21.UIScrollView（滑动视图）和UIPageControl()

UIScrollView为了显示多于一个屏幕的内容或者超过你能放在内存中的内容。

UIPageControl类提供一行点来指示当前显示的是多页面视图的哪一页。

初始化

UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame:[UIScreen mainScreen].bounds];

加个颜色

scrollView.backgroundColor = [UIColor redColor];

添加到视图上

[self.view addSubview:scrollView];

释放

[scrollView release];

添加一个图片

UIImageView *imageView = [[UIImageView alloc] initWithFrame:[UIScreen mainScreen].bounds];

设置一张显示的图片

注意:把图片加到scrollView上

添加tag值

imageView.tag = 100;

[scrollView addSubview:imageView];

[imageView release];

设置显示内容区域(滑动的范围)

scrollView.contentSize = CGSizeMake(kScreenwidth * 6, kScreenheight);

设置整页翻动

scrollView.pagingEnabled = YES;

设置滚动条

scrollView.showsHorizontalScrollIndicator = NO;

scrollView.showsVerticalScrollIndicator = NO;

设置回弹效果

scrollView.bounces = YES;

置水平回弹

scrollView.alwaysBounceHorizontal = YES;

设置垂直回弹

scrollView.alwaysBounceVertical = YES;

设置缩放比例

最小缩放比例

scrollView.minimumZoomScale = 0.5;

最大缩放比例

scrollView.maximumZoomScale = 2;

scrollView.exclusiveTouch = YES;

先遵守了协议 设置代理

scrollView.delegate = self;

给scrollView添加一个Tag值

scrollView.tag = 101;

添加一个 还原缩放父按钮

UIButton *button = [UIButton buttonWithType:(UIButtonTypeCustom)];

button.frame = CGRectMake(0, 100, 100, 100);

button.backgroundColor = [UIColor yellowColor];

[self.view addSubview:button];

[button addTarget:self action:@selector(buttonAction:) forControlEvents:(UIControlEventTouchUpInside)];

初始化UIPageControl一个

UIPageControl *pageControl = [[UIPageControl alloc] initWithFrame:CGRectMake(0, kScreenheight - 50, kScreenwidth, 50)];

pageControl.backgroundColor = [UIColor blackColor];

设置一共有多少页

pageControl.numberOfPages = 5;

设置当前显示第几页

pageControl.currentPage = 1;

设置未选中颜色

pageControl.pageIndicatorTintColor = [UIColor greenColor];

设置选中颜色

pageControl.currentPageIndicatorTintColor = [UIColor yellowColor];

添加点击事件

[pageControl addTarget:self action:@selector(pageControlAction:) forControlEvents:(UIControlEventValueChanged)];

不能加在图片上 否则 会被滑动走

[self.view addSubview:pageControl];

[pageControl release];

}

实现pageControl点击方法

-(void)pageControlAction:(UIPageControl *)pageControl

{

NSLog(@”%ld”,pageControl.currentPage);

}

-(void)buttonAction:(UIButton *)button

{

把scroolView取出来

UIScrollView scrollView = (UIScrollView )[self.view viewWithTag:101];

重置缩放比例

[scrollView setZoomScale:1 animated:YES];

-(void)scrollViewDidScroll:(UIScrollView *)scrollView

{

NSLog(@”滑动时 一直触发”);

}

-(void)scrollViewDidZoom:(UIScrollView *)scrollView

{

NSLog(@”缩放时触发”);

缩放时 按中心点来缩放

UIImageView imageView = (UIImageView )[self.view viewWithTag:100];

改变imageView的中心点

让imageView中心点 始终等于 self.view中心点

imageView.center = self.view.center;

}

指定要缩放的视图

-(UIView )viewForZoomingInScrollView:(UIScrollView )scrollView

{

指定要缩放的视图 并且是scrollView的子视图

return scrollView.subviews[0];

}

-(void)scrollViewWillBeginDragging:(UIScrollView *)scrollView

{

NSLog(@”将要开始拖拽”);

}

-(void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate

{

NSLog(@”已经结束拖拽”);

}

-(void)scrollViewWillBeginDecelerating:(UIScrollView *)scrollView

{

NSLog(@”将要开始减速”);

}

-(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView

{

最终图片停止在这个方法

NSLog(@”已经结束减速”);

}

-(void)scrollViewDidEndZooming:(UIScrollView )scrollView withView:(UIView )view atScale:(CGFloat)scale

{

NSLog(@”缩放已经结束触发”);

}

-(void)scrollViewDidEndScrollingAnimation:(UIScrollView *)scrollView

{

改变偏移量的动画结束后 会触发

NSLog(@”动画结束后触发”);

}