Only show delete button on selected rail item

Signal/Images.xcassets/ic_circled_x.imageset/Contents.json

@@ -2,17 +2,17 @@
   "images" : [
     {
       "idiom" : "universal",
-      "filename" : "x-shadow-12@1x.png",
+      "filename" : "x-circle-shadow-24@1x.png",
       "scale" : "1x"
     },
     {
       "idiom" : "universal",
-      "filename" : "x-shadow-12@2x.png",
+      "filename" : "x-circle-shadow-24@2x.png",
       "scale" : "2x"
     },
     {
       "idiom" : "universal",
-      "filename" : "x-shadow-12@3x.png",
+      "filename" : "x-circle-shadow-24@3x.png",
       "scale" : "3x"
     }
   ],

Signal/src/ViewControllers/MediaPageViewController.swift

@@ -1,5 +1,5 @@
 //
-//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2019 Open Whisper Systems. All rights reserved.
 //
 
 import UIKit
@@ -331,7 +331,9 @@ class MediaPageViewController: UIPageViewController, UIPageViewControllerDataSou
             return
         }
 
-        galleryRailView.configureCellViews(itemProvider: currentItem.album, focusedItem: currentItem, cellViewDecoratorBlock: { _ in })
+        galleryRailView.configureCellViews(itemProvider: currentItem.album,
+                                           focusedItem: currentItem,
+                                           cellViewBuilder: { return GalleryRailCellView() })
     }
 
     // MARK: Actions

SignalMessaging/ViewControllers/AttachmentApprovalViewController.swift

@@ -400,29 +400,6 @@ public class AttachmentApprovalViewController: UIPageViewController, UIPageViewC
         })
     }
 
-    func addDeleteIcon(cellView: GalleryRailCellView) {
-        guard let attachmentItem = cellView.item as? SignalAttachmentItem else {
-            owsFailDebug("attachmentItem was unexpectedly nil")
-            return
-        }
-
-        let button = OWSButton { [weak self] in
-            guard let strongSelf = self else { return }
-            strongSelf.remove(attachmentItem: attachmentItem)
-        }
-        button.setImage(#imageLiteral(resourceName: "ic_small_x"), for: .normal)
-
-        let kInsetDistance: CGFloat = 5
-        button.imageEdgeInsets = UIEdgeInsets(top: kInsetDistance, left: kInsetDistance, bottom: kInsetDistance, right: kInsetDistance)
-
-        cellView.addSubview(button)
-
-        let kButtonWidth: CGFloat = 9 + kInsetDistance * 2
-        button.autoSetDimensions(to: CGSize(width: kButtonWidth, height: kButtonWidth))
-        button.autoPinEdge(toSuperviewMargin: .top)
-        button.autoPinEdge(toSuperviewMargin: .trailing)
-    }
-
     lazy var pagerScrollView: UIScrollView? = {
         // This is kind of a hack. Since we don't have first class access to the superview's `scrollView`
         // we traverse the view hierarchy until we find it.
@@ -566,12 +543,15 @@ public class AttachmentApprovalViewController: UIPageViewController, UIPageViewC
             return
         }
 
-        let cellViewDecoratorBlock = { (cellView: GalleryRailCellView) in
-            self.addDeleteIcon(cellView: cellView)
+        let cellViewBuilder: () -> ApprovalRailCellView = { [weak self] in
+            let cell = ApprovalRailCellView()
+            cell.approvalRailCellDelegate = self
+            return cell
         }
+
         galleryRailView.configureCellViews(itemProvider: attachmentItemCollection,
                                            focusedItem: currentItem,
-                                           cellViewDecoratorBlock: cellViewDecoratorBlock)
+                                           cellViewBuilder: cellViewBuilder)
 
         galleryRailView.isHidden = attachmentItemCollection.attachmentItems.count < 2
     }
@@ -1934,3 +1914,54 @@ class MediaMessageTextToolbar: UIView, UITextViewDelegate {
         return CGFloatClamp(contentSize.height, kMinTextViewHeight, maxTextViewHeight)
     }
 }
+
+extension AttachmentApprovalViewController: ApprovalRailCellViewDelegate {
+    func approvalRailCellView(_ approvalRailCellView: ApprovalRailCellView, didRemoveItem attachmentItem: SignalAttachmentItem) {
+        remove(attachmentItem: attachmentItem)
+    }
+}
+
+protocol ApprovalRailCellViewDelegate: class {
+    func approvalRailCellView(_ approvalRailCellView: ApprovalRailCellView, didRemoveItem attachmentItem: SignalAttachmentItem)
+}
+
+public class ApprovalRailCellView: GalleryRailCellView {
+
+    weak var approvalRailCellDelegate: ApprovalRailCellViewDelegate?
+
+    lazy var deleteButton: UIButton = {
+        let button = OWSButton { [weak self] in
+            guard let strongSelf = self else { return }
+
+            guard let attachmentItem = strongSelf.item as? SignalAttachmentItem else {
+                owsFailDebug("attachmentItem was unexpectedly nil")
+                return
+            }
+
+            strongSelf.approvalRailCellDelegate?.approvalRailCellView(strongSelf, didRemoveItem: attachmentItem)
+        }
+
+        button.setImage(#imageLiteral(resourceName: "ic_circled_x"), for: .normal)
+
+        let kInsetDistance: CGFloat = 5
+        button.imageEdgeInsets = UIEdgeInsets(top: kInsetDistance, left: kInsetDistance, bottom: kInsetDistance, right: kInsetDistance)
+
+        let kButtonWidth: CGFloat = 24 + kInsetDistance * 2
+        button.autoSetDimensions(to: CGSize(width: kButtonWidth, height: kButtonWidth))
+
+        return button
+    }()
+
+    override func setIsSelected(_ isSelected: Bool) {
+        super.setIsSelected(isSelected)
+
+        if isSelected {
+            addSubview(deleteButton)
+
+            deleteButton.autoPinEdge(toSuperviewEdge: .top, withInset: -12)
+            deleteButton.autoPinEdge(toSuperviewEdge: .trailing, withInset: -8)
+        } else {
+            deleteButton.removeFromSuperview()
+        }
+    }
+}

SignalMessaging/Views/GalleryRailView.swift

@@ -1,5 +1,5 @@
 //
-//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2019 Open Whisper Systems. All rights reserved.
 //
 
 import PromiseKit
@@ -25,7 +25,7 @@ public class GalleryRailCellView: UIView {
         super.init(frame: frame)
 
         layoutMargins = .zero
-        self.clipsToBounds = true
+        clipsToBounds = false
         addSubview(imageView)
         imageView.autoPinEdgesToSuperviewMargins()
 
@@ -107,7 +107,9 @@ public class GalleryRailView: UIView, GalleryRailCellViewDelegate {
 
     override init(frame: CGRect) {
         super.init(frame: frame)
+        clipsToBounds = false
         addSubview(scrollView)
+        scrollView.clipsToBounds = false
         scrollView.layoutMargins = .zero
         scrollView.autoPinEdgesToSuperviewMargins()
     }
@@ -118,7 +120,7 @@ public class GalleryRailView: UIView, GalleryRailCellViewDelegate {
 
     // MARK: Public
 
-    public func configureCellViews(itemProvider: GalleryRailItemProvider?, focusedItem: GalleryRailItem?, cellViewDecoratorBlock: (GalleryRailCellView) -> Void) {
+    public func configureCellViews(itemProvider: GalleryRailItemProvider?, focusedItem: GalleryRailItem?, cellViewBuilder: () -> GalleryRailCellView) {
         let animationDuration: TimeInterval = 0.2
 
         guard let itemProvider = itemProvider else {
@@ -169,11 +171,12 @@ public class GalleryRailView: UIView, GalleryRailCellViewDelegate {
             self.isHidden = false
         }
 
-        let cellViews = buildCellViews(items: itemProvider.railItems, cellViewDecoratorBlock: cellViewDecoratorBlock)
+        let cellViews = buildCellViews(items: itemProvider.railItems, cellViewBuilder: cellViewBuilder)
         self.cellViews = cellViews
         let stackView = UIStackView(arrangedSubviews: cellViews)
         stackView.axis = .horizontal
         stackView.spacing = 2
+        stackView.clipsToBounds = false
 
         scrollView.addSubview(stackView)
         stackView.autoPinEdgesToSuperviewEdges()
@@ -203,11 +206,10 @@ public class GalleryRailView: UIView, GalleryRailCellViewDelegate {
         return scrollView
     }()
 
-    private func buildCellViews(items: [GalleryRailItem], cellViewDecoratorBlock: (GalleryRailCellView) -> Void) -> [GalleryRailCellView] {
+    private func buildCellViews(items: [GalleryRailItem], cellViewBuilder: () -> GalleryRailCellView) -> [GalleryRailCellView] {
         return items.map { item in
-            let cellView = GalleryRailCellView()
+            let cellView = cellViewBuilder()
             cellView.configure(item: item, delegate: self)
-            cellViewDecoratorBlock(cellView)
             return cellView
         }
     }