Implement InputTextView with support to a placeholder

MessageKit.xcodeproj/project.pbxproj

@@ -7,6 +7,7 @@
 	objects = {
 
 /* Begin PBXBuildFile section */
+		171D5AB91F36712B0053DF69 /* InputTextView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 171D5AB81F36712B0053DF69 /* InputTextView.swift */; };
 		882D75841DE507320033F95F /* MessagesDataSource.swift in Sources */ = {isa = PBXBuildFile; fileRef = 882D75831DE507320033F95F /* MessagesDataSource.swift */; };
 		888CEBFC1D3FD525005178DE /* MessagesViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 888CEBFB1D3FD525005178DE /* MessagesViewController.swift */; };
 		88916B2D1CF0DF2F00469F91 /* MessageKit.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 88916B221CF0DF2F00469F91 /* MessageKit.framework */; };
@@ -43,6 +44,7 @@
 /* End PBXContainerItemProxy section */
 
 /* Begin PBXFileReference section */
+		171D5AB81F36712B0053DF69 /* InputTextView.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = InputTextView.swift; sourceTree = "<group>"; };
 		882D75831DE507320033F95F /* MessagesDataSource.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = MessagesDataSource.swift; sourceTree = "<group>"; };
 		888CEBFB1D3FD525005178DE /* MessagesViewController.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = MessagesViewController.swift; sourceTree = "<group>"; };
 		88916B221CF0DF2F00469F91 /* MessageKit.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = MessageKit.framework; sourceTree = BUILT_PRODUCTS_DIR; };
@@ -157,6 +159,7 @@
 				B0655A2D1F23D8BC00542A83 /* MessagesCollectionView.swift */,
 				B0655A4C1F244C0600542A83 /* MessageCollectionViewCell.swift */,
 				B0655A371F23EE8B00542A83 /* MessageInputBar.swift */,
+				171D5AB81F36712B0053DF69 /* InputTextView.swift */,
 				B074EE921F35587100ABB8C8 /* MessageHeaderView.swift */,
 				B074EE941F35588A00ABB8C8 /* MessageFooterView.swift */,
 			);
@@ -328,6 +331,7 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				171D5AB91F36712B0053DF69 /* InputTextView.swift in Sources */,
 				B074EE971F355FBC00ABB8C8 /* MessagesLayoutDelegate.swift in Sources */,
 				882D75841DE507320033F95F /* MessagesDataSource.swift in Sources */,
 				888CEBFC1D3FD525005178DE /* MessagesViewController.swift in Sources */,

Sources/InputTextView.swift

@@ -0,0 +1,109 @@
+/*
+ MIT License
+ 
+ Copyright (c) 2017 MessageKit
+ 
+ Permission is hereby granted, free of charge, to any person obtaining a copy
+ of this software and associated documentation files (the "Software"), to deal
+ in the Software without restriction, including without limitation the rights
+ to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ copies of the Software, and to permit persons to whom the Software is
+ furnished to do so, subject to the following conditions:
+ 
+ The above copyright notice and this permission notice shall be included in all
+ copies or substantial portions of the Software.
+ 
+ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ SOFTWARE.
+ */
+
+import UIKit
+
+open class InputTextView: UITextView {
+
+    // MARK: - Properties
+
+    open var placeholder: NSString? {
+        didSet {
+            guard placeholder != oldValue else { return }
+            setNeedsDisplay()
+        }
+    }
+
+    open var placeholderTextColor: UIColor = .lightGray {
+        didSet {
+            guard placeholderTextColor != oldValue else { return }
+            setNeedsDisplay()
+        }
+    }
+
+    open var placeholderInsets: UIEdgeInsets = UIEdgeInsets(top: 7,
+                                                            left: 5,
+                                                            bottom: 7,
+                                                            right: 5) {
+        didSet {
+            guard placeholderInsets != oldValue else { return }
+            setNeedsDisplay()
+        }
+    }
+
+    // MARK: - Initializers
+
+    override public init(frame: CGRect, textContainer: NSTextContainer?) {
+        super.init(frame: frame, textContainer: textContainer)
+        commonInit()
+    }
+
+    required public init?(coder aDecoder: NSCoder) {
+        super.init(coder: aDecoder)
+        commonInit()
+    }
+
+    deinit {
+        NotificationCenter.default.removeObserver(self)
+    }
+
+    // MARK: - Methods
+
+    override open func draw(_ rect: CGRect) {
+        super.draw(rect)
+
+        guard text.isEmpty, let placeholder = placeholder else { return }
+
+        let paragraphStyle = NSMutableParagraphStyle()
+        paragraphStyle.alignment = textAlignment
+
+        var attributes: [String: Any] = [
+            NSForegroundColorAttributeName: placeholderTextColor,
+            NSParagraphStyleAttributeName: paragraphStyle
+        ]
+        if let font = font {
+            attributes[NSFontAttributeName] = font
+        }
+
+        placeholder.draw(in: UIEdgeInsetsInsetRect(rect, placeholderInsets),
+                         withAttributes: attributes)
+
+    }
+
+    fileprivate func commonInit() {
+        NotificationCenter.default.addObserver(self,
+                                               selector: #selector(textDidChange),
+                                               name: NSNotification.Name.UITextViewTextDidChange,
+                                               object: self)
+    }
+
+    func textDidChange(notification: Notification) {
+        guard let notificationObject = notification.object as? InputTextView,
+            notificationObject === self else { return }
+
+        setNeedsDisplay()
+
+    }
+
+}

Sources/MessageInputBar.swift

@@ -30,10 +30,10 @@ open class MessageInputBar: UIView, UITextViewDelegate {
 
     open let inputTextView: UITextView = {
 
-        let inputTextView = UITextView(frame: .zero)
+        let inputTextView = InputTextView(frame: .zero)
         inputTextView.font = UIFont.preferredFont(forTextStyle: .body)
-        inputTextView.text = "New Message"
-        inputTextView.textColor = .lightGray
+        inputTextView.textColor = .black
+        inputTextView.placeholder = "New Message"
         inputTextView.backgroundColor = .white
         inputTextView.layer.borderColor = UIColor.lightGray.cgColor
         inputTextView.layer.borderWidth = 1.0
@@ -97,7 +97,7 @@ open class MessageInputBar: UIView, UITextViewDelegate {
 
     public func textViewDidChange(_ textView: UITextView) {
         let trimmedText = textView.text.trimmingCharacters(in: .whitespacesAndNewlines)
-        sendButton.isEnabled = !trimmedText.isEmpty && textView.text != "New Message"
+        sendButton.isEnabled = !trimmedText.isEmpty
         invalidateIntrinsicContentSize()
     }