自定义pop返回手势 利用runtime

- (void)viewDidLoad {
    [super viewDidLoad];
    UIGestureRecognizer *recongnizer = self.interactivePopGestureRecognizer;
    recongnizer.enabled = NO;
    UIView *gestureView = recongnizer.view;
    
    /**
     * 创建拖动手势
     */
    UIPanGestureRecognizer *popRecognizer = [[UIPanGestureRecognizer alloc] init];
    popRecognizer.delegate = self;
    popRecognizer.maximumNumberOfTouches = 1;
    [gestureView addGestureRecognizer:popRecognizer];
    u_int  count;
    Ivar *ivars = class_copyIvarList([UIGestureRecognizer class], &count);
    for (int i =0; i<count; i++) {
        //获取对应的变量
        Ivar ivar = ivars[i];
        //获取变量的名字
        const char *ivarName  = ivar_getName(ivar);
        //获取对应变量的类型
        //const char *ivarEncodingName = ivar_getTypeEncoding(ivar);
        //通过Kvc获取这些
        if ([[NSString stringWithCString:ivarName encoding:NSUTF8StringEncoding] isEqualToString:@"_targets"]) {
            
            NSMutableArray *_targetsArray= [recongnizer valueForKey:@"_targets"];
            //获取对象
            id getRecongnizerTarget = _targetsArray[0];
            
            id uinavigationInteractiveTransition = [getRecongnizerTarget valueForKey:@"target"];
            
            SEL handleTransition = NSSelectorFromString(@"handleNavigationTransition:");
            //创建手势 跟系统一模一样的手势
            UIPanGestureRecognizer *pangesture =[[UIPanGestureRecognizer alloc]initWithTarget:uinavigationInteractiveTransition action:handleTransition];
            [self.view addGestureRecognizer:pangesture];
        }
    }
}

- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer {
    /**
     *  1.当这个控制器是只有一个时候不执行手势。
     *  2.当这push或者pop时候 不执行手势。
     */
    return self.viewControllers.count != 1 && ![[self valueForKey:@"_isTransitioning"] boolValue];
}