#import "XMGNavigationViewController.h"@interface XMGNavigationViewController ()<UIGestureRecognizerDelegate>@end@implementation XMGNavigationViewController- (void)viewDidLoad {    [super viewDidLoad];    UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self.interactivePopGestureRecognizer.delegate action:@selector(handleNavigationTransition:)];        [self.view addGestureRecognizer:pan];        // 控制手势什么时候触发,只有非根控制器才需要触发手势    pan.delegate = self;        // 禁止之前手势    self.interactivePopGestureRecognizer.enabled = NO;        // 假死状态:程序还在运行,但是界面死了.        /*        为什么导航控制器的手势不是全屏滑动 =>     */    }#pragma mark - UIGestureRecognizerDelegate// 决定是否触发手势- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch{    return self.childViewControllers.count > 1;}// <_UINavigationInteractiveTransition: 0x7f9c948302a0>:手势代理/* UIPanGestureRecognizer  UIScreenEdgePanGestureRecognizer:导航滑动手势 target=<_UINavigationInteractiveTransition 0x7fdc4a740440>) action=handleNavigationTransition:   <UIScreenEdgePanGestureRecognizer: 0x7fdc4a740120; state = Possible; delaysTouchesBegan = YES; view = <UILayoutContainerView 0x7fdc4a73e690>; target= <(action=handleNavigationTransition:, >> */- (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated{    if (self.childViewControllers.count > 0) { // 非根控制器                // 恢复滑动返回功能 -> 分析:把系统的返回按钮覆盖 -> 1.手势失效(1.手势被清空 2.可能手势代理做了一些事情,导致手势失效)                // 设置返回按钮,只有非根控制器        viewController.navigationItem.leftBarButtonItem = [UIBarButtonItem backItemWithimage:[UIImage imageNamed:@"navigationButtonReturn"] highImage:[UIImage imageNamed:@"navigationButtonReturnClick"]  target:self action:@selector(back) title:@"返回"];    }        // 真正在跳转    [super pushViewController:viewController animated:animated];    }@end