optimize custom empty data view layout

Author: hongxinhope

Example/EmptyDataDemoCollectionViewController.swift

@@ -118,6 +118,10 @@ class EmptyDataDemoCollectionViewController: UICollectionViewController, TBEmpty
 
     func customViewForEmptyDataSet(scrollView: UIScrollView!) -> UIView? {
         let loadingView: UIView = {
+            if indexPath.row == 2 {
+                return ExampleCustomView(frame: CGRect.zero)
+            }
+
             let loadingImageView = UIImageView(image: UIImage(named: "loading")!)
             let view = UIView(frame: loadingImageView.frame)
             view.addSubview(loadingImageView)
@@ -208,3 +212,41 @@ extension EmptyDataDemoCollectionViewController: UICollectionViewDelegateFlowLay
         }
     }
 }
+
+class ExampleCustomView: UIView {
+    private lazy var contentLabel: UILabel = {
+        let contentLabel = UILabel()
+        contentLabel.numberOfLines = 0
+        contentLabel.textColor = UIColor.whiteColor()
+        contentLabel.translatesAutoresizingMaskIntoConstraints = false
+        return contentLabel
+    }()
+
+    override init(frame: CGRect) {
+        super.init(frame: frame)
+        commonInit()
+    }
+
+    required init?(coder aDecoder: NSCoder) {
+        super.init(coder: aDecoder)
+        commonInit()
+    }
+
+    private func commonInit() {
+        backgroundColor = UIColor.lightGrayColor()
+        layer.cornerRadius = 6
+
+        let activityIndicatorView = UIActivityIndicatorView(activityIndicatorStyle: .WhiteLarge)
+        activityIndicatorView.translatesAutoresizingMaskIntoConstraints = false
+        activityIndicatorView.startAnimating()
+        contentLabel.text = "Loading... Please wait a moment...\n\n(This is a custom empty data view, which is using pure AutoLayout)"
+        addSubview(activityIndicatorView)
+        addSubview(contentLabel)
+
+        addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|-15-[activityIndicatorView]-20-[contentLabel]-15-|", options: [], metrics: nil, views: ["activityIndicatorView": activityIndicatorView, "contentLabel": contentLabel]))
+        addConstraint(NSLayoutConstraint(item: activityIndicatorView, attribute: .CenterX, relatedBy: .Equal, toItem: self, attribute: .CenterX, multiplier: 1, constant: 0))
+        addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|-15-[contentLabel]-15-|", options: [], metrics: nil, views: ["contentLabel": contentLabel]))
+
+        translatesAutoresizingMaskIntoConstraints = false
+    }
+}

Example/Info.plist

@@ -15,11 +15,11 @@
 	<key>CFBundlePackageType</key>
 	<string>APPL</string>
 	<key>CFBundleShortVersionString</key>
-	<string>1.7</string>
+	<string>1.8</string>
 	<key>CFBundleSignature</key>
 	<string>????</string>
 	<key>CFBundleVersion</key>
-	<string>8</string>
+	<string>9</string>
 	<key>LSRequiresIPhoneOS</key>
 	<true/>
 	<key>UILaunchStoryboardName</key>

TBEmptyDataSet.podspec

@@ -1,7 +1,7 @@
 Pod::Spec.new do |s|
 
   s.name         = "TBEmptyDataSet"
-  s.version      = "1.7"
+  s.version      = "1.8"
   s.summary      = "An extension of UITableView/UICollectionView's super class, it will display a placeholder when the data is empty."
 
   s.homepage     = "https://github.com/teambition/TBEmptyDataSet"

TBEmptyDataSet/EmptyDataView.swift

@@ -64,14 +64,13 @@ class EmptyDataView: UIView {
     var tapGesture: UITapGestureRecognizer!
     var customView: UIView? {
         willSet {
-            if let _ = customView {
-                customView!.removeFromSuperview()
+            if let customView = customView {
+                customView.removeFromSuperview()
             }
         }
         didSet {
-            if let _ = customView {
-                customView!.translatesAutoresizingMaskIntoConstraints = false
-                contentView.addSubview(customView!)
+            if let customView = customView {
+                contentView.addSubview(customView)
             }
         }
     }
@@ -133,11 +132,22 @@ class EmptyDataView: UIView {
         addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|[\(ViewStrings.contentView)]|", options: [], metrics: nil, views: [ViewStrings.contentView : contentView]))
 
         if let customView = customView {
-            contentView.addConstraint(NSLayoutConstraint(item: customView, attribute: .CenterX, relatedBy: .Equal, toItem: contentView, attribute: .CenterX, multiplier: 1, constant: 0))
-            contentView.addConstraint(NSLayoutConstraint(item: customView, attribute: .CenterY, relatedBy: .Equal, toItem: contentView, attribute: .CenterY, multiplier: 1, constant: 0))
-            contentView.addConstraint(NSLayoutConstraint(item: customView, attribute: .Width, relatedBy: .Equal, toItem: .None, attribute: .NotAnAttribute, multiplier: 1, constant: customView.frame.width))
-            contentView.addConstraint(NSLayoutConstraint(item: customView, attribute: .Height, relatedBy: .Equal, toItem: .None, attribute: .NotAnAttribute, multiplier: 1, constant: customView.frame.height))
-            contentView.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|[\(ViewStrings.customView)]|", options: [], metrics: nil, views: [ViewStrings.customView: customView]))
+            let translatesFrameIntoConstraints = customView.translatesAutoresizingMaskIntoConstraints
+            customView.translatesAutoresizingMaskIntoConstraints = false
+
+            if translatesFrameIntoConstraints {
+                contentView.addConstraint(NSLayoutConstraint(item: customView, attribute: .Width, relatedBy: .Equal, toItem: .None, attribute: .NotAnAttribute, multiplier: 1, constant: customView.frame.width))
+                contentView.addConstraint(NSLayoutConstraint(item: customView, attribute: .Height, relatedBy: .Equal, toItem: .None, attribute: .NotAnAttribute, multiplier: 1, constant: customView.frame.height))
+
+                contentView.addConstraint(NSLayoutConstraint(item: customView, attribute: .CenterX, relatedBy: .Equal, toItem: contentView, attribute: .CenterX, multiplier: 1, constant: 0))
+                contentView.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|[\(ViewStrings.customView)]|", options: [], metrics: nil, views: [ViewStrings.customView: customView]))
+            } else {
+                contentView.addConstraint(NSLayoutConstraint(item: customView, attribute: .CenterX, relatedBy: .Equal, toItem: contentView, attribute: .CenterX, multiplier: 1, constant: 0))
+                contentView.addConstraint(NSLayoutConstraint(item: customView, attribute: .Leading, relatedBy: .GreaterThanOrEqual, toItem: contentView, attribute: .Leading, multiplier: 1, constant: 0))
+                contentView.addConstraint(NSLayoutConstraint(item: customView, attribute: .Trailing, relatedBy: .LessThanOrEqual, toItem: contentView, attribute: .Trailing, multiplier: 1, constant: 0))
+
+                contentView.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|[\(ViewStrings.customView)]|", options: [], metrics: nil, views: [ViewStrings.customView: customView]))
+            }
         } else {
             var viewStrings = [String]()
             var views = [String: UIView]()

TBEmptyDataSet/Supporting Files/Info.plist

@@ -15,7 +15,7 @@
 	<key>CFBundlePackageType</key>
 	<string>FMWK</string>
 	<key>CFBundleShortVersionString</key>
-	<string>1.7</string>
+	<string>1.8</string>
 	<key>CFBundleSignature</key>
 	<string>????</string>
 	<key>CFBundleVersion</key>