iOS - Scroll View(滾動(dòng)視圖)

使用Scroll View

滾動(dòng)視圖用于顯示內(nèi)容超過屏幕大小。它可以包含所有其他用戶界面元素，如圖像視圖，標(biāo)簽，文本視圖，甚至是另一個(gè)滾動(dòng)視圖本身。

重要的屬性

• contentSize

• contentInset

• contentOffset

• delegate

重要的方法

- (void)scrollRectToVisible:(CGRect)rect animated:(BOOL)animated

- (void)setContentOffset:(CGYiibai)contentOffset animated:(BOOL)animated

重要的委托方法

- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView

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

- (void)scrollViewWillBeginDecelerating:(UIScrollView *)scrollView

- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView

更新ViewController.h 如下：

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController<UIScrollViewDelegate>
{
    UIScrollView *myScrollView;
}	

@end

添加一個(gè)自定義的方法addScrollView

-(void)addScrollView{
    myScrollView = [[UIScrollView alloc]initWithFrame:
    CGRectMake(20, 20, 280, 420)];
    myScrollView.accessibilityActivationYiibai = CGYiibaiMake(100, 100);
    imgView = [[UIImageView alloc]initWithImage:
    [UIImage imageNamed:@"AppleUSA.jpg"]];
    [myScrollView addSubview:imgView];
    myScrollView.minimumZoomScale = 0.5;
    myScrollView.maximumZoomScale = 3;
    myScrollView.contentSize = CGSizeMake(imgView.frame.size.width,
    imgView.frame.size.height);
    myScrollView.delegate = self;
    [self.view addSubview:myScrollView];
}

注意事項(xiàng)：

我們必須命名為 “AppleUSA1.jpg”，我們可以通過拖動(dòng)圖像到我們的導(dǎo)航區(qū)域，項(xiàng)目文件列出的項(xiàng)目中添加圖像。圖像的分辨率高于設(shè)備看到的圖像的滾動(dòng)。

實(shí)現(xiàn)滾動(dòng)視圖在 ViewController.m 委托

-(UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView{
    return imgView;
}
-(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{
    NSLog(@"Did end decelerating");
}	
-(void)scrollViewDidScroll:(UIScrollView *)scrollView{
//    NSLog(@"Did scroll");
}
-(void)scrollViewDidEndDragging:(UIScrollView *)scrollView 
  willDecelerate:(BOOL)decelerate{
    NSLog(@"Did end dragging");
}
-(void)scrollViewWillBeginDecelerating:(UIScrollView *)scrollView{
    NSLog(@"Did begin decelerating");
}
-(void)scrollViewWillBeginDragging:(UIScrollView *)scrollView{
    NSLog(@"Did begin dragging");
}

更新 ViewController.m 中的 viewDidLoad 方法如下

(void)viewDidLoad
{
   [super viewDidLoad];
   [self addScrollView];
   //Do any additional setup after loading the view, typically from a nib
}

輸出

現(xiàn)在，當(dāng)我們運(yùn)行程序時(shí)，我們會(huì)得到下面的輸出。一旦滾動(dòng)滾動(dòng)視圖，將能夠看到圖像的其余部分。