Add 'pagingDistance' property to FSPagerView.

bbkelleroglu · Sep 19, 2018 · 76f544f · 76f544f
1 parent 396cea1
commit 76f544f
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Showing 6 changed files with 55 additions and 21 deletions.
diff --git a/FSPageViewExample-Swift/FSPagerViewExample.xcodeproj/project.pbxproj b/FSPageViewExample-Swift/FSPagerViewExample.xcodeproj/project.pbxproj
@@ -43,6 +43,7 @@
 /* End PBXContainerItemProxy section */
 
 /* Begin PBXFileReference section */
+		50989DFE2151DB29004DBB4A /* FSPagerViewObjcCompat.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = FSPagerViewObjcCompat.h; sourceTree = "<group>"; };
 		F95483991E625F1E0069FD7E /* FSPagerViewLayoutAttributes.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = FSPagerViewLayoutAttributes.swift; sourceTree = "<group>"; };
 		F9580B511E5D995400C5B267 /* FSPageControl.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = FSPageControl.swift; sourceTree = "<group>"; };
 		F9580B521E5D995400C5B267 /* FSPagerCollectionView.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = FSPagerCollectionView.swift; sourceTree = "<group>"; };
@@ -99,6 +100,7 @@
 				F9580B551E5D995400C5B267 /* FSPageViewLayout.swift */,
 				F9580B561E5D995400C5B267 /* FSPageViewTransformer.swift */,
 				F95483991E625F1E0069FD7E /* FSPagerViewLayoutAttributes.swift */,
+				50989DFE2151DB29004DBB4A /* FSPagerViewObjcCompat.h */,
 			);
 			name = Sources;
 			path = ../Sources;

diff --git a/FSPagerView/FSPagerView.xcodeproj/project.pbxproj b/FSPagerView/FSPagerView.xcodeproj/project.pbxproj
@@ -7,6 +7,7 @@
 	objects = {
 
 /* Begin PBXBuildFile section */
+		50C44A1D2150E7800093B3E9 /* FSPagerViewObjcCompat.h in Headers */ = {isa = PBXBuildFile; fileRef = 50C44A1C2150E7800093B3E9 /* FSPagerViewObjcCompat.h */; };
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 		F9580B891E5D9F2B00C5B267 /* FSPagerCollectionView.swift in Sources */ = {isa = PBXBuildFile; fileRef = F9580B831E5D9F2B00C5B267 /* FSPagerCollectionView.swift */; };
@@ -18,6 +19,7 @@
 /* End PBXBuildFile section */
 
 /* Begin PBXFileReference section */
+		50C44A1C2150E7800093B3E9 /* FSPagerViewObjcCompat.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = FSPagerViewObjcCompat.h; sourceTree = "<group>"; };
 		F9580B761E5D9F0600C5B267 /* FSPagerView.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = FSPagerView.framework; sourceTree = BUILT_PRODUCTS_DIR; };
 		F9580B791E5D9F0600C5B267 /* FSPagerView.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = FSPagerView.h; sourceTree = "<group>"; };
 		F9580B7A1E5D9F0600C5B267 /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
@@ -77,6 +79,7 @@
 				F9580B861E5D9F2B00C5B267 /* FSPageViewLayout.swift */,
 				F9D7BD291E63DD5F003F6A0E /* FSPagerViewLayoutAttributes.swift */,
 				F9580B871E5D9F2B00C5B267 /* FSPageViewTransformer.swift */,
+				50C44A1C2150E7800093B3E9 /* FSPagerViewObjcCompat.h */,
 			);
 			name = Sources;
 			path = ../Sources;
@@ -90,6 +93,7 @@
 			buildActionMask = 2147483647;
 			files = (
 				F9580B7B1E5D9F0600C5B267 /* FSPagerView.h in Headers */,
+				50C44A1D2150E7800093B3E9 /* FSPagerViewObjcCompat.h in Headers */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};

diff --git a/FSPagerViewExample-Objc/FSPagerViewExample-Objc.xcodeproj/project.pbxproj b/FSPagerViewExample-Objc/FSPagerViewExample-Objc.xcodeproj/project.pbxproj
@@ -44,6 +44,7 @@
 /* End PBXContainerItemProxy section */
 
 /* Begin PBXFileReference section */
+		50989DFD2151DB25004DBB4A /* FSPagerViewObjcCompat.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = FSPagerViewObjcCompat.h; sourceTree = "<group>"; };
 		F908BC321E35AAE4002B2F51 /* 1.jpg */ = {isa = PBXFileReference; lastKnownFileType = image.jpeg; path = 1.jpg; sourceTree = "<group>"; };
 		F908BC3A1E35AAE4002B2F51 /* 2.jpg */ = {isa = PBXFileReference; lastKnownFileType = image.jpeg; path = 2.jpg; sourceTree = "<group>"; };
 		F908BC3B1E35AAE4002B2F51 /* 3.jpg */ = {isa = PBXFileReference; lastKnownFileType = image.jpeg; path = 3.jpg; sourceTree = "<group>"; };
@@ -121,6 +122,7 @@
 				F9580B621E5D997200C5B267 /* FSPageViewLayout.swift */,
 				F9FF349E1E65B38C001E943F /* FSPagerViewLayoutAttributes.swift */,
 				F9580B631E5D997200C5B267 /* FSPageViewTransformer.swift */,
+				50989DFD2151DB25004DBB4A /* FSPagerViewObjcCompat.h */,
 			);
 			name = Sources;
 			path = ../Sources;

diff --git a/Sources/FSPageViewLayout.swift b/Sources/FSPageViewLayout.swift
@@ -151,39 +151,49 @@ class FSPagerViewLayout: UICollectionViewLayout {
     }
 
     override open func targetContentOffset(forProposedContentOffset proposedContentOffset: CGPoint, withScrollingVelocity velocity: CGPoint) -> CGPoint {
-        guard let collectionView = self.collectionView else {
+        guard let collectionView = self.collectionView, let pagerView = self.pagerView else {
             return proposedContentOffset
         }
         var proposedContentOffset = proposedContentOffset
+        let touchedContentOffset: CGPoint = collectionView.panGestureRecognizer.location(in: collectionView)
+
+        func calculateTargetOffset(by proposedOffset: CGFloat, touchedOffset: CGFloat, boundedOffset: CGFloat) -> CGFloat {
+            var targetOffset: CGFloat
+            if pagerView.pagingDistance == FSPagerViewAutomaticPagingDistance {
+                if abs(velocity.x) >= 0.3 {
+                    let vector: CGFloat = velocity.x >= 0 ? 1.0 : -1.0
+                    targetOffset = round(proposedOffset/self.itemSpacing+0.35*vector) * self.itemSpacing // Ceil by 0.15, rather than 0.5
+                } else {
+                    targetOffset = round(proposedOffset/self.itemSpacing) * self.itemSpacing
+                }
+            } else {
+                let extraDistance = max(pagerView.pagingDistance-1, 0)
+                switch velocity.x {
+                case 0.3 ... CGFloat.greatestFiniteMagnitude:
+                    targetOffset = ceil(touchedOffset/self.itemSpacing+CGFloat(extraDistance)) * self.itemSpacing
+                case -CGFloat.greatestFiniteMagnitude ... -0.3:
+                    targetOffset = floor(touchedOffset/self.itemSpacing-1-CGFloat(extraDistance)) * self.itemSpacing
+                default:
+                    targetOffset = round(proposedOffset/self.itemSpacing) * self.itemSpacing
+                }
+            }
+            targetOffset = max(0, targetOffset)
+            targetOffset = min(boundedOffset, targetOffset)
+            return targetOffset
+        }
         let proposedContentOffsetX: CGFloat = {
             if self.scrollDirection == .vertical {
                 return proposedContentOffset.x
             }
-            let translation = -collectionView.panGestureRecognizer.translation(in: collectionView).x
-            var offset: CGFloat = round(proposedContentOffset.x/self.itemSpacing)*self.itemSpacing
-            let minFlippingDistance = min(0.5 * self.itemSpacing,150)
-            let originalContentOffsetX = collectionView.contentOffset.x - translation
-            if abs(translation) <= minFlippingDistance {
-                if abs(velocity.x) >= 0.3 && abs(proposedContentOffset.x-originalContentOffsetX) <= self.itemSpacing*0.5 {
-                    offset += self.itemSpacing * (velocity.x)/abs(velocity.x)
-                }
-            }
-            return offset
+            let boundedOffset = collectionView.contentSize.width-self.itemSpacing
+            return calculateTargetOffset(by: proposedContentOffset.x, touchedOffset: touchedContentOffset.x, boundedOffset: boundedOffset)
         }()
         let proposedContentOffsetY: CGFloat = {
             if self.scrollDirection == .horizontal {
                 return proposedContentOffset.y
             }
-            let translation = -collectionView.panGestureRecognizer.translation(in: collectionView).y
-            var offset: CGFloat = round(proposedContentOffset.y/self.itemSpacing)*self.itemSpacing
-            let minFlippingDistance = min(0.5 * self.itemSpacing,150)
-            let originalContentOffsetY = collectionView.contentOffset.y - translation
-            if abs(translation) <= minFlippingDistance {
-                if abs(velocity.y) >= 0.3 && abs(proposedContentOffset.y-originalContentOffsetY) <= self.itemSpacing*0.5 {
-                    offset += self.itemSpacing * (velocity.y)/abs(velocity.y)
-                }
-            }
-            return offset
+            let boundedOffset = collectionView.contentSize.height-self.itemSpacing
+            return calculateTargetOffset(by: proposedContentOffset.y, touchedOffset: touchedContentOffset.y, boundedOffset: boundedOffset)
         }()
         proposedContentOffset = CGPoint(x: proposedContentOffsetX, y: proposedContentOffsetY)
         return proposedContentOffset

diff --git a/Sources/FSPagerView.swift b/Sources/FSPagerView.swift
@@ -83,6 +83,9 @@ public enum FSPagerViewScrollDirection: Int {
     case vertical
 }
 
+/// The paging distance is automatically calculated according to the scrolling speed of the pager view.
+public let FSPagerViewAutomaticPagingDistance: UInt = 0
+
 @IBDesignable
 open class FSPagerView: UIView,UICollectionViewDataSource,UICollectionViewDelegate {
 
@@ -138,6 +141,10 @@ open class FSPagerView: UIView,UICollectionViewDataSource,UICollectionViewDelega
         }
     }
 
+    /// An unsigned integer value that determines the paging distance of the pager view, which indicates the number of passing items during a single paging. When the value of this property is FSPagerViewAutomaticPagingDistance(0), the actual 'distance' is automatically calculated according to the scrolling speed of the pager view. Default is 1.
+    @IBInspectable
+    open var pagingDistance: UInt = 1
+
     /// A Boolean value that determines whether bouncing always occurs when horizontal scrolling reaches the end of the content view.
     @IBInspectable
     open var alwaysBounceHorizontal: Bool {

diff --git a/Sources/FSPagerViewObjcCompat.h b/Sources/FSPagerViewObjcCompat.h
@@ -0,0 +1,9 @@
+//
+//  FSPagerViewObjcCompat.h
+//  FSPagerView
+//
+//  Created by 丁文超 on 2018/9/18.
+//  Copyright © 2018 Wenchao Ding. All rights reserved.
+//
+
+#define FSPagerViewAutomaticPagingDistance 0