我正在構建一個pdf查看器應用程序。我的技能現在處於中等的LOL巫術水平......我用這個應用程序自己做了很多,但我的理論或我的代碼相當困難。我的應用程序有一個分頁滾動視圖,它使自己成爲整個pdf文檔的長度,然後在另一個滾動視圖(ImageScrollView)中顯示當前頁面,這是它自己的類。 ImageScrollView使UIView能夠完成CATiledLayer的常規工作,而且一切正常! :)iphone:錯誤和pdf頁面問題
我的ImageScrollView顯示屏幕上的頁面(當您滾動到下一頁時ImageScrollView再次加載CATiledLayer屏幕上,你可以看到瓷磚)。我一直在研究如何讓當前頁面的左右頁面預先加載(因爲我不認爲將PDF加載到屏幕上的瓷磚對用戶體驗有好處),但我不確定是否我正確地思考它。
也許我應該做一個左邊和右邊的UIView坐在ImageScrollView中的屏幕上的UIView?
或者它可能與回收不再可見的頁面(如下所示)有關(但我認爲我仍然需要左側/右側的視圖,甚至仍然不需要回收視圖)
- (void)tilePages {
// Calculate which pages are visible
CGRect visibleBounds = pagingScrollView.bounds;//CGRect visibleBounds = CGRectMake(0.0f, 0.0f, 320.0f * [self pdfPageCount], 435.0f);
int firstNeededPageIndex = floorf(CGRectGetMinX(visibleBounds)/CGRectGetWidth(visibleBounds));
int lastNeededPageIndex = floorf((CGRectGetMaxX(visibleBounds)-1)/CGRectGetWidth(visibleBounds));
firstNeededPageIndex = MAX(firstNeededPageIndex, 0);
lastNeededPageIndex = MIN(lastNeededPageIndex, [self pdfPageCount] - 1);
// Recycle no-longer-visible pages
for (ImageScrollView *page in visiblePages) {
if (page.index < firstNeededPageIndex || page.index > lastNeededPageIndex) {
[recycledPages addObject:page];
[page removeFromSuperview];}}
[visiblePages minusSet:recycledPages];
// add missing pages
for (int index = firstNeededPageIndex; index <= lastNeededPageIndex; index++) {
if (![self isDisplayingPageForIndex:index]) {
ImageScrollView *page = [self dequeueRecycledPage];
if (page == nil) {
page = [[[ImageScrollView alloc] init] autorelease];}
[self configurePage:page forIndex:index];
[pagingScrollView addSubview:page];
[visiblePages addObject:page];}}}
我改變了代碼,看看下面發生了什麼(不知道),我也得到錯誤:初始化時將整數指針不進行強制轉換
- (void)tilePages:(NSUInteger) index {
// Calculate which pages are visible
CGRect visibleBounds = pagingScrollView.bounds;
int firstNeededPageIndex = floorf(CGRectGetMinX(visibleBounds)/CGRectGetWidth(visibleBounds));
int lastNeededPageIndex = floorf((CGRectGetMaxX(visibleBounds)-1)/CGRectGetWidth(visibleBounds));
firstNeededPageIndex = MAX(firstNeededPageIndex, 0);
lastNeededPageIndex = MIN(lastNeededPageIndex, [self pdfPageCount] - 1);
// Recycle no-longer-visible pages
for (ImageScrollView *page in visiblePages) {
if (page.index < firstNeededPageIndex || page.index > lastNeededPageIndex) {
// visible N/Ppages *start*
if (index == 1) {
ImageScrollView *Npage = Npage.index +1;
Npage = [[[ImageScrollView alloc] init] autorelease];
[self configurePage:Npage forIndex:index +1];
[pagingScrollView addSubview:Npage];
[visiblePages addObject:Npage];}
if (index < 2 || index > [self pdfPageCount] -2) {
ImageScrollView *Ppage = Ppage.index -1;
ImageScrollView *Npage = Npage.index +1;
Ppage = [[[ImageScrollView alloc] init] autorelease];
[self configurePage:Ppage forIndex:index -1];
[pagingScrollView addSubview:Ppage];
[visiblePages addObject:Ppage];
Npage = [[[ImageScrollView alloc] init] autorelease];
[self configurePage:Npage forIndex:index +1];
[pagingScrollView addSubview:Npage];
[visiblePages addObject:Npage];}
if (index == [self pdfPageCount] -1) {
ImageScrollView *Ppage = Ppage.index -1;
Ppage = [[[ImageScrollView alloc] init] autorelease];
[self configurePage:Ppage forIndex:index -1];
[pagingScrollView addSubview:Ppage];
[visiblePages addObject:Ppage];}
// visible N/Ppages *end*
[recycledPages addObject:page];
[page removeFromSuperview];}}
[visiblePages minusSet:recycledPages];
// add missing pages
for (int index = firstNeededPageIndex; index <= lastNeededPageIndex; index++) {
// recycled N/Ppages *start*
if (index == firstNeededPageIndex +1) {
ImageScrollView *Npage = Npage.index +1;
[recycledPages addObject:Npage];
[Npage removeFromSuperview];}
if (index < firstNeededPageIndex +2 || index > lastNeededPageIndex -2) {
ImageScrollView *Ppage = Ppage.index -1;
ImageScrollView *Npage = Npage.index +1;
[recycledPages addObject:Ppage];
[Ppage removeFromSuperview];
[recycledPages addObject:Npage];
[Npage removeFromSuperview];}
if (index == lastNeededPageIndex -1) {
ImageScrollView *Ppage = Ppage.index -1;
[recycledPages addObject:Ppage];
[Ppage removeFromSuperview];}
// recycled N/Ppages *end*
if (![self isDisplayingPageForIndex:index]) {
ImageScrollView *page = [self dequeueRecycledPage];
if (page == nil) {
page = [[[ImageScrollView alloc] init] autorelease];}
[self configurePage:page forIndex:index];
[pagingScrollView addSubview:page];
[visiblePages addObject:page];}}}
我能存儲在一個NSIndex 3個PDF頁面?例如:previousPageToRecycle,previousPage,currentPage,nextPage,nextPageToRecycle
我不確定如何做到這一點。