2010-08-29 77 views
3

我在處理旋轉時在iPhone上使用UIScrollView時遇到了問題。我使用Apple的PageControl示例作爲模型,但是我自己在View中創建了scrollview。使用分頁旋轉UIScrollView的問題

1)滾動視圖按預期工作在默認的縱向加載時,向左滾動向右水平

2)開箱,旋轉CW和重新初始化時,大多把它在其一側,現在旋轉垂直向下,而不是期望的水平靜止。看起來scrollview框架的寬度/高度不會改變,只是它自己的方向。

3)我試圖添加一些方向檢測邏輯,以正確的大小和頁面滾動視圖的方向,這種工作方式,但只有當我將CCW旋轉到橫向。如果我去CW,它會從右邊開始滾動到左邊,並且不起作用。

很明顯,這是越來越hackish,所以有沒有一種適當的方式來設置我的UIScrollview並重新使它旋轉,所以它總是從左到右滾動?


- (void)loadView { 
    [self setupPage]; 
} 

-(void) setupPage { 
    // lazy init view controllers 
    NSMutableArray *controllers = [[NSMutableArray alloc] init]; 
    for (unsigned i = 0; i = kNumberOfPages) return; 

    // replace the placeholder if necessary 
    MyViewController *controller = [viewControllers objectAtIndex:page]; 
    if ((NSNull *)controller == [NSNull null]) { 
     controller = [[MyViewController alloc] initWithPageNumber:page]; 
     [viewControllers replaceObjectAtIndex:page withObject:controller]; 
     [controller release]; 
    } 

    // add the controller's view to the scroll view 
    if (nil == controller.view.superview) { 
     CGRect frame = scrollView.frame; 

     int x = 0; 
     int y = 0; 
     UIDeviceOrientation orientation = [[UIDevice currentDevice] orientation]; 
     if(orientation == UIDeviceOrientationLandscapeLeft || orientation == UIDeviceOrientationLandscapeRight){ 
      x = 0; 
      y = frame.size.height * page; 
     } else { 
      x = frame.size.width * page; 
      y = 0; 
     } 

     frame.origin.x = x; 
     frame.origin.y = y; 
     controller.view.frame = frame; 
     [scrollView addSubview:controller.view]; 
    } 
} 

- (void)scrollViewDidScroll:(UIScrollView *)sender { 
    // We don't want a "feedback loop" between the UIPageControl and the scroll delegate in 
    // which a scroll event generated from the user hitting the page control triggers updates from 
    // the delegate method. We use a boolean to disable the delegate logic when the page control is used. 
    if (pageControlUsed) { 
     // do nothing - the scroll was initiated from the page control, not the user dragging 
     return; 
    } 

    // Switch the indicator when more than 50% of the previous/next page is visible 
    CGFloat pageWidth = scrollView.frame.size.width; 
    int offset = 0; 
    UIDeviceOrientation orientation = [[UIDevice currentDevice] orientation]; 
    if(orientation == UIDeviceOrientationLandscapeLeft || orientation == UIDeviceOrientationLandscapeRight){ 
     pageWidth = scrollView.frame.size.height; 
     offset = scrollView.contentOffset.y; 
    } else { 
     pageWidth = scrollView.frame.size.width; 
     offset = scrollView.contentOffset.x ; 
    } 

    //CGFloat pageWidth = scrollView.frame.size.width; 
    int page = floor((offset - pageWidth/2)/pageWidth) + 1; 
    pageControl.currentPage = page; 

    // load the visible page and the page on either side of it (to avoid flashes when the user starts scrolling) 
    [self loadScrollViewWithPage:page - 1]; 
    [self loadScrollViewWithPage:page]; 
    [self loadScrollViewWithPage:page + 1]; 

    // A possible optimization would be to unload the views+controllers which are no longer visible 
} 

// At the begin of scroll dragging, reset the boolean used when scrolls originate from the UIPageControl 
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView { 
    pageControlUsed = NO; 
} 

// At the end of scroll animation, reset the boolean used when scrolls originate from the UIPageControl 
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView { 
    pageControlUsed = NO; 
} 


- (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation 
{ 
    [self setupPage]; 
} 
 

回答

2

你沒有改變你的滾動視圖的contentSize,所以當它旋轉時它不知道它比它更高。另外,作爲一個快捷方式,每個VC都有一個已經設置的interfaceOrientation屬性,並且內置了檢測方向的函數:UIInterfaceOrientationIsPortrait(self.interfaceOrientation)和UIInterfaceOrientationIsLandscape(self.interfaceOrientation)。

最後,使用willRotateToInterfaceOrientation只是一種視覺效果:持續時間在眼睛上稍微好一些,並且用戶從未感覺到變化,因爲它幾乎與旋轉同時發生。