我有一個ContentViewController含有滾動視圖。加載在特定索引一個第二的UIScrollView並顯示結果
滾動視圖示出了跨越3頁(9項每頁)27個可選項目。這工作正常。
當用戶點擊的項目之一,我重建滾動視圖的陣列,以包含所有27項在27頁,每頁1個項目(使用不同的視圖控制器,以顯示它)。所以當你選擇一個項目時,你會得到一個細節視圖。
然而,無論哪個項目的用戶選擇的,所述第二渦旋視圖載荷爲空。根據頁面控制,滾動視圖位於正確的位置,但不顯示任何內容。直到我滾動顯示一個項目的視圖,但它將索引重置爲列表的開始。
很抱歉的代碼可怕量,但也許這將有助於說明什麼錯。
非常感謝您的任何意見。
- (void)objectSelected: (SelectableObject *)objectSelected {
detailView = TRUE;
self.selectedObject = objectSelected;
[self drawScrollingView];
}
- (void)drawScrollingView {
//Clear out any previous views
[scrollView.subviews makeObjectsPerformSelector:@selector(removeFromSuperview)];
//Set the background and other interface elements
if (detailView) {
self.background.image = [UIImage imageNamed:@"SelectB.png"];
self.nameField.hidden = FALSE;
pageControl.frame = CGRectMake(0, 380, pageControl.frame.size.width, pageControl.frame.size.height);
numberPages = [self.contentList count];
}
else {
self.background.image = [UIImage imageNamed:@"SelectA1.png"];
pageControl.backgroundColor = [UIColor orangeColor];
//Determine the number of pages
int items = [self.contentList count];
numberPages = items/9;
if (items % 9 != 0)
numberPages++;
}
// view controllers are created lazily
// in the meantime, load the array with placeholders which will be replaced on demand
NSMutableArray *controllers = [[NSMutableArray alloc] init];
for (unsigned i = 0; i < numberPages; i++) {
[controllers addObject:[NSNull null]];
}
self.viewControllers = controllers;
[controllers release];
// a page is the width of the scroll view
scrollView.pagingEnabled = YES;
scrollView.contentSize = CGSizeMake(scrollView.frame.size.width * numberPages, scrollView.frame.size.height);
scrollView.showsHorizontalScrollIndicator = NO;
scrollView.showsVerticalScrollIndicator = NO;
scrollView.scrollsToTop = NO;
scrollView.delegate = self;
pageControl.numberOfPages = numberPages;
pageControl.hidesForSinglePage = TRUE;
if (!detailView)
pageControl.currentPage = 0;
else
pageControl.currentPage = self.selectedObject.number;
// pages are created on demand
// load the visible page
// load the page on either side to avoid flashes when the user starts scrolling
[self loadScrollViewWithPage:pageControl.currentPage-1];
[self loadScrollViewWithPage:pageControl.currentPage];
[self loadScrollViewWithPage:pageControl.currentPage+1];
}
- (void)loadScrollViewWithPage:(int)page {
if (page < 0)
return;
if (page >= numberPages)
return;
NSLog(@"PAGE: %i", page);
if (!detailView) {
//Get the subset of objects, depending on the page, and pass it to the controller
//There are 9 objects per page, so page 0 covers 0-8, page 1 covers 9-17, 2 18-26.
//However, there may not be a total of 9
int startIndex = page*9;
int length = 9;
int total = [self.contentList count];
if (startIndex+length > total)
length = total-startIndex;
NSRange theRange;
theRange.location = startIndex;
theRange.length = length;
NSArray *selectionSubset = [self.contentList subarrayWithRange:theRange];
// replace the placeholder if necessary
SelectionScreenViewController *controller = [viewControllers objectAtIndex:page];
if ((NSNull *)controller == [NSNull null]) {
controller = [[SelectionScreenViewController alloc] initWithSet:selectionSubset];
[controller setDelegate:self];
[viewControllers replaceObjectAtIndex:page withObject:controller];
[controller release];
}
// add the controller's view to the scroll view
if (controller.view.superview == nil) {
CGRect frame = scrollView.frame;
frame.origin.x = frame.size.width * page;
frame.origin.y = 0;
controller.view.frame = frame;
[scrollView addSubview:controller.view];
}
}
else {
NSLog(@"DETAIL VIEW");
[self.navigationController setToolbarHidden:NO animated:YES];
// replace the placeholder if necessary
SelectionDetailViewController *controller = [viewControllers objectAtIndex:page];
if ((NSNull *)controller == [NSNull null]) {
NSLog(@"controller is NULL");
controller = [[SelectionDetailViewController alloc] initWithObject:[self.contentList objectAtIndex:page]];
[controller setDelegate:self];
[viewControllers replaceObjectAtIndex:page withObject:controller];
[controller release];
}
// add the controller's view to the scroll view
if (controller.view.superview == nil) {
NSLog(@"controller superview is NIL");
CGRect frame = scrollView.frame;
frame.origin.x = frame.size.width * page;
frame.origin.y = 0;
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;
NSLog(@"contentOffset: %g", scrollView.contentOffset);
int page = floor((scrollView.contentOffset.x - pageWidth/2)/pageWidth) + 1;
if (detailView) { //some other formula here to determine page???
}
pageControl.currentPage = page;
// Set the name
self.selectedObject = [self.contentList objectAtIndex:page];
self.nameField.text = self.selectedObject.name;
NSLog(@"NAME: %@", [[self.contentList objectAtIndex:page] name]);
NSLog(@"ScrollViewDidScrool page: %i", 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];
}
太長問題 – 2012-02-07 17:07:43