navigationController

//設置頁面有上拉手勢的時候隱藏導航欄，快速下拉則顯示導航欄
self.navigationController.hidesBarsOnSwipe = YES;
//設置頁面有單擊事件的時候隱藏導航欄，再次點擊顯示導航欄
self.navigationController.hidesBarsOnTap = YES;
//這兩個設置會影響navigationController中的所有控制器，所以在不用的時候要設置爲NO;


//隱藏導航欄
1.self.navigationController.navigationBar.hidden = YES;
2.self.navigationController.navigationBarHidden = YES;
//第二種隱藏會使右滑pop手勢失效，解決方案
self.navigationController.interactivePopGestureRecognizer.delegate = self;
#pragma mark - <UIGestureRecognizerDelegate>
- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer {
    return YES;
}


//消除navigationBar底部的分割線
1.設置空圖片
[self.navigationBar setShadowImage:[UIImage new]];
2.刪除shadowImage
for (UIView *sub in self.navigationBar.subviews) {
        if ([sub isKindOfClass:[UIImageView class]]) {
            [[sub.subviews firstObject]removeFromSuperview];
        }
    }