UIScrollView

#import "ViewController.h"

@interface ViewController ()
@property (strong, nonatomic) UIImageView *imageView;
@property (strong, nonatomic) UIScrollView *scrollView;
@end

@implementation ViewController



- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    UIImage *image = [UIImage imageNamed:@"mac.png"];
    self.imageView = [[UIImageView alloc] initWithImage:image];//图片加入imageView
    self.scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, 320, 260)];//设置scrollView
    [self.scrollView addSubview:self.imageView];//iamgeView加到scrollView里
    self.scrollView.pagingEnabled = NO;//拖动时手指松开后图片时候继续滑行，no表示可以（这是自己的理解）
    self.scrollView.contentSize = self.imageView.bounds.size;//scrollView里可滚动的空间，这里以imageView的大小为准
    self.scrollView.delaysContentTouches = YES;//判断是否有拖动意图，yes时点一会再拖动，no则可以点上立刻拖动
    self.scrollView.canCancelContentTouches = NO;//是否可以取消拖动意图，用户触摸一会后，yes可以再拖动，no则不可以再拖动
    self.scrollView.bounces = YES;//用户拖动到边界后是否有回弹效果
    self.scrollView.directionalLockEnabled = NO;//是否可以各方向拖动，yes时，当上下拖动时不能左右，左右时不能上下，斜着不受影响
    self.scrollView.delegate = self;
    [self.view addSubview:self.scrollView];
}

//只要滚动了就会触发
-(void) scrollViewDidScroll:(UIScrollView *)scrollView
{
    NSLog(@"scrollViewDidScroll");
    NSLog(@"contentOffSet x is %f, y is %f",self.scrollView.contentOffset.x,self.scrollView.contentOffset.y);
    self.scrollView.alpha = 0.5f;
}
//开始拖拽视图
-(void) scrollViewWillBeginDragging:(UIScrollView *)scrollView
{
    NSLog(@"scrollViewWillBeginDragging");
}
//完成拖拽
-(void) scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate
{
    NSLog(@"scrollViewDidEndDragging");
    self.scrollView.alpha = 1.0f;
}
//开始降速时
-(void) scrollViewWillBeginDecelerating:(UIScrollView *)scrollView
{
    NSLog(@"scrollViewWillBeginDecelerating");
}
//减速停止、手触摸时执行
-(void) scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
    NSLog(@"scrollViewDidEndDecelerating");
    self.scrollView.alpha = 1.0f;
}
//滚动动画停止时执行,代码改变时出发,也就是setContentOffset改变时
- (void)scrollViewDidEndScrollingAnimation:(UIScrollView *)scrollView;
{
    NSLog(@"scrollViewDidEndScrollingAnimation");
}
//设置放大缩小的视图，要是uiscrollview的subview
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView;
{
    NSLog(@"viewForZoomingInScrollView");
    return self.imageView;
}
//完成放大缩小时调用
- (void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(UIView *)view atScale:(float)scale;
{
    self.imageView.frame=CGRectMake(50,0,100,400);
    NSLog(@"scale between minimum and maximum. called after any 'bounce' animations");
}
//如果你不是完全滚动到滚轴视图的顶部，你可以轻点状态栏，那个可视的滚轴视图会一直滚动到顶部，那是默认行为，你可以通过该方法返回NO来关闭它
- (BOOL)scrollViewShouldScrollToTop:(UIScrollView *)scrollView;
{
    NSLog(@"scrollViewShouldScrollToTop");
    return YES;
}
- (void)scrollViewDidScrollToTop:(UIScrollView *)scrollView;
{
    NSLog(@"scrollViewDidScrollToTop");
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end