如何像Safari应用程序一样拖动时隐藏标签栏？

Question

我想知道如何实现一个动画,当向下拖动时隐藏标签栏,如iOS 7上的Safari应用程序.任何来自您的信息将不胜感激.

类似的问题: 显示/隐藏UIToolbar,"匹配手指运动",就像在iOS7 Safari中一样.

Answer 1

这样的事情应该有效.我不知道这是否与Safari应用程序具有完全相同的外观,但它很接近:

@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大量单元格时,接受的答案不起作用 - 如果您一直滚动到顶部,则仅显示标签栏.

我改进了这样:

- (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);
        }];
    }

}

}