adds the StatefulPlaceholderView protocol to configure custom insets …

…for placeholder views
aschuch · Apr 13, 2016 · b4d6c10 · b4d6c10
1 parent 3b54a1c
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diff --git a/Example.xcodeproj/project.pbxproj b/Example.xcodeproj/project.pbxproj
@@ -8,6 +8,8 @@
 
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@@ -70,6 +72,7 @@
 
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@@ -132,6 +135,7 @@
 				4D6451661A64089800108EA3 /* StatefulViewController.swift */,
 				4DC230DC1BB5BA810083B95A /* StatefulViewControllerImplementation.swift */,
 				4D6451671A64089800108EA3 /* ViewStateMachine.swift */,
+				4D4ECAD31CBE89EA000CF6FA /* StatefulPlaceholderView.swift */,
 				4D64514A1A64079200108EA3 /* StatefulViewController.h */,
 				4D6451481A64079200108EA3 /* Supporting Files */,
 			);
@@ -401,6 +405,7 @@
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 				4DC230DD1BB5BA810083B95A /* StatefulViewControllerImplementation.swift in Sources */,
 				4D6451691A64089800108EA3 /* ViewStateMachine.swift in Sources */,
+				4D4ECAD51CBE8B32000CF6FA /* StatefulPlaceholderView.swift in Sources */,
 				4D6451681A64089800108EA3 /* StatefulViewController.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
@@ -432,6 +437,7 @@
 			files = (
 				523646921C6F88CF00392180 /* StatefulViewControllerImplementation.swift in Sources */,
 				523646931C6F88CF00392180 /* ViewStateMachine.swift in Sources */,
+				4D4ECAD61CBE8B33000CF6FA /* StatefulPlaceholderView.swift in Sources */,
 				523646911C6F88CF00392180 /* StatefulViewController.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;

diff --git a/Example/PlaceholderViews/LoadingView.swift b/Example/PlaceholderViews/LoadingView.swift
@@ -7,15 +7,16 @@
 //
 
 import UIKit
+import StatefulViewController
 
-class LoadingView: BasicPlaceholderView {
+class LoadingView: BasicPlaceholderView, StatefulPlaceholderView {
 
 	let label = UILabel()
 
 	override func setupView() {
 		super.setupView()
 
-		backgroundColor = UIColor.whiteColor()
+		backgroundColor = UIColor.redColor()
 
 		label.text = "Loading..."
 		label.translatesAutoresizingMaskIntoConstraints = false
@@ -36,4 +37,8 @@ class LoadingView: BasicPlaceholderView {
 		centerView.addConstraints(vConstraintsActivity)
 	}
 
+    func placeholderViewInsets() -> UIEdgeInsets {
+        return UIEdgeInsets(top: 100, left: 10, bottom: 200, right: 50)
+    }
+
 }
diff --git a/README.md b/README.md
@@ -98,7 +98,24 @@ func handleErrorWhenContentAvailable(error: ErrorType) {
 }
 ```
 
+
+
+### Custom Placeholder View insets
+
+Per default, StatefulViewController presents all configured placeholder views fullscreen (i.e. with 0 insets from top, bottom, left & right from the superview). In case a placeholder view should have custom insets the configured placeholderview may conform to the `StatefulPlaceholderView` protocol and override the `placeholderViewInsets` method to return custom edge insets.
+
+```swift
+class MyPlaceholderView: UIView, StatefulPlaceholderView {
+  func placeholderViewInsets() -> UIEdgeInsets {
+	return UIEdgeInsets(top: 20, left: 20, bottom: 20, right: 20)
+  }
+}
+```
+
+
+
 <a name="viewstatemachine"></a>
+
 ### View State Machine
 
 > Note: The following section is only intended for those, who want to create a stateful controller that differs from the flow described above.

diff --git a/StatefulViewController/StatefulPlaceholderView.swift b/StatefulViewController/StatefulPlaceholderView.swift
@@ -0,0 +1,24 @@
+//
+//  StatefulPlaceholderView.swift
+//  Example
+//
+//  Created by Alexander Schuch on 13/04/16.
+//  Copyright © 2016 Alexander Schuch. All rights reserved.
+//
+
+import UIKit
+
+public protocol StatefulPlaceholderView {
+    /// Defines the insets to apply when presented via the `StatefulViewController`
+    /// Return insets here in order to inset the current placeholder view from the edges 
+    /// of the parent view.
+    func placeholderViewInsets() -> UIEdgeInsets
+}
+
+extension StatefulPlaceholderView {
+
+    public func placeholderViewInsets() -> UIEdgeInsets {
+        return UIEdgeInsets()
+    }
+
+}
diff --git a/StatefulViewController/ViewStateMachine.swift b/StatefulViewController/ViewStateMachine.swift
@@ -149,10 +149,13 @@ public class ViewStateMachine {
             newView.alpha = animated ? 0.0 : 1.0
             newView.translatesAutoresizingMaskIntoConstraints = false
             self.view.addSubview(newView)
-
+
+            let insets = (newView as? StatefulPlaceholderView)?.placeholderViewInsets() ?? UIEdgeInsets()
+            let metrics = ["top": insets.top, "bottom": insets.bottom, "left": insets.left, "right": insets.right]
             let views = ["view": newView]
-            let hConstraints = NSLayoutConstraint.constraintsWithVisualFormat("|[view]|", options: [], metrics: nil, views: views)
-            let vConstraints = NSLayoutConstraint.constraintsWithVisualFormat("V:|[view]|", options: [], metrics: nil, views: views)
+
+            let hConstraints = NSLayoutConstraint.constraintsWithVisualFormat("|-left-[view]-right-|", options: [], metrics: metrics, views: views)
+            let vConstraints = NSLayoutConstraint.constraintsWithVisualFormat("V:|-top-[view]-bottom-|", options: [], metrics: metrics, views: views)
             self.view.addConstraints(hConstraints)
             self.view.addConstraints(vConstraints)
         }