iOS控件：UIScrollView
一、
#import "RootViewController.h"
#define SelfViewWidth self.view.bounds.size.width
#define SelfViewHeight self.view.bounds.size.height//view的高度不会因为有导航条存在而发生变化
#define SelfScrollViewWidth SelfViewWidth
#define SelfScrollViewHeight (SelfViewHeight - 64)
@interface RootViewController ()
@property (nonatomic, strong) UIImageView * imagev1;
@end
二、相关属性
- (void)viewDidLoad {
[super viewDidLoad];
self.view.backgroundColor = [UIColor greenColor];
/**
* 以只有导航条为例scrollView的原点坐标为（0，0）
* 当为yes时（默认），scrollView的原点坐标为(0,64)
* 当为no时，原点坐标才为(0,0)
*/
self.automaticallyAdjustsScrollViewInsets = NO;
//创建一个UIScrollView
UIScrollView * scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 64, SelfViewWidth, SelfViewHeight-64)];//需要减去导航条的高度
scrollView.delegate = self;
scrollView.backgroundColor = [UIColor redColor];
[self.view addSubview:scrollView];
//
UIImage * image1 = [UIImage imageNamed:@"1001"];
UIImageView * imagev1 = [[UIImageView alloc]initWithFrame:CGRectMake(0,0,SelfScrollViewWidth,SelfScrollViewHeight)];
self.imagev1 = imagev1;
imagev1.image = image1;
[scrollView addSubview:imagev1];
//
UIImage * image2 = [UIImage imageNamed:@"1002"];
UIImageView * imagev2 = [[UIImageView alloc] initWithFrame:CGRectMake(SelfScrollViewWidth,0,SelfViewWidth,SelfScrollViewHeight)];
imagev2.image = image2;
[scrollView addSubview:imagev2];
//
UIImage * image3 = [UIImage imageNamed:@"1002"];
UIImageView * imagev3 = [[UIImageView alloc] initWithFrame:CGRectMake(0,SelfScrollViewHeight,SelfScrollViewWidth,SelfScrollViewHeight)];
imagev3.image = image3;
[scrollView addSubview:imagev3];
//1、contentSize 内容的大小 如果想滚动 contentSize的大小要大于本身Frame的大小
scrollView.contentSize = CGSizeMake(2 * SelfScrollViewWidth,2*SelfScrollViewHeight);
scrollView.showsHorizontalScrollIndicator = YES;
scrollView.showsVerticalScrollIndicator = YES;
scrollView.alwaysBounceVertical = YES;
//2、是否可以滚动
scrollView.scrollEnabled = YES;
//3、是否停留在scrollView的宽度的倍数处
scrollView.pagingEnabled = YES;
// //4、设置内边距
// [scrollView setContentInset:UIEdgeInsetsMake(40, 40, 40, 40)];
// UIView * blueView = [[UIView alloc] initWithFrame:CGRectMake(-40, -40, 10, 10)];
// blueView.backgroundColor = [UIColor blueColor];
// [scrollView addSubview:blueView];
// //5、设置偏移量
// [scrollView setContentOffset:CGPointMake(-40, -40) animated:NO];
// //6、让某个区域显示
// [scrollView scrollRectToVisible:CGRectMake(100, 100, 500, 100) animated:YES];
// UIView * redView = [[UIView alloc] initWithFrame:CGRectMake(100, 100, 500, 100)];
// redView.backgroundColor = [UIColor redColor];
// [scrollView addSubview:redView];
// UIView * greenView = [[UIView alloc] initWithFrame:CGRectMake(590, 100, 10, 10)];
// greenView.backgroundColor = [UIColor greenColor];
// [scrollView addSubview:greenView];
// //7、 设置最大、最小缩放比例(只有最大、最小缩放比不同缩放才会起作用)
// scrollView. maximumZoomScale = 4.0;
// scrollView. minimumZoomScale = 1.0;
}
三、相关代理方法
#pragma mark -
#pragma mark PS:Responding to Scrolling and Dragging
//偏移量发生变化就会调用
- (void)scrollViewDidScroll:(UIScrollView *)scrollView{
// any offset changes
}
//将要拖拽的时候
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView{
// called on start of dragging (may require some time and or distance to move)
// Tells the delegate when the scroll view is about to start scrolling the content.
}
//将要结束拖拽的时候
//velocity:手指将要离开时的速度
//velocity:The velocity of the scroll view (in points) at the moment the touch was released.
//targetContentOffset：惯性滑动结束时的偏移量(目标偏移量)
//targetContentOffset:The expected offset when the scrolling action decelerates to a stop.
- (void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset {
/*********************************************************************************************************\
* PS：重要说明
* velocity:通过这个参数可以判断滚动的方向
* targetContentOffset：通过这个参数可以判断视图是否滚动到了边界。
*
\**********************************************************************************************************/
CGFloat x = fabs(velocity.x);
CGFloat y = fabs(velocity.y);
if (x > y) {
NSLog(@"水平滑动");
}
else{
NSLog(@"垂直滑动");
}
CGFloat targetOffsetX = targetContentOffset->x;//目标偏移量
CGFloat targetOffsetY = targetContentOffset->y;//目标偏移量
}
//拖拽结束的时候
//decelerate:手指离开后是否有惯性滑动 yes为有 no为没有
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate{
/*********************************************************************************************************\
* PS：重要说明
* decelerate:通过这个参数就可以确定拖拽结束之后是否还有惯性滑动
* yes：为有 那么减速的代理方法就会被调用
* no：为没有 那么减速的代理方法就不会被调用
*
\**********************************************************************************************************/
//下面代码可以禁止惯性滑动
// if (decelerate) {
// dispatch_async(dispatch_get_main_queue(), ^{
// printf("STOP IT!!\n");
// [scrollView setContentOffset:scrollView.contentOffset animated:NO];
// });
// }
}
# pragma mark PS:有惯性滑动时才会来到这两个代理方法
//将要减速调用：拖拽结束 若有惯性滑动就来到此方法，若拖拽结束时是静止的就不会来到此方法
//或者设置了 scrollView.pagingEnabled = YES;
- (void)scrollViewWillBeginDecelerating:(UIScrollView *)scrollView{
// called on finger up as we are moving
//Tells the delegate that the scroll view is starting to decelerate the scrolling movement.
}
//减速结束调用
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{
// called when scroll view grinds to a halt
//Tells the delegate that the scroll view has ended decelerating the scrolling movement.
CGFloat scrollViewH = scrollView.frame.size.height;
CGFloat scrollViewW = scrollView.frame.size.width;
CGFloat contentH = scrollView.contentSize.height;
CGFloat contentW = scrollView.contentSize.width;
CGFloat offsetX = scrollView.contentOffset.x;//实时偏移量
CGFloat offsetY = scrollView.contentOffset.y;//实时偏移量
NSLog(@"scrollViewH=%lf",scrollViewH);
NSLog(@"scrollViewW=%lf",scrollViewW);
NSLog(@"contentH=%lf",contentH);
NSLog(@"contentW=%lf",contentW);
NSLog(@"offsetX=%lf",offsetX);
NSLog(@"offsetY=%lf",offsetY);
if (offsetY <= 0) {
NSLog(@"滑动到了顶部");
}
if (offsetX <= 0) {
NSLog(@"滑动到了左边");
}
if (offsetY + scrollViewH >= contentH) {
NSLog(@"滚动到了底部");
}
if (offsetX + scrollViewW >= contentW) {
NSLog(@"滚动到了右边");
}
}
#pragma mark PS:点击状态栏时才会来到这两个代理方法
//是否允许回到顶部(点击状态栏时)
- (BOOL)scrollViewShouldScrollToTop:(UIScrollView *)scrollView{
// return a yes if you want to scroll to the top. if not defined, assumes YES
return NO;
}
//点击状态栏 scrollView 回到顶部时调用
- (void)scrollViewDidScrollToTop:(UIScrollView *)scrollView{
// called when scrolling animation finished. may be called immediately if already at top
}
#pragma mark PS:Responding to Scrolling Animations
- (void)scrollViewDidEndScrollingAnimation:(UIScrollView *)scrollView{
// called when setContentOffset/scrollRectVisible:animated: finishes. not called if not animating
//Tells the delegate when a scrolling animation in the scroll view concludes.
}
#pragma mark PS:Managing Zooming
// any zoom scale changes 缩放发生变化就会调用
- (void)scrollViewDidZoom:(UIScrollView *)scrollView{
NSLog(@"缩放发生变化");
}
// return a view that will be scaled. if delegate returns nil, nothing happens
- (nullable UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView{
//返回要缩放的子视图
return self.imagev1;
}
// called before the scroll view begins zooming its content
- (void)scrollViewWillBeginZooming:(UIScrollView *)scrollView withView:(nullable UIView *)view{
NSLog(@"将要开始缩放");
}
// scale between minimum and maximum. called after any 'bounce' animations
- (void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(nullable UIView *)view atScale:(CGFloat)scale{
NSLog(@"缩放已经结束");
}
参考文章：
1、UIScrollView的属性总结 - woainilsr - 博客园
2、【急急急】怎么禁止uiscrollview垂直方向滚动，只允许水平方向滚动！！ | iOS开发 - CocoaChina CocoaChina_让移动开发更简单
3、关于scrollView禁止惯性滑动与UIScrollView左右滚动判断 - Man_OC的专栏 - 博客频道 - CSDN.NET
4、[转载]有关UIScrollView zoom的一点心得_Hcat阳光_新浪博客
5、UIScrollView控件的常用属性与