#import "ViewController.h"

@interface ViewController ()<UIScrollViewDelegate>

@property (strong, nonatomic) IBOutlet UIScrollView *scrollView;
@property (weak, nonatomic) IBOutlet UIImageView *imageView;

@end

@implementation ViewController

- (void)viewDidLoad
{
  [super viewDidLoad];

  // 設(shè)置內(nèi)容尺寸
  self.scrollView.contentSize = self.imageView.frame.size;

  // 設(shè)置
  self.scrollView.delegate = self;

  // 設(shè)置最大和最小的縮放比例
  self.scrollView.maximumZoomScale = 2.0;
  self.scrollView.minimumZoomScale = 0.2;

  // 設(shè)置邊距
  self.scrollView.contentInset = UIEdgeInsetsMake(20, 20, 20, 20);

  // 不顯示水平滾動(dòng)標(biāo)示
  self.scrollView.showsHorizontalScrollIndicator = NO;

  // 不顯示垂直滾動(dòng)標(biāo)示
  self.scrollView.showsVerticalScrollIndicator = NO;

  // 偏移位置
  self.scrollView.contentOffset = CGPointMake(0, -100);

  // 取消彈簧效果
  self.scrollView.bounces = NO;

  //設(shè)置按鈕
  UIButton *btn = [UIButton buttonWithType:UIButtonTypeContactAdd];
  btn.center = self.view.center;

  [self.view addSubview:btn];

  //設(shè)置按鈕的監(jiān)聽方法
  [btn addTarget:self action:@selector(click) forControlEvents:UIControlEventTouchUpInside];

}

 // 移動(dòng)大圖的偏移位置
- (void)click
{
  //取出offset
  CGPoint offset = self.scrollView.contentOffset;

  offset.x += 20;
  offset.y += 20;

  // 更新contentOffset
  self.scrollView.contentOffset = offset;
}


#pragma mark - UIScrollView的代理方法

// 1> scrollView要知道縮放誰

/**
 * 當(dāng)用戶開始拖拽scrollView時(shí)就會(huì)調(diào)用
 */
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{
  NSLog(@"開始拖拽");
}

/**
 * 只要scrollView正在滾動(dòng),就會(huì)調(diào)用
 */
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
  NSLog(@"正在滾動(dòng)%@", NSStringFromCGPoint(scrollView.contentOffset));
}

/**
 * 當(dāng)用戶使用捏合手勢(shì)的時(shí)候會(huì)調(diào)用
 *
 * @return 返回的控件就是需要進(jìn)行縮放的控件
 */
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
{
  NSLog(@"開始縮放");
  return self.imageView;
}

/**
 * 正在縮放的時(shí)候會(huì)調(diào)用
 */
- (void)scrollViewDidZoom:(UIScrollView *)scrollView
{
  NSLog(@"正在縮放");
}
@end

self.scrollView.contentInset = UIEdgeInsetsMake(20, 20, 20, 20);

 UIButton *btn = [UIButton buttonWithType:UIButtonTypeContactAdd];

- (void)click
{
  CGPoint offset = self.scrollView.contentOffset;

  offset.x += 20;
  offset.y += 20;

  self.scrollView.contentOffset = offset;
}

@property(nonatomic) UIEdgeInsets contentInset; 
這個(gè)屬性能夠在UIScrollView的4周增加額外的滾動(dòng)區(qū)域
@property(nonatomic) CGPoint contentOffset; 
這個(gè)屬性用來表示UIScrollView滾動(dòng)的位置

@property(nonatomic) CGSize contentSize; 
這個(gè)屬性用來表示UIScrollView內(nèi)容的尺寸，滾動(dòng)范圍（能滾多遠(yuǎn)）

@property(nonatomic) BOOL bounces;
設(shè)置UIScrollView是否需要彈簧效果

@property(nonatomic,getter=isScrollEnabled) BOOL scrollEnabled; 
設(shè)置UIScrollView是否能滾動(dòng)

@property(nonatomic) BOOL showsHorizontalScrollIndicator;
是否顯示水平滾動(dòng)條

@property(nonatomic) BOOL showsVerticalScrollIndicator;
是否顯示垂直滾動(dòng)條