可能是使用的版本有点老，git上最新的变化比较大

- (void)updateTopViewHorizontalCenter:(CGFloat)newHorizontalCenter { CGPoint center = self.topView.center; center.x = newHorizontalCenter; self.topView.layer.position = center; /* Adding by Jwt */ //NSLog(@"new center x : %f", newHorizontalCenter); if (floor(NSFoundationVersionNumber) <= NSFoundationVersionNumber_iOS_6_1) { } else { //if (newHorizontalCenter == 160.0 || newHorizontalCenter == 480.0) { if (newHorizontalCenter == ([[UIScreen mainScreen] bounds].size.width) / 2 || newHorizontalCenter == 480.0) { self.topView.transform = CGAffineTransformMakeScale(1.0, 1.0); } else { CGFloat scale = 1 - 0.08 * ((newHorizontalCenter - 160) / 220); self.topView.transform = CGAffineTransformMakeScale(scale, scale); } } }

updateTopViewHorizontalCenter: 方法，里面写死了数值
160 是主屏幕宽度的一半
但是 480 和 220 还有 0.08 的调整，我不知道是怎么算出来

附上完整代码

// // ECSlidingViewController.m // ECSlidingViewController // // Created by Michael Enriquez on 1/23/12. // Copyright (c) 2012 EdgeCase. All rights reserved. // #import "ECSlidingViewController.h" NSString *const ECSlidingViewUnderRightWillAppear = @"ECSlidingViewUnderRightWillAppear"; NSString *const ECSlidingViewUnderLeftWillAppear = @"ECSlidingViewUnderLeftWillAppear"; NSString *const ECSlidingViewUnderLeftWillDisappear = @"ECSlidingViewUnderLeftWillDisappear"; NSString *const ECSlidingViewUnderRightWillDisappear = @"ECSlidingViewUnderRightWillDisappear"; NSString *const ECSlidingViewTopDidAnchorLeft = @"ECSlidingViewTopDidAnchorLeft"; NSString *const ECSlidingViewTopDidAnchorRight = @"ECSlidingViewTopDidAnchorRight"; NSString *const ECSlidingViewTopWillReset = @"ECSlidingViewTopWillReset"; NSString *const ECSlidingViewTopDidReset = @"ECSlidingViewTopDidReset"; @interface ECSlidingViewController() @property (nonatomic, strong) UIView *topViewSnapshot; @property (nonatomic, assign) CGFloat initialTouchPositionX; @property (nonatomic, assign) CGFloat initialHoizontalCenter; @property (nonatomic, strong) UIPanGestureRecognizer *panGesture; @property (nonatomic, strong) UITapGestureRecognizer *resetTapGesture; @property (nonatomic, strong) UIPanGestureRecognizer *topViewSnapshotPanGesture; @property (nonatomic, assign) BOOL underLeftShowing; @property (nonatomic, assign) BOOL underRightShowing; @property (nonatomic, assign) BOOL topViewIsOffScreen; - (NSUInteger)autoResizeToFillScreen; - (UIView *)topView; - (UIView *)underLeftView; - (UIView *)underRightView; - (void)adjustLayout; - (void)updateTopViewHorizontalCenterWithRecognizer:(UIPanGestureRecognizer *)recognizer; - (void)updateTopViewHorizontalCenter:(CGFloat)newHorizontalCenter; - (void)topViewHorizontalCenterWillChange:(CGFloat)newHorizontalCenter; - (void)topViewHorizontalCenterDidChange:(CGFloat)newHorizontalCenter; - (void)addTopViewSnapshot; - (void)removeTopViewSnapshot; - (CGFloat)anchorRightTopViewCenter; - (CGFloat)anchorLeftTopViewCenter; - (CGFloat)resettedCenter; - (void)underLeftWillAppear; - (void)underRightWillAppear; - (void)topDidReset; - (BOOL)topViewHasFocus; - (void)updateUnderLeftLayout; - (void)updateUnderRightLayout; @end @implementation UIViewController(SlidingViewExtension) - (ECSlidingViewController *)slidingViewController { UIViewController *viewController = self.parentViewController; while (!(viewController == nil || [viewController isKindOfClass:[ECSlidingViewController class]])) { viewController = viewController.parentViewController; } return (ECSlidingViewController *)viewController; } @end @implementation ECSlidingViewController // public properties @synthesize underLeftViewController = _underLeftViewController; @synthesize underRightViewController = _underRightViewController; @synthesize topViewController = _topViewController; @synthesize anchorLeftPeekAmount; @synthesize anchorRightPeekAmount; @synthesize anchorLeftRevealAmount; @synthesize anchorRightRevealAmount; @synthesize underRightWidthLayout = _underRightWidthLayout; @synthesize underLeftWidthLayout = _underLeftWidthLayout; @synthesize shouldAllowPanningPastAnchor; @synthesize shouldAllowUserInteractionsWhenAnchored; @synthesize shouldAddPanGestureRecognizerToTopViewSnapshot; @synthesize resetStrategy = _resetStrategy; // category properties @synthesize topViewSnapshot; @synthesize initialTouchPositionX; @synthesize initialHoizontalCenter; @synthesize panGesture = _panGesture; @synthesize resetTapGesture; @synthesize underLeftShowing = _underLeftShowing; @synthesize underRightShowing = _underRightShowing; @synthesize topViewIsOffScreen = _topViewIsOffScreen; @synthesize topViewSnapshotPanGesture = _topViewSnapshotPanGesture; - (void)setTopViewController:(UIViewController *)theTopViewController { CGRect topViewFrame = _topViewController ? _topViewController.view.frame : self.view.bounds; [self removeTopViewSnapshot]; [_topViewController.view removeFromSuperview]; [_topViewController willMoveToParentViewController:nil]; [_topViewController removeFromParentViewController]; _topViewController = theTopViewController; [self addChildViewController:self.topViewController]; [self.topViewController didMoveToParentViewController:self]; [_topViewController.view setAutoresizingMask:self.autoResizeToFillScreen]; [_topViewController.view setFrame:topViewFrame]; _topViewController.view.layer.shadowOffset = CGSizeZero; _topViewController.view.layer.shadowPath = [UIBezierPath bezierPathWithRect:self.view.layer.bounds].CGPath; [self.view addSubview:_topViewController.view]; } - (void)setUnderLeftViewController:(UIViewController *)theUnderLeftViewController { [_underLeftViewController.view removeFromSuperview]; [_underLeftViewController willMoveToParentViewController:nil]; [_underLeftViewController removeFromParentViewController]; _underLeftViewController = theUnderLeftViewController; if (_underLeftViewController) { [self addChildViewController:self.underLeftViewController]; [self.underLeftViewController didMoveToParentViewController:self]; [self updateUnderLeftLayout]; } } - (void)setUnderRightViewController:(UIViewController *)theUnderRightViewController { [_underRightViewController.view removeFromSuperview]; [_underRightViewController willMoveToParentViewController:nil]; [_underRightViewController removeFromParentViewController]; _underRightViewController = theUnderRightViewController; if (_underRightViewController) { [self addChildViewController:self.underRightViewController]; [self.underRightViewController didMoveToParentViewController:self]; [self updateUnderRightLayout]; } } - (void)setUnderLeftWidthLayout:(ECViewWidthLayout)underLeftWidthLayout { if (underLeftWidthLayout == ECVariableRevealWidth && self.anchorRightPeekAmount <= 0) { [NSException raise:@"Invalid Width Layout" format:@"anchorRightPeekAmount must be set"]; } else if (underLeftWidthLayout == ECFixedRevealWidth && self.anchorRightRevealAmount <= 0) { [NSException raise:@"Invalid Width Layout" format:@"anchorRightRevealAmount must be set"]; } _underLeftWidthLayout = underLeftWidthLayout; } - (void)setUnderRightWidthLayout:(ECViewWidthLayout)underRightWidthLayout { if (underRightWidthLayout == ECVariableRevealWidth && self.anchorLeftPeekAmount <= 0) { [NSException raise:@"Invalid Width Layout" format:@"anchorLeftPeekAmount must be set"]; } else if (underRightWidthLayout == ECFixedRevealWidth && self.anchorLeftRevealAmount <= 0) { [NSException raise:@"Invalid Width Layout" format:@"anchorLeftRevealAmount must be set"]; } _underRightWidthLayout = underRightWidthLayout; } - (void)viewDidLoad { [super viewDidLoad]; self.shouldAllowPanningPastAnchor = YES; self.shouldAllowUserInteractionsWhenAnchored = NO; self.shouldAddPanGestureRecognizerToTopViewSnapshot = NO; self.resetTapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(resetTopView)]; _panGesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(updateTopViewHorizontalCenterWithRecognizer:)]; self.resetTapGesture.enabled = NO; self.resetStrategy = ECTapping | ECPanning; self.topViewSnapshot = [[UIView alloc] initWithFrame:self.topView.bounds]; [self.topViewSnapshot setAutoresizingMask:self.autoResizeToFillScreen]; [self.topViewSnapshot addGestureRecognizer:self.resetTapGesture]; } - (void)viewWillAppear:(BOOL)animated { [super viewWillAppear:animated]; self.topView.layer.shadowOffset = CGSizeZero; self.topView.layer.shadowPath = [UIBezierPath bezierPathWithRect:self.view.layer.bounds].CGPath; [self adjustLayout]; } - (void)willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration { self.topView.layer.shadowPath = nil; self.topView.layer.shouldRasterize = YES; if(![self topViewHasFocus]){ [self removeTopViewSnapshot]; } [self adjustLayout]; } - (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation { self.topView.layer.shadowPath = [UIBezierPath bezierPathWithRect:self.view.layer.bounds].CGPath; self.topView.layer.shouldRasterize = NO; if(![self topViewHasFocus]){ [self addTopViewSnapshot]; } } - (void)setResetStrategy:(ECResetStrategy)theResetStrategy { _resetStrategy = theResetStrategy; if (_resetStrategy & ECTapping) { self.resetTapGesture.enabled = YES; } else { self.resetTapGesture.enabled = NO; } } - (void)adjustLayout { self.topViewSnapshot.frame = self.topView.bounds; if ([self underRightShowing] && ![self topViewIsOffScreen]) { [self updateUnderRightLayout]; [self updateTopViewHorizontalCenter:self.anchorLeftTopViewCenter]; } else if ([self underRightShowing] && [self topViewIsOffScreen]) { [self updateUnderRightLayout]; [self updateTopViewHorizontalCenter:-self.resettedCenter]; } else if ([self underLeftShowing] && ![self topViewIsOffScreen]) { [self updateUnderLeftLayout]; [self updateTopViewHorizontalCenter:self.anchorRightTopViewCenter]; } else if ([self underLeftShowing] && [self topViewIsOffScreen]) { [self updateUnderLeftLayout]; [self updateTopViewHorizontalCenter:self.view.bounds.size.width + self.resettedCenter]; } } - (void)updateTopViewHorizontalCenterWithRecognizer:(UIPanGestureRecognizer *)recognizer { CGPoint currentTouchPoint = [recognizer locationInView:self.view]; CGFloat currentTouchPositionX = currentTouchPoint.x; if (recognizer.state == UIGestureRecognizerStateBegan) { self.initialTouchPositionX = currentTouchPositionX; self.initialHoizontalCenter = self.topView.center.x; } else if (recognizer.state == UIGestureRecognizerStateChanged) { CGFloat panAmount = self.initialTouchPositionX - currentTouchPositionX; CGFloat newCenterPosition = self.initialHoizontalCenter - panAmount; if ((newCenterPosition < self.resettedCenter && (self.anchorLeftTopViewCenter == NSNotFound || self.underRightViewController == nil)) || (newCenterPosition > self.resettedCenter && (self.anchorRightTopViewCenter == NSNotFound || self.underLeftViewController == nil))) { newCenterPosition = self.resettedCenter; } BOOL newCenterPositionIsOutsideAnchor = newCenterPosition < self.anchorLeftTopViewCenter || self.anchorRightTopViewCenter < newCenterPosition; if ((newCenterPositionIsOutsideAnchor && self.shouldAllowPanningPastAnchor) || !newCenterPositionIsOutsideAnchor) { [self topViewHorizontalCenterWillChange:newCenterPosition]; [self updateTopViewHorizontalCenter:newCenterPosition]; [self topViewHorizontalCenterDidChange:newCenterPosition]; } } else if (recognizer.state == UIGestureRecognizerStateEnded || recognizer.state == UIGestureRecognizerStateCancelled) { CGPoint currentVelocityPoint = [recognizer velocityInView:self.view]; CGFloat currentVelocityX = currentVelocityPoint.x; if ([self underLeftShowing] && currentVelocityX > 100) { [self anchorTopViewTo:ECRight]; } else if ([self underRightShowing] && currentVelocityX < 100) { [self anchorTopViewTo:ECLeft]; } else { [self resetTopView]; } } } - (UIPanGestureRecognizer *)panGesture { return _panGesture; } - (void)anchorTopViewTo:(ECSide)side { [self anchorTopViewTo:side animations:nil onComplete:nil]; } - (void)anchorTopViewTo:(ECSide)side animations:(void (^)())animations onComplete:(void (^)())complete { CGFloat newCenter = self.topView.center.x; if (side == ECLeft) { newCenter = self.anchorLeftTopViewCenter; } else if (side == ECRight) { newCenter = self.anchorRightTopViewCenter; } [self topViewHorizontalCenterWillChange:newCenter]; [UIView animateWithDuration:0.25f animations:^{ if (animations) { animations(); } [self updateTopViewHorizontalCenter:newCenter]; } completion:^(BOOL finished){ if (_resetStrategy & ECPanning) { self.panGesture.enabled = YES; } else { self.panGesture.enabled = NO; } if (complete) { complete(); } _topViewIsOffScreen = NO; [self addTopViewSnapshot]; dispatch_async(dispatch_get_main_queue(), ^{ NSString *key = (side == ECLeft) ? ECSlidingViewTopDidAnchorLeft : ECSlidingViewTopDidAnchorRight; [[NSNotificationCenter defaultCenter] postNotificationName:key object:self userInfo:nil]; }); }]; } - (void)anchorTopViewOffScreenTo:(ECSide)side { [self anchorTopViewOffScreenTo:side animations:nil onComplete:nil]; } - (void)anchorTopViewOffScreenTo:(ECSide)side animations:(void(^)())animations onComplete:(void(^)())complete { CGFloat newCenter = self.topView.center.x; if (side == ECLeft) { newCenter = -self.resettedCenter; } else if (side == ECRight) { newCenter = self.view.bounds.size.width + self.resettedCenter; } [self topViewHorizontalCenterWillChange:newCenter]; [UIView animateWithDuration:0.25f animations:^{ if (animations) { animations(); } [self updateTopViewHorizontalCenter:newCenter]; } completion:^(BOOL finished){ if (complete) { complete(); } _topViewIsOffScreen = YES; [self addTopViewSnapshot]; dispatch_async(dispatch_get_main_queue(), ^{ NSString *key = (side == ECLeft) ? ECSlidingViewTopDidAnchorLeft : ECSlidingViewTopDidAnchorRight; [[NSNotificationCenter defaultCenter] postNotificationName:key object:self userInfo:nil]; }); }]; } - (void)resetTopView { dispatch_async(dispatch_get_main_queue(), ^{ [[NSNotificationCenter defaultCenter] postNotificationName:ECSlidingViewTopWillReset object:self userInfo:nil]; }); [self resetTopViewWithAnimations:nil onComplete:nil]; } - (void)resetTopViewWithAnimations:(void(^)())animations onComplete:(void(^)())complete { [self topViewHorizontalCenterWillChange:self.resettedCenter]; [UIView animateWithDuration:0.25f animations:^{ if (animations) { animations(); } [self updateTopViewHorizontalCenter:self.resettedCenter]; } completion:^(BOOL finished) { if (complete) { complete(); } [self topViewHorizontalCenterDidChange:self.resettedCenter]; }]; } - (NSUInteger)autoResizeToFillScreen { return (UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleTopMargin | UIViewAutoresizingFlexibleBottomMargin | UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleRightMargin); } - (UIView *)topView { return self.topViewController.view; } - (UIView *)underLeftView { return self.underLeftViewController.view; } - (UIView *)underRightView { return self.underRightViewController.view; } - (void)updateTopViewHorizontalCenter:(CGFloat)newHorizontalCenter { CGPoint center = self.topView.center; center.x = newHorizontalCenter; self.topView.layer.position = center; /* Adding by Jwt */ //NSLog(@"new center x : %f", newHorizontalCenter); if (floor(NSFoundationVersionNumber) <= NSFoundationVersionNumber_iOS_6_1) { } else { //if (newHorizontalCenter == 160.0 || newHorizontalCenter == 480.0) { if (newHorizontalCenter == ([[UIScreen mainScreen] bounds].size.width) / 2 || newHorizontalCenter == 480.0) { self.topView.transform = CGAffineTransformMakeScale(1.0, 1.0); } else { CGFloat scale = 1 - 0.08 * ((newHorizontalCenter - 160) / 220); self.topView.transform = CGAffineTransformMakeScale(scale, scale); } } } - (void)topViewHorizontalCenterWillChange:(CGFloat)newHorizontalCenter { CGPoint center = self.topView.center; if (center.x >= self.resettedCenter && newHorizontalCenter == self.resettedCenter) { dispatch_async(dispatch_get_main_queue(), ^{ [[NSNotificationCenter defaultCenter] postNotificationName:ECSlidingViewUnderLeftWillDisappear object:self userInfo:nil]; }); } if (center.x <= self.resettedCenter && newHorizontalCenter == self.resettedCenter) { dispatch_async(dispatch_get_main_queue(), ^{ [[NSNotificationCenter defaultCenter] postNotificationName:ECSlidingViewUnderRightWillDisappear object:self userInfo:nil]; }); } if (center.x <= self.resettedCenter && newHorizontalCenter > self.resettedCenter) { [self underLeftWillAppear]; } else if (center.x >= self.resettedCenter && newHorizontalCenter < self.resettedCenter) { [self underRightWillAppear]; } } - (void)topViewHorizontalCenterDidChange:(CGFloat)newHorizontalCenter { if (newHorizontalCenter == self.resettedCenter) { [self topDidReset]; } } - (void)addTopViewSnapshot { if (!self.topViewSnapshot.superview && !self.shouldAllowUserInteractionsWhenAnchored) { topViewSnapshot.layer.contents = (id)[UIImage imageWithUIView:self.topView].CGImage; if (self.shouldAddPanGestureRecognizerToTopViewSnapshot && (_resetStrategy & ECPanning)) { if (!_topViewSnapshotPanGesture) { _topViewSnapshotPanGesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(updateTopViewHorizontalCenterWithRecognizer:)]; } [topViewSnapshot addGestureRecognizer:_topViewSnapshotPanGesture]; } [self.topView addSubview:self.topViewSnapshot]; } } - (void)removeTopViewSnapshot { if (self.topViewSnapshot.superview) { [self.topViewSnapshot removeFromSuperview]; } } - (CGFloat)anchorRightTopViewCenter { if (self.anchorRightPeekAmount) { return self.view.bounds.size.width + self.resettedCenter - self.anchorRightPeekAmount; } else if (self.anchorRightRevealAmount) { return self.resettedCenter + self.anchorRightRevealAmount; } else { return NSNotFound; } } - (CGFloat)anchorLeftTopViewCenter { if (self.anchorLeftPeekAmount) { return -self.resettedCenter + self.anchorLeftPeekAmount; } else if (self.anchorLeftRevealAmount) { return -self.resettedCenter + (self.view.bounds.size.width - self.anchorLeftRevealAmount); } else { return NSNotFound; } } - (CGFloat)resettedCenter { return (self.view.bounds.size.width / 2); } - (void)underLeftWillAppear { dispatch_async(dispatch_get_main_queue(), ^{ [[NSNotificationCenter defaultCenter] postNotificationName:ECSlidingViewUnderLeftWillAppear object:self userInfo:nil]; }); [self.underRightView removeFromSuperview]; [self updateUnderLeftLayout]; [self.view insertSubview:self.underLeftView belowSubview:self.topView]; _underLeftShowing = YES; _underRightShowing = NO; } - (void)underRightWillAppear { dispatch_async(dispatch_get_main_queue(), ^{ [[NSNotificationCenter defaultCenter] postNotificationName:ECSlidingViewUnderRightWillAppear object:self userInfo:nil]; }); [self.underLeftView removeFromSuperview]; [self updateUnderRightLayout]; [self.view insertSubview:self.underRightView belowSubview:self.topView]; _underLeftShowing = NO; _underRightShowing = YES; } - (void)topDidReset { dispatch_async(dispatch_get_main_queue(), ^{ [[NSNotificationCenter defaultCenter] postNotificationName:ECSlidingViewTopDidReset object:self userInfo:nil]; }); [self.topView removeGestureRecognizer:self.resetTapGesture]; [self removeTopViewSnapshot]; self.panGesture.enabled = YES; [self.underRightView removeFromSuperview]; [self.underLeftView removeFromSuperview]; _underLeftShowing = NO; _underRightShowing = NO; _topViewIsOffScreen = NO; } - (BOOL)topViewHasFocus { return !_underLeftShowing && !_underRightShowing && !_topViewIsOffScreen; } - (void)updateUnderLeftLayout { if (self.underLeftWidthLayout == ECFullWidth) { [self.underLeftView setAutoresizingMask:self.autoResizeToFillScreen]; [self.underLeftView setFrame:self.view.bounds]; } else if (self.underLeftWidthLayout == ECVariableRevealWidth && !self.topViewIsOffScreen) { CGRect frame = self.view.bounds; frame.size.width = frame.size.width - self.anchorRightPeekAmount; self.underLeftView.frame = frame; } else if (self.underLeftWidthLayout == ECFixedRevealWidth) { CGRect frame = self.view.bounds; frame.size.width = self.anchorRightRevealAmount; self.underLeftView.frame = frame; } else { [NSException raise:@"Invalid Width Layout" format:@"underLeftWidthLayout must be a valid ECViewWidthLayout"]; } } - (void)updateUnderRightLayout { if (self.underRightWidthLayout == ECFullWidth) { [self.underRightViewController.view setAutoresizingMask:self.autoResizeToFillScreen]; self.underRightView.frame = self.view.bounds; } else if (self.underRightWidthLayout == ECVariableRevealWidth) { CGRect frame = self.view.bounds; CGFloat newLeftEdge; CGFloat newWidth = frame.size.width; if (self.topViewIsOffScreen) { newLeftEdge = 0; } else { newLeftEdge = self.anchorLeftPeekAmount; newWidth -= self.anchorLeftPeekAmount; } frame.origin.x = newLeftEdge; frame.size.width = newWidth; self.underRightView.frame = frame; } else if (self.underRightWidthLayout == ECFixedRevealWidth) { CGRect frame = self.view.bounds; CGFloat newLeftEdge = frame.size.width - self.anchorLeftRevealAmount; CGFloat newWidth = self.anchorLeftRevealAmount; frame.origin.x = newLeftEdge; frame.size.width = newWidth; self.underRightView.frame = frame; } else { [NSException raise:@"Invalid Width Layout" format:@"underRightWidthLayout must be a valid ECViewWidthLayout"]; } } @end