[ios] Facebook 숨기기 / 표시 확장 / 계약 탐색 모음 모방

@peerless가 제공하는 솔루션은 훌륭한 시작이지만 스크롤 속도를 고려하지 않고 드래그가 시작될 때마다 애니메이션을 시작합니다. 이로 인해 Facebook 앱보다 더 쾌적하게 경험할 수 있습니다. Facebook의 행동과 일치하려면 다음을 수행해야합니다.

• 탐색 속도에 비례하는 속도로 탐색 표시 줄 숨기기 / 표시
• 막대가 부분적으로 숨겨져있을 때 스크롤이 중지되면 애니메이션을 시작하여 막대를 완전히 숨 깁니다.
• 막대가 줄어들면 탐색 모음의 항목이 희미 해집니다.

먼저 다음 속성이 필요합니다.

@property (nonatomic) CGFloat previousScrollViewYOffset;

그리고 UIScrollViewDelegate방법 은 다음과 같습니다 .

- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
    CGRect frame = self.navigationController.navigationBar.frame;
    CGFloat size = frame.size.height - 21;
    CGFloat framePercentageHidden = ((20 - frame.origin.y) / (frame.size.height - 1));
    CGFloat scrollOffset = scrollView.contentOffset.y;
    CGFloat scrollDiff = scrollOffset - self.previousScrollViewYOffset;
    CGFloat scrollHeight = scrollView.frame.size.height;
    CGFloat scrollContentSizeHeight = scrollView.contentSize.height + scrollView.contentInset.bottom;

    if (scrollOffset <= -scrollView.contentInset.top) {
        frame.origin.y = 20;
    } else if ((scrollOffset + scrollHeight) >= scrollContentSizeHeight) {
        frame.origin.y = -size;
    } else {
        frame.origin.y = MIN(20, MAX(-size, frame.origin.y - scrollDiff));
    }

    [self.navigationController.navigationBar setFrame:frame];
    [self updateBarButtonItems:(1 - framePercentageHidden)];
    self.previousScrollViewYOffset = scrollOffset;
}

- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
    [self stoppedScrolling];
}

- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView
                  willDecelerate:(BOOL)decelerate
{
    if (!decelerate) {
        [self stoppedScrolling];
    }
}

다음과 같은 도우미 메소드가 필요합니다.

- (void)stoppedScrolling
{
    CGRect frame = self.navigationController.navigationBar.frame;
    if (frame.origin.y < 20) {
        [self animateNavBarTo:-(frame.size.height - 21)];
    }
}

- (void)updateBarButtonItems:(CGFloat)alpha
{
    [self.navigationItem.leftBarButtonItems enumerateObjectsUsingBlock:^(UIBarButtonItem* item, NSUInteger i, BOOL *stop) {
        item.customView.alpha = alpha;
    }];
    [self.navigationItem.rightBarButtonItems enumerateObjectsUsingBlock:^(UIBarButtonItem* item, NSUInteger i, BOOL *stop) {
        item.customView.alpha = alpha;
    }];
    self.navigationItem.titleView.alpha = alpha;
    self.navigationController.navigationBar.tintColor = [self.navigationController.navigationBar.tintColor colorWithAlphaComponent:alpha];
}

- (void)animateNavBarTo:(CGFloat)y
{
    [UIView animateWithDuration:0.2 animations:^{
        CGRect frame = self.navigationController.navigationBar.frame;
        CGFloat alpha = (frame.origin.y >= y ? 0 : 1);
        frame.origin.y = y;
        [self.navigationController.navigationBar setFrame:frame];
        [self updateBarButtonItems:alpha];
    }];
}

약간 다른 동작을하려면 스크롤 할 때 막대의 위치를 ​​바꾸는 선 ( else블록의 scrollViewDidScroll)을 다음과 같이 바꾸십시오 .

frame.origin.y = MIN(20,
                     MAX(-size, frame.origin.y -
                               (frame.size.height * (scrollDiff / scrollHeight))));

막대가 절대 값 대신 마지막 스크롤 비율을 기준으로 배치되어 페이드가 느려집니다. 원래의 행동은 Facebook과 비슷하지만 나도 이것을 좋아합니다.

참고 :이 솔루션은 iOS 7 이상입니다. 이전 버전의 iOS를 지원하는 경우 필요한 검사를 추가하십시오.

답변

self.navigationController.hidesBarsOnSwipe = YES;

navigationController?.hidesBarsOnSwipe = true

self.shyNavBarManager.scrollView = self.scrollView;

class QuotesTableViewController: UITableViewController {

override func viewDidAppear(animated: Bool) {
    super.viewDidAppear(animated)

    navigationController?.hidesBarsOnSwipe = true
}

class UINavigationController : UIViewController {

    //... truncated

    /// When the keyboard appears, the navigation controller's navigationBar toolbar will be hidden. The bars will remain hidden when the keyboard dismisses, but a tap in the content area will show them.
    @availability(iOS, introduced=8.0)
    var hidesBarsWhenKeyboardAppears: Bool
    /// When the user swipes, the navigation controller's navigationBar & toolbar will be hidden (on a swipe up) or shown (on a swipe down). The toolbar only participates if it has items.
    @availability(iOS, introduced=8.0)
    var hidesBarsOnSwipe: Bool
    /// The gesture recognizer that triggers if the bars will hide or show due to a swipe. Do not change the delegate or attempt to replace this gesture by overriding this method.
    @availability(iOS, introduced=8.0)
    var barHideOnSwipeGestureRecognizer: UIPanGestureRecognizer { get }
    /// When the UINavigationController's vertical size class is compact, hide the UINavigationBar and UIToolbar. Unhandled taps in the regions that would normally be occupied by these bars will reveal the bars.
    @availability(iOS, introduced=8.0)
    var hidesBarsWhenVerticallyCompact: Bool
    /// When the user taps, the navigation controller's navigationBar & toolbar will be hidden or shown, depending on the hidden state of the navigationBar. The toolbar will only be shown if it has items to display.
    @availability(iOS, introduced=8.0)
    var hidesBarsOnTap: Bool
    /// The gesture recognizer used to recognize if the bars will hide or show due to a tap in content. Do not change the delegate or attempt to replace this gesture by overriding this method.
    @availability(iOS, introduced=8.0)
    unowned(unsafe) var barHideOnTapGestureRecognizer: UITapGestureRecognizer { get }
}

@property (strong, nonatomic) NSArray *navBarItems;

-(void)scrollViewDidScrollToTop:(UIScrollView *)scrollView
{
    if([[[UIDevice currentDevice] systemVersion] floatValue] < 7.0f){
        return;
    }

    CGRect frame = self.navigationController.navigationBar.frame;
    frame.origin.y = 20;

    if(self.navBarItems.count > 0){
        [self.navigationController.navigationBar setItems:self.navBarItems];
    }

    [self.navigationController.navigationBar setFrame:frame];
}

-(void)scrollViewDidScroll:(UIScrollView *)scrollView
{
    if([[[UIDevice currentDevice] systemVersion] floatValue] < 7.0f){
        return;
    }

    CGRect frame = self.navigationController.navigationBar.frame;
    CGFloat size = frame.size.height - 21;

    if([scrollView.panGestureRecognizer translationInView:self.view].y < 0)
    {
        frame.origin.y = -size;

        if(self.navigationController.navigationBar.items.count > 0){
            self.navBarItems = [self.navigationController.navigationBar.items copy];
            [self.navigationController.navigationBar setItems:nil];
        }
    }
    else if([scrollView.panGestureRecognizer translationInView:self.view].y > 0)
    {
        frame.origin.y = 20;

        if(self.navBarItems.count > 0){
            [self.navigationController.navigationBar setItems:self.navBarItems];
        }
    }

    [UIView beginAnimations:@"toggleNavBar" context:nil];
    [UIView setAnimationDuration:0.2];
    [self.navigationController.navigationBar setFrame:frame];
    [UIView commitAnimations];
}

self.navigationController.hidesBarsOnSwipe = YES;
CGRect statuBarFrame = [UIApplication sharedApplication].statusBarFrame;
UIView *statusbarBg = [[UIView alloc] initWithFrame:statuBarFrame];
statusbarBg.backgroundColor = [UIColor blackColor];
[self.navigationController.view addSubview:statusbarBg];

- (void)scrollViewDidScrollToTop:(UIScrollView *)scrollView {
     self.navigationController.navigationBarHidden = NO;
}