IOS开发之UIScrollVIew运用

UIScrollView可以实现在一个界面看到所有内容，同时也不需要担心所显示的内容超出屏幕的大小，当超出之后可以翻阅至下一页浏览。

#pragma mark - UIScrollViewDelegate

- (void)scrollViewDidScroll:(UIScrollView *)scrollView { //在UIScrollView滑动的时候调用此代理函数

CGRect visibleBounds = scrollView.bounds;
//得到当前UIScrollView在屏幕中显示区域相对于scrollview的位置

NSLog(@"%lf, %lf, %lf, %lf", visibleBounds.origin.x,
visibleBounds.origin.y, visibleBounds.size.width, visibleBounds.size.height);

NSLog(@"%lf, %lf", CGRectGetMinX(visibleBounds), CGRectGetMaxX(visibleBounds));

int firstNeededPageIndex = floorf(CGRectGetMinX(visibleBounds) / CGRectGetWidth(visibleBounds));

int lastNeededPageIndex = floorf((CGRectGetMaxX(visibleBounds)-1)
/ CGRectGetWidth(visibleBounds));

NSLog(@"firsr:%d, last:%d", firstNeededPageIndex, lastNeededPageIndex);

--firstNeededPageIndex;

++lastNeededPageIndex;

firstNeededPageIndex = MAX(firstNeededPageIndex, 0);

lastNeededPageIndex = MIN(lastNeededPageIndex, 7);

NSLog(@"firsr:%d, last:%d", firstNeededPageIndex, lastNeededPageIndex);

/*

2012-03-16 14:22:01.531 skoda[3459:11903] 297.000000, 0.000000, 300.000000, 276.000000

2012-03-16 14:22:01.531 skoda[3459:11903] 297.000000, 597.000000

CGRectGetMinX方法的作用得到目前scrollview在当前屏幕中相对于整个UIScrollView的最小值（位于屏幕的最左边）

[b]CGRectGetMaxX方法的作用得到目前scrollview在当前屏幕中相对于整个UIScrollView的最大值（位于屏幕的最右边）[/b]

CGRectGetMinY方法的作用得到目前scrollview在当前屏幕中相对于整个UIScrollView的最小值（位于屏幕的最上边）

[b]CGRectGetMaxY方法的作用得到目前scrollview在当前屏幕中相对于整个UIScrollView的最大值（位于屏幕的最下边）[/b]



[b]CGRectGetMaxX-CGRectGetMinX)/2）[/b]

[b]CGRectGetMaxY-CGRectGetMinY)/2）[/b]



2012-03-16 14:22:01.531 skoda[3459:11903] firsr:0, last:1

2012-03-16 14:22:01.531 skoda[3459:11903] firsr:0, last:2

2012-03-16 14:22:01.547 skoda[3459:11903] 298.000000, 0.000000, 300.000000, 276.000000

2012-03-16 14:22:01.548 skoda[3459:11903] 298.000000, 598.000000

2012-03-16 14:22:01.548 skoda[3459:11903] firsr:0, last:1

2012-03-16 14:22:01.548 skoda[3459:11903] firsr:0, last:2

2012-03-16 14:22:01.564 skoda[3459:11903] 299.000000, 0.000000, 300.000000, 276.000000

2012-03-16 14:22:01.564 skoda[3459:11903] 299.000000, 599.000000

2012-03-16 14:22:01.564 skoda[3459:11903] firsr:0, last:1

2012-03-16 14:22:01.565 skoda[3459:11903] firsr:0, last:2

2012-03-16 14:22:01.581 skoda[3459:11903] 300.000000, 0.000000, 300.000000, 276.000000

2012-03-16 14:22:01.581 skoda[3459:11903] 300.000000, 600.000000

2012-03-16 14:22:01.581 skoda[3459:11903] firsr:1, last:1

2012-03-16 14:22:01.581 skoda[3459:11903] firsr:0, last:2

*/

for (int index = firstNeededPageIndex; index <= lastNeededPageIndex; index++) {

if (![self isDisplayingPageForIndex:index])
{

UIWebView *webView = [[UIWebView alloc] initWithFrame:CGRectMake(index
* self.scrollView.frame.size.width, 0,self.scrollView.frame.size.width, self.scrollView.frame.size.height)];

webView.backgroundColor = [UIColor clearColor];

[self setCornerRadius:webView];

[self.scrollView addSubview:webView];

[self.visiblePages setObject:webView forKey:[NSNumber numberWithInt:index]];

[webView release];

NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL fileURLWithPath:[kFileDirectoryPathstringByAppendingFormat:@"/service%d.html",
index+1]]];

[webView loadRequest:request];

}

}

属性：

contentOffset计算内容位移

contentInset表格外面得东西

- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView // 滚动停止时，触发该函数

- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate //触摸屏幕并拖拽画面，再松开，最后停止时，触发该函数

// 调用以下函数，来自动滚动到想要的位置，此过程中设置有动画效果，停止时，触发该函数
setContentOffset:animated:

scrollRectToVisible:animated:
scrollToRowAtIndexPath:atScrollPosition:animated:
selectRowAtIndexPath:animated:scrollPosition:
scrollViewDidEndScrollingAnimation: