iOS中的UIScrollView（滑动视图）

#import "ViewController.h"

@interface ViewController (){
UIImageView *imgV;

}

@end

@implementation ViewController

- (void)viewDidLoad {
[super viewDidLoad];

//新加一个UIScrollView
UIScrollView *myScrollView = [[UIScrollView alloc]initWithFrame:self.view.frame];

//改变UIScrollView的颜色
myScrollView.backgroundColor = [UIColor redColor];

//也可以将UIScrollView换成一张图片
myScrollView.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"444"]];

//添加一个图片
UIImage *img = [UIImage imageNamed:@"qidong.jpg"];
imgV = [[UIImageView alloc]initWithImage:img];
imgV.frame = CGRectMake(0, 0, img.size.width, img.size.height);

//将图片添加到UIScrollView上
[myScrollView addSubview:imgV];

//将UIScrollView添加到手机界面上
[self.view addSubview:myScrollView];

//让UIScrollView可以交互（滑动）
myScrollView.scrollEnabled = YES;

//可以滑动的限制(设置这一步才可以滑动)
//在这里只能上下滑动，不能左右滑动，因为可以滑动的宽度设置为屏幕的宽度，而高度是图片的高度
[myScrollView setContentSize:CGSizeMake(self.view.frame.size.width, img.size.width)];

//显示滑条
[myScrollView showsHorizontalScrollIndicator];

//设置减小速度
myScrollView.decelerationRate = 0.1;

//关闭滑条
//关闭竖着的滑条
myScrollView.showsVerticalScrollIndicator = NO;
//关闭横着的滑条
myScrollView.showsHorizontalScrollIndicator = NO;

//设置滑条的位置
myScrollView.scrollIndicatorInsets = UIEdgeInsetsMake(0, 0, 100, 100);

//设置滑条的颜色
myScrollView.indicatorStyle = UIScrollViewIndicatorStyleWhite;

//图片的位置(可以设置下拉刷新用)
myScrollView.contentInset = UIEdgeInsetsMake(100, 0, 0, 0);

//锁定滑动的方向，只能向单一方向滑动，不能斜着跑偏
myScrollView.directionalLockEnabled = YES;

//不让自动跳到顶部（点上面的时候不能回去）
myScrollView.scrollsToTop = NO;

//滑动时候自动分页
myScrollView.pagingEnabled = YES;

//取消反弹
myScrollView.bounces = YES;

//设置UIScrollView的代理方法
myScrollView.delegate = self;

//放大缩小
//最小可以缩小到1.0倍
myScrollView.minimumZoomScale = 1.0;
//最大可以放大到1.5倍
myScrollView.maximumZoomScale = 1.5;

//放大缩小后是不是反弹回来
myScrollView.bouncesZoom = YES;

}

//引入UIScrollView的代理方法,注意在“.h”文件中要引入<UIScrollViewDelegate>
- (void)scrollViewDidScroll:(UIScrollView *)scrollView{
NSLog(@"已经滑动");

}

- (void)scrollViewDidZoom:(UIScrollView *)scrollView NS_AVAILABLE_IOS(3_2){

NSLog(@"已经缩放");

}

- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView{
NSLog(@"将要开始拖拽");

}

- (void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset NS_AVAILABLE_IOS(5_0){
NSLog(@"横着偏移%f  竖着偏移%f", velocity.x,targetContentOffset->y);
NSLog(@"%f", targetContentOffset->y);

//如果竖着偏移的距离为33，则滑动的图片下面的颜色改为黄色
if((targetContentOffset->y = 33)){
scrollView.backgroundColor = [UIColor yellowColor];
}

}

- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate{
NSLog(@"结束拖拽");
}

- (void)scrollViewWillBeginDecelerating:(UIScrollView *)scrollView{
NSLog(@"将要开始降速");

}
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{
NSLog(@"结束减速");

}

- (void)scrollViewDidEndScrollingAnimation:(UIScrollView *)scrollView{

NSLog(@"结束滑动动画");

}

- (nullable UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView{

return imgV;

}

- (void)scrollViewWillBeginZooming:(UIScrollView *)scrollView withView:(nullable UIView *)view NS_AVAILABLE_IOS(3_2){

NSLog(@"开始缩放");

}

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

NSLog(@"结束缩放 %f", scale);
}

- (BOOL)scrollViewShouldScrollToTop:(UIScrollView *)scrollView{

return YES;

}

- (void)scrollViewDidScrollToTop:(UIScrollView *)scrollView{

NSLog(@"已经滑动到底部");

}