我做了以下代码，其中三个视图可以在UIScrollView中的分页期间重复使用以节省实时内存 - ＆gt;
#pragma mark - UIScrollView Delegates
- (void)scrollViewDidScroll:(UIScrollView *)scrollView{
CGFloat pageWidth = self.view.frame.size.width;
CGPoint aContentOffSet = [[self scrollView] contentOffset] ;
float currPos = aContentOffSet.x;
int selectedPage = roundf(currPos/pageWidth);
[[self pageControl] setCurrentPage:selectedPage];
[self update:selectedPage];
}
#pragma mark - Custom methods
-(void)update:(int) selectedPage{
BOOL view1FrameShallBeUnchanged = false;
BOOL view2FrameShallBeUnchanged = false;
BOOL view3FrameShallBeUnchanged = false;
BOOL aFrame1Matched = false;
BOOL aFrame2Matched = false;
BOOL aFrame3Matched = false;
CGRect aFrame1 = CGRectMake(selectedPage*self.view.frame.size.width, 0.0f, self.view.frame.size.width, self.scrollView.frame.size.height);
CGRect aFrame2 = CGRectMake((selectedPage-1)*self.view.frame.size.width, 0.0f, self.view.frame.size.width, self.scrollView.frame.size.height);
CGRect aFrame3 = CGRectMake((selectedPage+1)*self.view.frame.size.width, 0.0f, self.view.frame.size.width, self.scrollView.frame.size.height);
ViewOnScrollView *aView1 = (ViewOnScrollView*)[[self scrollView] viewWithTag:1234];
ViewOnScrollView *aView2 = (ViewOnScrollView*)[[self scrollView] viewWithTag:12345];
ViewOnScrollView *aView3 = (ViewOnScrollView*)[[self scrollView] viewWithTag:123456];
if(aView1 && aView2 && aView3){
//Check for Frame 1
if(aFrame1.origin.x == aView1.frame.origin.x){
view1FrameShallBeUnchanged = true;
aFrame1Matched = true;
}
else if(aFrame1.origin.x == aView2.frame.origin.x){
view2FrameShallBeUnchanged = true;
aFrame1Matched = true;
}
else if(aFrame1.origin.x ==aView3.frame.origin.x){
view3FrameShallBeUnchanged = true;
aFrame1Matched = true;
}
//Check for Frame 2
if(aFrame2.origin.x == aView1.frame.origin.x){
view1FrameShallBeUnchanged = true;
aFrame2Matched = true;
}
else if(aFrame2.origin.x == aView2.frame.origin.x){
view2FrameShallBeUnchanged = true;
aFrame2Matched = true;
}
else if(aFrame2.origin.x == aView3.frame.origin.x){
view3FrameShallBeUnchanged = true;
aFrame2Matched = true;
}
//Check for Frame 3
if(aFrame3.origin.x == aView1.frame.origin.x){
view1FrameShallBeUnchanged = true;
aFrame3Matched = true;
}
else if(aFrame3.origin.x == aView2.frame.origin.x){
view2FrameShallBeUnchanged = true;
aFrame3Matched = true;
}
else if(aFrame3.origin.x == aView3.frame.origin.x){
view3FrameShallBeUnchanged = true;
aFrame3Matched = true;
}
if(!view1FrameShallBeUnchanged){
if(!aFrame1Matched){
[aView1 setFrame:aFrame1];
}
else if(!aFrame2Matched){
[aView1 setFrame:aFrame2];
}
else{
[aView1 setFrame:aFrame3];
}
[self hideOrShowTheTabs:aView1];
[self hideShowView:aView1];
}
if(!view2FrameShallBeUnchanged){
if(!aFrame1Matched){
[aView2 setFrame:aFrame1];
}
else if(!aFrame2Matched){
[aView2 setFrame:aFrame2];
}
else{
[aView2 setFrame:aFrame3];
}
[self hideShowView:aView2];
}
if(!view3FrameShallBeUnchanged){
if(!aFrame1Matched){
[aView3 setFrame:aFrame1];
}
else if(!aFrame2Matched){
[aView3 setFrame:aFrame2];
}
else{
[aView3 setFrame:aFrame3];
}
[self hideShowView:aView3];
}
}
}
-(void)hideShowView:(ViewOnScrollView*)theView{
if(theView.frame.origin.x<0 || theView.frame.origin.x>[self.scrollView contentSize].width )
theView.hidden = YES;
else{
theView.hidden = NO;
}
}
评论/建议/欢迎更好的方法...
答案 0 :(得分：4)
查看这个课程..可以帮助..易于使用...就像UITableview
答案 1 :(得分：2)
没关系，但你有太多代码（约40行）和太多不必要的处理。您只需知道一帧何时匹配（假设中心框架），并且您应该仅在页面即将更改时执行此操作，而不是在每个滚动事件上执行此操作。
这样，只要左页或右页成为当前页面，就会将相反的页面移动到另一侧。
你遇到的另一个错误是，当 frame.origin.x 与内容大小相等（==，或＆gt; =）时，你应该隐藏最后的+1页，不仅更大（大于）。
#pragma mark - UIScrollView Delegates
- (void)scrollViewDidScroll:(UIScrollView *)scrollView{
int selectedPage = roundf(newsPagesView.contentOffset.x/_pageWidth);
if (selectedPage != _currentPage) {
_currentPage = selectedPage;
[self update:selectedPage];
}
}
#pragma mark - Custom methods
-(void)update:(int) selectedPage{
BOOL page1FrameMatched = false;
BOOL page2FrameMatched = false;
BOOL page3FrameMatched = false;
BOOL frameCurrentMatched = false;
CGRect frameCurrent = CGRectMake(selectedPage*_pageWidth, 0.0f, _pageWidth, _pageHeight);
CGRect frameLeft = CGRectMake((selectedPage-1)*_pageWidth, 0.0f, _pageWidth, _pageHeight);
CGRect frameRight = CGRectMake((selectedPage+1)*_pageWidth, 0.0f, _pageWidth, _pageHeight);
NewsPage *page1 = (NewsPage*)[newsPagesView viewWithTag:100];
NewsPage *page2 = (NewsPage*)[newsPagesView viewWithTag:101];
NewsPage *page3 = (NewsPage*)[newsPagesView viewWithTag:102];
if(page1 && page2 && page3){
//Check for Current
if(frameCurrent.origin.x == page1.frame.origin.x){
page1FrameMatched = true;
frameCurrentMatched = true;
}
else if(frameCurrent.origin.x == page2.frame.origin.x){
page2FrameMatched = true;
frameCurrentMatched = true;
}
else if(frameCurrent.origin.x ==page3.frame.origin.x){
page3FrameMatched = true;
frameCurrentMatched = true;
}
if(frameCurrentMatched){
if(page1FrameMatched){
[page1 setFrame:frameCurrent];
[page2 setFrame:frameLeft];
[page3 setFrame:frameRight];
}
else if(page2FrameMatched){
[page1 setFrame:frameRight];
[page2 setFrame:frameCurrent];
[page3 setFrame:frameLeft];
}
else{
[page1 setFrame:frameLeft];
[page2 setFrame:frameRight];
[page3 setFrame:frameCurrent];
}
[self hideShowView:page1];
[self hideShowView:page2];
[self hideShowView:page3];
}
}
}
/**
* This method hides the view if it is outside the scrollview content bounds, i.e. the
* view before page 0, or the view after last page.
*/
-(void)hideShowView:(NewsPage*)aPage{
if(aPage.frame.origin.x<0 || aPage.frame.origin.x>=[newsPagesView contentSize].width )
aPage.hidden = YES;
else{
aPage.hidden = NO;
}
}
答案 2 :(得分：0)