滑动返回

#import "XMGNavigationViewController.h"

@interface XMGNavigationViewController ()<UIGestureRecognizerDelegate>

@end

@implementation XMGNavigationViewController

+ (void)load
{
    UINavigationBar *navBar = [UINavigationBar appearanceWhenContainedIn:self, nil];
    
    // 只要是通过模型设置,都是通过富文本设置
    // 设置导航条标题 => UINavigationBar
    NSMutableDictionary *attrs = [NSMutableDictionary dictionary];
    attrs[NSFontAttributeName] = [UIFont boldSystemFontOfSize:20];
    [navBar setTitleTextAttributes:attrs];
    
    // 设置导航条背景图片
    [navBar setBackgroundImage:[UIImage imageNamed:@"navigationbarBackgroundWhite"] forBarMetrics:UIBarMetricsDefault];
}

- (void)viewDidLoad {
    [super viewDidLoad];
    
    // 控制手势什么时候触发,只有非根控制器才需要触发手势
    self.interactivePopGestureRecognizer.delegate = self;
    
    // 假死状态:程序还在运行,但是界面死了.
}

#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

/*
 <UIScreenEdgePanGestureRecognizer: 0x7fdc4a740120; state = Possible; delaysTouchesBegan = YES; view = <UILayoutContainerView 0x7fdc4a73e690>; target= <(action=handleNavigationTransition:, target=<_UINavigationInteractiveTransition 0x7fdc4a740440>)>>

 */

- (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];
    
}

- (void)back
{
    [self popViewControllerAnimated:YES];
}

@end