updatePlaceholderLabelColor()
+    }
+  }
+  
+  /// The scale of the active placeholder in relation to the inactive.
+  @IBInspectable
+  open var placeholderActiveScale: CGFloat = 0.75 {
+    didSet {
+      layoutPlaceholderLabel()
+    }
+  }
+  
+  /// This property adds a padding to placeholder y position animation
+  @IBInspectable
+  open var placeholderVerticalOffset: CGFloat = 0
+  
+  /// This property adds a padding to placeholder x position animation
+  @IBInspectable
+  open var placeholderHorizontalOffset: CGFloat = 0
+  
+  /// A reference to titleLabel.textAlignment observation.
+  private var placeholderLabelTextObserver: NSKeyValueObservation!
+  
+  /**
+   A reference to textView.text observation.
+   Only observes programmatic changes.
+   */
+  private var textViewTextObserver: NSKeyValueObservation!
+  
+  open override func prepare() {
+    super.prepare()
+    prepareTextView()
+    preparePlaceholderLabel()
+    prepareNotificationHandlers()
+  }
+  
+  open override func layoutSubviews() {
+    super.layoutSubviews()
+    layoutPlaceholderLabel()
+  }
+}
+
+
+private extension Editor {
+  /// Prepares the textView.
+  func prepareTextView() {
+    layout(textView).edges()
+    textView.isPlaceholderLabelEnabled = false
+    
+    textViewTextObserver = textView.observe(\.text) { [weak self] _, _ in
+      self?.updateEditorState()
+    }
+  }
+  
+  /// Prepares the placeholderLabel.
+  func preparePlaceholderLabel() {
+    addSubview(placeholderLabel)
+    placeholderLabelTextObserver = placeholderLabel.observe(\.text) { [weak self] _, _ in
+      self?.layoutPlaceholderLabel()
+    }
+  }
+  
+  /// Prepares the Notification handlers.
+  func prepareNotificationHandlers() {
+    let center = NotificationCenter.default
+    center.addObserver(self, selector: #selector(handleTextViewTextDidBegin), name: UITextView.textDidBeginEditingNotification, object: textView)
+    center.addObserver(self, selector: #selector(handleTextViewTextDidChange), name: UITextView.textDidChangeNotification, object: textView)
+    center.addObserver(self, selector: #selector(handleTextViewTextDidEnd), name: UITextView.textDidEndEditingNotification, object: textView)
+  }
+}
+
+private extension Editor {
+  /// Updates the placeholderLabel text color.
+  func updatePlaceholderLabelColor() {
+    tintColor = placeholderActiveColor
+    placeholderLabel.textColor = isEditing ? placeholderActiveColor : placeholderNormalColor
+  }
+  
+  /// Updates the placeholder visibility.
+  func updatePlaceholderVisibility() {
+    guard isEditing else {
+      placeholderLabel.isHidden = !isEmpty && .hidden == placeholderAnimation
+      return
+    }
+    
+    placeholderLabel.isHidden = .hidden == placeholderAnimation
+  }
+}
+
+private extension Editor {
+  /// Layout the placeholderLabel.
+  func layoutPlaceholderLabel() {
+    let inset = textView.textContainerInsets
+    let leftPadding = inset.left + textView.textContainer.lineFragmentPadding
+    let rightPadding = inset.right + textView.textContainer.lineFragmentPadding
+    let w = bounds.width - leftPadding - rightPadding
+    var h = placeholderLabel.sizeThatFits(CGSize(width: w, height: .greatestFiniteMagnitude)).height
+    h = min(h, bounds.height - inset.top - inset.bottom)
+    
+    guard isEditing || !isEmpty || !isPlaceholderAnimated else {
+      placeholderLabel.transform = CGAffineTransform.identity
+      placeholderLabel.frame = CGRect(x: leftPadding, y: inset.top, width: w, height: h)
+      return
+    }
+    
+    placeholderLabel.transform = CGAffineTransform(scaleX: placeholderActiveScale, y: placeholderActiveScale)
+    placeholderLabel.frame.size = CGSize(width: w * placeholderActiveScale, height: h * placeholderActiveScale)
+    placeholderLabel.frame.origin.y = -placeholderLabel.frame.height + placeholderVerticalOffset
+    
+    switch placeholderLabel.textAlignment {
+    case .left, .natural:
+      placeholderLabel.frame.origin.x = leftPadding + placeholderHorizontalOffset
+    case .right:
+      let scaledWidth = w * placeholderActiveScale
+      placeholderLabel.frame.origin.x = bounds.width - scaledWidth - rightPadding + placeholderHorizontalOffset
+    default:break
+    }
+  }
+}
+
+private extension Editor {
+  /// Notification handler for when text editing began.
+  @objc
+  func handleTextViewTextDidBegin() {
+    updateEditorState(animated: true)
+  }
+  
+  /// Notification handler for when text changed.
+  @objc
+  func handleTextViewTextDidChange() {
+    updateEditorState()
+  }
+  
+  /// Notification handler for when text editing ended.
+  @objc
+  func handleTextViewTextDidEnd() {
+    updateEditorState(animated: true)
+  }
+  
+  func updateEditorState(animated: Bool = false) {
+    updatePlaceholderVisibility()
+    updatePlaceholderLabelColor()
+    
+    guard isPlaceholderAnimated else {
+      layoutPlaceholderLabel()
+      return
+    }
+    
+    UIView.animate(withDuration: 0.15, animations: layoutPlaceholderLabel)
+  }
+}