像 Safari 应用程序一样拖动时如何隐藏标签栏？

Question

我想知道如何实现一个在向下拖动时隐藏标签栏的动画，例如 iOS 7 上的 Safari 应用程序。如果您提供任何信息，我们将不胜感激。

类似问题：Show/hide UIToolbar, "match finger movement", precisely as in for example iOS7 Safari.

Answer 1

这样的事情应该可以工作。我不知道这是否与 Safari 应用程序的外观完全相同，但很接近：

@interface ViewController ()
@property (weak, nonatomic) IBOutlet UIScrollView *scrollView;
@property (nonatomic) CGRect originalFrame;
@end

@implementation ViewController

- (void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];
    self.scrollView.contentSize = CGSizeMake(self.view.frame.size.width, 1000);
    self.originalFrame = self.tabBarController.tabBar.frame;
}


-(void)scrollViewDidScroll:(UIScrollView *)scrollView {
    UITabBar *tb = self.tabBarController.tabBar;
    NSInteger yOffset = scrollView.contentOffset.y;
    if (yOffset > 0) {
        tb.frame = CGRectMake(tb.frame.origin.x, self.originalFrame.origin.y + yOffset, tb.frame.size.width, tb.frame.size.height);
    }
   if (yOffset < 1) tb.frame = self.originalFrame;
}

Answer 2

当您在表格视图中有很多单元格时，接受的答案不起作用 - 只有当您一直滚动到顶部时，标签栏才会显示。

我是这样改进的：

- (void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];
    self.scrollView.contentSize = CGSizeMake(self.view.frame.size.width, 1000);
    self.originalFrame = self.tabBarController.tabBar.frame;
}


-(void)scrollViewDidScroll:(UIScrollView *)scrollView{

UITabBar *tabBar = self.tabBarController.tabBar;

NSInteger yOffset = scrollView.contentOffset.y;
CGFloat yPanGesture = [scrollView.panGestureRecognizer translationInView:self.view].y;
CGFloat heightTabBar = tabBar.frame.size.height;

CGFloat tabBarOriginY = tabBar.frame.origin.y;
CGFloat frameHeight = self.view.frame.size.height;

if(yOffset>=heightTabBar)
    yOffset = heightTabBar;

// GOING UP ------------------
if(yPanGesture >= 0 && yPanGesture < heightTabBar && tabBarOriginY > frameHeight-heightTabBar){
    yOffset = heightTabBar - fabsf(yPanGesture);
}
else if(yPanGesture >= 0 && yPanGesture < heightTabBar && tabBarOriginY <= frameHeight-heightTabBar){
    yOffset = 0;
}
// GOING DOWN ------------------
else if(yPanGesture < 0 && tabBarOriginY < frameHeight){
    yOffset = fabsf(yPanGesture);
}else if(yPanGesture < 0 && tabBarOriginY >= frameHeight){
    yOffset = heightTabBar;
}
else{
    yOffset = 0;
}

if (yOffset > 0) {
    tabBar.frame = CGRectMake(tabBar.frame.origin.x, self.originalFrame.origin.y + yOffset, tabBar.frame.size.width, tabBar.frame.size.height);
}
else if (yOffset <= 0){
    tabBar.frame = self.originalFrame;
}
}

    - (void)scrollViewWillEndDragging:(UIScrollView*)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset{ 

// Handle unfinished animations   
    UITabBar *tabBar = self.tabBarController.tabBar;
    CGFloat yPanGesture = [scrollView.panGestureRecognizer translationInView:self.view].y;
    CGFloat heightTabBar = tabBar.frame.size.height;
    CGFloat tabBarOriginY = tabBar.frame.origin.y;
    CGFloat frameHeight = self.view.frame.size.height;


    if(yPanGesture > 0){

        if(tabBarOriginY != frameHeight - heightTabBar) {

            [UIView animateWithDuration:0.3 animations:^(void){
                tabBar.frame = self.originalFrame;
            }];

        }

    }else if(yPanGesture < 0){

    if (tabBarOriginY != frameHeight) {
        [UIView animateWithDuration:0.3 animations:^(void){
            tabBar.frame = CGRectMake(tabBar.frame.origin.x, frameHeight, tabBar.frame.size.width, tabBar.frame.size.height);
        }];
    }

}

}

Answer 3

老实说，我尝试了所有这些解决方案，但它们对我来说还不够强大。他们会隐藏应该显示的标签栏，或者他们以一种奇怪的方式向上移动标签栏。

我最终花了一整天的时间让他们工作。终于放弃使用了：https://github.com/tristanhimmelman/HidingNavigationBar。

这给了我隐藏导航栏和标签栏的功能（这是我最初真正想要的）。它运行得非常好，我在 10 分钟内就完成了设置。

希望这可以帮助其他人不要为此浪费一天的编码：-0。

Answer 4

您可以使用变量来保留 lastContentOffset 值。 关键思想是标签栏 origin.y 介于 CGRectGetMaxY(screenRect) 和 CGRectGetMaxY(screenRect) - CGRectGetHeight(tabBarRect) 之间。

它在我的项目中运行良好。

@interface ViewController ()
    @property (nonatomic, assign) CGFloat lastContentOffsetY;
@end

@implementation ViewController
-(void)scrollViewDidScroll:(UIScrollView *)scrollView
{
    if (!self.tabBarController) {
      return;
    }

  BOOL isStatusBarHidden = [UIApplication sharedApplication].isStatusBarHidden;
  CGFloat kStatusBarHeight = [UIApplication sharedApplication].statusBarFrame.size.height;

if (scrollView.contentOffset.y > (scrollView.contentSize.height - scrollView.frame.size.height)
    || (scrollView.contentOffset.y < (isStatsuBarHidden ? 0 : -kStatusBarHeight))) {
    // bottom & top bouncing - don't need to update
    return;
}

CGFloat offset = scrollView.contentOffset.y - self.lastContentOffsetY;
CGRect tabBarRect = self.tabBarController.tabBar.frame;
CGRect screenRect = [UIScreen mainScreen].bounds;

if (CGRectGetMaxY(tabBarRect) == CGRectGetMaxY(screenRect) + CGRectGetHeight(tabBarRect)) {
    //view could only scroll downward
    if (offset < 0) {
        tabBarRect.origin.y += offset;
    }
} else if (CGRectGetMaxY(tabBarRect) == CGRectGetMaxY(screenRect)) {
    //view could only scroll upward
    if (offset > 0) {
        tabBarRect.origin.y += offset;
    }
} else {
    //view could scroll upward & downward
    tabBarRect.origin.y += offset;
}

//safty reset handling
if (CGRectGetMaxY(tabBarRect) > CGRectGetMaxY(screenRect) + CGRectGetHeight(tabBarRect)) {
    tabBarRect.origin.y = CGRectGetMaxY(screenRect);
} else if (CGRectGetMaxY(tabBarRect) < CGRectGetMaxY(screenRect)) {
    tabBarRect.origin.y = CGRectGetMaxY(screenRect) - CGRectGetHeight(tabBarRect); // over bouncing, set it back
}

self.tabBarController.tabBar.frame = tabBarRect;
self.lastContentOffsetY = scrollView.contentOffset.y;
}

Answer 5

好吧，虽然其他人的所有答案都不起作用或部分起作用，但 @RobNorback 的 HidingNavigationBar 非常出色，而且实际上很容易设置。

但是，我在框架方面遇到了一些困难，并且花了 2 个小时来修复它，所以我加了两分钱，以免有人陷入同样的​​困境。

如果您的集合视图或表格视图中的项目或行数很少，它不会隐藏导航栏（或选项卡栏或工具栏），即使项目或行数足够大超出屏幕。您应该添加更多项目或行以使框架正确隐藏栏。

Answer 6

static CGFloat navBarOriginY = 20.0;

为导航栏原点 Y 位置的基值创建常量

- (void)viewDidLoad {
[super viewDidLoad];
 self.navigationController.hidesBarsOnSwipe = true;
[self.navigationController.barHideOnSwipeGestureRecognizer addTarget:self action:@selector(swipe:)];
}

添加您的自定义选择器以处理将在 navBar 隐藏之前和隐藏期间触发的系统滑动手势

- (void)swipe:(UIPanGestureRecognizer *)recognizer {
if (recognizer.state == UIGestureRecognizerStateEnded || recognizer.state == UIGestureRecognizerStateCancelled || recognizer.state == UIGestureRecognizerStateFailed) {

如果手势状态结束/取消或失败，您需要完全更改 tabBar 的框架

    CGRect finalFrame = self.tabBarController.tabBar.frame;
    if (self.navigationController.navigationBar.frame.origin.y < 0) {
         //Tab bar will be hidden
        finalFrame.origin.y = self.maxTabBarY;
    } else {
         //Tab bar will be visible
        finalFrame.origin.y = self.minTabBarY;
    }

    [self setFrameForTabBar:finalFrame animationDuration:0.3];

} else if (recognizer.state == UIGestureRecognizerStateChanged) {

如果 state == 发生变化，您需要像在 Safari 应用程序中一样使用 navBar 平移 tabBar。

    CGRect frame = self.tabBarController.tabBar.frame;
    CGFloat delta = navBarOriginY - self.navigationController.navigationBar.layer.presentationLayer.frame.origin.y;
    frame.origin.y = self.minTabBarY + delta;
    [self setFrameForTabBar:frame animationDuration:0.0];
} } }

- (void)setFrameForTabBar:(CGRect)frame animationDuration:(CGFloat)duration {
dispatch_async(dispatch_get_main_queue(), ^{
    [UIView animateWithDuration:duration delay:0.0 options:UIViewAnimationOptionCurveLinear animations:^{
        self.tabBarController.tabBar.frame = frame;
    } completion:^(BOOL finished) {}];
});