右滑返回上一个界面FDFullscreenPopGesture

// The MIT License (MIT)

//

// Copyright (c) 2015-2016 forkingdog ( https://github.com/forkingdog )

//

// Permission is hereby granted, free of charge, to any person obtaining a copy

// of this software and associated documentation files (the "Software"), to deal

// in the Software without restriction, including without limitation the rights

// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

// copies of the Software, and to permit persons to whom the Software is

// furnished to do so, subject to the following conditions:

//

// The above copyright notice and this permission notice shall be included in all

// copies or substantial portions of the Software.

//

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

// SOFTWARE.

#import <UIKit/UIKit.h>

/// "UINavigation+FDFullscreenPopGesture" extends UINavigationController's swipe-

/// to-pop behavior in iOS 7+ by supporting fullscreen pan gesture. Instead of

/// screen edge, you can now swipe from any place on the screen and the onboard

/// interactive pop transition works seamlessly.

///

/// Adding the implementation file of this category to your target will

/// automatically patch UINavigationController with this feature.

@interface UINavigationController (FDFullscreenPopGesture)

/// The gesture recognizer that actually handles interactive pop.

@property (nonatomic,strong, readonly)UIPanGestureRecognizer *fd_fullscreenPopGestureRecognizer;

/// A view controller is able to control navigation bar's appearance by itself,

/// rather than a global way, checking "fd_prefersNavigationBarHidden" property.

/// Default to YES, disable it if you don't want so.

@property (nonatomic,assign) BOOL fd_viewControllerBasedNavigationBarAppearanceEnabled;

@end

/// Allows any view controller to disable interactive pop gesture, which might

/// be necessary when the view controller itself handles pan gesture in some

/// cases.

@interface UIViewController (FDFullscreenPopGesture)

/// Whether the interactive pop gesture is disabled when contained in a navigation

/// stack.

@property (nonatomic,assign) BOOL fd_interactivePopDisabled;

/// Indicate this view controller prefers its navigation bar hidden or not,

/// checked when view controller based navigation bar's appearance is enabled.

/// Default to NO, bars are more likely to show.

@property (nonatomic,assign) BOOL fd_prefersNavigationBarHidden;

/// Max allowed initial distance to left edge when you begin the interactive pop

/// gesture. 0 by default, which means it will ignore this limit.

@property (nonatomic,assign) CGFloat fd_interactivePopMaxAllowedInitialDistanceToLeftEdge;

@end

// The MIT License (MIT)

//

// Copyright (c) 2015-2016 forkingdog ( https://github.com/forkingdog )

//

// Permission is hereby granted, free of charge, to any person obtaining a copy

// of this software and associated documentation files (the "Software"), to deal

// in the Software without restriction, including without limitation the rights

// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

// copies of the Software, and to permit persons to whom the Software is

// furnished to do so, subject to the following conditions:

//

// The above copyright notice and this permission notice shall be included in all

// copies or substantial portions of the Software.

//

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

// SOFTWARE.

#import "UINavigationController+FDFullscreenPopGesture.h"

#import <objc/runtime.h>

@interface _FDFullscreenPopGestureRecognizerDelegate :NSObject <UIGestureRecognizerDelegate>

@property (nonatomic,weak) UINavigationController *navigationController;

@end

@implementation _FDFullscreenPopGestureRecognizerDelegate

- (BOOL)gestureRecognizerShouldBegin:(UIPanGestureRecognizer *)gestureRecognizer

{

    // Ignore when no view controller is pushed into the navigation stack.

    if (self.navigationController.viewControllers.count <= 1) {

        returnNO;

    }

    

    // Ignore when the active view controller doesn't allow interactive pop.

    UIViewController *topViewController =self.navigationController.viewControllers.lastObject;

    if (topViewController.fd_interactivePopDisabled) {

        returnNO;

    }

    

    // Ignore when the beginning location is beyond max allowed initial distance to left edge.

    CGPoint beginningLocation = [gestureRecognizerlocationInView:gestureRecognizer.view];

    CGFloat maxAllowedInitialDistance = topViewController.fd_interactivePopMaxAllowedInitialDistanceToLeftEdge;

    if (maxAllowedInitialDistance >0 && beginningLocation.x > maxAllowedInitialDistance) {

        returnNO;

    }

    // Ignore pan gesture when the navigation controller is currently in transition.

    if ([[self.navigationControllervalueForKey:@"_isTransitioning"]boolValue]) {

        returnNO;

    }

    

    // Prevent calling the handler when the gesture begins in an opposite direction.

    CGPoint translation = [gestureRecognizertranslationInView:gestureRecognizer.view];

    if (translation.x <=0) {

        returnNO;

    }

    

    returnYES;

}

@end

typedef void (^_FDViewControllerWillAppearInjectBlock)(UIViewController *viewController,BOOL animated);

@interface UIViewController (FDFullscreenPopGesturePrivate)

@property (nonatomic,copy) _FDViewControllerWillAppearInjectBlock fd_willAppearInjectBlock;

@end

@implementation UIViewController (FDFullscreenPopGesturePrivate)

+ (void)load

{

    staticdispatch_once_t onceToken;

    dispatch_once(&onceToken, ^{

        Class class = [selfclass];

        

        SEL originalSelector =@selector(viewWillAppear:);

        SEL swizzledSelector =@selector(fd_viewWillAppear:);

        

        Method originalMethod =class_getInstanceMethod(class, originalSelector);

        Method swizzledMethod =class_getInstanceMethod(class, swizzledSelector);

        

        BOOL success =class_addMethod(class, originalSelector,method_getImplementation(swizzledMethod),method_getTypeEncoding(swizzledMethod));

        if (success) {

            class_replaceMethod(class, swizzledSelector,method_getImplementation(originalMethod),method_getTypeEncoding(originalMethod));

        } else {

            method_exchangeImplementations(originalMethod, swizzledMethod);

        }

    });

}

- (void)fd_viewWillAppear:(BOOL)animated

{

    // Forward to primary implementation.

    [selffd_viewWillAppear:animated];

    

    if (self.fd_willAppearInjectBlock) {

        self.fd_willAppearInjectBlock(self, animated);

    }

}

- (_FDViewControllerWillAppearInjectBlock)fd_willAppearInjectBlock

{

    returnobjc_getAssociatedObject(self,_cmd);

}

- (void)setFd_willAppearInjectBlock:(_FDViewControllerWillAppearInjectBlock)block

{

    objc_setAssociatedObject(self,@selector(fd_willAppearInjectBlock), block,OBJC_ASSOCIATION_COPY_NONATOMIC);

}

@end

@implementation UINavigationController (FDFullscreenPopGesture)

+ (void)load

{

    // Inject "-pushViewController:animated:"

    staticdispatch_once_t onceToken;

    dispatch_once(&onceToken, ^{

        Class class = [selfclass];

        

        SEL originalSelector =@selector(pushViewController:animated:);

        SEL swizzledSelector =@selector(fd_pushViewController:animated:);

        

        Method originalMethod =class_getInstanceMethod(class, originalSelector);

        Method swizzledMethod =class_getInstanceMethod(class, swizzledSelector);

        

        BOOL success =class_addMethod(class, originalSelector,method_getImplementation(swizzledMethod),method_getTypeEncoding(swizzledMethod));

        if (success) {

            class_replaceMethod(class, swizzledSelector,method_getImplementation(originalMethod),method_getTypeEncoding(originalMethod));

        } else {

            method_exchangeImplementations(originalMethod, swizzledMethod);

        }

    });

}

- (void)fd_pushViewController:(UIViewController *)viewController animated:(BOOL)animated

{

    if (![self.interactivePopGestureRecognizer.view.gestureRecognizerscontainsObject:self.fd_fullscreenPopGestureRecognizer]) {

        

        // Add our own gesture recognizer to where the onboard screen edge pan gesture recognizer is attached to.

        [self.interactivePopGestureRecognizer.viewaddGestureRecognizer:self.fd_fullscreenPopGestureRecognizer];

        // Forward the gesture events to the private handler of the onboard gesture recognizer.

        NSArray *internalTargets = [self.interactivePopGestureRecognizervalueForKey:@"targets"];

        id internalTarget = [internalTargets.firstObjectvalueForKey:@"target"];

        SEL internalAction =NSSelectorFromString(@"handleNavigationTransition:");

        self.fd_fullscreenPopGestureRecognizer.delegate = self.fd_popGestureRecognizerDelegate;

        [self.fd_fullscreenPopGestureRecognizeraddTarget:internalTargetaction:internalAction];

        // Disable the onboard gesture recognizer.

        self.interactivePopGestureRecognizer.enabled = NO;

    }

    

    // Handle perferred navigation bar appearance.

    [selffd_setupViewControllerBasedNavigationBarAppearanceIfNeeded:viewController];

    

    // Forward to primary implementation.

    if (![self.viewControllerscontainsObject:viewController]) {

        [selffd_pushViewController:viewControlleranimated:animated];

    }

}

- (void)fd_setupViewControllerBasedNavigationBarAppearanceIfNeeded:(UIViewController *)appearingViewController

{

    if (!self.fd_viewControllerBasedNavigationBarAppearanceEnabled) {

        return;

    }

    

    __weaktypeof(self) weakSelf =self;

    _FDViewControllerWillAppearInjectBlock block = ^(UIViewController *viewController,BOOL animated) {

        __strongtypeof(weakSelf) strongSelf = weakSelf;

        if (strongSelf) {

            [strongSelf setNavigationBarHidden:viewController.fd_prefersNavigationBarHiddenanimated:animated];

        }

    };

    

    // Setup will appear inject block to appearing view controller.

    // Setup disappearing view controller as well, because not every view controller is added into

    // stack by pushing, maybe by "-setViewControllers:".

    appearingViewController.fd_willAppearInjectBlock = block;

    UIViewController *disappearingViewController =self.viewControllers.lastObject;

    if (disappearingViewController && !disappearingViewController.fd_willAppearInjectBlock) {

        disappearingViewController.fd_willAppearInjectBlock = block;

    }

}

- (_FDFullscreenPopGestureRecognizerDelegate *)fd_popGestureRecognizerDelegate

{

    _FDFullscreenPopGestureRecognizerDelegate *delegate =objc_getAssociatedObject(self,_cmd);

    if (!delegate) {

        delegate = [[_FDFullscreenPopGestureRecognizerDelegatealloc] init];

        delegate.navigationController =self;

        

        objc_setAssociatedObject(self,_cmd, delegate,OBJC_ASSOCIATION_RETAIN_NONATOMIC);

    }

    return delegate;

}

- (UIPanGestureRecognizer *)fd_fullscreenPopGestureRecognizer

{

    UIPanGestureRecognizer *panGestureRecognizer =objc_getAssociatedObject(self,_cmd);

    if (!panGestureRecognizer) {

        panGestureRecognizer = [[UIPanGestureRecognizeralloc] init];

        panGestureRecognizer.maximumNumberOfTouches =1;

        

        objc_setAssociatedObject(self,_cmd, panGestureRecognizer,OBJC_ASSOCIATION_RETAIN_NONATOMIC);

    }

    return panGestureRecognizer;

}

- (BOOL)fd_viewControllerBasedNavigationBarAppearanceEnabled

{

    NSNumber *number =objc_getAssociatedObject(self,_cmd);

    if (number) {

        return number.boolValue;

    }

    self.fd_viewControllerBasedNavigationBarAppearanceEnabled =YES;

    returnYES;

}

- (void)setFd_viewControllerBasedNavigationBarAppearanceEnabled:(BOOL)enabled

{

    SEL key =@selector(fd_viewControllerBasedNavigationBarAppearanceEnabled);

    objc_setAssociatedObject(self, key,@(enabled),OBJC_ASSOCIATION_RETAIN_NONATOMIC);

}

@end

@implementation UIViewController (FDFullscreenPopGesture)

- (BOOL)fd_interactivePopDisabled

{

    return [objc_getAssociatedObject(self,_cmd) boolValue];

}

- (void)setFd_interactivePopDisabled:(BOOL)disabled

{

    objc_setAssociatedObject(self,@selector(fd_interactivePopDisabled),@(disabled),OBJC_ASSOCIATION_RETAIN_NONATOMIC);

}

- (BOOL)fd_prefersNavigationBarHidden

{

    return [objc_getAssociatedObject(self,_cmd) boolValue];

}

- (void)setFd_prefersNavigationBarHidden:(BOOL)hidden

{

    objc_setAssociatedObject(self,@selector(fd_prefersNavigationBarHidden),@(hidden),OBJC_ASSOCIATION_RETAIN_NONATOMIC);

}

- (CGFloat)fd_interactivePopMaxAllowedInitialDistanceToLeftEdge

{

#if CGFLOAT_IS_DOUBLE

    return [objc_getAssociatedObject(self,_cmd) doubleValue];

#else

    return [objc_getAssociatedObject(self,_cmd) floatValue];

#endif

}

- (void)setFd_interactivePopMaxAllowedInitialDistanceToLeftEdge:(CGFloat)distance

{

    SEL key =@selector(fd_interactivePopMaxAllowedInitialDistanceToLeftEdge);

    objc_setAssociatedObject(self, key,@(MAX(0, distance)),OBJC_ASSOCIATION_RETAIN_NONATOMIC);

}

@end