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ZLSwipeableView.m
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ZLSwipeableView.m
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//
// ZLSwipeableView.m
// ZLSwipeableViewDemo
//
// Created by Zhixuan Lai on 11/1/14.
// Copyright (c) 2014 Zhixuan Lai. All rights reserved.
//
#import "ZLSwipeableView.h"
#import "ZLPanGestureRecognizer.h"
static const int numPrefetchedViews = 3;
@interface ZLSwipeableView () <UICollisionBehaviorDelegate, UIDynamicAnimatorDelegate>
// UIDynamicAnimators
@property (strong, nonatomic) UIDynamicAnimator *animator;
@property (nonatomic, strong) UISnapBehavior *swipeableViewSnapBehavior;
@property (strong, nonatomic) UIAttachmentBehavior *swipeableViewAttachmentBehavior;
@property (strong, nonatomic) UIAttachmentBehavior *anchorViewAttachmentBehavior;
// AnchorView
@property (strong, nonatomic) UIView *anchorContainerView;
@property (strong, nonatomic) UIView *anchorView;
@property (nonatomic) BOOL isAnchorViewVisiable;
// ContainerView
@property (strong, nonatomic) UIView *reuseCoverContainerView;
@property (strong, nonatomic) UIView *containerView;
@end
@implementation ZLSwipeableView
#pragma mark - Init
- (instancetype)initWithFrame:(CGRect)frame {
self = [super initWithFrame:frame];
if (self) {
[self setup];
}
return self;
}
- (instancetype)initWithCoder:(NSCoder *)aDecoder {
if(self = [super initWithCoder:aDecoder]) {
[self setup];
}
return self;
}
-(void)setup {
self.animator = [[UIDynamicAnimator alloc] initWithReferenceView:self];
self.animator.delegate = self;
self.anchorContainerView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 1, 1)];
[self addSubview:self.anchorContainerView];
self.isAnchorViewVisiable = NO;
self.containerView = [[UIView alloc] initWithFrame:self.bounds];
[self addSubview:self.containerView];
self.reuseCoverContainerView = [[UIView alloc] initWithFrame:self.bounds];
self.reuseCoverContainerView.userInteractionEnabled = false;
[self addSubview:self.reuseCoverContainerView];
// Default properties
self.isRotationEnabled = YES;
self.rotationDegree = 1;
self.rotationRelativeYOffsetFromCenter = 0.3;
self.pushVelocityMagnitude = 1500;
self.escapeVelocityThreshold = 750;
self.relativeDisplacementThreshold = 0.25;
self.manualSwipeRotationRelativeYOffsetFromCenter = -0.2;
self.swipeableViewsCenter = CGPointMake(self.bounds.size.width/2, self.bounds.size.height/2);
self.collisionRect = [self defaultCollisionRect];
}
-(void)layoutSubviews {
[super layoutSubviews];
self.anchorContainerView.frame = CGRectMake(0, 0, 1, 1);
self.containerView.frame = self.bounds;
self.reuseCoverContainerView.frame = self.bounds;
self.swipeableViewsCenter = CGPointMake(self.bounds.size.width/2, self.bounds.size.height/2);
}
-(void)setSwipeableViewsCenter:(CGPoint)swipeableViewsCenter {
_swipeableViewsCenter = swipeableViewsCenter;
[self animateSwipeableViewsIfNeeded];
}
#pragma mark - Properties
- (void)setDataSource:(id<ZLSwipeableViewDataSource>)dataSource {
_dataSource = dataSource;
[self loadNextSwipeableViewsIfNeeded:NO];
}
#pragma mark - DataSource
- (void)discardAllSwipeableViews {
[self.animator removeBehavior:self.anchorViewAttachmentBehavior];
for (UIView *view in self.containerView.subviews) {
[view removeFromSuperview];
}
}
- (void)loadNextSwipeableViewsIfNeeded {
[self loadNextSwipeableViewsIfNeeded:NO];
}
- (void)loadNextSwipeableViewsIfNeeded:(BOOL)animated {
NSInteger numViews = self.containerView.subviews.count;
NSMutableSet *newViews = [NSMutableSet set];
for (NSInteger i=numViews; i<numPrefetchedViews; i++) {
UIView *nextView = [self nextSwipeableView];
if (nextView) {
[self.containerView addSubview:nextView];
[self.containerView sendSubviewToBack:nextView];
nextView.center = self.swipeableViewsCenter;
[newViews addObject:nextView];
}
}
if (animated) {
NSTimeInterval maxDelay = 0.3;
NSTimeInterval delayStep = maxDelay/numPrefetchedViews;
NSTimeInterval aggregatedDelay = maxDelay;
NSTimeInterval animationDuration = 0.25;
for (UIView *view in newViews) {
view.center = CGPointMake(view.center.x, -view.frame.size.height);
[UIView animateWithDuration: animationDuration
delay: aggregatedDelay
options: UIViewAnimationOptionCurveEaseIn
animations: ^{
view.center = self.swipeableViewsCenter;
}
completion: nil];
aggregatedDelay -= delayStep;
}
[self performSelector:@selector(animateSwipeableViewsIfNeeded) withObject:nil afterDelay:animationDuration];
} else {
[self animateSwipeableViewsIfNeeded];
}
}
- (void)animateSwipeableViewsIfNeeded {
UIView *topSwipeableView = [self topSwipeableView];
if (!topSwipeableView) {return;}
for (UIView *cover in self.containerView.subviews) {
cover.userInteractionEnabled = NO;
}
topSwipeableView.userInteractionEnabled = YES;
for (UIGestureRecognizer *recognizer in topSwipeableView.gestureRecognizers) {
if (recognizer.state != UIGestureRecognizerStatePossible) {
return;
}
}
if (self.isRotationEnabled) {
// rotation
NSUInteger numSwipeableViews = self.containerView.subviews.count;
if (numSwipeableViews>=1) {
[self.animator removeBehavior:self.swipeableViewSnapBehavior];
self.swipeableViewSnapBehavior = [self snapBehaviorThatSnapView:self.containerView.subviews[numSwipeableViews-1] toPoint:self.swipeableViewsCenter];
[self.animator addBehavior:self.swipeableViewSnapBehavior];
}
CGPoint rotationCenterOffset = {0,CGRectGetHeight(topSwipeableView.frame)*self.rotationRelativeYOffsetFromCenter};
if (numSwipeableViews>=2) {
[self rotateView:self.containerView.subviews[numSwipeableViews-2] forDegree:self.rotationDegree atOffsetFromCenter:rotationCenterOffset animated:YES];
}
if (numSwipeableViews>=3) {
[self rotateView:self.containerView.subviews[numSwipeableViews-3] forDegree:-self.rotationDegree atOffsetFromCenter:rotationCenterOffset animated:YES];
}
}
}
#pragma mark - Action
-(void)handlePan:(UIPanGestureRecognizer *)recognizer {
CGPoint translation = [recognizer translationInView:self];
CGPoint location = [recognizer locationInView:self];
UIView *swipeableView = recognizer.view;
if (recognizer.state == UIGestureRecognizerStateBegan) {
[self createAnchorViewForCover:swipeableView atLocation:location shouldAttachAnchorViewToPoint:YES];
}
if (recognizer.state == UIGestureRecognizerStateChanged) {
self.anchorViewAttachmentBehavior.anchorPoint = location;
if (self.delegate && [self.delegate respondsToSelector:@selector(swipeableView:swipingView:atLocation:)]) {
[self.delegate swipeableView:self swipingView:swipeableView atLocation:location];
}
}
if(recognizer.state == UIGestureRecognizerStateEnded || recognizer.state == UIGestureRecognizerStateCancelled) {
CGPoint velocity = [recognizer velocityInView:self];
CGFloat velocityMagnitude = sqrt(pow(velocity.x,2)+pow(velocity.y,2));
CGPoint normalizedVelocity = CGPointMake(velocity.x/velocityMagnitude, velocity.y/velocityMagnitude);
if ((ABS(translation.x) > self.relativeDisplacementThreshold*self.bounds.size.width //displacement
|| velocityMagnitude > self.escapeVelocityThreshold) //velocity
&& (signum(translation.x)==signum(normalizedVelocity.x)) //sign X
&& (signum(translation.y)==signum(normalizedVelocity.y)) //sign Y
&& ABS(normalizedVelocity.y)<0.8f) { // confine veritcal direction
CGFloat scale = velocityMagnitude > self.escapeVelocityThreshold ? self.pushVelocityMagnitude:self.pushVelocityMagnitude*0.66;
CGFloat translationMagnitude = sqrtf(translation.x*translation.x+translation.y*translation.y);
CGVector direction = CGVectorMake(translation.x/translationMagnitude*scale, translation.y/translationMagnitude*scale);
[self pushAnchorViewForCover:swipeableView inDirection:direction andCollideInRect:self.collisionRect];
} else {
[self.animator removeBehavior:self.swipeableViewAttachmentBehavior];
[self.animator removeBehavior:self.anchorViewAttachmentBehavior];
[self.anchorView removeFromSuperview];
self.swipeableViewSnapBehavior = [self snapBehaviorThatSnapView:swipeableView toPoint:self.swipeableViewsCenter];
[self.animator addBehavior:self.swipeableViewSnapBehavior];
}
}
}
- (void)swipeTopViewToLeft {
[self swipeTopViewToLeft:YES];
}
- (void)swipeTopViewToRight {
[self swipeTopViewToLeft:NO];
}
- (void)swipeTopViewToLeft:(BOOL)left {
UIView *topSwipeableView = [self topSwipeableView];
if (!topSwipeableView) {return;}
CGPoint location = CGPointMake(topSwipeableView.center.x, topSwipeableView.center.y*(1+self.manualSwipeRotationRelativeYOffsetFromCenter));
[self createAnchorViewForCover:topSwipeableView atLocation:location shouldAttachAnchorViewToPoint:YES];
CGVector direction = CGVectorMake((left?-1:1)*self.escapeVelocityThreshold, 0);
[self pushAnchorViewForCover:topSwipeableView inDirection:direction andCollideInRect:self.collisionRect];
}
#pragma mark - UIDynamicAnimationHelpers
- (UICollisionBehavior *)collisionBehaviorThatBoundsView:(UIView *)view inRect:(CGRect)rect {
if (!view) {return nil;}
UICollisionBehavior *collisionBehavior = [[UICollisionBehavior alloc]
initWithItems:@[view]];
UIBezierPath *collisionBound = [UIBezierPath bezierPathWithRect:rect];
[collisionBehavior addBoundaryWithIdentifier:@"c" forPath:collisionBound];
collisionBehavior.collisionMode = UICollisionBehaviorModeBoundaries;
return collisionBehavior;
}
- (UIPushBehavior *)pushBehaviorThatPushView:(UIView *)view toDirection:(CGVector)direction {
if (!view) {return nil;}
UIPushBehavior *pushBehavior = [[UIPushBehavior alloc]
initWithItems:@[view]
mode:UIPushBehaviorModeInstantaneous];
pushBehavior.pushDirection = direction;
return pushBehavior;
}
- (UISnapBehavior *)snapBehaviorThatSnapView:(UIView *)view toPoint:(CGPoint)point {
if (!view) {return nil;}
UISnapBehavior *snapBehavior = [[UISnapBehavior alloc]
initWithItem:view
snapToPoint:point];
snapBehavior.damping = 0.75f; /* Medium oscillation */
return snapBehavior;
}
- (UIAttachmentBehavior *)attachmentBehaviorThatAnchorsView:(UIView *) aView toView:(UIView *)anchorView {
if (!aView) {return nil;}
CGPoint anchorPoint = anchorView.center;
CGPoint p = [self convertPoint:aView.center toView:self];
UIAttachmentBehavior* attachment = [[UIAttachmentBehavior alloc]
initWithItem:aView
offsetFromCenter: UIOffsetMake(-(p.x-anchorPoint.x),
-(p.y-anchorPoint.y))
attachedToItem:anchorView
offsetFromCenter:
UIOffsetMake(0,0)];
attachment.length = 0;
return attachment;
}
- (UIAttachmentBehavior *)attachmentBehaviorThatAnchorsView:(UIView *) aView toPoint:(CGPoint )aPoint
{
if (!aView) {return nil;}
CGPoint p = aView.center;
UIAttachmentBehavior *attachmentBehavior = [[UIAttachmentBehavior alloc]
initWithItem:aView
offsetFromCenter: UIOffsetMake(-(p.x-aPoint.x),
-(p.y-aPoint.y))
attachedToAnchor:aPoint];
attachmentBehavior.damping = 100;
attachmentBehavior.length = 0;
return attachmentBehavior;
}
- (void)createAnchorViewForCover:(UIView *)swipeableView atLocation: (CGPoint)location shouldAttachAnchorViewToPoint: (BOOL) shouldAttachToPoint{
[self.animator removeBehavior:self.swipeableViewSnapBehavior];
self.swipeableViewSnapBehavior = nil;
self.anchorView = [[UIView alloc] initWithFrame: CGRectMake(location.x-500, location.y-500, 1000, 1000)];
[self.anchorView setBackgroundColor:[UIColor blueColor]];
[self.anchorView setHidden:!self.isAnchorViewVisiable];
[self.anchorContainerView addSubview: self.anchorView];
UIAttachmentBehavior *attachToView = [self attachmentBehaviorThatAnchorsView:swipeableView toView:self.anchorView];
[self.animator addBehavior:attachToView];
self.swipeableViewAttachmentBehavior = attachToView;
if (shouldAttachToPoint) {
UIAttachmentBehavior *attachToPoint = [self attachmentBehaviorThatAnchorsView:self.anchorView toPoint:location];
[self.animator addBehavior:attachToPoint];
self.anchorViewAttachmentBehavior = attachToPoint;
}
}
- (void)pushAnchorViewForCover:(UIView *)swipeableView inDirection:(CGVector)direction andCollideInRect: (CGRect) collisionRect {
if (direction.dx>0) {
if (self.delegate && [self.delegate respondsToSelector:@selector(swipeableView:didSwipeRight:)]) {
[self.delegate swipeableView:self didSwipeRight:swipeableView];
}
} else {
if (self.delegate && [self.delegate respondsToSelector:@selector(swipeableView:didSwipeLeft:)]) {
[self.delegate swipeableView:self didSwipeLeft:swipeableView];
}
}
// NSLog(@"pushing cover to direction: %f, %f", direction.dx, direction.dy);
[self.animator removeBehavior:self.anchorViewAttachmentBehavior];
UICollisionBehavior *collisionBehavior = [self collisionBehaviorThatBoundsView:self.anchorView inRect:collisionRect];
collisionBehavior.collisionDelegate = self;
[self.animator addBehavior:collisionBehavior];
UIPushBehavior *pushBehavior = [self pushBehaviorThatPushView:self.anchorView toDirection:direction];
[self.animator addBehavior:pushBehavior];
[self.reuseCoverContainerView addSubview:self.anchorView];
[self.reuseCoverContainerView addSubview:swipeableView];
[self.reuseCoverContainerView sendSubviewToBack:swipeableView];
self.anchorView = nil;
[self loadNextSwipeableViewsIfNeeded:NO];
}
#pragma mark - UICollisionBehaviorDelegate
- (void)collisionBehavior:(UICollisionBehavior *)behavior endedContactForItem:(id<UIDynamicItem>)item withBoundaryIdentifier:(id<NSCopying>)identifier
{
// NSLog(@"ended contact");
NSMutableSet *viewsToRemove = [[NSMutableSet alloc] init];
for (id aBehavior in self.animator.behaviors) {
if ([aBehavior isKindOfClass:[UIAttachmentBehavior class]]) {
NSArray *items = ((UIAttachmentBehavior *)aBehavior).items;
if ([items containsObject:item]) {
[self.animator removeBehavior:aBehavior];
[viewsToRemove addObjectsFromArray:items];
}
}
if ([aBehavior isKindOfClass:[UIPushBehavior class]]) {
NSArray *items = ((UIPushBehavior *)aBehavior).items;
if ([((UIPushBehavior *)aBehavior).items containsObject:item]) {
if ([items containsObject:item]) {
[self.animator removeBehavior:aBehavior];
[viewsToRemove addObjectsFromArray:items];
}
}
}
if ([aBehavior isKindOfClass:[UICollisionBehavior class]]) {
NSArray *items = ((UICollisionBehavior *)aBehavior).items;
if ([((UICollisionBehavior *)aBehavior).items containsObject:item]) {
if ([items containsObject:item]) {
[self.animator removeBehavior:aBehavior];
[viewsToRemove addObjectsFromArray:items];
}
}
}
}
for (UIView *view in viewsToRemove) {
[view removeFromSuperview];
}
}
#pragma mark - ()
- (CGFloat) degreesToRadians: (CGFloat) degrees
{
return degrees * M_PI / 180;
};
- (CGFloat) radiansToDegrees: (CGFloat) radians
{
return radians * 180 / M_PI;
};
int signum(float n) { return (n < 0) ? -1 : (n > 0) ? +1 : 0; }
- (CGRect)defaultCollisionRect {
CGSize viewSize = [UIScreen mainScreen].applicationFrame.size;
CGFloat collisionSizeScale = 6;
CGSize collisionSize = CGSizeMake(viewSize.width*collisionSizeScale, viewSize.height*collisionSizeScale);
CGRect collisionRect = CGRectMake(-collisionSize.width/2+viewSize.width/2, -collisionSize.height/2+viewSize.height/2, collisionSize.width, collisionSize.height);
return collisionRect;
}
- (UIView *)nextSwipeableView {
UIView *nextView = nil;
if (self.dataSource && [self.dataSource respondsToSelector:@selector(nextViewForSwipeableView:)]) {
nextView = [self.dataSource nextViewForSwipeableView:self];
}
if (nextView) {
[nextView addGestureRecognizer:[[ZLPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePan:)]];
}
return nextView;
}
- (void)rotateView:(UIView*)view forDegree:(float)degree atOffsetFromCenter:(CGPoint)offset animated:(BOOL)animated {
float duration = animated? 0.4:0;
float rotationRadian = [self degreesToRadians:degree];
[UIView animateWithDuration:duration animations:^{
view.center = self.swipeableViewsCenter;
CGAffineTransform transform = CGAffineTransformMakeTranslation(offset.x, offset.y);
transform = CGAffineTransformRotate(transform, rotationRadian);
transform = CGAffineTransformTranslate(transform,-offset.x,-offset.y);
view.transform=transform;
}];
}
- (UIView *)topSwipeableView {
return self.containerView.subviews.lastObject;
}
@end